Annex A
(normative)
Predefined Language Environment
1 This Annex contains the specifications of library units that shall be
provided by every implementation. There are three root library units: Ada,
Interfaces, and System; other library units are children of these:
2/2
Standard - A.1
Ada - A.2
Assertions - 11.4.2
Asynchronous_Task_Control - D.11
Calendar - 9.6
Arithmetic - 9.6.1
Formatting - 9.6.1
Time_Zones - 9.6.1
Characters - A.3.1
Conversions - A.3.4
Handling - A.3.2
Latin_1 - A.3.3
Command_Line - A.15
Complex_Text_IO - G.1.3
Containers - A.18.1
Doubly_Linked_Lists - A.18.3
Generic_Array_Sort - A.18.16
Generic_Constrained_Array_Sort
- A.18.16
Hashed_Maps - A.18.5
Hashed_Sets - A.18.8
Indefinite_Doubly_Linked_Lists
- A.18.11
Indefinite_Hashed_Maps - A.18.12
Indefinite_Hashed_Sets - A.18.14
Indefinite_Ordered_Maps - A.18.13
Indefinite_Ordered_Sets - A.18.15
Indefinite_Vectors - A.18.10
Ordered_Maps - A.18.6
Ordered_Sets - A.18.9
Vectors - A.18.2
Decimal - F.2
Direct_IO - A.8.4
Directories - A.16
Information - A.16
Dispatching - D.2.1
EDF - D.2.6
Round_Robin - D.2.5
Dynamic_Priorities - D.5
Standard (...continued)
Ada (...continued)
Environment_Variables - A.17
Exceptions - 11.4.1
Execution_Time - D.14
Group_Budgets - D.14.2
Timers - D.14.1
Finalization - 7.6
Float_Text_IO - A.10.9
Float_Wide_Text_IO - A.11
Float_Wide_Wide_Text_IO - A.11
Integer_Text_IO - A.10.8
Integer_Wide_Text_IO - A.11
Integer_Wide_Wide_Text_IO - A.11
Interrupts - C.3.2
Names - C.3.2
IO_Exceptions - A.13
Numerics - A.5
Complex_Arrays - G.3.2
Complex_Elementary_Functions - G.1.2
Complex_Types - G.1.1
Discrete_Random - A.5.2
Elementary_Functions - A.5.1
Float_Random - A.5.2
Generic_Complex_Arrays - G.3.2
Generic_Complex_Elementary_Functions
- G.1.2
Generic_Complex_Types - G.1.1
Generic_Elementary_Functions - A.5.1
Generic_Real_Arrays - G.3.1
Real_Arrays - G.3.1
Real_Time - D.8
Timing_Events - D.15
Sequential_IO - A.8.1
Storage_IO - A.9
Streams - 13.13.1
Stream_IO - A.12.1
Standard (...continued)
Ada (...continued)
Strings - A.4.1
Bounded - A.4.4
Hash - A.4.9
Fixed - A.4.3
Hash - A.4.9
Hash - A.4.9
Maps - A.4.2
Constants - A.4.6
Unbounded - A.4.5
Hash - A.4.9
Wide_Bounded - A.4.7
Wide_Hash - A.4.7
Wide_Fixed - A.4.7
Wide_Hash - A.4.7
Wide_Hash - A.4.7
Wide_Maps - A.4.7
Wide_Constants - A.4.7
Wide_Unbounded - A.4.7
Wide_Hash - A.4.7
Wide_Wide_Bounded - A.4.8
Wide_Wide_Hash - A.4.8
Wide_Wide_Fixed - A.4.8
Wide_Wide_Hash - A.4.8
Wide_Wide_Hash - A.4.8
Wide_Wide_Maps - A.4.8
Wide_Wide_Constants - A.4.8
Wide_Wide_Unbounded - A.4.8
Wide_Wide_Hash - A.4.8
Synchronous_Task_Control - D.10
Tags - 3.9
Generic_Dispatching_Constructor - 3.9
Task_Attributes - C.7.2
Task_Identification - C.7.1
Task_Termination - C.7.3
Standard (...continued)
Ada (...continued)
Text_IO - A.10.1
Bounded_IO - A.10.11
Complex_IO - G.1.3
Editing - F.3.3
Text_Streams - A.12.2
Unbounded_IO - A.10.12
Unchecked_Conversion - 13.9
Unchecked_Deallocation - 13.11.2
Wide_Characters - A.3.1
Wide_Text_IO - A.11
Complex_IO - G.1.4
Editing - F.3.4
Text_Streams - A.12.3
Wide_Bounded_IO - A.11
Wide_Unbounded_IO - A.11
Wide_Wide_Characters - A.3.1
Wide_Wide_Text_IO - A.11
Complex_IO - G.1.5
Editing - F.3.5
Text_Streams - A.12.4
Wide_Wide_Bounded_IO - A.11
Wide_Wide_Unbounded_IO - A.11
Interfaces - B.2
C - B.3
Pointers - B.3.2
Strings - B.3.1
COBOL - B.4
Fortran - B.5
System - 13.7
Address_To_Access_Conversions - 13.7.2
Machine_Code - 13.8
RPC - E.5
Storage_Elements - 13.7.1
Storage_Pools - 13.11
Implementation Requirements
3/2 The implementation shall ensure that each language-defined subprogram is
reentrant in the sense that concurrent calls on the same subprogram perform as
specified, so long as all parameters that could be passed by reference denote
nonoverlapping objects.
Implementation Permissions
4 The implementation may restrict the replacement of language-defined
compilation units. The implementation may restrict children of
language-defined library units (other than Standard).
A.1 The Package Standard
1 This clause outlines the specification of the package Standard containing
all predefined identifiers in the language. The corresponding package body is
not specified by the language.
2 The operators that are predefined for the types declared in the package
Standard are given in comments since they are implicitly declared. Italics are
used for pseudo-names of anonymous types (such as root_real) and for undefined
information (such as implementation-defined).
Static Semantics
3 The library package Standard has the following declaration:
4 package Standard is
pragma Pure(Standard);
5 type Boolean is (False, True);
6 -- The predefined relational operators for this type are as follows:
7/1 -- function "=" (Left, Right : Boolean'Base) return Boolean;
-- function "/=" (Left, Right : Boolean'Base) return Boolean;
-- function "<" (Left, Right : Boolean'Base) return Boolean;
-- function "<=" (Left, Right : Boolean'Base) return Boolean;
-- function ">" (Left, Right : Boolean'Base) return Boolean;
-- function ">=" (Left, Right : Boolean'Base) return Boolean;
8 -- The predefined logical operators and the predefined logical
-- negation operator are as follows:
9/1 -- function "and" (Left, Right : Boolean'Base) return Boolean'Base;
-- function "or" (Left, Right : Boolean'Base) return Boolean'Base;
-- function "xor" (Left, Right : Boolean'Base) return Boolean'Base;
10/1 -- function "not" (Right : Boolean'Base) return Boolean'Base;
11/2 -- The integer type root_integer and the
-- corresponding universal type universal_integer are predefined.
12 type Integer is range implementation-defined;
13 subtype Natural is Integer range 0 .. Integer'Last;
subtype Positive is Integer range 1 .. Integer'Last;
14 -- The predefined operators for type Integer are as follows:
15 -- function "=" (Left, Right : Integer'Base) return Boolean;
-- function "/=" (Left, Right : Integer'Base) return Boolean;
-- function "<" (Left, Right : Integer'Base) return Boolean;
-- function "<=" (Left, Right : Integer'Base) return Boolean;
-- function ">" (Left, Right : Integer'Base) return Boolean;
-- function ">=" (Left, Right : Integer'Base) return Boolean;
16 -- function "+" (Right : Integer'Base) return Integer'Base;
-- function "-" (Right : Integer'Base) return Integer'Base;
-- function "abs" (Right : Integer'Base) return Integer'Base;
17 -- function "+" (Left, Right : Integer'Base) return Integer'Base;
-- function "-" (Left, Right : Integer'Base) return Integer'Base;
-- function "*" (Left, Right : Integer'Base) return Integer'Base;
-- function "/" (Left, Right : Integer'Base) return Integer'Base;
-- function "rem" (Left, Right : Integer'Base) return Integer'Base;
-- function "mod" (Left, Right : Integer'Base) return Integer'Base;
18 -- function "**" (Left : Integer'Base; Right : Natural)
-- return Integer'Base;
19 -- The specification of each operator for the type
-- root_integer, or for any additional predefined integer
-- type, is obtained by replacing Integer by the name of the type
-- in the specification of the corresponding operator of the type
-- Integer. The right operand of the exponentiation operator
-- remains as subtype Natural.
20/2 -- The floating point type root_real and the
-- corresponding universal type universal_real are predefined.
21 type Float is digits implementation-defined;
22 -- The predefined operators for this type are as follows:
23 -- function "=" (Left, Right : Float) return Boolean;
-- function "/=" (Left, Right : Float) return Boolean;
-- function "<" (Left, Right : Float) return Boolean;
-- function "<=" (Left, Right : Float) return Boolean;
-- function ">" (Left, Right : Float) return Boolean;
-- function ">=" (Left, Right : Float) return Boolean;
24 -- function "+" (Right : Float) return Float;
-- function "-" (Right : Float) return Float;
-- function "abs" (Right : Float) return Float;
25 -- function "+" (Left, Right : Float) return Float;
-- function "-" (Left, Right : Float) return Float;
-- function "*" (Left, Right : Float) return Float;
-- function "/" (Left, Right : Float) return Float;
26 -- function "**" (Left : Float; Right : Integer'Base) return Float;
27 -- The specification of each operator for the type root_real, or for
-- any additional predefined floating point type, is obtained by
-- replacing Float by the name of the type in the specification of the
-- corresponding operator of the type Float.
28 -- In addition, the following operators are predefined for the root
-- numeric types:
29 function "*" (Left : root_integer; Right : root_real)
return root_real;
30 function "*" (Left : root_real; Right : root_integer)
return root_real;
31 function "/" (Left : root_real; Right : root_integer)
return root_real;
32 -- The type universal_fixed is predefined.
-- The only multiplying operators defined between
-- fixed point types are
33 function "*" (Left : universal_fixed; Right : universal_fixed)
return universal_fixed;
34 function "/" (Left : universal_fixed; Right : universal_fixed)
return universal_fixed;
34.1/2 -- The type universal_access is predefined.
-- The following equality operators are predefined:
34.2/2 function "=" (Left, Right: universal_access) return Boolean;
function "/=" (Left, Right: universal_access) return Boolean;
35/2 -- The declaration of type Character is based on the standard ISO 8859-1 character set.
-- There are no character literals corresponding to the positions for control characters.
-- They are indicated in italics in this definition. See 3.5.2.
type Character is
(nul, soh, stx, etx, eot, enq, ack,
bel, --0 (16#00#) .. 7 (16#07#)
bs, ht, lf, vt, ff, cr, so,
si, --8 (16#08#) .. 15 (16#0F#)
dle, dc1, dc2, dc3, dc4, nak, syn,
etb, --16 (16#10#) .. 23 (16#17#)
can, em, sub, esc, fs, gs, rs,
us, --24 (16#18#) .. 31 (16#1F#)
' ', '!', '"', '#', '$', '%', '&',
''', --32 (16#20#) .. 39 (16#27#)
'(', ')', '*', '+', ',', '-', '.',
'/', --40 (16#28#) .. 47 (16#2F#)
'0', '1', '2', '3', '4', '5', '6',
'7', --48 (16#30#) .. 55 (16#37#)
'8', '9', ':', ';', '<', '=', '>',
'?', --56 (16#38#) .. 63 (16#3F#)
'@', 'A', 'B', 'C', 'D', 'E', 'F',
'G', --64 (16#40#) .. 71 (16#47#)
'H', 'I', 'J', 'K', 'L', 'M', 'N',
'O', --72 (16#48#) .. 79 (16#4F#)
'P', 'Q', 'R', 'S', 'T', 'U', 'V',
'W', --80 (16#50#) .. 87 (16#57#)
'X', 'Y', 'Z', '[', '\', ']', '^',
'_', --88 (16#58#) .. 95 (16#5F#)
'`', 'a', 'b', 'c', 'd', 'e', 'f',
'g', --96 (16#60#) .. 103 (16#67#)
'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', --104 (16#68#) .. 111 (16#6F#)
'p', 'q', 'r', 's', 't', 'u', 'v',
'w', --112 (16#70#) .. 119 (16#77#)
'x', 'y', 'z', '{', '|', '}', '~',
del, --120 (16#78#) .. 127 (16#7F#)
reserved_128, reserved_129, bph, nbh,
--128 (16#80#) .. 131 (16#83#)
reserved_132, nel, ssa, esa,
--132 (16#84#) .. 135 (16#87#)
hts, htj, vts, pld, plu, ri, ss2,
ss3, --136 (16#88#) .. 143 (16#8F#)
dcs, pu1, pu2, sts, cch, mw, spa,
epa, --144 (16#90#) .. 151 (16#97#)
sos, reserved_153, sci, csi,
--152 (16#98#) .. 155 (16#9B#)
st, osc, pm, apc,
--156 (16#9C#) .. 159 (16#9F#)
' ', '¡', '¢', '£', '¤', '¥', '¦',
'§', --160 (16#A0#) .. 167 (16#A7#)
'¨', '©', 'ª', '«', '¬', '', '®',
'¯', --168 (16#A8#) .. 175 (16#AF#)
'°', '±', '²', '³', '´', 'µ', '¶',
'·', --176 (16#B0#) .. 183 (16#B7#)
'¸', '¹', 'º', '»', '¼', '½', '¾',
'¿', --184 (16#B8#) .. 191 (16#BF#)
'À', 'Á', 'Â', 'Ã', 'Ä', 'Å', 'Æ',
'Ç', --192 (16#C0#) .. 199 (16#C7#)
'È', 'É', 'Ê', 'Ë', 'Ì', 'Í', 'Î',
'Ï', --200 (16#C8#) .. 207 (16#CF#)
'Ð', 'Ñ', 'Ò', 'Ó', 'Ô', 'Õ', 'Ö',
'×', --208 (16#D0#) .. 215 (16#D7#)
'Ø', 'Ù', 'Ú', 'Û', 'Ü', 'Ý', 'Þ',
'ß', --216 (16#D8#) .. 223 (16#DF#)
'à', 'á', 'â', 'ã', 'ä', 'å', 'æ',
'ç', --224 (16#E0#) .. 231 (16#E7#)
'è', 'é', 'ê', 'ë', 'ì', 'í', 'î',
'ï', --232 (16#E8#) .. 239 (16#EF#)
'ð', 'ñ', 'ò', 'ó', 'ô', 'õ', 'ö',
'÷', --240 (16#F0#) .. 247 (16#F7#)
'ø', 'ù', 'ú', 'û', 'ü', 'ý', 'þ',
'ÿ');--248 (16#F8#) .. 255 (16#FF#)
36 -- The predefined operators for the type Character are the same as for
-- any enumeration type.
36.1/2 -- The declaration of type Wide_Character is based on the standard ISO/IEC 10646:2003 BMP character
-- set. The first 256 positions have the same contents as type Character. See 3.5.2
.
type Wide_Character is (nul, soh ... Hex_0000FFFE, Hex_0000FFFF);
36.2/2 -- The declaration of type Wide_Wide_Character is based on the full
-- ISO/IEC 10646:2003 character set. The first 65536 positions have the
-- same contents as type Wide_Character. See 3.5.2.
type Wide_Wide_Character
is (nul, soh ... Hex_7FFFFFFE, Hex_7FFFFFFF);
for Wide_Wide_Character'Size use 32;
36.3/2 package ASCII is ... end ASCII; --Obsolescent; see J.5
37 -- Predefined string types:
type String is array(Positive range <>) of Character;
pragma Pack(String);
38 -- The predefined operators for this type are as follows:
39 -- function "=" (Left, Right: String) return Boolean;
-- function "/=" (Left, Right: String) return Boolean;
-- function "<" (Left, Right: String) return Boolean;
-- function "<=" (Left, Right: String) return Boolean;
-- function ">" (Left, Right: String) return Boolean;
-- function ">=" (Left, Right: String) return Boolean;
40 -- function "&" (Left: String; Right: String) return String;
-- function "&" (Left: Character; Right: String) return String;
-- function "&" (Left: String; Right: Character) return String;
-- function "&" (Left: Character; Right: Character) return String;
41 type Wide_String is array(Positive range <>) of Wide_Character;
pragma Pack(Wide_String);
42 -- The predefined operators for this type correspond to those for String.
42.1/2 type Wide_Wide_String is array (Positive range <>)
of Wide_Wide_Character;
pragma Pack (Wide_Wide_String);
42.2/2 -- The predefined operators for this type correspond to those for String.
43 type Duration
is delta implementation-defined range implementation-defined;
44 -- The predefined operators for the type Duration are the same as for
-- any fixed point type.
45 -- The predefined exceptions:
46 Constraint_Error: exception;
Program_Error : exception;
Storage_Error : exception;
Tasking_Error : exception;
47 end Standard;
48 Standard has no private part.
49/2 In each of the types Character, Wide_Character, and Wide_Wide_Character,
the character literals for the space character (position 32) and the
non-breaking space character (position 160) correspond to different values.
Unless indicated otherwise, each occurrence of the character literal ' ' in
this International Standard refers to the space character. Similarly, the
character literals for hyphen (position 45) and soft hyphen (position 173)
correspond to different values. Unless indicated otherwise, each occurrence of
the character literal '-' in this International Standard refers to the hyphen
character.
Dynamic Semantics
50 Elaboration of the body of Standard has no effect.
Implementation Permissions
51 An implementation may provide additional predefined integer types and
additional predefined floating point types. Not all of these types need have
names.
Implementation Advice
52 If an implementation provides additional named predefined integer types,
then the names should end with "Integer" as in "Long_Integer". If an
implementation provides additional named predefined floating point types, then
the names should end with "Float" as in "Long_Float".
NOTES
53 1 Certain aspects of the predefined entities cannot be completely
described in the language itself. For example, although the
enumeration type Boolean can be written showing the two enumeration
literals False and True, the short-circuit control forms cannot be
expressed in the language.
54 2 As explained in 8.1, "Declarative Region" and 10.1.4, "
The Compilation Process", the declarative region of the package
Standard encloses every library unit and consequently the main
subprogram; the declaration of every library unit is assumed to occur
within this declarative region. Library_items are assumed to be
ordered in such a way that there are no forward semantic dependences.
However, as explained in 8.3, "Visibility", the only library units
that are visible within a given compilation unit are the library units
named by all with_clauses that apply to the given unit, and moreover,
within the declarative region of a given library unit, that library
unit itself.
55 3 If all block_statements of a program are named, then the name of
each program unit can always be written as an expanded name starting
with Standard (unless Standard is itself hidden). The name of a
library unit cannot be a homograph of a name (such as Integer) that is
already declared in Standard.
56 4 The exception Standard.Numeric_Error is defined in J.6.
A.2 The Package Ada
Static Semantics
1 The following language-defined library package exists:
2 package Ada is
pragma Pure(Ada);
end Ada;
3 Ada serves as the parent of most of the other language-defined library
units; its declaration is empty (except for the pragma Pure).
Legality Rules
4 In the standard mode, it is illegal to compile a child of package Ada.
A.3 Character Handling
1/2 This clause presents the packages related to character processing: an
empty pure package Characters and child packages Characters.Handling and
Characters.Latin_1. The package Characters.Handling provides classification
and conversion functions for Character data, and some simple functions for
dealing with Wide_Character and Wide_Wide_Character data. The child package
Characters.Latin_1 declares a set of constants initialized to values of type
Character.
A.3.1 The Packages Characters, Wide_Characters, and Wide_Wide_Characters
Static Semantics
1 The library package Characters has the following declaration:
2 package Ada.Characters is
pragma Pure(Characters);
end Ada.Characters;
3/2 The library package Wide_Characters has the following declaration:
4/2 package Ada.Wide_Characters is
pragma Pure(Wide_Characters);
end Ada.Wide_Characters;
5/2 The library package Wide_Wide_Characters has the following declaration:
6/2 package Ada.Wide_Wide_Characters is
pragma Pure(Wide_Wide_Characters);
end Ada.Wide_Wide_Characters;
Implementation Advice
7/2 If an implementation chooses to provide implementation-defined operations
on Wide_Character or Wide_String (such as case mapping, classification,
collating and sorting, etc.) it should do so by providing child units of
Wide_Characters. Similarly if it chooses to provide implementation-defined
operations on Wide_Wide_Character or Wide_Wide_String it should do so by
providing child units of Wide_Wide_Characters.
A.3.2 The Package Characters.Handling
Static Semantics
1 The library package Characters.Handling has the following declaration:
2/2 with Ada.Characters.Conversions;
package Ada.Characters.Handling is
pragma Pure(Handling);
3 --Character classification functions
4 function Is_Control (Item : in Character) return Boolean;
function Is_Graphic (Item : in Character) return Boolean;
function Is_Letter (Item : in Character) return Boolean;
function Is_Lower (Item : in Character) return Boolean;
function Is_Upper (Item : in Character) return Boolean;
function Is_Basic (Item : in Character) return Boolean;
function Is_Digit (Item : in Character) return Boolean;
function Is_Decimal_Digit (Item : in Character) return Boolean
renames Is_Digit;
function Is_Hexadecimal_Digit (Item : in Character) return Boolean;
function Is_Alphanumeric (Item : in Character) return Boolean;
function Is_Special (Item : in Character) return Boolean;
5 --Conversion functions for Character and String
6 function To_Lower (Item : in Character) return Character;
function To_Upper (Item : in Character) return Character;
function To_Basic (Item : in Character) return Character;
7 function To_Lower (Item : in String) return String;
function To_Upper (Item : in String) return String;
function To_Basic (Item : in String) return String;
8 --Classifications of and conversions between Character and ISO 646
9 subtype ISO_646 is
Character range Character'Val(0) .. Character'Val(127);
10 function Is_ISO_646 (Item : in Character) return Boolean;
function Is_ISO_646 (Item : in String) return Boolean;
11 function To_ISO_646 (Item : in Character;
Substitute : in ISO_646 := ' ')
return ISO_646;
12 function To_ISO_646 (Item : in String;
Substitute : in ISO_646 := ' ')
return String;
13/2 -- The functions Is_Character, Is_String, To_Character, To_String, To_Wide_Character,
-- and To_Wide_String are obsolescent; see J.14.
Paragraphs 14 through 18 were deleted.
19 end Ada.Characters.Handling;
20 In the description below for each function that returns a Boolean result,
the effect is described in terms of the conditions under which the value True
is returned. If these conditions are not met, then the function returns False.
21 Each of the following classification functions has a formal Character
parameter, Item, and returns a Boolean result.
22 Is_Control True if Item is a control character. A control character is a
character whose position is in one of the ranges 0..31 or
127..159.
23 Is_Graphic True if Item is a graphic character. A graphic character is a
character whose position is in one of the ranges 32..126 or
160..255.
24 Is_Letter True if Item is a letter. A letter is a character that is in
one of the ranges 'A'..'Z' or 'a'..'z', or whose position is
in one of the ranges 192..214, 216..246, or 248..255.
25 Is_Lower True if Item is a lower-case letter. A lower-case letter is a
character that is in the range 'a'..'z', or whose position is
in one of the ranges 223..246 or 248..255.
26 Is_Upper True if Item is an upper-case letter. An upper-case letter is
a character that is in the range 'A'..'Z' or whose position is
in one of the ranges 192..214 or 216.. 222.
27 Is_Basic True if Item is a basic letter. A basic letter is a character
that is in one of the ranges 'A'..'Z' and 'a'..'z', or that is
one of the following: 'Æ', 'æ', 'Ð', 'ð', 'Þ', 'þ', or 'ß'.
28 Is_Digit True if Item is a decimal digit. A decimal digit is a
character in the range '0'..'9'.
29 Is_Decimal_Digit
A renaming of Is_Digit.
30 Is_Hexadecimal_Digit
True if Item is a hexadecimal digit. A hexadecimal digit is a
character that is either a decimal digit or that is in one of
the ranges 'A' .. 'F' or 'a' .. 'f'.
31 Is_Alphanumeric
True if Item is an alphanumeric character. An alphanumeric
character is a character that is either a letter or a decimal
digit.
32 Is_Special True if Item is a special graphic character. A special graphic
character is a graphic character that is not alphanumeric.
33 Each of the names To_Lower, To_Upper, and To_Basic refers to two
functions: one that converts from Character to Character, and the other that
converts from String to String. The result of each Character-to-Character
function is described below, in terms of the conversion applied to Item, its
formal Character parameter. The result of each String-to-String conversion is
obtained by applying to each element of the function's String parameter the
corresponding Character-to-Character conversion; the result is the null String
if the value of the formal parameter is the null String. The lower bound of
the result String is 1.
34 To_Lower Returns the corresponding lower-case value for Item if
Is_Upper(Item), and returns Item otherwise.
35 To_Upper Returns the corresponding upper-case value for Item if
Is_Lower(Item) and Item has an upper-case form, and returns
Item otherwise. The lower case letters 'ß' and 'ÿ' do not have
upper case forms.
36 To_Basic Returns the letter corresponding to Item but with no
diacritical mark, if Item is a letter but not a basic letter;
returns Item otherwise.
37 The following set of functions test for membership in the ISO 646
character range, or convert between ISO 646 and Character.
38 Is_ISO_646 The function whose formal parameter, Item, is of type
Character returns True if Item is in the subtype ISO_646.
39 Is_ISO_646 The function whose formal parameter, Item, is of type String
returns True if Is_ISO_646(Item(I)) is True for each I in
Item'Range.
40 To_ISO_646 The function whose first formal parameter, Item, is of type
Character returns Item if Is_ISO_646(Item), and returns the
Substitute ISO_646 character otherwise.
41 To_ISO_646 The function whose first formal parameter, Item, is of type
String returns the String whose Range is 1..Item'Length and
each of whose elements is given by To_ISO_646 of the
corresponding element in Item.
Paragraphs 42 through 48 were deleted.
Implementation Advice
49/2 This paragraph was deleted.
NOTES
50 5 A basic letter is a letter without a diacritical mark.
51 6 Except for the hexadecimal digits, basic letters, and ISO_646
characters, the categories identified in the classification functions
form a strict hierarchy:
52 - Control characters
53 - Graphic characters
54 - Alphanumeric characters
55 - Letters
56 - Upper-case letters
57 - Lower-case letters
58 - Decimal digits
59 - Special graphic characters
A.3.3 The Package Characters.Latin_1
1 The package Characters.Latin_1 declares constants for characters in ISO
8859-1.
Static Semantics
2 The library package Characters.Latin_1 has the following declaration:
3 package Ada.Characters.Latin_1 is
pragma Pure(Latin_1);
4 -- Control characters:
5 NUL : constant Character := Character'Val(0);
SOH : constant Character := Character'Val(1);
STX : constant Character := Character'Val(2);
ETX : constant Character := Character'Val(3);
EOT : constant Character := Character'Val(4);
ENQ : constant Character := Character'Val(5);
ACK : constant Character := Character'Val(6);
BEL : constant Character := Character'Val(7);
BS : constant Character := Character'Val(8);
HT : constant Character := Character'Val(9);
LF : constant Character := Character'Val(10);
VT : constant Character := Character'Val(11);
FF : constant Character := Character'Val(12);
CR : constant Character := Character'Val(13);
SO : constant Character := Character'Val(14);
SI : constant Character := Character'Val(15);
6 DLE : constant Character := Character'Val(16);
DC1 : constant Character := Character'Val(17);
DC2 : constant Character := Character'Val(18);
DC3 : constant Character := Character'Val(19);
DC4 : constant Character := Character'Val(20);
NAK : constant Character := Character'Val(21);
SYN : constant Character := Character'Val(22);
ETB : constant Character := Character'Val(23);
CAN : constant Character := Character'Val(24);
EM : constant Character := Character'Val(25);
SUB : constant Character := Character'Val(26);
ESC : constant Character := Character'Val(27);
FS : constant Character := Character'Val(28);
GS : constant Character := Character'Val(29);
RS : constant Character := Character'Val(30);
US : constant Character := Character'Val(31);
7 -- ISO 646 graphic characters:
8 Space
: constant Character := ' '; -- Character'Val(32)
Exclamation
: constant Character := '!'; -- Character'Val(33)
Quotation
: constant Character := '"'; -- Character'Val(34)
Number_Sign
: constant Character := '#'; -- Character'Val(35)
Dollar_Sign
: constant Character := '$'; -- Character'Val(36)
Percent_Sign
: constant Character := '%'; -- Character'Val(37)
Ampersand
: constant Character := '&'; -- Character'Val(38)
Apostrophe
: constant Character := '''; -- Character'Val(39)
Left_Parenthesis
: constant Character := '('; -- Character'Val(40)
Right_Parenthesis
: constant Character := ')'; -- Character'Val(41)
Asterisk
: constant Character := '*'; -- Character'Val(42)
Plus_Sign
: constant Character := '+'; -- Character'Val(43)
Comma
: constant Character := ','; -- Character'Val(44)
Hyphen
: constant Character := '-'; -- Character'Val(45)
Minus_Sign : Character renames Hyphen;
Full_Stop
: constant Character := '.'; -- Character'Val(46)
Solidus
: constant Character := '/'; -- Character'Val(47)
9 -- Decimal digits '0' though '9' are at positions 48 through 57
10 Colon
: constant Character := ':'; -- Character'Val(58)
Semicolon
: constant Character := ';'; -- Character'Val(59)
Less_Than_Sign
: constant Character := '<'; -- Character'Val(60)
Equals_Sign
: constant Character := '='; -- Character'Val(61)
Greater_Than_Sign
: constant Character := '>'; -- Character'Val(62)
Question
: constant Character := '?'; -- Character'Val(63)
Commercial_At
: constant Character := '@'; -- Character'Val(64)
11 -- Letters 'A' through 'Z' are at positions 65 through 90
12 Left_Square_Bracket
: constant Character := '['; -- Character'Val(91)
Reverse_Solidus
: constant Character := '\'; -- Character'Val(92)
Right_Square_Bracket
: constant Character := ']'; -- Character'Val(93)
Circumflex
: constant Character := '^'; -- Character'Val(94)
Low_Line
: constant Character := '_'; -- Character'Val(95)
13 Grave
: constant Character := '`'; -- Character'Val(96)
LC_A
: constant Character := 'a'; -- Character'Val(97)
LC_B
: constant Character := 'b'; -- Character'Val(98)
LC_C
: constant Character := 'c'; -- Character'Val(99)
LC_D
: constant Character := 'd'; -- Character'Val(100)
LC_E
: constant Character := 'e'; -- Character'Val(101)
LC_F
: constant Character := 'f'; -- Character'Val(102)
LC_G
: constant Character := 'g'; -- Character'Val(103)
LC_H
: constant Character := 'h'; -- Character'Val(104)
LC_I
: constant Character := 'i'; -- Character'Val(105)
LC_J
: constant Character := 'j'; -- Character'Val(106)
LC_K
: constant Character := 'k'; -- Character'Val(107)
LC_L
: constant Character := 'l'; -- Character'Val(108)
LC_M
: constant Character := 'm'; -- Character'Val(109)
LC_N
: constant Character := 'n'; -- Character'Val(110)
LC_O
: constant Character := 'o'; -- Character'Val(111)
14 LC_P
: constant Character := 'p'; -- Character'Val(112)
LC_Q
: constant Character := 'q'; -- Character'Val(113)
LC_R
: constant Character := 'r'; -- Character'Val(114)
LC_S
: constant Character := 's'; -- Character'Val(115)
LC_T
: constant Character := 't'; -- Character'Val(116)
LC_U
: constant Character := 'u'; -- Character'Val(117)
LC_V
: constant Character := 'v'; -- Character'Val(118)
LC_W
: constant Character := 'w'; -- Character'Val(119)
LC_X
: constant Character := 'x'; -- Character'Val(120)
LC_Y
: constant Character := 'y'; -- Character'Val(121)
LC_Z
: constant Character := 'z'; -- Character'Val(122)
Left_Curly_Bracket
: constant Character := '{'; -- Character'Val(123)
Vertical_Line
: constant Character := '|'; -- Character'Val(124)
Right_Curly_Bracket
: constant Character := '}'; -- Character'Val(125)
Tilde
: constant Character := '~'; -- Character'Val(126)
DEL : constant Character := Character'Val(127);
15 -- ISO 6429 control characters:
16 IS4 : Character renames FS;
IS3 : Character renames GS;
IS2 : Character renames RS;
IS1 : Character renames US;
17 Reserved_128 : constant Character := Character'Val(128);
Reserved_129 : constant Character := Character'Val(129);
BPH : constant Character := Character'Val(130);
NBH : constant Character := Character'Val(131);
Reserved_132 : constant Character := Character'Val(132);
NEL : constant Character := Character'Val(133);
SSA : constant Character := Character'Val(134);
ESA : constant Character := Character'Val(135);
HTS : constant Character := Character'Val(136);
HTJ : constant Character := Character'Val(137);
VTS : constant Character := Character'Val(138);
PLD : constant Character := Character'Val(139);
PLU : constant Character := Character'Val(140);
RI : constant Character := Character'Val(141);
SS2 : constant Character := Character'Val(142);
SS3 : constant Character := Character'Val(143);
18 DCS : constant Character := Character'Val(144);
PU1 : constant Character := Character'Val(145);
PU2 : constant Character := Character'Val(146);
STS : constant Character := Character'Val(147);
CCH : constant Character := Character'Val(148);
MW : constant Character := Character'Val(149);
SPA : constant Character := Character'Val(150);
EPA : constant Character := Character'Val(151);
19 SOS : constant Character := Character'Val(152);
Reserved_153 : constant Character := Character'Val(153);
SCI : constant Character := Character'Val(154);
CSI : constant Character := Character'Val(155);
ST : constant Character := Character'Val(156);
OSC : constant Character := Character'Val(157);
PM : constant Character := Character'Val(158);
APC : constant Character := Character'Val(159);
20 -- Other graphic characters:
21 -- Character positions 160 (16#A0#) .. 175 (16#AF#):
No_Break_Space
: constant Character := ' '; --Character'Val(160)
NBSP : Character renames No_Break_Space;
Inverted_Exclamation
: constant Character := '¡'; --Character'Val(161)
Cent_Sign
: constant Character := '¢'; --Character'Val(162)
Pound_Sign
: constant Character := '£'; --Character'Val(163)
Currency_Sign
: constant Character := '¤'; --Character'Val(164)
Yen_Sign
: constant Character := '¥'; --Character'Val(165)
Broken_Bar
: constant Character := '¦'; --Character'Val(166)
Section_Sign
: constant Character := '§'; --Character'Val(167)
Diaeresis
: constant Character := '¨'; --Character'Val(168)
Copyright_Sign
: constant Character := '©'; --Character'Val(169)
Feminine_Ordinal_Indicator
: constant Character := 'ª'; --Character'Val(170)
Left_Angle_Quotation
: constant Character := '«'; --Character'Val(171)
Not_Sign
: constant Character := '¬'; --Character'Val(172)
Soft_Hyphen
: constant Character := ''; --Character'Val(173)
Registered_Trade_Mark_Sign
: constant Character := '®'; --Character'Val(174)
Macron
: constant Character := '¯'; --Character'Val(175)
22 -- Character positions 176 (16#B0#) .. 191 (16#BF#):
Degree_Sign
: constant Character := '°'; --Character'Val(176)
Ring_Above : Character renames Degree_Sign;
Plus_Minus_Sign
: constant Character := '±'; --Character'Val(177)
Superscript_Two
: constant Character := '²'; --Character'Val(178)
Superscript_Three
: constant Character := '³'; --Character'Val(179)
Acute
: constant Character := '´'; --Character'Val(180)
Micro_Sign
: constant Character := 'µ'; --Character'Val(181)
Pilcrow_Sign
: constant Character := '¶'; --Character'Val(182)
Paragraph_Sign : Character renames Pilcrow_Sign;
Middle_Dot
: constant Character := '·'; --Character'Val(183)
Cedilla
: constant Character := '¸'; --Character'Val(184)
Superscript_One
: constant Character := '¹'; --Character'Val(185)
Masculine_Ordinal_Indicator
: constant Character := 'º'; --Character'Val(186)
Right_Angle_Quotation
: constant Character := '»'; --Character'Val(187)
Fraction_One_Quarter
: constant Character := '¼'; --Character'Val(188)
Fraction_One_Half
: constant Character := '½'; --Character'Val(189)
Fraction_Three_Quarters
: constant Character := '¾'; --Character'Val(190)
Inverted_Question
: constant Character := '¿'; --Character'Val(191)
23 -- Character positions 192 (16#C0#) .. 207 (16#CF#):
UC_A_Grave
: constant Character := 'À'; --Character'Val(192)
UC_A_Acute
: constant Character := 'Á'; --Character'Val(193)
UC_A_Circumflex
: constant Character := 'Â'; --Character'Val(194)
UC_A_Tilde
: constant Character := 'Ã'; --Character'Val(195)
UC_A_Diaeresis
: constant Character := 'Ä'; --Character'Val(196)
UC_A_Ring
: constant Character := 'Å'; --Character'Val(197)
UC_AE_Diphthong
: constant Character := 'Æ'; --Character'Val(198)
UC_C_Cedilla
: constant Character := 'Ç'; --Character'Val(199)
UC_E_Grave
: constant Character := 'È'; --Character'Val(200)
UC_E_Acute
: constant Character := 'É'; --Character'Val(201)
UC_E_Circumflex
: constant Character := 'Ê'; --Character'Val(202)
UC_E_Diaeresis
: constant Character := 'Ë'; --Character'Val(203)
UC_I_Grave
: constant Character := 'Ì'; --Character'Val(204)
UC_I_Acute
: constant Character := 'Í'; --Character'Val(205)
UC_I_Circumflex
: constant Character := 'Î'; --Character'Val(206)
UC_I_Diaeresis
: constant Character := 'Ï'; --Character'Val(207)
24 -- Character positions 208 (16#D0#) .. 223 (16#DF#):
UC_Icelandic_Eth
: constant Character := 'Ð'; --Character'Val(208)
UC_N_Tilde
: constant Character := 'Ñ'; --Character'Val(209)
UC_O_Grave
: constant Character := 'Ò'; --Character'Val(210)
UC_O_Acute
: constant Character := 'Ó'; --Character'Val(211)
UC_O_Circumflex
: constant Character := 'Ô'; --Character'Val(212)
UC_O_Tilde
: constant Character := 'Õ'; --Character'Val(213)
UC_O_Diaeresis
: constant Character := 'Ö'; --Character'Val(214)
Multiplication_Sign
: constant Character := '×'; --Character'Val(215)
UC_O_Oblique_Stroke
: constant Character := 'Ø'; --Character'Val(216)
UC_U_Grave
: constant Character := 'Ù'; --Character'Val(217)
UC_U_Acute
: constant Character := 'Ú'; --Character'Val(218)
UC_U_Circumflex
: constant Character := 'Û'; --Character'Val(219)
UC_U_Diaeresis
: constant Character := 'Ü'; --Character'Val(220)
UC_Y_Acute
: constant Character := 'Ý'; --Character'Val(221)
UC_Icelandic_Thorn
: constant Character := 'Þ'; --Character'Val(222)
LC_German_Sharp_S
: constant Character := 'ß'; --Character'Val(223)
25 -- Character positions 224 (16#E0#) .. 239 (16#EF#):
LC_A_Grave
: constant Character := 'à'; --Character'Val(224)
LC_A_Acute
: constant Character := 'á'; --Character'Val(225)
LC_A_Circumflex
: constant Character := 'â'; --Character'Val(226)
LC_A_Tilde
: constant Character := 'ã'; --Character'Val(227)
LC_A_Diaeresis
: constant Character := 'ä'; --Character'Val(228)
LC_A_Ring
: constant Character := 'å'; --Character'Val(229)
LC_AE_Diphthong
: constant Character := 'æ'; --Character'Val(230)
LC_C_Cedilla
: constant Character := 'ç'; --Character'Val(231)
LC_E_Grave
: constant Character := 'è'; --Character'Val(232)
LC_E_Acute
: constant Character := 'é'; --Character'Val(233)
LC_E_Circumflex
: constant Character := 'ê'; --Character'Val(234)
LC_E_Diaeresis
: constant Character := 'ë'; --Character'Val(235)
LC_I_Grave
: constant Character := 'ì'; --Character'Val(236)
LC_I_Acute
: constant Character := 'í'; --Character'Val(237)
LC_I_Circumflex
: constant Character := 'î'; --Character'Val(238)
LC_I_Diaeresis
: constant Character := 'ï'; --Character'Val(239)
26 -- Character positions 240 (16#F0#) .. 255 (16#FF#):
LC_Icelandic_Eth
: constant Character := 'ð'; --Character'Val(240)
LC_N_Tilde
: constant Character := 'ñ'; --Character'Val(241)
LC_O_Grave
: constant Character := 'ò'; --Character'Val(242)
LC_O_Acute
: constant Character := 'ó'; --Character'Val(243)
LC_O_Circumflex
: constant Character := 'ô'; --Character'Val(244)
LC_O_Tilde
: constant Character := 'õ'; --Character'Val(245)
LC_O_Diaeresis
: constant Character := 'ö'; --Character'Val(246)
Division_Sign
: constant Character := '÷'; --Character'Val(247)
LC_O_Oblique_Stroke
: constant Character := 'ø'; --Character'Val(248)
LC_U_Grave
: constant Character := 'ù'; --Character'Val(249)
LC_U_Acute
: constant Character := 'ú'; --Character'Val(250)
LC_U_Circumflex
: constant Character := 'û'; --Character'Val(251)
LC_U_Diaeresis
: constant Character := 'ü'; --Character'Val(252)
LC_Y_Acute
: constant Character := 'ý'; --Character'Val(253)
LC_Icelandic_Thorn
: constant Character := 'þ'; --Character'Val(254)
LC_Y_Diaeresis
: constant Character := 'ÿ'; --Character'Val(255)
end Ada.Characters.Latin_1;
Implementation Permissions
27 An implementation may provide additional packages as children of
Ada.Characters, to declare names for the symbols of the local character set or
other character sets.
A.3.4 The Package Characters.Conversions
Static Semantics
1/2 The library package Characters.Conversions has the following declaration:
2/2 package Ada.Characters.Conversions is
pragma Pure(Conversions);
3/2 function Is_Character
(Item : in Wide_Character) return Boolean;
function Is_String
(Item : in Wide_String) return Boolean;
function Is_Character
(Item : in Wide_Wide_Character) return Boolean;
function Is_String
(Item : in Wide_Wide_String) return Boolean;
function Is_Wide_Character (Item : in Wide_Wide_Character)
return Boolean;
function Is_Wide_String (Item : in Wide_Wide_String)
return Boolean;
4/2 function To_Wide_Character
(Item : in Character) return Wide_Character;
function To_Wide_String
(Item : in String) return Wide_String;
function To_Wide_Wide_Character (Item : in Character)
return Wide_Wide_Character;
function To_Wide_Wide_String (Item : in String)
return Wide_Wide_String;
function To_Wide_Wide_Character (Item : in Wide_Character)
return Wide_Wide_Character;
function To_Wide_Wide_String (Item : in Wide_String)
return Wide_Wide_String;
5/2 function To_Character (Item : in Wide_Character;
Substitute : in Character := ' ')
return Character;
function To_String (Item : in Wide_String;
Substitute : in Character := ' ')
return String;
function To_Character (Item : in Wide_Wide_Character;
Substitute : in Character := ' ')
return Character;
function To_String (Item : in Wide_Wide_String;
Substitute : in Character := ' ')
return String;
function To_Wide_Character (Item : in Wide_Wide_Character;
Substitute : in Wide_Character := ' ')
return Wide_Character;
function To_Wide_String (Item : in Wide_Wide_String;
Substitute : in Wide_Character := ' ')
return Wide_String;
6/2 end Ada.Characters.Conversions;
7/2 The functions in package Characters.Conversions test Wide_Wide_Character
or Wide_Character values for membership in Wide_Character or Character, or
convert between corresponding characters of Wide_Wide_Character,
Wide_Character, and Character.
8/2 function Is_Character (Item : in Wide_Character) return Boolean;
9/2 Returns True if Wide_Character'Pos(Item) <=
Character'Pos(Character'Last).
10/2 function Is_Character (Item : in Wide_Wide_Character) return Boolean;
11/2 Returns True if Wide_Wide_Character'Pos(Item) <=
Character'Pos(Character'Last).
12/2 function Is_Wide_Character (Item : in Wide_Wide_Character) return Boolean;
13/2 Returns True if Wide_Wide_Character'Pos(Item) <=
Wide_Character'Pos(Wide_Character'Last).
14/2 function Is_String (Item : in Wide_String) return Boolean;
function Is_String (Item : in Wide_Wide_String) return Boolean;
15/2 Returns True if Is_Character(Item(I)) is True for each I in
Item'Range.
16/2 function Is_Wide_String (Item : in Wide_Wide_String) return Boolean;
17/2 Returns True if Is_Wide_Character(Item(I)) is True for each I in
Item'Range.
18/2 function To_Character (Item : in Wide_Character;
Substitute : in Character := ' ') return Character;
function To_Character (Item : in Wide_Wide_Character;
Substitute : in Character := ' ') return Character;
19/2 Returns the Character corresponding to Item if Is_Character(Item),
and returns the Substitute Character otherwise.
20/2 function To_Wide_Character (Item : in Character) return Wide_Character;
21/2 Returns the Wide_Character X such that Character'Pos(Item) =
Wide_Character'Pos (X).
22/2 function To_Wide_Character (Item : in Wide_Wide_Character;
Substitute : in Wide_Character := ' ')
return Wide_Character;
23/2 Returns the Wide_Character corresponding to Item if
Is_Wide_Character(Item), and returns the Substitute Wide_Character
otherwise.
24/2 function To_Wide_Wide_Character (Item : in Character)
return Wide_Wide_Character;
25/2 Returns the Wide_Wide_Character X such that Character'Pos(Item) =
Wide_Wide_Character'Pos (X).
26/2 function To_Wide_Wide_Character (Item : in Wide_Character)
return Wide_Wide_Character;
27/2 Returns the Wide_Wide_Character X such that
Wide_Character'Pos(Item) = Wide_Wide_Character'Pos (X).
28/2 function To_String (Item : in Wide_String;
Substitute : in Character := ' ') return String;
function To_String (Item : in Wide_Wide_String;
Substitute : in Character := ' ') return String;
29/2 Returns the String whose range is 1..Item'Length and each of whose
elements is given by To_Character of the corresponding element in
Item.
30/2 function To_Wide_String (Item : in String) return Wide_String;
31/2 Returns the Wide_String whose range is 1..Item'Length and each of
whose elements is given by To_Wide_Character of the corresponding
element in Item.
32/2 function To_Wide_String (Item : in Wide_Wide_String;
Substitute : in Wide_Character := ' ')
return Wide_String;
33/2 Returns the Wide_String whose range is 1..Item'Length and each of
whose elements is given by To_Wide_Character of the corresponding
element in Item with the given Substitute Wide_Character.
34/2 function To_Wide_Wide_String (Item : in String) return Wide_Wide_String;
function To_Wide_Wide_String (Item : in Wide_String)
return Wide_Wide_String;
35/2 Returns the Wide_Wide_String whose range is 1..Item'Length and
each of whose elements is given by To_Wide_Wide_Character of the
corresponding element in Item.
A.4 String Handling
1/2 This clause presents the specifications of the package Strings and several
child packages, which provide facilities for dealing with string data.
Fixed-length, bounded-length, and unbounded-length strings are supported, for
String, Wide_String, and Wide_Wide_String. The string-handling subprograms
include searches for pattern strings and for characters in program-specified
sets, translation (via a character-to-character mapping), and transformation
(replacing, inserting, overwriting, and deleting of substrings).
A.4.1 The Package Strings
1 The package Strings provides declarations common to the string handling
packages.
Static Semantics
2 The library package Strings has the following declaration:
3 package Ada.Strings is
pragma Pure(Strings);
4/2 Space : constant Character := ' ';
Wide_Space : constant Wide_Character := ' ';
Wide_Wide_Space : constant Wide_Wide_Character := ' ';
5 Length_Error, Pattern_Error, Index_Error, Translation_Error
: exception;
6 type Alignment is (Left, Right, Center);
type Truncation is (Left, Right, Error);
type Membership is (Inside, Outside);
type Direction is (Forward, Backward);
type Trim_End is (Left, Right, Both);
end Ada.Strings;
A.4.2 The Package Strings.Maps
1 The package Strings.Maps defines the types, operations, and other entities
needed for character sets and character-to-character mappings.
Static Semantics
2 The library package Strings.Maps has the following declaration:
3/2 package Ada.Strings.Maps is
pragma Pure(Maps);
4/2 -- Representation for a set of character values:
type Character_Set is private;
pragma Preelaborable_Initialization(Character_Set);
5 Null_Set : constant Character_Set;
6 type Character_Range is
record
Low : Character;
High : Character;
end record;
-- Represents Character range Low..High
7 type Character_Ranges
is array (Positive range <>) of Character_Range;
8 function To_Set
(Ranges : in Character_Ranges)return Character_Set;
9 function To_Set
(Span : in Character_Range)return Character_Set;
10 function To_Ranges
(Set : in Character_Set) return Character_Ranges;
11 function "=" (Left, Right : in Character_Set) return Boolean;
12 function "not" (Right : in Character_Set) return Character_Set;
function "and" (Left, Right : in Character_Set) return Character_Set;
function "or" (Left, Right : in Character_Set) return Character_Set;
function "xor" (Left, Right : in Character_Set) return Character_Set;
function "-" (Left, Right : in Character_Set) return Character_Set;
13 function Is_In (Element : in Character;
Set : in Character_Set)
return Boolean;
14 function Is_Subset (Elements : in Character_Set;
Set : in Character_Set)
return Boolean;
15 function "<=" (Left : in Character_Set;
Right : in Character_Set)
return Boolean renames Is_Subset;
16 -- Alternative representation for a set of character values:
subtype Character_Sequence is String;
17 function To_Set
(Sequence : in Character_Sequence)return Character_Set;
18 function To_Set
(Singleton : in Character) return Character_Set;
19 function To_Sequence
(Set : in Character_Set) return Character_Sequence;
20/2 -- Representation for a character to character mapping:
type Character_Mapping is private;
pragma Preelaborable_Initialization(Character_Mapping);
21 function Value (Map : in Character_Mapping;
Element : in Character)
return Character;
22 Identity : constant Character_Mapping;
23 function To_Mapping (From, To : in Character_Sequence)
return Character_Mapping;
24 function To_Domain (Map : in Character_Mapping)
return Character_Sequence;
function To_Range (Map : in Character_Mapping)
return Character_Sequence;
25 type Character_Mapping_Function is
access function (From : in Character) return Character;
26 private
... -- not specified by the language
end Ada.Strings.Maps;
27 An object of type Character_Set represents a set of characters.
28 Null_Set represents the set containing no characters.
29 An object Obj of type Character_Range represents the set of characters in
the range Obj.Low .. Obj.High.
30 An object Obj of type Character_Ranges represents the union of the sets
corresponding to Obj(I) for I in Obj'Range.
31 function To_Set (Ranges : in Character_Ranges) return Character_Set;
32 If Ranges'Length=0 then Null_Set is returned; otherwise the
returned value represents the set corresponding to Ranges.
33 function To_Set (Span : in Character_Range) return Character_Set;
34 The returned value represents the set containing each character in
Span.
35 function To_Ranges (Set : in Character_Set) return Character_Ranges;
36 If Set = Null_Set then an empty Character_Ranges array is
returned; otherwise the shortest array of contiguous ranges of
Character values in Set, in increasing order of Low, is returned.
37 function "=" (Left, Right : in Character_Set) return Boolean;
38 The function "=" returns True if Left and Right represent
identical sets, and False otherwise.
39 Each of the logical operators "not", "and", "or", and "xor" returns a
Character_Set value that represents the set obtained by applying the
corresponding operation to the set(s) represented by the parameter(s) of the
operator. "-"(Left, Right) is equivalent to "and"(Left, "not"(Right)).
40 function Is_In (Element : in Character;
Set : in Character_Set);
return Boolean;
41 Is_In returns True if Element is in Set, and False otherwise.
42 function Is_Subset (Elements : in Character_Set;
Set : in Character_Set)
return Boolean;
43 Is_Subset returns True if Elements is a subset of Set, and False
otherwise.
44 subtype Character_Sequence is String;
45 The Character_Sequence subtype is used to portray a set of
character values and also to identify the domain and range of a
character mapping.
46 function To_Set (Sequence : in Character_Sequence) return Character_Set;
function To_Set (Singleton : in Character) return Character_Set;
47 Sequence portrays the set of character values that it explicitly
contains (ignoring duplicates). Singleton portrays the set
comprising a single Character. Each of the To_Set functions
returns a Character_Set value that represents the set portrayed by
Sequence or Singleton.
48 function To_Sequence (Set : in Character_Set) return Character_Sequence;
49 The function To_Sequence returns a Character_Sequence value
containing each of the characters in the set represented by Set,
in ascending order with no duplicates.
50 type Character_Mapping is private;
51 An object of type Character_Mapping represents a
Character-to-Character mapping.
52 function Value (Map : in Character_Mapping;
Element : in Character)
return Character;
53 The function Value returns the Character value to which Element
maps with respect to the mapping represented by Map.
54 A character C matches a pattern character P with respect to a given
Character_Mapping value Map if Value(Map, C) = P. A string S matches a pattern
string P with respect to a given Character_Mapping if their lengths are the
same and if each character in S matches its corresponding character in the
pattern string P.
55 String handling subprograms that deal with character mappings have
parameters whose type is Character_Mapping.
56 Identity : constant Character_Mapping;
57 Identity maps each Character to itself.
58 function To_Mapping (From, To : in Character_Sequence)
return Character_Mapping;
59 To_Mapping produces a Character_Mapping such that each element of
From maps to the corresponding element of To, and each other
character maps to itself. If From'Length /= To'Length, or if some
character is repeated in From, then Translation_Error is
propagated.
60 function To_Domain (Map : in Character_Mapping) return Character_Sequence;
61 To_Domain returns the shortest Character_Sequence value D such
that each character not in D maps to itself, and such that the
characters in D are in ascending order. The lower bound of D is 1.
62 function To_Range (Map : in Character_Mapping) return Character_Sequence;
63/1 To_Range returns the Character_Sequence value R, such that if D =
To_Domain(Map), then R has the same bounds as D, and D(I) maps to
R(I) for each I in D'Range.
64 An object F of type Character_Mapping_Function maps a Character value C to
the Character value F.all(C), which is said to match C with respect to mapping
function F.
NOTES
65 7 Character_Mapping and Character_Mapping_Function are used both for
character equivalence mappings in the search subprograms (such as for
case insensitivity) and as transformational mappings in the Translate
subprograms.
66 8 To_Domain(Identity) and To_Range(Identity) each returns the null
string.
Examples
67 To_Mapping("ABCD", "ZZAB") returns a Character_Mapping that maps 'A' and
'B' to 'Z', 'C' to 'A', 'D' to 'B', and each other Character to itself.
A.4.3 Fixed-Length String Handling
1 The language-defined package Strings.Fixed provides string-handling
subprograms for fixed-length strings; that is, for values of type
Standard.String. Several of these subprograms are procedures that modify the
contents of a String that is passed as an out or an in out parameter; each has
additional parameters to control the effect when the logical length of the
result differs from the parameter's length.
2 For each function that returns a String, the lower bound of the returned
value is 1.
3 The basic model embodied in the package is that a fixed-length string
comprises significant characters and possibly padding (with space characters)
on either or both ends. When a shorter string is copied to a longer string,
padding is inserted, and when a longer string is copied to a shorter one,
padding is stripped. The Move procedure in Strings.Fixed, which takes a String
as an out parameter, allows the programmer to control these effects. Similar
control is provided by the string transformation procedures.
Static Semantics
4 The library package Strings.Fixed has the following declaration:
5 with Ada.Strings.Maps;
package Ada.Strings.Fixed is
pragma Preelaborate(Fixed);
6 -- "Copy" procedure for strings of possibly different lengths
7 procedure Move (Source : in String;
Target : out String;
Drop : in Truncation := Error;
Justify : in Alignment := Left;
Pad : in Character := Space);
8 -- Search subprograms
8.1/2 function Index (Source : in String;
Pattern : in String;
From : in Positive;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping := Maps.Identity)
return Natural;
8.2/2 function Index (Source : in String;
Pattern : in String;
From : in Positive;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
9 function Index (Source : in String;
Pattern : in String;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping
:= Maps.Identity)
return Natural;
10 function Index (Source : in String;
Pattern : in String;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
10.1/2 function Index (Source : in String;
Set : in Maps.Character_Set;
From : in Positive;
Test : in Membership := Inside;
Going : in Direction := Forward)
return Natural;
11 function Index (Source : in String;
Set : in Maps.Character_Set;
Test : in Membership := Inside;
Going : in Direction := Forward)
return Natural;
11.1/2 function Index_Non_Blank (Source : in String;
From : in Positive;
Going : in Direction := Forward)
return Natural;
12 function Index_Non_Blank (Source : in String;
Going : in Direction := Forward)
return Natural;
13 function Count (Source : in String;
Pattern : in String;
Mapping : in Maps.Character_Mapping
:= Maps.Identity)
return Natural;
14 function Count (Source : in String;
Pattern : in String;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
15 function Count (Source : in String;
Set : in Maps.Character_Set)
return Natural;
16 procedure Find_Token (Source : in String;
Set : in Maps.Character_Set;
Test : in Membership;
First : out Positive;
Last : out Natural);
17 -- String translation subprograms
18 function Translate (Source : in String;
Mapping : in Maps.Character_Mapping)
return String;
19 procedure Translate (Source : in out String;
Mapping : in Maps.Character_Mapping);
20 function Translate (Source : in String;
Mapping : in Maps.Character_Mapping_Function)
return String;
21 procedure Translate (Source : in out String;
Mapping : in Maps.Character_Mapping_Function);
22 -- String transformation subprograms
23 function Replace_Slice (Source : in String;
Low : in Positive;
High : in Natural;
By : in String)
return String;
24 procedure Replace_Slice (Source : in out String;
Low : in Positive;
High : in Natural;
By : in String;
Drop : in Truncation := Error;
Justify : in Alignment := Left;
Pad : in Character := Space);
25 function Insert (Source : in String;
Before : in Positive;
New_Item : in String)
return String;
26 procedure Insert (Source : in out String;
Before : in Positive;
New_Item : in String;
Drop : in Truncation := Error);
27 function Overwrite (Source : in String;
Position : in Positive;
New_Item : in String)
return String;
28 procedure Overwrite (Source : in out String;
Position : in Positive;
New_Item : in String;
Drop : in Truncation := Right);
29 function Delete (Source : in String;
From : in Positive;
Through : in Natural)
return String;
30 procedure Delete (Source : in out String;
From : in Positive;
Through : in Natural;
Justify : in Alignment := Left;
Pad : in Character := Space);
31 --String selector subprograms
function Trim (Source : in String;
Side : in Trim_End)
return String;
32 procedure Trim (Source : in out String;
Side : in Trim_End;
Justify : in Alignment := Left;
Pad : in Character := Space);
33 function Trim (Source : in String;
Left : in Maps.Character_Set;
Right : in Maps.Character_Set)
return String;
34 procedure Trim (Source : in out String;
Left : in Maps.Character_Set;
Right : in Maps.Character_Set;
Justify : in Alignment := Strings.Left;
Pad : in Character := Space);
35 function Head (Source : in String;
Count : in Natural;
Pad : in Character := Space)
return String;
36 procedure Head (Source : in out String;
Count : in Natural;
Justify : in Alignment := Left;
Pad : in Character := Space);
37 function Tail (Source : in String;
Count : in Natural;
Pad : in Character := Space)
return String;
38 procedure Tail (Source : in out String;
Count : in Natural;
Justify : in Alignment := Left;
Pad : in Character := Space);
39 --String constructor functions
40 function "*" (Left : in Natural;
Right : in Character) return String;
41 function "*" (Left : in Natural;
Right : in String) return String;
42 end Ada.Strings.Fixed;
43 The effects of the above subprograms are as follows.
44 procedure Move (Source : in String;
Target : out String;
Drop : in Truncation := Error;
Justify : in Alignment := Left;
Pad : in Character := Space);
45 The Move procedure copies characters from Source to Target. If
Source has the same length as Target, then the effect is to assign
Source to Target. If Source is shorter than Target then:
46 * If Justify=Left, then Source is copied into the first
Source'Length characters of Target.
47 * If Justify=Right, then Source is copied into the last
Source'Length characters of Target.
48 * If Justify=Center, then Source is copied into the middle
Source'Length characters of Target. In this case, if the
difference in length between Target and Source is odd, then
the extra Pad character is on the right.
49 * Pad is copied to each Target character not otherwise assigned.
50 If Source is longer than Target, then the effect is based on Drop.
51 * If Drop=Left, then the rightmost Target'Length characters of
Source are copied into Target.
52 * If Drop=Right, then the leftmost Target'Length characters of
Source are copied into Target.
53 * If Drop=Error, then the effect depends on the value of the
Justify parameter and also on whether any characters in Source
other than Pad would fail to be copied:
54 * If Justify=Left, and if each of the rightmost
Source'Length-Target'Length characters in Source is Pad,
then the leftmost Target'Length characters of Source are
copied to Target.
55 * If Justify=Right, and if each of the leftmost
Source'Length-Target'Length characters in Source is Pad,
then the rightmost Target'Length characters of Source are
copied to Target.
56 * Otherwise, Length_Error is propagated.
56.1/2 function Index (Source : in String;
Pattern : in String;
From : in Positive;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping := Maps.Identity)
return Natural;
function Index (Source : in String;
Pattern : in String;
From : in Positive;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
56.2/2 Each Index function searches, starting from From, for a slice of
Source, with length Pattern'Length, that matches Pattern with
respect to Mapping; the parameter Going indicates the direction of
the lookup. If From is not in Source'Range, then Index_Error is
propagated. If Going = Forward, then Index returns the smallest
index I which is greater than or equal to From such that the slice
of Source starting at I matches Pattern. If Going = Backward, then
Index returns the largest index I such that the slice of Source
starting at I matches Pattern and has an upper bound less than or
equal to From. If there is no such slice, then 0 is returned. If
Pattern is the null string, then Pattern_Error is propagated.
57 function Index (Source : in String;
Pattern : in String;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping
:= Maps.Identity)
return Natural;
function Index (Source : in String;
Pattern : in String;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
58/2 If Going = Forward, returns
58.1/2 Index (Source, Pattern, Source'First, Forward, Mapping);
58.2/2 otherwise returns
58.3/2 Index (Source, Pattern, Source'Last, Backward, Mapping);
58.4/2 function Index (Source : in String;
Set : in Maps.Character_Set;
From : in Positive;
Test : in Membership := Inside;
Going : in Direction := Forward)
return Natural;
58.5/2 Index searches for the first or last occurrence of any of a set of
characters (when Test=Inside), or any of the complement of a set
of characters (when Test=Outside). If From is not in Source'Range,
then Index_Error is propagated. Otherwise, it returns the smallest
index I >= From (if Going=Forward) or the largest index I <= From
(if Going=Backward) such that Source(I) satisfies the Test
condition with respect to Set; it returns 0 if there is no such
Character in Source.
59 function Index (Source : in String;
Set : in Maps.Character_Set;
Test : in Membership := Inside;
Going : in Direction := Forward)
return Natural;
60/2 If Going = Forward, returns
60.1/2 Index (Source, Set, Source'First, Test, Forward);
60.2/2 otherwise returns
60.3/2 Index (Source, Set, Source'Last, Test, Backward);
60.4/2 function Index_Non_Blank (Source : in String;
From : in Positive;
Going : in Direction := Forward)
return Natural;
60.5/2 Returns Index (Source, Maps.To_Set(Space), From, Outside, Going);
61 function Index_Non_Blank (Source : in String;
Going : in Direction := Forward)
return Natural;
62 Returns Index(Source, Maps.To_Set(Space), Outside, Going)
63 function Count (Source : in String;
Pattern : in String;
Mapping : in Maps.Character_Mapping
:= Maps.Identity)
return Natural;
function Count (Source : in String;
Pattern : in String;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
64 Returns the maximum number of nonoverlapping slices of Source that
match Pattern with respect to Mapping. If Pattern is the null
string then Pattern_Error is propagated.
65 function Count (Source : in String;
Set : in Maps.Character_Set)
return Natural;
66 Returns the number of occurrences in Source of characters that are
in Set.
67 procedure Find_Token (Source : in String;
Set : in Maps.Character_Set;
Test : in Membership;
First : out Positive;
Last : out Natural);
68/1 Find_Token returns in First and Last the indices of the beginning
and end of the first slice of Source all of whose elements satisfy
the Test condition, and such that the elements (if any)
immediately before and after the slice do not satisfy the Test
condition. If no such slice exists, then the value returned for
Last is zero, and the value returned for First is Source'First;
however, if Source'First is not in Positive then Constraint_Error
is raised.
69 function Translate (Source : in String;
Mapping : in Maps.Character_Mapping)
return String;
function Translate (Source : in String;
Mapping : in Maps.Character_Mapping_Function)
return String;
70 Returns the string S whose length is Source'Length and such that
S(I) is the character to which Mapping maps the corresponding
element of Source, for I in 1..Source'Length.
71 procedure Translate (Source : in out String;
Mapping : in Maps.Character_Mapping);
procedure Translate (Source : in out String;
Mapping : in Maps.Character_Mapping_Function);
72 Equivalent to Source := Translate(Source, Mapping).
73 function Replace_Slice (Source : in String;
Low : in Positive;
High : in Natural;
By : in String)
return String;
74/1 If Low > Source'Last+1, or High < Source'First-1, then Index_Error
is propagated. Otherwise:
74.1/1 * If High >= Low, then the returned string comprises
Source(Source'First..Low-1) & By &
Source(High+1..Source'Last), but with lower bound 1.
74.2/1 * If High < Low, then the returned string is Insert(Source,
Before=>Low, New_Item=>By).
75 procedure Replace_Slice (Source : in out String;
Low : in Positive;
High : in Natural;
By : in String;
Drop : in Truncation := Error;
Justify : in Alignment := Left;
Pad : in Character := Space);
76 Equivalent to Move(Replace_Slice(Source, Low, High, By), Source,
Drop, Justify, Pad).
77 function Insert (Source : in String;
Before : in Positive;
New_Item : in String)
return String;
78 Propagates Index_Error if Before is not in Source'First ..
Source'Last+1; otherwise returns Source(Source'First..Before-1) &
New_Item & Source(Before..Source'Last), but with lower bound 1.
79 procedure Insert (Source : in out String;
Before : in Positive;
New_Item : in String;
Drop : in Truncation := Error);
80 Equivalent to Move(Insert(Source, Before, New_Item), Source, Drop).
81 function Overwrite (Source : in String;
Position : in Positive;
New_Item : in String)
return String;
82 Propagates Index_Error if Position is not in Source'First ..
Source'Last+1; otherwise returns the string obtained from Source
by consecutively replacing characters starting at Position with
corresponding characters from New_Item. If the end of Source is
reached before the characters in New_Item are exhausted, the
remaining characters from New_Item are appended to the string.
83 procedure Overwrite (Source : in out String;
Position : in Positive;
New_Item : in String;
Drop : in Truncation := Right);
84 Equivalent to Move(Overwrite(Source, Position, New_Item), Source,
Drop).
85 function Delete (Source : in String;
From : in Positive;
Through : in Natural)
return String;
86/1 If From <= Through, the returned string is Replace_Slice(Source,
From, Through, ""), otherwise it is Source with lower bound 1.
87 procedure Delete (Source : in out String;
From : in Positive;
Through : in Natural;
Justify : in Alignment := Left;
Pad : in Character := Space);
88 Equivalent to Move(Delete(Source, From, Through), Source, Justify
=> Justify, Pad => Pad).
89 function Trim (Source : in String;
Side : in Trim_End)
return String;
90 Returns the string obtained by removing from Source all leading
Space characters (if Side = Left), all trailing Space characters
(if Side = Right), or all leading and trailing Space characters
(if Side = Both).
91 procedure Trim (Source : in out String;
Side : in Trim_End;
Justify : in Alignment := Left;
Pad : in Character := Space);
92 Equivalent to Move(Trim(Source, Side), Source, Justify=>Justify,
Pad=>Pad).
93 function Trim (Source : in String;
Left : in Maps.Character_Set;
Right : in Maps.Character_Set)
return String;
94 Returns the string obtained by removing from Source all leading
characters in Left and all trailing characters in Right.
95 procedure Trim (Source : in out String;
Left : in Maps.Character_Set;
Right : in Maps.Character_Set;
Justify : in Alignment := Strings.Left;
Pad : in Character := Space);
96 Equivalent to Move(Trim(Source, Left, Right), Source, Justify =>
Justify, Pad=>Pad).
97 function Head (Source : in String;
Count : in Natural;
Pad : in Character := Space)
return String;
98 Returns a string of length Count. If Count <= Source'Length, the
string comprises the first Count characters of Source. Otherwise
its contents are Source concatenated with Count-Source'Length Pad
characters.
99 procedure Head (Source : in out String;
Count : in Natural;
Justify : in Alignment := Left;
Pad : in Character := Space);
100 Equivalent to Move(Head(Source, Count, Pad), Source, Drop=>Error,
Justify=>Justify, Pad=>Pad).
101 function Tail (Source : in String;
Count : in Natural;
Pad : in Character := Space)
return String;
102 Returns a string of length Count. If Count <= Source'Length, the
string comprises the last Count characters of Source. Otherwise
its contents are Count-Source'Length Pad characters concatenated
with Source.
103 procedure Tail (Source : in out String;
Count : in Natural;
Justify : in Alignment := Left;
Pad : in Character := Space);
104 Equivalent to Move(Tail(Source, Count, Pad), Source, Drop=>Error,
Justify=>Justify, Pad=>Pad).
105 function "*" (Left : in Natural;
Right : in Character) return String;
function "*" (Left : in Natural;
Right : in String) return String;
106/1 These functions replicate a character or string a specified number
of times. The first function returns a string whose length is Left
and each of whose elements is Right. The second function returns a
string whose length is Left*Right'Length and whose value is the
null string if Left = 0 and otherwise is (Left-1)*Right & Right
with lower bound 1.
NOTES
107 9 In the Index and Count functions taking Pattern and Mapping
parameters, the actual String parameter passed to Pattern should
comprise characters occurring as target characters of the mapping.
Otherwise the pattern will not match.
108 10 In the Insert subprograms, inserting at the end of a string is
obtained by passing Source'Last+1 as the Before parameter.
109 11 If a null Character_Mapping_Function is passed to any of the
string handling subprograms, Constraint_Error is propagated.
A.4.4 Bounded-Length String Handling
1 The language-defined package Strings.Bounded provides a generic package
each of whose instances yields a private type Bounded_String and a set of
operations. An object of a particular Bounded_String type represents a String
whose low bound is 1 and whose length can vary conceptually between 0 and a
maximum size established at the generic instantiation. The subprograms for
fixed-length string handling are either overloaded directly for
Bounded_String, or are modified as needed to reflect the variability in
length. Additionally, since the Bounded_String type is private, appropriate
constructor and selector operations are provided.
Static Semantics
2 The library package Strings.Bounded has the following declaration:
3 with Ada.Strings.Maps;
package Ada.Strings.Bounded is
pragma Preelaborate(Bounded);
4 generic
Max : Positive; -- Maximum length of a Bounded_String
package Generic_Bounded_Length is
5 Max_Length : constant Positive := Max;
6 type Bounded_String is private;
7 Null_Bounded_String : constant Bounded_String;
8 subtype Length_Range is Natural range 0 .. Max_Length;
9 function Length
(Source : in Bounded_String) return Length_Range;
10 -- Conversion, Concatenation, and Selection functions
11 function To_Bounded_String (Source : in String;
Drop : in Truncation := Error)
return Bounded_String;
12 function To_String (Source : in Bounded_String) return String;
12.1/2 procedure Set_Bounded_String
(Target : out Bounded_String;
Source : in String;
Drop : in Truncation := Error);
13 function Append (Left, Right : in Bounded_String;
Drop : in Truncation := Error)
return Bounded_String;
14 function Append (Left : in Bounded_String;
Right : in String;
Drop : in Truncation := Error)
return Bounded_String;
15 function Append (Left : in String;
Right : in Bounded_String;
Drop : in Truncation := Error)
return Bounded_String;
16 function Append (Left : in Bounded_String;
Right : in Character;
Drop : in Truncation := Error)
return Bounded_String;
17 function Append (Left : in Character;
Right : in Bounded_String;
Drop : in Truncation := Error)
return Bounded_String;
18 procedure Append (Source : in out Bounded_String;
New_Item : in Bounded_String;
Drop : in Truncation := Error);
19 procedure Append (Source : in out Bounded_String;
New_Item : in String;
Drop : in Truncation := Error);
20 procedure Append (Source : in out Bounded_String;
New_Item : in Character;
Drop : in Truncation := Error);
21 function "&" (Left, Right : in Bounded_String)
return Bounded_String;
22 function "&" (Left : in Bounded_String; Right : in String)
return Bounded_String;
23 function "&" (Left : in String; Right : in Bounded_String)
return Bounded_String;
24 function "&" (Left : in Bounded_String; Right : in Character)
return Bounded_String;
25 function "&" (Left : in Character; Right : in Bounded_String)
return Bounded_String;
26 function Element (Source : in Bounded_String;
Index : in Positive)
return Character;
27 procedure Replace_Element (Source : in out Bounded_String;
Index : in Positive;
By : in Character);
28 function Slice (Source : in Bounded_String;
Low : in Positive;
High : in Natural)
return String;
28.1/2 function Bounded_Slice
(Source : in Bounded_String;
Low : in Positive;
High : in Natural)
return Bounded_String;
28.2/2 procedure Bounded_Slice
(Source : in Bounded_String;
Target : out Bounded_String;
Low : in Positive;
High : in Natural);
29 function "=" (Left, Right : in Bounded_String) return Boolean;
function "=" (Left : in Bounded_String; Right : in String)
return Boolean;
30 function "=" (Left : in String; Right : in Bounded_String)
return Boolean;
31 function "<" (Left, Right : in Bounded_String) return Boolean;
32 function "<" (Left : in Bounded_String; Right : in String)
return Boolean;
33 function "<" (Left : in String; Right : in Bounded_String)
return Boolean;
34 function "<=" (Left, Right : in Bounded_String) return Boolean;
35 function "<=" (Left : in Bounded_String; Right : in String)
return Boolean;
36 function "<=" (Left : in String; Right : in Bounded_String)
return Boolean;
37 function ">" (Left, Right : in Bounded_String) return Boolean;
38 function ">" (Left : in Bounded_String; Right : in String)
return Boolean;
39 function ">" (Left : in String; Right : in Bounded_String)
return Boolean;
40 function ">=" (Left, Right : in Bounded_String) return Boolean;
41 function ">=" (Left : in Bounded_String; Right : in String)
return Boolean;
42 function ">=" (Left : in String; Right : in Bounded_String)
return Boolean;
43/2 -- Search subprograms
43.1/2 function Index (Source : in Bounded_String;
Pattern : in String;
From : in Positive;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping := Maps.Identity)
return Natural;
43.2/2 function Index (Source : in Bounded_String;
Pattern : in String;
From : in Positive;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
44 function Index (Source : in Bounded_String;
Pattern : in String;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping
:= Maps.Identity)
return Natural;
45 function Index (Source : in Bounded_String;
Pattern : in String;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
45.1/2 function Index (Source : in Bounded_String;
Set : in Maps.Character_Set;
From : in Positive;
Test : in Membership := Inside;
Going : in Direction := Forward)
return Natural;
46 function Index (Source : in Bounded_String;
Set : in Maps.Character_Set;
Test : in Membership := Inside;
Going : in Direction := Forward)
return Natural;
46.1/2 function Index_Non_Blank (Source : in Bounded_String;
From : in Positive;
Going : in Direction := Forward)
return Natural;
47 function Index_Non_Blank (Source : in Bounded_String;
Going : in Direction := Forward)
return Natural;
48 function Count (Source : in Bounded_String;
Pattern : in String;
Mapping : in Maps.Character_Mapping
:= Maps.Identity)
return Natural;
49 function Count (Source : in Bounded_String;
Pattern : in String;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
50 function Count (Source : in Bounded_String;
Set : in Maps.Character_Set)
return Natural;
51 procedure Find_Token (Source : in Bounded_String;
Set : in Maps.Character_Set;
Test : in Membership;
First : out Positive;
Last : out Natural);
52 -- String translation subprograms
53 function Translate (Source : in Bounded_String;
Mapping : in Maps.Character_Mapping)
return Bounded_String;
54 procedure Translate (Source : in out Bounded_String;
Mapping : in Maps.Character_Mapping);
55 function Translate (Source : in Bounded_String;
Mapping : in Maps.Character_Mapping_Function)
return Bounded_String;
56 procedure Translate (Source : in out Bounded_String;
Mapping : in Maps.Character_Mapping_Function);
57 -- String transformation subprograms
58 function Replace_Slice (Source : in Bounded_String;
Low : in Positive;
High : in Natural;
By : in String;
Drop : in Truncation := Error)
return Bounded_String;
59 procedure Replace_Slice (Source : in out Bounded_String;
Low : in Positive;
High : in Natural;
By : in String;
Drop : in Truncation := Error);
60 function Insert (Source : in Bounded_String;
Before : in Positive;
New_Item : in String;
Drop : in Truncation := Error)
return Bounded_String;
61 procedure Insert (Source : in out Bounded_String;
Before : in Positive;
New_Item : in String;
Drop : in Truncation := Error);
62 function Overwrite (Source : in Bounded_String;
Position : in Positive;
New_Item : in String;
Drop : in Truncation := Error)
return Bounded_String;
63 procedure Overwrite (Source : in out Bounded_String;
Position : in Positive;
New_Item : in String;
Drop : in Truncation := Error);
64 function Delete (Source : in Bounded_String;
From : in Positive;
Through : in Natural)
return Bounded_String;
65 procedure Delete (Source : in out Bounded_String;
From : in Positive;
Through : in Natural);
66 --String selector subprograms
67 function Trim (Source : in Bounded_String;
Side : in Trim_End)
return Bounded_String;
procedure Trim (Source : in out Bounded_String;
Side : in Trim_End);
68 function Trim (Source : in Bounded_String;
Left : in Maps.Character_Set;
Right : in Maps.Character_Set)
return Bounded_String;
69 procedure Trim (Source : in out Bounded_String;
Left : in Maps.Character_Set;
Right : in Maps.Character_Set);
70 function Head (Source : in Bounded_String;
Count : in Natural;
Pad : in Character := Space;
Drop : in Truncation := Error)
return Bounded_String;
71 procedure Head (Source : in out Bounded_String;
Count : in Natural;
Pad : in Character := Space;
Drop : in Truncation := Error);
72 function Tail (Source : in Bounded_String;
Count : in Natural;
Pad : in Character := Space;
Drop : in Truncation := Error)
return Bounded_String;
73 procedure Tail (Source : in out Bounded_String;
Count : in Natural;
Pad : in Character := Space;
Drop : in Truncation := Error);
74 --String constructor subprograms
75 function "*" (Left : in Natural;
Right : in Character)
return Bounded_String;
76 function "*" (Left : in Natural;
Right : in String)
return Bounded_String;
77 function "*" (Left : in Natural;
Right : in Bounded_String)
return Bounded_String;
78 function Replicate (Count : in Natural;
Item : in Character;
Drop : in Truncation := Error)
return Bounded_String;
79 function Replicate (Count : in Natural;
Item : in String;
Drop : in Truncation := Error)
return Bounded_String;
80 function Replicate (Count : in Natural;
Item : in Bounded_String;
Drop : in Truncation := Error)
return Bounded_String;
81 private
... -- not specified by the language
end Generic_Bounded_Length;
82 end Ada.Strings.Bounded;
83 Null_Bounded_String represents the null string. If an object of type
Bounded_String is not otherwise initialized, it will be initialized to the
same value as Null_Bounded_String.
84 function Length (Source : in Bounded_String) return Length_Range;
85 The Length function returns the length of the string represented
by Source.
86 function To_Bounded_String (Source : in String;
Drop : in Truncation := Error)
return Bounded_String;
87 If Source'Length <= Max_Length then this function returns a
Bounded_String that represents Source. Otherwise the effect
depends on the value of Drop:
88 * If Drop=Left, then the result is a Bounded_String that
represents the string comprising the rightmost Max_Length
characters of Source.
89 * If Drop=Right, then the result is a Bounded_String that
represents the string comprising the leftmost Max_Length
characters of Source.
90 * If Drop=Error, then Strings.Length_Error is propagated.
91 function To_String (Source : in Bounded_String) return String;
92 To_String returns the String value with lower bound 1 represented
by Source. If B is a Bounded_String, then B =
To_Bounded_String(To_String(B)).
92.1/2 procedure Set_Bounded_String
(Target : out Bounded_String;
Source : in String;
Drop : in Truncation := Error);
92.2/2 Equivalent to Target := To_Bounded_String (Source, Drop);
93 Each of the Append functions returns a Bounded_String obtained by
concatenating the string or character given or represented by one of the
parameters, with the string or character given or represented by the other
parameter, and applying To_Bounded_String to the concatenation result string,
with Drop as provided to the Append function.
94 Each of the procedures Append(Source, New_Item, Drop) has the same effect
as the corresponding assignment Source := Append(Source, New_Item, Drop).
95 Each of the "&" functions has the same effect as the corresponding Append
function, with Error as the Drop parameter.
96 function Element (Source : in Bounded_String;
Index : in Positive)
return Character;
97 Returns the character at position Index in the string represented
by Source; propagates Index_Error if Index > Length(Source).
98 procedure Replace_Element (Source : in out Bounded_String;
Index : in Positive;
By : in Character);
99 Updates Source such that the character at position Index in the
string represented by Source is By; propagates Index_Error if
Index > Length(Source).
100 function Slice (Source : in Bounded_String;
Low : in Positive;
High : in Natural)
return String;
101/1 Returns the slice at positions Low through High in the string
represented by Source; propagates Index_Error if Low >
Length(Source)+1 or High > Length(Source). The bounds of the
returned string are Low and High..
101.1/2 function Bounded_Slice
(Source : in Bounded_String;
Low : in Positive;
High : in Natural)
return Bounded_String;
101.2/2 Returns the slice at positions Low through High in the string
represented by Source as a bounded string; propagates Index_Error
if Low > Length(Source)+1 or High > Length(Source).
101.3/2 procedure Bounded_Slice
(Source : in Bounded_String;
Target : out Bounded_String;
Low : in Positive;
High : in Natural);
101.4/2 Equivalent to Target := Bounded_Slice (Source, Low, High);
102 Each of the functions "=", "<", ">", "<=", and ">=" returns the same
result as the corresponding String operation applied to the String values
given or represented by the two parameters.
103 Each of the search subprograms (Index, Index_Non_Blank, Count, Find_Token)
has the same effect as the corresponding subprogram in Strings.Fixed applied
to the string represented by the Bounded_String parameter.
104 Each of the Translate subprograms, when applied to a Bounded_String, has
an analogous effect to the corresponding subprogram in Strings.Fixed. For the
Translate function, the translation is applied to the string represented by
the Bounded_String parameter, and the result is converted (via
To_Bounded_String) to a Bounded_String. For the Translate procedure, the
string represented by the Bounded_String parameter after the translation is
given by the Translate function for fixed-length strings applied to the string
represented by the original value of the parameter.
105/1 Each of the transformation subprograms (Replace_Slice, Insert,
Overwrite, Delete), selector subprograms (Trim, Head, Tail), and constructor
functions ("*") has an effect based on its corresponding subprogram in
Strings.Fixed, and Replicate is based on Fixed."*". In the case of a function,
the corresponding fixed-length string subprogram is applied to the string
represented by the Bounded_String parameter. To_Bounded_String is applied the
result string, with Drop (or Error in the case of Generic_Bounded_Length."*")
determining the effect when the string length exceeds Max_Length. In the case
of a procedure, the corresponding function in Strings.Bounded.Generic_Bounded_-
Length is applied, with the result assigned into the Source parameter.
Implementation Advice
106 Bounded string objects should not be implemented by implicit pointers and
dynamic allocation.
A.4.5 Unbounded-Length String Handling
1 The language-defined package Strings.Unbounded provides a private type
Unbounded_String and a set of operations. An object of type Unbounded_String
represents a String whose low bound is 1 and whose length can vary
conceptually between 0 and Natural'Last. The subprograms for fixed-length
string handling are either overloaded directly for Unbounded_String, or are
modified as needed to reflect the flexibility in length. Since the
Unbounded_String type is private, relevant constructor and selector operations
are provided.
Static Semantics
2 The library package Strings.Unbounded has the following declaration:
3 with Ada.Strings.Maps;
package Ada.Strings.Unbounded is
pragma Preelaborate(Unbounded);
4/2 type Unbounded_String is private;
pragma Preelaborable_Initialization(Unbounded_String);
5 Null_Unbounded_String : constant Unbounded_String;
6 function Length (Source : in Unbounded_String) return Natural;
7 type String_Access is access all String;
procedure Free (X : in out String_Access);
8 -- Conversion, Concatenation, and Selection functions
9 function To_Unbounded_String (Source : in String)
return Unbounded_String;
10 function To_Unbounded_String (Length : in Natural)
return Unbounded_String;
11 function To_String (Source : in Unbounded_String) return String;
11.1/2 procedure Set_Unbounded_String
(Target : out Unbounded_String;
Source : in String);
12 procedure Append (Source : in out Unbounded_String;
New_Item : in Unbounded_String);
13 procedure Append (Source : in out Unbounded_String;
New_Item : in String);
14 procedure Append (Source : in out Unbounded_String;
New_Item : in Character);
15 function "&" (Left, Right : in Unbounded_String)
return Unbounded_String;
16 function "&" (Left : in Unbounded_String; Right : in String)
return Unbounded_String;
17 function "&" (Left : in String; Right : in Unbounded_String)
return Unbounded_String;
18 function "&" (Left : in Unbounded_String; Right : in Character)
return Unbounded_String;
19 function "&" (Left : in Character; Right : in Unbounded_String)
return Unbounded_String;
20 function Element (Source : in Unbounded_String;
Index : in Positive)
return Character;
21 procedure Replace_Element (Source : in out Unbounded_String;
Index : in Positive;
By : in Character);
22 function Slice (Source : in Unbounded_String;
Low : in Positive;
High : in Natural)
return String;
22.1/2 function Unbounded_Slice
(Source : in Unbounded_String;
Low : in Positive;
High : in Natural)
return Unbounded_String;
22.2/2 procedure Unbounded_Slice
(Source : in Unbounded_String;
Target : out Unbounded_String;
Low : in Positive;
High : in Natural);
23 function "=" (Left, Right : in Unbounded_String) return Boolean;
24 function "=" (Left : in Unbounded_String; Right : in String)
return Boolean;
25 function "=" (Left : in String; Right : in Unbounded_String)
return Boolean;
26 function "<" (Left, Right : in Unbounded_String) return Boolean;
27 function "<" (Left : in Unbounded_String; Right : in String)
return Boolean;
28 function "<" (Left : in String; Right : in Unbounded_String)
return Boolean;
29 function "<=" (Left, Right : in Unbounded_String) return Boolean;
30 function "<=" (Left : in Unbounded_String; Right : in String)
return Boolean;
31 function "<=" (Left : in String; Right : in Unbounded_String)
return Boolean;
32 function ">" (Left, Right : in Unbounded_String) return Boolean;
33 function ">" (Left : in Unbounded_String; Right : in String)
return Boolean;
34 function ">" (Left : in String; Right : in Unbounded_String)
return Boolean;
35 function ">=" (Left, Right : in Unbounded_String) return Boolean;
36 function ">=" (Left : in Unbounded_String; Right : in String)
return Boolean;
37 function ">=" (Left : in String; Right : in Unbounded_String)
return Boolean;
38 -- Search subprograms
38.1/2 function Index (Source : in Unbounded_String;
Pattern : in String;
From : in Positive;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping := Maps.Identity)
return Natural;
38.2/2 function Index (Source : in Unbounded_String;
Pattern : in String;
From : in Positive;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
39 function Index (Source : in Unbounded_String;
Pattern : in String;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping
:= Maps.Identity)
return Natural;
40 function Index (Source : in Unbounded_String;
Pattern : in String;
Going : in Direction := Forward;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
40.1/2 function Index (Source : in Unbounded_String;
Set : in Maps.Character_Set;
From : in Positive;
Test : in Membership := Inside;
Going : in Direction := Forward)
return Natural;
41 function Index (Source : in Unbounded_String;
Set : in Maps.Character_Set;
Test : in Membership := Inside;
Going : in Direction := Forward) return Natural;
41.1/2 function Index_Non_Blank (Source : in Unbounded_String;
From : in Positive;
Going : in Direction := Forward)
return Natural;
42 function Index_Non_Blank (Source : in Unbounded_String;
Going : in Direction := Forward)
return Natural;
43 function Count (Source : in Unbounded_String;
Pattern : in String;
Mapping : in Maps.Character_Mapping
:= Maps.Identity)
return Natural;
44 function Count (Source : in Unbounded_String;
Pattern : in String;
Mapping : in Maps.Character_Mapping_Function)
return Natural;
45 function Count (Source : in Unbounded_String;
Set : in Maps.Character_Set)
return Natural;
46 procedure Find_Token (Source : in Unbounded_String;
Set : in Maps.Character_Set;
Test : in Membership;
First : out Positive;
Last : out Natural);
47 -- String translation subprograms
48 function Translate (Source : in Unbounded_String;
Mapping : in Maps.Character_Mapping)
return Unbounded_String;
49 procedure Translate (Source : in out Unbounded_String;
Mapping : in Maps.Character_Mapping);
50 function Translate (Source : in Unbounded_String;
Mapping : in Maps.Character_Mapping_Function)
return Unbounded_String;
51 procedure Translate (Source : in out Unbounded_String;
Mapping : in Maps.Character_Mapping_Function);
52 -- String transformation subprograms
53 function Replace_Slice (Source : in Unbounded_String;
Low : in Positive;
High : in Natural;
By : in String)
return Unbounded_String;
54 procedure Replace_Slice (Source : in out Unbounded_String;
Low : in Positive;
High : in Natural;
By : in String);
55 function Insert (Source : in Unbounded_String;
Before : in Positive;
New_Item : in String)
return Unbounded_String;
56 procedure Insert (Source : in out Unbounded_String;
Before : in Positive;
New_Item : in String);
57 function Overwrite (Source : in Unbounded_String;
Position : in Positive;
New_Item : in String)
return Unbounded_String;
58 procedure Overwrite (Source : in out Unbounded_String;
Position : in Positive;
New_Item : in String);
59 function Delete (Source : in Unbounded_String;
From : in Positive;
Through : in Natural)
return Unbounded_String;
60 procedure Delete (Source : in out Unbounded_String;
From : in Positive;
Through : in Natural);
61 function Trim (Source : in Unbounded_String;
Side : in Trim_End)
return Unbounded_String;
62 procedure Trim (Source : in out Unbounded_String;
Side : in Trim_End);
63 function Trim (Source : in Unbounded_String;
Left : in Maps.Character_Set;
Right : in Maps.Character_Set)
return Unbounded_String;
64 procedure Trim (Source : in out Unbounded_String;
Left : in Maps.Character_Set;
Right : in Maps.Character_Set);
65 function Head (Source : in Unbounded_String;
Count : in Natural;
Pad : in Character := Space)
return Unbounded_String;
66 procedure Head (Source : in out Unbounded_String;
Count : in Natural;
Pad : in Character := Space);
67 function Tail (Source : in Unbounded_String;
Count : in Natural;
Pad : in Character := Space)
return Unbounded_String;
68 procedure Tail (Source : in out Unbounded_String;
Count : in Natural;
Pad : in Character := Space);
69 function "*" (Left : in Natural;
Right : in Character)
return Unbounded_String;
70 function "*" (Left : in Natural;
Right : in String)
return Unbounded_String;
71 function "*" (Left : in Natural;
Right : in Unbounded_String)
return Unbounded_String;
72 private
... -- not specified by the language
end Ada.Strings.Unbounded;
72.1/2 The type Unbounded_String needs finalization (see 7.6).
73 Null_Unbounded_String represents the null String. If an object of type
Unbounded_String is not otherwise initialized, it will be initialized to the
same value as Null_Unbounded_String.
74 The function Length returns the length of the String represented by Source.
75 The type String_Access provides a (non-private) access type for explicit
processing of unbounded-length strings. The procedure Free performs an
unchecked deallocation of an object of type String_Access.
76 The function To_Unbounded_String(Source : in String) returns an
Unbounded_String that represents Source. The function
To_Unbounded_String(Length : in Natural) returns an Unbounded_String that
represents an uninitialized String whose length is Length.
77 The function To_String returns the String with lower bound 1 represented
by Source. To_String and To_Unbounded_String are related as follows:
78 * If S is a String, then To_String(To_Unbounded_String(S)) = S.
79 * If U is an Unbounded_String, then To_Unbounded_String(To_String(U)) =
U.
79.1/2 The procedure Set_Unbounded_String sets Target to an Unbounded_String
that represents Source.
80 For each of the Append procedures, the resulting string represented by the
Source parameter is given by the concatenation of the original value of Source
and the value of New_Item.
81 Each of the "&" functions returns an Unbounded_String obtained by
concatenating the string or character given or represented by one of the
parameters, with the string or character given or represented by the other
parameter, and applying To_Unbounded_String to the concatenation result string.
82 The Element, Replace_Element, and Slice subprograms have the same effect
as the corresponding bounded-length string subprograms.
82.1/2 The function Unbounded_Slice returns the slice at positions Low through
High in the string represented by Source as an Unbounded_String. The procedure
Unbounded_Slice sets Target to the Unbounded_String representing the slice at
positions Low through High in the string represented by Source. Both routines
propagate Index_Error if Low > Length(Source)+1 or High > Length(Source).
83 Each of the functions "=", "<", ">", "<=", and ">=" returns the same
result as the corresponding String operation applied to the String values
given or represented by Left and Right.
84 Each of the search subprograms (Index, Index_Non_Blank, Count, Find_Token)
has the same effect as the corresponding subprogram in Strings.Fixed applied
to the string represented by the Unbounded_String parameter.
85 The Translate function has an analogous effect to the corresponding
subprogram in Strings.Fixed. The translation is applied to the string
represented by the Unbounded_String parameter, and the result is converted
(via To_Unbounded_String) to an Unbounded_String.
86 Each of the transformation functions (Replace_Slice, Insert, Overwrite,
Delete), selector functions (Trim, Head, Tail), and constructor functions
("*") is likewise analogous to its corresponding subprogram in Strings.Fixed.
For each of the subprograms, the corresponding fixed-length string subprogram
is applied to the string represented by the Unbounded_String parameter, and
To_Unbounded_String is applied the result string.
87 For each of the procedures Translate, Replace_Slice, Insert, Overwrite,
Delete, Trim, Head, and Tail, the resulting string represented by the Source
parameter is given by the corresponding function for fixed-length strings
applied to the string represented by Source's original value.
Implementation Requirements
88 No storage associated with an Unbounded_String object shall be lost upon
assignment or scope exit.
A.4.6 String-Handling Sets and Mappings
1 The language-defined package Strings.Maps.Constants declares Character_Set
and Character_Mapping constants corresponding to classification and conversion
functions in package Characters.Handling.
Static Semantics
2 The library package Strings.Maps.Constants has the following declaration:
3/2 package Ada.Strings.Maps.Constants is
pragma Pure(Constants);
4 Control_Set : constant Character_Set;
Graphic_Set : constant Character_Set;
Letter_Set : constant Character_Set;
Lower_Set : constant Character_Set;
Upper_Set : constant Character_Set;
Basic_Set : constant Character_Set;
Decimal_Digit_Set : constant Character_Set;
Hexadecimal_Digit_Set : constant Character_Set;
Alphanumeric_Set : constant Character_Set;
Special_Set : constant Character_Set;
ISO_646_Set : constant Character_Set;
5 Lower_Case_Map : constant Character_Mapping;
--Maps to lower case for letters, else identity
Upper_Case_Map : constant Character_Mapping;
--Maps to upper case for letters, else identity
Basic_Map : constant Character_Mapping;
--Maps to basic letter for letters, else identity
6 private
... -- not specified by the language
end Ada.Strings.Maps.Constants;
7 Each of these constants represents a correspondingly named set of
characters or character mapping in Characters.Handling (see A.3.2).
A.4.7 Wide_String Handling
1/2 Facilities for handling strings of Wide_Character elements are found in
the packages Strings.Wide_Maps, Strings.Wide_Fixed, Strings.Wide_Bounded,
Strings.Wide_Unbounded, and Strings.Wide_Maps.Wide_Constants, and in the
functions Strings.Wide_Hash, Strings.Wide_Fixed.Wide_Hash,
Strings.Wide_Bounded.Wide_Hash, and Strings.Wide_Unbounded.Wide_Hash. They
provide the same string-handling operations as the corresponding packages and
functions for strings of Character elements.
Static Semantics
2 The package Strings.Wide_Maps has the following declaration.
3 package Ada.Strings.Wide_Maps is
pragma Preelaborate(Wide_Maps);
4/2 -- Representation for a set of Wide_Character values:
type Wide_Character_Set is private;
pragma Preelaborable_Initialization(Wide_Character_Set);
5 Null_Set : constant Wide_Character_Set;
6 type Wide_Character_Range is
record
Low : Wide_Character;
High : Wide_Character;
end record;
-- Represents Wide_Character range Low..High
7 type Wide_Character_Ranges is array (Positive range <>)
of Wide_Character_Range;
8 function To_Set (Ranges : in Wide_Character_Ranges)
return Wide_Character_Set;
9 function To_Set (Span : in Wide_Character_Range)
return Wide_Character_Set;
10 function To_Ranges (Set : in Wide_Character_Set)
return Wide_Character_Ranges;
11 function "=" (Left, Right : in Wide_Character_Set) return Boolean;
12 function "not" (Right : in Wide_Character_Set)
return Wide_Character_Set;
function "and" (Left, Right : in Wide_Character_Set)
return Wide_Character_Set;
function "or" (Left, Right : in Wide_Character_Set)
return Wide_Character_Set;
function "xor" (Left, Right : in Wide_Character_Set)
return Wide_Character_Set;
function "-" (Left, Right : in Wide_Character_Set)
return Wide_Character_Set;
13 function Is_In (Element : in Wide_Character;
Set : in Wide_Character_Set)
return Boolean;
14 function Is_Subset (Elements : in Wide_Character_Set;
Set : in Wide_Character_Set)
return Boolean;
15 function "<=" (Left : in Wide_Character_Set;
Right : in Wide_Character_Set)
return Boolean renames Is_Subset;
16 -- Alternative representation for a set of Wide_Character values:
subtype Wide_Character_Sequence is Wide_String;
17 function To_Set (Sequence : in Wide_Character_Sequence)
return Wide_Character_Set;
18 function To_Set (Singleton : in Wide_Character)
return Wide_Character_Set;
19 function To_Sequence (Set : in Wide_Character_Set)
return Wide_Character_Sequence;
20/2 -- Representation for a Wide_Character to Wide_Character mapping:
type Wide_Character_Mapping is private;
pragma Preelaborable_Initialization(Wide_Character_Mapping);
21 function Value (Map : in Wide_Character_Mapping;
Element : in Wide_Character)
return Wide_Character;
22 Identity : constant Wide_Character_Mapping;
23 function To_Mapping (From, To : in Wide_Character_Sequence)
return Wide_Character_Mapping;
24 function To_Domain (Map : in Wide_Character_Mapping)
return Wide_Character_Sequence;
25 function To_Range (Map : in Wide_Character_Mapping)
return Wide_Character_Sequence;
26 type Wide_Character_Mapping_Function is
access function (From : in Wide_Character) return Wide_Character;
27 private
... -- not specified by the language
end Ada.Strings.Wide_Maps;
28 The context clause for each of the packages Strings.Wide_Fixed,
Strings.Wide_Bounded, and Strings.Wide_Unbounded identifies Strings.Wide_Maps
instead of Strings.Maps.
29/2 For each of the packages Strings.Fixed, Strings.Bounded,
Strings.Unbounded, and Strings.Maps.Constants, and for functions Strings.Hash,
Strings.Fixed.Hash, Strings.Bounded.Hash, and Strings.Unbounded.Hash, the
corresponding wide string package has the same contents except that
30 * Wide_Space replaces Space
31 * Wide_Character replaces Character
32 * Wide_String replaces String
33 * Wide_Character_Set replaces Character_Set
34 * Wide_Character_Mapping replaces Character_Mapping
35 * Wide_Character_Mapping_Function replaces Character_Mapping_Function
36 * Wide_Maps replaces Maps
37 * Bounded_Wide_String replaces Bounded_String
38 * Null_Bounded_Wide_String replaces Null_Bounded_String
39 * To_Bounded_Wide_String replaces To_Bounded_String
40 * To_Wide_String replaces To_String
40.1/2 * Set_Bounded_Wide_String replaces Set_Bounded_String
41 * Unbounded_Wide_String replaces Unbounded_String
42 * Null_Unbounded_Wide_String replaces Null_Unbounded_String
43 * Wide_String_Access replaces String_Access
44 * To_Unbounded_Wide_String replaces To_Unbounded_String
44.1/2 * Set_Unbounded_Wide_String replaces Set_Unbounded_String
45 The following additional declaration is present in
Strings.Wide_Maps.Wide_Constants:
46/2 Character_Set : constant Wide_Maps.Wide_Character_Set;
--Contains each Wide_Character value WC such that
--Characters.Conversions.Is_Character(WC) is True
46.1/2 Each Wide_Character_Set constant in the package
Strings.Wide_Maps.Wide_Constants contains no values outside the Character
portion of Wide_Character. Similarly, each Wide_Character_Mapping constant in
this package is the identity mapping when applied to any element outside the
Character portion of Wide_Character.
46.2/2 Pragma Pure is replaced by pragma Preelaborate in
Strings.Wide_Maps.Wide_Constants.
NOTES
47 12 If a null Wide_Character_Mapping_Function is passed to any of the
Wide_String handling subprograms, Constraint_Error is propagated.
48/2 This paragraph was deleted.
A.4.8 Wide_Wide_String Handling
1/2 Facilities for handling strings of Wide_Wide_Character elements are found
in the packages Strings.Wide_Wide_Maps, Strings.Wide_Wide_Fixed, Strings.-
Wide_Wide_Bounded, Strings.Wide_Wide_Unbounded, and Strings.Wide_Wide_Maps.-
Wide_Wide_Constants, and in the functions Strings.Wide_Wide_Hash, Strings.-
Wide_Wide_Fixed.Wide_Wide_Hash, Strings.Wide_Wide_Bounded.Wide_Wide_Hash, and
Strings.Wide_Wide_Unbounded.Wide_Wide_Hash. They provide the same
string-handling operations as the corresponding packages and functions for
strings of Character elements.
Static Semantics
2/2 The library package Strings.Wide_Wide_Maps has the following declaration.
3/2 package Ada.Strings.Wide_Wide_Maps is
pragma Preelaborate(Wide_Wide_Maps);
4/2 -- Representation for a set of Wide_Wide_Character values:
type Wide_Wide_Character_Set is private;
pragma Preelaborable_Initialization(Wide_Wide_Character_Set);
5/2 Null_Set : constant Wide_Wide_Character_Set;
6/2 type Wide_Wide_Character_Range is
record
Low : Wide_Wide_Character;
High : Wide_Wide_Character;
end record;
-- Represents Wide_Wide_Character range Low..High
7/2 type Wide_Wide_Character_Ranges is array (Positive range <>)
of Wide_Wide_Character_Range;
8/2 function To_Set (Ranges : in Wide_Wide_Character_Ranges)
return Wide_Wide_Character_Set;
9/2 function To_Set (Span : in Wide_Wide_Character_Range)
return Wide_Wide_Character_Set;
10/2 function To_Ranges (Set : in Wide_Wide_Character_Set)
return Wide_Wide_Character_Ranges;
11/2 function "=" (Left, Right : in Wide_Wide_Character_Set) return Boolean;
12/2 function "not" (Right : in Wide_Wide_Character_Set)
return Wide_Wide_Character_Set;
function "and" (Left, Right : in Wide_Wide_Character_Set)
return Wide_Wide_Character_Set;
function "or" (Left, Right : in Wide_Wide_Character_Set)
return Wide_Wide_Character_Set;
function "xor" (Left, Right : in Wide_Wide_Character_Set)
return Wide_Wide_Character_Set;
function "-" (Left, Right : in Wide_Wide_Character_Set)
return Wide_Wide_Character_Set;
13/2 function Is_In (Element : in Wide_Wide_Character;
Set : in Wide_Wide_Character_Set)
return Boolean;
14/2 function Is_Subset (Elements : in Wide_Wide_Character_Set;
Set : in Wide_Wide_Character_Set)
return Boolean;
15/2 function "<=" (Left : in Wide_Wide_Character_Set;
Right : in Wide_Wide_Character_Set)
return Boolean renames Is_Subset;
16/2 -- Alternative representation for a set of Wide_Wide_Character values:
subtype Wide_Wide_Character_Sequence is Wide_Wide_String;
17/2 function To_Set (Sequence : in Wide_Wide_Character_Sequence)
return Wide_Wide_Character_Set;
18/2 function To_Set (Singleton : in Wide_Wide_Character)
return Wide_Wide_Character_Set;
19/2 function To_Sequence (Set : in Wide_Wide_Character_Set)
return Wide_Wide_Character_Sequence;
20/2 -- Representation for a Wide_Wide_Character to Wide_Wide_Character
-- mapping:
type Wide_Wide_Character_Mapping is private;
pragma Preelaborable_Initialization(Wide_Wide_Character_Mapping);
21/2 function Value (Map : in Wide_Wide_Character_Mapping;
Element : in Wide_Wide_Character)
return Wide_Wide_Character;
22/2 Identity : constant Wide_Wide_Character_Mapping;
23/2 function To_Mapping (From, To : in Wide_Wide_Character_Sequence)
return Wide_Wide_Character_Mapping;
24/2 function To_Domain (Map : in Wide_Wide_Character_Mapping)
return Wide_Wide_Character_Sequence;
25/2 function To_Range (Map : in Wide_Wide_Character_Mapping)
return Wide_Wide_Character_Sequence;
26/2 type Wide_Wide_Character_Mapping_Function is
access function (From : in Wide_Wide_Character)
return Wide_Wide_Character;
27/2 private
... -- not specified by the language
end Ada.Strings.Wide_Wide_Maps;
28/2 The context clause for each of the packages Strings.Wide_Wide_Fixed,
Strings.Wide_Wide_Bounded, and Strings.Wide_Wide_Unbounded identifies
Strings.Wide_Wide_Maps instead of Strings.Maps.
29/2 For each of the packages Strings.Fixed, Strings.Bounded,
Strings.Unbounded, and Strings.Maps.Constants, and for functions Strings.-
Hash, Strings.Fixed.Hash, Strings.Bounded.Hash, and Strings.Unbounded.Hash,
the corresponding wide wide string package or function has the same contents
except that
30/2 * Wide_Wide_Space replaces Space
31/2 * Wide_Wide_Character replaces Character
32/2 * Wide_Wide_String replaces String
33/2 * Wide_Wide_Character_Set replaces Character_Set
34/2 * Wide_Wide_Character_Mapping replaces Character_Mapping
35/2 * Wide_Wide_Character_Mapping_Function replaces
Character_Mapping_Function
36/2 * Wide_Wide_Maps replaces Maps
37/2 * Bounded_Wide_Wide_String replaces Bounded_String
38/2 * Null_Bounded_Wide_Wide_String replaces Null_Bounded_String
39/2 * To_Bounded_Wide_Wide_String replaces To_Bounded_String
40/2 * To_Wide_Wide_String replaces To_String
41/2 * Set_Bounded_Wide_Wide_String replaces Set_Bounded_String
42/2 * Unbounded_Wide_Wide_String replaces Unbounded_String
43/2 * Null_Unbounded_Wide_Wide_String replaces Null_Unbounded_String
44/2 * Wide_Wide_String_Access replaces String_Access
45/2 * To_Unbounded_Wide_Wide_String replaces To_Unbounded_String
46/2 * Set_Unbounded_Wide_Wide_String replaces Set_Unbounded_String
47/2 The following additional declarations are present in
Strings.Wide_Wide_Maps.Wide_Wide_Constants:
48/2 Character_Set : constant Wide_Wide_Maps.Wide_Wide_Character_Set;
-- Contains each Wide_Wide_Character value WWC such that
-- Characters.Conversions.Is_Character(WWC) is True
Wide_Character_Set : constant Wide_Wide_Maps.Wide_Wide_Character_Set;
-- Contains each Wide_Wide_Character value WWC such that
-- Characters.Conversions.Is_Wide_Character(WWC) is True
49/2 Each Wide_Wide_Character_Set constant in the package Strings.Wide_Wide_-
Maps.Wide_Wide_Constants contains no values outside the Character portion of
Wide_Wide_Character. Similarly, each Wide_Wide_Character_Mapping constant in
this package is the identity mapping when applied to any element outside the
Character portion of Wide_Wide_Character.
50/2 Pragma Pure is replaced by pragma Preelaborate in
Strings.Wide_Wide_Maps.Wide_Wide_Constants.
NOTES
51/2 13 If a null Wide_Wide_Character_Mapping_Function is passed to any of
the Wide_Wide_String handling subprograms, Constraint_Error is
propagated.
A.4.9 String Hashing
Static Semantics
1/2 The library function Strings.Hash has the following declaration:
2/2 with Ada.Containers;
function Ada.Strings.Hash (Key : String) return Containers.Hash_Type;
pragma Pure(Hash);
3/2 Returns an implementation-defined value which is a function of the
value of Key. If A and B are strings such that A equals B, Hash(A)
equals Hash(B).
4/2 The library function Strings.Fixed.Hash has the following declaration:
5/2 with Ada.Containers, Ada.Strings.Hash;
function Ada.Strings.Fixed.Hash (Key : String) return Containers.Hash_Type
renames Ada.Strings.Hash;
pragma Pure(Hash);
6/2 The generic library function Strings.Bounded.Hash has the following
declaration:
7/2 with Ada.Containers;
generic
with package Bounded is
new Ada.Strings.Bounded.Generic_Bounded_Length (<>);
function Ada.Strings.Bounded.Hash (Key : Bounded.Bounded_String)
return Containers.Hash_Type;
pragma Preelaborate(Hash);
8/2 Strings.Bounded.Hash is equivalent to the function call
Strings.Hash (Bounded.To_String (Key));
9/2 The library function Strings.Unbounded.Hash has the following declaration:
10/2 with Ada.Containers;
function Ada.Strings.Unbounded.Hash (Key : Unbounded_String)
return Containers.Hash_Type;
pragma Preelaborate(Hash);
11/2 Strings.Unbounded.Hash is equivalent to the function call
Strings.Hash (To_String (Key));
Implementation Advice
12/2 The Hash functions should be good hash functions, returning a wide spread
of values for different string values. It should be unlikely for similar
strings to return the same value.
A.5 The Numerics Packages
1 The library package Numerics is the parent of several child units that
provide facilities for mathematical computation. One child, the generic
package Generic_Elementary_Functions, is defined in A.5.1, together with
nongeneric equivalents; two others, the package Float_Random and the generic
package Discrete_Random, are defined in A.5.2. Additional (optional) children
are defined in Annex G, "Numerics".
Static Semantics
2/1 This paragraph was deleted.
3/2 package Ada.Numerics is
pragma Pure(Numerics);
Argument_Error : exception;
Pi : constant :=
3.14159_26535_89793_23846_26433_83279_50288_41971_69399_37511;
PI : constant := Pi;
e : constant :=
2.71828_18284_59045_23536_02874_71352_66249_77572_47093_69996;
end Ada.Numerics;
4 The Argument_Error exception is raised by a subprogram in a child unit of
Numerics to signal that one or more of the actual subprogram parameters are
outside the domain of the corresponding mathematical function.
Implementation Permissions
5 The implementation may specify the values of Pi and e to a larger number
of significant digits.
A.5.1 Elementary Functions
1 Implementation-defined approximations to the mathematical functions known
as the "elementary functions" are provided by the subprograms in Numerics.-
Generic_Elementary_Functions. Nongeneric equivalents of this generic package
for each of the predefined floating point types are also provided as children
of Numerics.
Static Semantics
2 The generic library package Numerics.Generic_Elementary_Functions has the
following declaration:
3 generic
type Float_Type is digits <>;
package Ada.Numerics.Generic_Elementary_Functions is
pragma Pure(Generic_Elementary_Functions);
4 function Sqrt
(X : Float_Type'Base) return Float_Type'Base;
function Log
(X : Float_Type'Base) return Float_Type'Base;
function Log
(X, Base : Float_Type'Base) return Float_Type'Base;
function Exp
(X : Float_Type'Base) return Float_Type'Base;
function "**" (Left, Right : Float_Type'Base) return Float_Type'Base;
5 function Sin
(X : Float_Type'Base) return Float_Type'Base;
function Sin
(X, Cycle : Float_Type'Base) return Float_Type'Base;
function Cos
(X : Float_Type'Base) return Float_Type'Base;
function Cos
(X, Cycle : Float_Type'Base) return Float_Type'Base;
function Tan
(X : Float_Type'Base) return Float_Type'Base;
function Tan
(X, Cycle : Float_Type'Base) return Float_Type'Base;
function Cot
(X : Float_Type'Base) return Float_Type'Base;
function Cot
(X, Cycle : Float_Type'Base) return Float_Type'Base;
6 function Arcsin
(X : Float_Type'Base) return Float_Type'Base;
function Arcsin
(X, Cycle : Float_Type'Base) return Float_Type'Base;
function Arccos
(X : Float_Type'Base) return Float_Type'Base;
function Arccos
(X, Cycle : Float_Type'Base) return Float_Type'Base;
function Arctan (Y : Float_Type'Base;
X : Float_Type'Base := 1.0)
return Float_Type'Base;
function Arctan (Y : Float_Type'Base;
X : Float_Type'Base := 1.0;
Cycle : Float_Type'Base) return Float_Type'Base;
function Arccot (X : Float_Type'Base;
Y : Float_Type'Base := 1.0)
return Float_Type'Base;
function Arccot (X : Float_Type'Base;
Y : Float_Type'Base := 1.0;
Cycle : Float_Type'Base) return Float_Type'Base;
7 function Sinh
(X : Float_Type'Base) return Float_Type'Base;
function Cosh
(X : Float_Type'Base) return Float_Type'Base;
function Tanh
(X : Float_Type'Base) return Float_Type'Base;
function Coth
(X : Float_Type'Base) return Float_Type'Base;
function Arcsinh
(X : Float_Type'Base) return Float_Type'Base;
function Arccosh
(X : Float_Type'Base) return Float_Type'Base;
function Arctanh
(X : Float_Type'Base) return Float_Type'Base;
function Arccoth
(X : Float_Type'Base) return Float_Type'Base;
8 end Ada.Numerics.Generic_Elementary_Functions;
9/1 The library package Numerics.Elementary_Functions is declared pure and
defines the same subprograms as Numerics.Generic_Elementary_Functions, except
that the predefined type Float is systematically substituted for
Float_Type'Base throughout. Nongeneric equivalents of Numerics.Generic_-
Elementary_Functions for each of the other predefined floating point types are
defined similarly, with the names Numerics.Short_Elementary_Functions,
Numerics.Long_Elementary_Functions, etc.
10 The functions have their usual mathematical meanings. When the Base
parameter is specified, the Log function computes the logarithm to the given
base; otherwise, it computes the natural logarithm. When the Cycle parameter
is specified, the parameter X of the forward trigonometric functions (Sin,
Cos, Tan, and Cot) and the results of the inverse trigonometric functions
(Arcsin, Arccos, Arctan, and Arccot) are measured in units such that a full
cycle of revolution has the given value; otherwise, they are measured in
radians.
11 The computed results of the mathematically multivalued functions are
rendered single-valued by the following conventions, which are meant to imply
the principal branch:
12 * The results of the Sqrt and Arccosh functions and that of the
exponentiation operator are nonnegative.
13 * The result of the Arcsin function is in the quadrant containing the
point (1.0, x), where x is the value of the parameter X. This quadrant
is I or IV; thus, the range of the Arcsin function is approximately
-PI/2.0 to PI/2.0 (-Cycle/4.0 to Cycle/4.0, if the parameter Cycle is
specified).
14 * The result of the Arccos function is in the quadrant containing the
point (x, 1.0), where x is the value of the parameter X. This quadrant
is I or II; thus, the Arccos function ranges from 0.0 to approximately
PI (Cycle/2.0, if the parameter Cycle is specified).
15 * The results of the Arctan and Arccot functions are in the quadrant
containing the point (x, y), where x and y are the values of the
parameters X and Y, respectively. This may be any quadrant (I through
IV) when the parameter X (resp., Y) of Arctan (resp., Arccot) is
specified, but it is restricted to quadrants I and IV (resp., I and
II) when that parameter is omitted. Thus, the range when that
parameter is specified is approximately -PI to PI (-Cycle/2.0 to
Cycle/2.0, if the parameter Cycle is specified); when omitted, the
range of Arctan (resp., Arccot) is that of Arcsin (resp., Arccos), as
given above. When the point (x, y) lies on the negative x-axis, the
result approximates
16 * PI (resp., -PI) when the sign of the parameter Y is positive
(resp., negative), if Float_Type'Signed_Zeros is True;
17 * PI, if Float_Type'Signed_Zeros is False.
18 (In the case of the inverse trigonometric functions, in which a result
lying on or near one of the axes may not be exactly representable, the
approximation inherent in computing the result may place it in an adjacent
quadrant, close to but on the wrong side of the axis.)
Dynamic Semantics
19 The exception Numerics.Argument_Error is raised, signaling a parameter
value outside the domain of the corresponding mathematical function, in the
following cases:
20 * by any forward or inverse trigonometric function with specified cycle,
when the value of the parameter Cycle is zero or negative;
21 * by the Log function with specified base, when the value of the
parameter Base is zero, one, or negative;
22 * by the Sqrt and Log functions, when the value of the parameter X is
negative;
23 * by the exponentiation operator, when the value of the left operand is
negative or when both operands have the value zero;
24 * by the Arcsin, Arccos, and Arctanh functions, when the absolute value
of the parameter X exceeds one;
25 * by the Arctan and Arccot functions, when the parameters X and Y both
have the value zero;
26 * by the Arccosh function, when the value of the parameter X is less
than one; and
27 * by the Arccoth function, when the absolute value of the parameter X is
less than one.
28 The exception Constraint_Error is raised, signaling a pole of the
mathematical function (analogous to dividing by zero), in the following cases,
provided that Float_Type'Machine_Overflows is True:
29 * by the Log, Cot, and Coth functions, when the value of the parameter X
is zero;
30 * by the exponentiation operator, when the value of the left operand is
zero and the value of the exponent is negative;
31 * by the Tan function with specified cycle, when the value of the
parameter X is an odd multiple of the quarter cycle;
32 * by the Cot function with specified cycle, when the value of the
parameter X is zero or a multiple of the half cycle; and
33 * by the Arctanh and Arccoth functions, when the absolute value of the
parameter X is one.
34 Constraint_Error can also be raised when a finite result overflows (see
G.2.4); this may occur for parameter values sufficiently near poles, and, in
the case of some of the functions, for parameter values with sufficiently
large magnitudes. When Float_Type'Machine_Overflows is False, the result at
poles is unspecified.
35 When one parameter of a function with multiple parameters represents a
pole and another is outside the function's domain, the latter takes precedence
(i.e., Numerics.Argument_Error is raised).
Implementation Requirements
36 In the implementation of Numerics.Generic_Elementary_Functions, the range
of intermediate values allowed during the calculation of a final result shall
not be affected by any range constraint of the subtype Float_Type.
37 In the following cases, evaluation of an elementary function shall yield
the prescribed result, provided that the preceding rules do not call for an
exception to be raised:
38 * When the parameter X has the value zero, the Sqrt, Sin, Arcsin, Tan,
Sinh, Arcsinh, Tanh, and Arctanh functions yield a result of zero, and
the Exp, Cos, and Cosh functions yield a result of one.
39 * When the parameter X has the value one, the Sqrt function yields a
result of one, and the Log, Arccos, and Arccosh functions yield a
result of zero.
40 * When the parameter Y has the value zero and the parameter X has a
positive value, the Arctan and Arccot functions yield a result of zero.
41 * The results of the Sin, Cos, Tan, and Cot functions with specified
cycle are exact when the mathematical result is zero; those of the
first two are also exact when the mathematical result is ± 1.0.
42 * Exponentiation by a zero exponent yields the value one. Exponentiation
by a unit exponent yields the value of the left operand.
Exponentiation of the value one yields the value one. Exponentiation
of the value zero yields the value zero.
43 Other accuracy requirements for the elementary functions, which apply only
in implementations conforming to the Numerics Annex, and then only in the "
strict" mode defined there (see G.2), are given in G.2.4.
44 When Float_Type'Signed_Zeros is True, the sign of a zero result shall be
as follows:
45 * A prescribed zero result delivered at the origin by one of the odd
functions (Sin, Arcsin, Sinh, Arcsinh, Tan, Arctan or Arccot as a
function of Y when X is fixed and positive, Tanh, and Arctanh) has the
sign of the parameter X (Y, in the case of Arctan or Arccot).
46 * A prescribed zero result delivered by one of the odd functions away
from the origin, or by some other elementary function, has an
implementation-defined sign.
47 * A zero result that is not a prescribed result (i.e., one that results
from rounding or underflow) has the correct mathematical sign.
Implementation Permissions
48 The nongeneric equivalent packages may, but need not, be actual
instantiations of the generic package for the appropriate predefined type.
A.5.2 Random Number Generation
1 Facilities for the generation of pseudo-random floating point numbers are
provided in the package Numerics.Float_Random; the generic package
Numerics.Discrete_Random provides similar facilities for the generation of
pseudo-random integers and pseudo-random values of enumeration types. For
brevity, pseudo-random values of any of these types are called random numbers.
2 Some of the facilities provided are basic to all applications of random
numbers. These include a limited private type each of whose objects serves as
the generator of a (possibly distinct) sequence of random numbers; a function
to obtain the "next" random number from a given sequence of random numbers
(that is, from its generator); and subprograms to initialize or reinitialize a
given generator to a time-dependent state or a state denoted by a single
integer.
3 Other facilities are provided specifically for advanced applications.
These include subprograms to save and restore the state of a given generator;
a private type whose objects can be used to hold the saved state of a
generator; and subprograms to obtain a string representation of a given
generator state, or, given such a string representation, the corresponding
state.
Static Semantics
4 The library package Numerics.Float_Random has the following declaration:
5 package Ada.Numerics.Float_Random is
6 -- Basic facilities
7 type Generator is limited private;
8 subtype Uniformly_Distributed is Float range 0.0 .. 1.0;
function Random (Gen : Generator) return Uniformly_Distributed;
9 procedure Reset (Gen : in Generator;
Initiator : in Integer);
procedure Reset (Gen : in Generator);
10 -- Advanced facilities
11 type State is private;
12 procedure Save (Gen : in Generator;
To_State : out State);
procedure Reset (Gen : in Generator;
From_State : in State);
13 Max_Image_Width : constant := implementation-defined integer value;
14 function Image (Of_State : State) return String;
function Value (Coded_State : String) return State;
15 private
... -- not specified by the language
end Ada.Numerics.Float_Random;
15.1/2 The type Generator needs finalization (see 7.6).
16 The generic library package Numerics.Discrete_Random has the following
declaration:
17
generic
type Result_Subtype is (<>);
package Ada.Numerics.Discrete_Random is
18 -- Basic facilities
19 type Generator is limited private;
20 function Random (Gen : Generator) return Result_Subtype;
21 procedure Reset (Gen : in Generator;
Initiator : in Integer);
procedure Reset (Gen : in Generator);
22 -- Advanced facilities
23 type State is private;
24 procedure Save (Gen : in Generator;
To_State : out State);
procedure Reset (Gen : in Generator;
From_State : in State);
25 Max_Image_Width : constant := implementation-defined integer value;
26 function Image (Of_State : State) return String;
function Value (Coded_State : String) return State;
27 private
... -- not specified by the language
end Ada.Numerics.Discrete_Random;
27.1/2 The type Generator needs finalization (see 7.6) in every instantiation
of Numerics.Discrete_Random.
28 An object of the limited private type Generator is associated with a
sequence of random numbers. Each generator has a hidden (internal) state,
which the operations on generators use to determine the position in the
associated sequence. All generators are implicitly initialized to an
unspecified state that does not vary from one program execution to another;
they may also be explicitly initialized, or reinitialized, to a time-dependent
state, to a previously saved state, or to a state uniquely denoted by an
integer value.
29 An object of the private type State can be used to hold the internal state
of a generator. Such objects are only needed if the application is designed to
save and restore generator states or to examine or manufacture them.
30 The operations on generators affect the state and therefore the future
values of the associated sequence. The semantics of the operations on
generators and states are defined below.
31 function Random (Gen : Generator) return Uniformly_Distributed;
function Random (Gen : Generator) return Result_Subtype;
32 Obtains the "next" random number from the given generator,
relative to its current state, according to an
implementation-defined algorithm. The result of the function in
Numerics.Float_Random is delivered as a value of the subtype
Uniformly_Distributed, which is a subtype of the predefined type
Float having a range of 0.0 .. 1.0. The result of the function in
an instantiation of Numerics.Discrete_Random is delivered as a
value of the generic formal subtype Result_Subtype.
33 procedure Reset (Gen : in Generator;
Initiator : in Integer);
procedure Reset (Gen : in Generator);
34 Sets the state of the specified generator to one that is an
unspecified function of the value of the parameter Initiator (or
to a time-dependent state, if only a generator parameter is
specified). The latter form of the procedure is known as the
time-dependent Reset procedure.
35 procedure Save (Gen : in Generator;
To_State : out State);
procedure Reset (Gen : in Generator;
From_State : in State);
36 Save obtains the current state of a generator. Reset gives a
generator the specified state. A generator that is reset to a
state previously obtained by invoking Save is restored to the
state it had when Save was invoked.
37 function Image (Of_State : State) return String;
function Value (Coded_State : String) return State;
38 Image provides a representation of a state coded (in an
implementation-defined way) as a string whose length is bounded by
the value of Max_Image_Width. Value is the inverse of Image:
Value(Image(S)) = S for each state S that can be obtained from a
generator by invoking Save.
Dynamic Semantics
39 Instantiation of Numerics.Discrete_Random with a subtype having a null
range raises Constraint_Error.
40/1 This paragraph was deleted.
Bounded (Run-Time) Errors
40.1/1 It is a bounded error to invoke Value with a string that is not the
image of any generator state. If the error is detected, Constraint_Error or
Program_Error is raised. Otherwise, a call to Reset with the resulting state
will produce a generator such that calls to Random with this generator will
produce a sequence of values of the appropriate subtype, but which might not
be random in character. That is, the sequence of values might not fulfill the
implementation requirements of this subclause.
Implementation Requirements
41 A sufficiently long sequence of random numbers obtained by successive
calls to Random is approximately uniformly distributed over the range of the
result subtype.
42 The Random function in an instantiation of Numerics.Discrete_Random is
guaranteed to yield each value in its result subtype in a finite number of
calls, provided that the number of such values does not exceed 2 (15).
43 Other performance requirements for the random number generator, which
apply only in implementations conforming to the Numerics Annex, and then only
in the "strict" mode defined there (see G.2), are given in G.2.5.
Documentation Requirements
44 No one algorithm for random number generation is best for all
applications. To enable the user to determine the suitability of the random
number generators for the intended application, the implementation shall
describe the algorithm used and shall give its period, if known exactly, or a
lower bound on the period, if the exact period is unknown. Periods that are so
long that the periodicity is unobservable in practice can be described in such
terms, without giving a numerical bound.
45 The implementation also shall document the minimum time interval between
calls to the time-dependent Reset procedure that are guaranteed to initiate
different sequences, and it shall document the nature of the strings that
Value will accept without raising Constraint_Error.
Implementation Advice
46 Any storage associated with an object of type Generator should be
reclaimed on exit from the scope of the object.
47 If the generator period is sufficiently long in relation to the number of
distinct initiator values, then each possible value of Initiator passed to
Reset should initiate a sequence of random numbers that does not, in a
practical sense, overlap the sequence initiated by any other value. If this is
not possible, then the mapping between initiator values and generator states
should be a rapidly varying function of the initiator value.
NOTES
48 14 If two or more tasks are to share the same generator, then the
tasks have to synchronize their access to the generator as for any
shared variable (see 9.10).
49 15 Within a given implementation, a repeatable random number sequence
can be obtained by relying on the implicit initialization of
generators or by explicitly initializing a generator with a repeatable
initiator value. Different sequences of random numbers can be obtained
from a given generator in different program executions by explicitly
initializing the generator to a time-dependent state.
50 16 A given implementation of the Random function in
Numerics.Float_Random may or may not be capable of delivering the
values 0.0 or 1.0. Portable applications should assume that these
values, or values sufficiently close to them to behave
indistinguishably from them, can occur. If a sequence of random
integers from some fixed range is needed, the application should use
the Random function in an appropriate instantiation of
Numerics.Discrete_Random, rather than transforming the result of the
Random function in Numerics.Float_Random. However, some applications
with unusual requirements, such as for a sequence of random integers
each drawn from a different range, will find it more convenient to
transform the result of the floating point Random function. For M >=
1, the expression
51 Integer(Float(M) * Random(G)) mod M
52 transforms the result of Random(G) to an integer uniformly distributed
over the range 0 .. M-1; it is valid even if Random delivers 0.0 or
1.0. Each value of the result range is possible, provided that M is
not too large. Exponentially distributed (floating point) random
numbers with mean and standard deviation 1.0 can be obtained by the
transformation
53/2 -Log(Random(G) + Float'Model_Small)
54 where Log comes from Numerics.Elementary_Functions (see A.5.1); in
this expression, the addition of Float'Model_Small avoids the
exception that would be raised were Log to be given the value zero,
without affecting the result (in most implementations) when Random
returns a nonzero value.
Examples
55 Example of a program that plays a simulated dice game:
56 with Ada.Numerics.Discrete_Random;
procedure Dice_Game is
subtype Die is Integer range 1 .. 6;
subtype Dice is Integer range 2*Die'First .. 2*Die'Last;
package Random_Die is new Ada.Numerics.Discrete_Random (Die);
use Random_Die;
G : Generator;
D : Dice;
begin
Reset (G); -- Start the generator in a unique state in each run
loop
-- Roll a pair of dice; sum and process the results
D := Random(G) + Random(G);
...
end loop;
end Dice_Game;
57 Example of a program that simulates coin tosses:
58 with Ada.Numerics.Discrete_Random;
procedure Flip_A_Coin is
type Coin is (Heads, Tails);
package Random_Coin is new Ada.Numerics.Discrete_Random (Coin);
use Random_Coin;
G : Generator;
begin
Reset (G); -- Start the generator in a unique state in each run
loop
-- Toss a coin and process the result
case Random(G) is
when Heads =>
...
when Tails =>
...
end case;
...
end loop;
end Flip_A_Coin;
59 Example of a parallel simulation of a physical system, with a separate
generator of event probabilities in each task:
60 with Ada.Numerics.Float_Random;
procedure Parallel_Simulation is
use Ada.Numerics.Float_Random;
task type Worker is
entry Initialize_Generator (Initiator : in Integer);
...
end Worker;
W : array (1 .. 10) of Worker;
task body Worker is
G : Generator;
Probability_Of_Event : Uniformly_Distributed;
begin
accept Initialize_Generator (Initiator : in Integer) do
Reset (G, Initiator);
end Initialize_Generator;
loop
...
Probability_Of_Event := Random(G);
...
end loop;
end Worker;
begin
-- Initialize the generators in the Worker tasks to different states
for I in W'Range loop
W(I).Initialize_Generator (I);
end loop;
... -- Wait for the Worker tasks to terminate
end Parallel_Simulation;
NOTES
61 17 Notes on the last example: Although each Worker task initializes
its generator to a different state, those states will be the same in
every execution of the program. The generator states can be
initialized uniquely in each program execution by instantiating
Ada.Numerics.Discrete_Random for the type Integer in the main
procedure, resetting the generator obtained from that instance to a
time-dependent state, and then using random integers obtained from
that generator to initialize the generators in each Worker task.
A.5.3 Attributes of Floating Point Types
Static Semantics
1 The following representation-oriented attributes are defined for every
subtype S of a floating point type T.
2 S'Machine_Radix
Yields the radix of the hardware representation of the type T.
The value of this attribute is of the type universal_integer.
3 The values of other representation-oriented attributes of a floating point
subtype, and of the "primitive function" attributes of a floating point
subtype described later, are defined in terms of a particular representation
of nonzero values called the canonical form. The canonical form (for the type
T) is the form
± mantissa · T'Machine_Radix(exponent)
where
4 * mantissa is a fraction in the number base T'Machine_Radix, the first
digit of which is nonzero, and
5 * exponent is an integer.
6 S'Machine_Mantissa
Yields the largest value of p such that every value
expressible in the canonical form (for the type T), having a
p-digit mantissa and an exponent between T'Machine_Emin and
T'Machine_Emax, is a machine number (see 3.5.7) of the type T.
This attribute yields a value of the type universal_integer.
7 S'Machine_Emin
Yields the smallest (most negative) value of exponent such
that every value expressible in the canonical form (for the
type T), having a mantissa of T'Machine_Mantissa digits, is a
machine number (see 3.5.7) of the type T. This attribute
yields a value of the type universal_integer.
8 S'Machine_Emax
Yields the largest (most positive) value of exponent such that
every value expressible in the canonical form (for the type
T), having a mantissa of T'Machine_Mantissa digits, is a
machine number (see 3.5.7) of the type T. This attribute
yields a value of the type universal_integer.
9 S'Denorm Yields the value True if every value expressible in the form
± mantissa · T'Machine_Radix(T'Machine_Emin)
where mantissa is a nonzero T'Machine_Mantissa-digit fraction
in the number base T'Machine_Radix, the first digit of which
is zero, is a machine number (see 3.5.7) of the type T; yields
the value False otherwise. The value of this attribute is of
the predefined type Boolean.
10 The values described by the formula in the definition of S'Denorm are
called denormalized numbers. A nonzero machine number that is not a
denormalized number is a normalized number. A normalized number x of a given
type T is said to be represented in canonical form when it is expressed in the
canonical form (for the type T) with a mantissa having T'Machine_Mantissa
digits; the resulting form is the canonical-form representation of x.
11 S'Machine_Rounds
Yields the value True if rounding is performed on inexact
results of every predefined operation that yields a result of
the type T; yields the value False otherwise. The value of
this attribute is of the predefined type Boolean.
12 S'Machine_Overflows
Yields the value True if overflow and divide-by-zero are
detected and reported by raising Constraint_Error for every
predefined operation that yields a result of the type T;
yields the value False otherwise. The value of this attribute
is of the predefined type Boolean.
13 S'Signed_Zeros
Yields the value True if the hardware representation for the
type T has the capability of representing both positively and
negatively signed zeros, these being generated and used by the
predefined operations of the type T as specified in IEC
559:1989; yields the value False otherwise. The value of this
attribute is of the predefined type Boolean.
14 For every value x of a floating point type T, the normalized exponent of x
is defined as follows:
15 * the normalized exponent of zero is (by convention) zero;
16 * for nonzero x, the normalized exponent of x is the unique integer k
such that T'Machine_Radix(k-1) <= |x| < T'Machine_Radix(k).
17 The following primitive function attributes are defined for any subtype S
of a floating point type T.
18 S'Exponent S'Exponent denotes a function with the following
specification:
19 function S'Exponent (X : T)
return universal_integer
20 The function yields the normalized exponent of X.
21 S'Fraction S'Fraction denotes a function with the following
specification:
22 function S'Fraction (X : T)
return T
23 The function yields the value X · T'Machine_Radix(-k), where k
is the normalized exponent of X. A zero result, which can only
occur when X is zero, has the sign of X.
24 S'Compose S'Compose denotes a function with the following specification:
25 function S'Compose (Fraction : T;
Exponent : universal_integer)
return T
26 Let v be the value Fraction · T'Machine_Radix(Exponent-k),
where k is the normalized exponent of Fraction. If v is a
machine number of the type T, or if |v| >= T'Model_Small, the
function yields v; otherwise, it yields either one of the
machine numbers of the type T adjacent to v. Constraint_Error
is optionally raised if v is outside the base range of S. A
zero result has the sign of Fraction when S'Signed_Zeros is
True.
27 S'Scaling S'Scaling denotes a function with the following specification:
28 function S'Scaling (X : T;
Adjustment : universal_integer)
return T
29 Let v be the value X · T'Machine_Radix(Adjustment). If v is a
machine number of the type T, or if |v| >= T'Model_Small, the
function yields v; otherwise, it yields either one of the
machine numbers of the type T adjacent to v. Constraint_Error
is optionally raised if v is outside the base range of S. A
zero result has the sign of X when S'Signed_Zeros is True.
30 S'Floor S'Floor denotes a function with the following specification:
31 function S'Floor (X : T)
return T
32 The function yields the value Floor(X), i.e., the largest
(most positive) integral value less than or equal to X. When X
is zero, the result has the sign of X; a zero result otherwise
has a positive sign.
33 S'Ceiling S'Ceiling denotes a function with the following specification:
34 function S'Ceiling (X : T)
return T
35 The function yields the value Ceiling(X), i.e., the smallest
(most negative) integral value greater than or equal to X.
When X is zero, the result has the sign of X; a zero result
otherwise has a negative sign when S'Signed_Zeros is True.
36 S'Rounding S'Rounding denotes a function with the following
specification:
37 function S'Rounding (X : T)
return T
38 The function yields the integral value nearest to X, rounding
away from zero if X lies exactly halfway between two integers.
A zero result has the sign of X when S'Signed_Zeros is True.
39 S'Unbiased_Rounding
S'Unbiased_Rounding denotes a function with the following
specification:
40 function S'Unbiased_Rounding (X : T)
return T
41 The function yields the integral value nearest to X, rounding
toward the even integer if X lies exactly halfway between two
integers. A zero result has the sign of X when S'Signed_Zeros
is True.
41.1/2 S'Machine_Rounding
S'Machine_Rounding denotes a function with the following
specification:
41.2/2 function S'Machine_Rounding (X : T)
return T
41.3/2 The function yields the integral value nearest to X. If X lies
exactly halfway between two integers, one of those integers is
returned, but which of them is returned is unspecified. A zero
result has the sign of X when S'Signed_Zeros is True. This
function provides access to the rounding behavior which is
most efficient on the target processor.
42 S'Truncation
S'Truncation denotes a function with the following
specification:
43 function S'Truncation (X : T)
return T
44 The function yields the value Ceiling(X) when X is negative,
and Floor(X) otherwise. A zero result has the sign of X when
S'Signed_Zeros is True.
45 S'Remainder S'Remainder denotes a function with the following
specification:
46 function S'Remainder (X, Y : T)
return T
47 For nonzero Y, let v be the value X - n · Y, where n is the
integer nearest to the exact value of X/Y; if |n - X/Y| = 1/2,
then n is chosen to be even. If v is a machine number of the
type T, the function yields v; otherwise, it yields zero.
Constraint_Error is raised if Y is zero. A zero result has the
sign of X when S'Signed_Zeros is True.
48 S'Adjacent S'Adjacent denotes a function with the following
specification:
49 function S'Adjacent (X, Towards : T)
return T
50 If Towards = X, the function yields X; otherwise, it yields
the machine number of the type T adjacent to X in the
direction of Towards, if that machine number exists. If the
result would be outside the base range of S, Constraint_Error
is raised. When T'Signed_Zeros is True, a zero result has the
sign of X. When Towards is zero, its sign has no bearing on
the result.
51 S'Copy_Sign S'Copy_Sign denotes a function with the following
specification:
52 function S'Copy_Sign (Value, Sign : T)
return T
53 If the value of Value is nonzero, the function yields a result
whose magnitude is that of Value and whose sign is that of
Sign; otherwise, it yields the value zero. Constraint_Error is
optionally raised if the result is outside the base range of
S. A zero result has the sign of Sign when S'Signed_Zeros is
True.
54 S'Leading_Part
S'Leading_Part denotes a function with the following
specification:
55 function S'Leading_Part (X : T;
Radix_Digits : universal_integer)
return T
56 Let v be the value T'Machine_Radix(k-Radix_Digits), where k is
the normalized exponent of X. The function yields the value
57 * Floor(X/v) · v, when X is nonnegative and Radix_Digits is
positive;
58 * Ceiling(X/v) · v, when X is negative and Radix_Digits is
positive.
59 Constraint_Error is raised when Radix_Digits is zero or
negative. A zero result, which can only occur when X is zero,
has the sign of X.
60 S'Machine S'Machine denotes a function with the following specification:
61 function S'Machine (X : T)
return T
62 If X is a machine number of the type T, the function yields X;
otherwise, it yields the value obtained by rounding or
truncating X to either one of the adjacent machine numbers of
the type T. Constraint_Error is raised if rounding or
truncating X to the precision of the machine numbers results
in a value outside the base range of S. A zero result has the
sign of X when S'Signed_Zeros is True.
63 The following model-oriented attributes are defined for any subtype S of a
floating point type T.
64 S'Model_Mantissa
If the Numerics Annex is not supported, this attribute yields
an implementation defined value that is greater than or equal
to Ceiling(d · log(10) / log(T'Machine_Radix)) + 1, where d is
the requested decimal precision of T, and less than or equal
to the value of T'Machine_Mantissa. See G.2.2 for further
requirements that apply to implementations supporting the
Numerics Annex. The value of this attribute is of the type
universal_integer.
65 S'Model_Emin
If the Numerics Annex is not supported, this attribute yields
an implementation defined value that is greater than or equal
to the value of T'Machine_Emin. See G.2.2 for further
requirements that apply to implementations supporting the
Numerics Annex. The value of this attribute is of the type
universal_integer.
66 S'Model_Epsilon
Yields the value T'Machine_Radix(1 - T'Model_Mantissa). The
value of this attribute is of the type universal_real.
67 S'Model_Small
Yields the value T'Machine_Radix(T'Model_Emin - 1). The value
of this attribute is of the type universal_real.
68 S'Model S'Model denotes a function with the following specification:
69 function S'Model (X : T)
return T
70 If the Numerics Annex is not supported, the meaning of this
attribute is implementation defined; see G.2.2 for the
definition that applies to implementations supporting the
Numerics Annex.
71 S'Safe_First
Yields the lower bound of the safe range (see 3.5.7) of the
type T. If the Numerics Annex is not supported, the value of
this attribute is implementation defined; see G.2.2 for the
definition that applies to implementations supporting the
Numerics Annex. The value of this attribute is of the type
universal_real.
72 S'Safe_Last Yields the upper bound of the safe range (see 3.5.7) of the
type T. If the Numerics Annex is not supported, the value of
this attribute is implementation defined; see G.2.2 for the
definition that applies to implementations supporting the
Numerics Annex. The value of this attribute is of the type
universal_real.
A.5.4 Attributes of Fixed Point Types
Static Semantics
1 The following representation-oriented attributes are defined for every
subtype S of a fixed point type T.
2 S'Machine_Radix
Yields the radix of the hardware representation of the type T.
The value of this attribute is of the type universal_integer.
3 S'Machine_Rounds
Yields the value True if rounding is performed on inexact
results of every predefined operation that yields a result of
the type T; yields the value False otherwise. The value of
this attribute is of the predefined type Boolean.
4 S'Machine_Overflows
Yields the value True if overflow and divide-by-zero are
detected and reported by raising Constraint_Error for every
predefined operation that yields a result of the type T;
yields the value False otherwise. The value of this attribute
is of the predefined type Boolean.
A.6 Input-Output
1/2 Input-output is provided through language-defined packages, each of which
is a child of the root package Ada. The generic packages Sequential_IO and
Direct_IO define input-output operations applicable to files containing
elements of a given type. The generic package Storage_IO supports reading from
and writing to an in-memory buffer. Additional operations for text
input-output are supplied in the packages Text_IO, Wide_Text_IO, and
Wide_Wide_Text_IO. Heterogeneous input-output is provided through the child
packages Streams.Stream_IO and Text_IO.Text_Streams (see also 13.13). The
package IO_Exceptions defines the exceptions needed by the predefined
input-output packages.
A.7 External Files and File Objects
Static Semantics
1 Values input from the external environment of the program, or output to
the external environment, are considered to occupy external files. An external
file can be anything external to the program that can produce a value to be
read or receive a value to be written. An external file is identified by a
string (the name). A second string (the form) gives further system-dependent
characteristics that may be associated with the file, such as the physical
organization or access rights. The conventions governing the interpretation of
such strings shall be documented.
2 Input and output operations are expressed as operations on objects of some
file type, rather than directly in terms of the external files. In the
remainder of this section, the term file is always used to refer to a file
object; the term external file is used otherwise.
3 Input-output for sequential files of values of a single element type is
defined by means of the generic package Sequential_IO. In order to define
sequential input-output for a given element type, an instantiation of this
generic unit, with the given type as actual parameter, has to be declared. The
resulting package contains the declaration of a file type (called File_Type)
for files of such elements, as well as the operations applicable to these
files, such as the Open, Read, and Write procedures.
4/2 Input-output for direct access files is likewise defined by a generic
package called Direct_IO. Input-output in human-readable form is defined by
the (nongeneric) packages Text_IO for Character and String data, Wide_Text_IO
for Wide_Character and Wide_String data, and Wide_Wide_Text_IO for
Wide_Wide_Character and Wide_Wide_String data. Input-output for files
containing streams of elements representing values of possibly different types
is defined by means of the (nongeneric) package Streams.Stream_IO.
5 Before input or output operations can be performed on a file, the file
first has to be associated with an external file. While such an association is
in effect, the file is said to be open, and otherwise the file is said to be
closed.
6 The language does not define what happens to external files after the
completion of the main program and all the library tasks (in particular, if
corresponding files have not been closed). The effect of input-output for
access types is unspecified.
7 An open file has a current mode, which is a value of one of the following
enumeration types:
8 type File_Mode is (In_File, Inout_File, Out_File); -- for Direct_IO
9 These values correspond respectively to the cases where only
reading, both reading and writing, or only writing are to be
performed.
10/2 type File_Mode is (In_File, Out_File, Append_File);
-- for Sequential_IO, Text_IO, Wide_Text_IO, Wide_Wide_Text_IO, and Stream_IO
11 These values correspond respectively to the cases where only
reading, only writing, or only appending are to be performed.
12 The mode of a file can be changed.
13/2 Several file management operations are common to Sequential_IO,
Direct_IO, Text_IO, Wide_Text_IO, and Wide_Wide_Text_IO. These operations are
described in subclause A.8.2 for sequential and direct files. Any additional
effects concerning text input-output are described in subclause A.10.2.
14 The exceptions that can be propagated by the execution of an input-output
subprogram are defined in the package IO_Exceptions; the situations in which
they can be propagated are described following the description of the
subprogram (and in clause A.13). The exceptions Storage_Error and
Program_Error may be propagated. (Program_Error can only be propagated due to
errors made by the caller of the subprogram.) Finally, exceptions can be
propagated in certain implementation-defined situations.
NOTES
15/2 18 Each instantiation of the generic packages Sequential_IO and
Direct_IO declares a different type File_Type. In the case of Text_IO,
Wide_Text_IO, Wide_Wide_Text_IO, and Streams.Stream_IO, the
corresponding type File_Type is unique.
16 19 A bidirectional device can often be modeled as two sequential
files associated with the device, one of mode In_File, and one of mode
Out_File. An implementation may restrict the number of files that may
be associated with a given external file.
A.8 Sequential and Direct Files
Static Semantics
1/2 Two kinds of access to external files are defined in this subclause:
sequential access and direct access. The corresponding file types and the
associated operations are provided by the generic packages Sequential_IO and
Direct_IO. A file object to be used for sequential access is called a
sequential file, and one to be used for direct access is called a direct file.
Access to stream files is described in A.12.1.
2 For sequential access, the file is viewed as a sequence of values that are
transferred in the order of their appearance (as produced by the program or by
the external environment). When the file is opened with mode In_File or
Out_File, transfer starts respectively from or to the beginning of the file.
When the file is opened with mode Append_File, transfer to the file starts
after the last element of the file.
3 For direct access, the file is viewed as a set of elements occupying
consecutive positions in linear order; a value can be transferred to or from
an element of the file at any selected position. The position of an element is
specified by its index, which is a number, greater than zero, of the
implementation-defined integer type Count. The first element, if any, has
index one; the index of the last element, if any, is called the current size;
the current size is zero if there are no elements. The current size is a
property of the external file.
4 An open direct file has a current index, which is the index that will be
used by the next read or write operation. When a direct file is opened, the
current index is set to one. The current index of a direct file is a property
of a file object, not of an external file.
A.8.1 The Generic Package Sequential_IO
Static Semantics
1 The generic library package Sequential_IO has the following declaration:
2 with Ada.IO_Exceptions;
generic
type Element_Type(<>) is private;
package Ada.Sequential_IO is
3 type File_Type is limited private;
4 type File_Mode is (In_File, Out_File, Append_File);
5 -- File management
6 procedure Create(File : in out File_Type;
Mode : in File_Mode := Out_File;
Name : in String := "";
Form : in String := "");
7 procedure Open (File : in out File_Type;
Mode : in File_Mode;
Name : in String;
Form : in String := "");
8 procedure Close (File : in out File_Type);
procedure Delete(File : in out File_Type);
procedure Reset (File : in out File_Type; Mode : in File_Mode);
procedure Reset (File : in out File_Type);
9 function Mode (File : in File_Type) return File_Mode;
function Name (File : in File_Type) return String;
function Form (File : in File_Type) return String;
10 function Is_Open(File : in File_Type) return Boolean;
11 -- Input and output operations
12 procedure Read (File : in File_Type; Item : out Element_Type);
procedure Write (File : in File_Type; Item : in Element_Type);
13 function End_Of_File(File : in File_Type) return Boolean;
14 -- Exceptions
15 Status_Error : exception renames IO_Exceptions.Status_Error;
Mode_Error : exception renames IO_Exceptions.Mode_Error;
Name_Error : exception renames IO_Exceptions.Name_Error;
Use_Error : exception renames IO_Exceptions.Use_Error;
Device_Error : exception renames IO_Exceptions.Device_Error;
End_Error : exception renames IO_Exceptions.End_Error;
Data_Error : exception renames IO_Exceptions.Data_Error;
16 private
... -- not specified by the language
end Ada.Sequential_IO;
17/2 The type File_Type needs finalization (see 7.6) in every instantiation of
Sequential_IO.
A.8.2 File Management
Static Semantics
1 The procedures and functions described in this subclause provide for the
control of external files; their declarations are repeated in each of the
packages for sequential, direct, text, and stream input-output. For text
input-output, the procedures Create, Open, and Reset have additional effects
described in subclause A.10.2.
2 procedure Create(File : in out File_Type;
Mode : in File_Mode := default_mode;
Name : in String := "";
Form : in String := "");
3/2 Establishes a new external file, with the given name and form, and
associates this external file with the given file. The given file
is left open. The current mode of the given file is set to the
given access mode. The default access mode is the mode Out_File
for sequential, stream, and text input-output; it is the mode
Inout_File for direct input-output. For direct access, the size of
the created file is implementation defined.
4 A null string for Name specifies an external file that is not
accessible after the completion of the main program (a temporary
file). A null string for Form specifies the use of the default
options of the implementation for the external file.
5 The exception Status_Error is propagated if the given file is
already open. The exception Name_Error is propagated if the string
given as Name does not allow the identification of an external
file. The exception Use_Error is propagated if, for the specified
mode, the external environment does not support creation of an
external file with the given name (in the absence of Name_Error)
and form.
6 procedure Open(File : in out File_Type;
Mode : in File_Mode;
Name : in String;
Form : in String := "");
7 Associates the given file with an existing external file having
the given name and form, and sets the current mode of the given
file to the given mode. The given file is left open.
8 The exception Status_Error is propagated if the given file is
already open. The exception Name_Error is propagated if the string
given as Name does not allow the identification of an external
file; in particular, this exception is propagated if no external
file with the given name exists. The exception Use_Error is
propagated if, for the specified mode, the external environment
does not support opening for an external file with the given name
(in the absence of Name_Error) and form.
9 procedure Close(File : in out File_Type);
10 Severs the association between the given file and its associated
external file. The given file is left closed. In addition, for
sequential files, if the file being closed has mode Out_File or
Append_File, then the last element written since the most recent
open or reset is the last element that can be read from the file.
If no elements have been written and the file mode is Out_File,
then the closed file is empty. If no elements have been written
and the file mode is Append_File, then the closed file is
unchanged.
11 The exception Status_Error is propagated if the given file is not
open.
12 procedure Delete(File : in out File_Type);
13 Deletes the external file associated with the given file. The
given file is closed, and the external file ceases to exist.
14 The exception Status_Error is propagated if the given file is not
open. The exception Use_Error is propagated if deletion of the
external file is not supported by the external environment.
15 procedure Reset(File : in out File_Type; Mode : in File_Mode);
procedure Reset(File : in out File_Type);
16/2 Resets the given file so that reading from its elements can be
restarted from the beginning of the external file (for modes
In_File and Inout_File), and so that writing to its elements can
be restarted at the beginning of the external file (for modes
Out_File and Inout_File) or after the last element of the external
file (for mode Append_File). In particular, for direct access this
means that the current index is set to one. If a Mode parameter is
supplied, the current mode of the given file is set to the given
mode. In addition, for sequential files, if the given file has
mode Out_File or Append_File when Reset is called, the last
element written since the most recent open or reset is the last
element that can be read from the external file. If no elements
have been written and the file mode is Out_File, the reset file is
empty. If no elements have been written and the file mode is
Append_File, then the reset file is unchanged.
17 The exception Status_Error is propagated if the file is not open.
The exception Use_Error is propagated if the external environment
does not support resetting for the external file and, also, if the
external environment does not support resetting to the specified
mode for the external file.
18 function Mode(File : in File_Type) return File_Mode;
19 Returns the current mode of the given file.
20 The exception Status_Error is propagated if the file is not open.
21 function Name(File : in File_Type) return String;
22/2 Returns a string which uniquely identifies the external file
currently associated with the given file (and may thus be used in
an Open operation).
23 The exception Status_Error is propagated if the given file is not
open. The exception Use_Error is propagated if the associated
external file is a temporary file that cannot be opened by any
name.
24 function Form(File : in File_Type) return String;
25 Returns the form string for the external file currently associated
with the given file. If an external environment allows alternative
specifications of the form (for example, abbreviations using
default options), the string returned by the function should
correspond to a full specification (that is, it should indicate
explicitly all options selected, including default options).
26 The exception Status_Error is propagated if the given file is not
open.
27 function Is_Open(File : in File_Type) return Boolean;
28 Returns True if the file is open (that is, if it is associated
with an external file), otherwise returns False.
Implementation Permissions
29 An implementation may propagate Name_Error or Use_Error if an attempt is
made to use an I/O feature that cannot be supported by the implementation due
to limitations in the external environment. Any such restriction should be
documented.
A.8.3 Sequential Input-Output Operations
Static Semantics
1 The operations available for sequential input and output are described in
this subclause. The exception Status_Error is propagated if any of these
operations is attempted for a file that is not open.
2 procedure Read(File : in File_Type; Item : out Element_Type);
3 Operates on a file of mode In_File. Reads an element from the
given file, and returns the value of this element in the Item
parameter.
4 The exception Mode_Error is propagated if the mode is not In_File.
The exception End_Error is propagated if no more elements can be
read from the given file. The exception Data_Error can be
propagated if the element read cannot be interpreted as a value of
the subtype Element_Type (see A.13, "Exceptions in Input-Output
").
5 procedure Write(File : in File_Type; Item : in Element_Type);
6 Operates on a file of mode Out_File or Append_File. Writes the
value of Item to the given file.
7 The exception Mode_Error is propagated if the mode is not Out_File
or Append_File. The exception Use_Error is propagated if the
capacity of the external file is exceeded.
8 function End_Of_File(File : in File_Type) return Boolean;
9 Operates on a file of mode In_File. Returns True if no more
elements can be read from the given file; otherwise returns False.
10 The exception Mode_Error is propagated if the mode is not In_File.
A.8.4 The Generic Package Direct_IO
Static Semantics
1 The generic library package Direct_IO has the following declaration:
2 with Ada.IO_Exceptions;
generic
type Element_Type is private;
package Ada.Direct_IO is
3 type File_Type is limited private;
4 type File_Mode is (In_File, Inout_File, Out_File);
type Count is range 0 .. implementation-defined;
subtype Positive_Count is Count range 1 .. Count'Last;
5 -- File management
6 procedure Create(File : in out File_Type;
Mode : in File_Mode := Inout_File;
Name : in String := "";
Form : in String := "");
7 procedure Open (File : in out File_Type;
Mode : in File_Mode;
Name : in String;
Form : in String := "");
8 procedure Close (File : in out File_Type);
procedure Delete(File : in out File_Type);
procedure Reset (File : in out File_Type; Mode : in File_Mode);
procedure Reset (File : in out File_Type);
9 function Mode (File : in File_Type) return File_Mode;
function Name (File : in File_Type) return String;
function Form (File : in File_Type) return String;
10 function Is_Open(File : in File_Type) return Boolean;
11 -- Input and output operations
12 procedure Read (File : in File_Type; Item : out Element_Type;
From : in Positive_Count);
procedure Read (File : in File_Type; Item : out Element_Type);
13 procedure Write(File : in File_Type; Item : in Element_Type;
To : in Positive_Count);
procedure Write(File : in File_Type; Item : in Element_Type);
14 procedure Set_Index(File : in File_Type; To : in Positive_Count);
15 function Index(File : in File_Type) return Positive_Count;
function Size (File : in File_Type) return Count;
16 function End_Of_File(File : in File_Type) return Boolean;
17 -- Exceptions
18 Status_Error : exception renames IO_Exceptions.Status_Error;
Mode_Error : exception renames IO_Exceptions.Mode_Error;
Name_Error : exception renames IO_Exceptions.Name_Error;
Use_Error : exception renames IO_Exceptions.Use_Error;
Device_Error : exception renames IO_Exceptions.Device_Error;
End_Error : exception renames IO_Exceptions.End_Error;
Data_Error : exception renames IO_Exceptions.Data_Error;
19 private
... -- not specified by the language
end Ada.Direct_IO;
20/2 The type File_Type needs finalization (see 7.6) in every instantiation of
Direct_IO.
A.8.5 Direct Input-Output Operations
Static Semantics
1 The operations available for direct input and output are described in this
subclause. The exception Status_Error is propagated if any of these operations
is attempted for a file that is not open.
2 procedure Read(File : in File_Type; Item : out Element_Type;
From : in Positive_Count);
procedure Read(File : in File_Type; Item : out Element_Type);
3 Operates on a file of mode In_File or Inout_File. In the case of
the first form, sets the current index of the given file to the
index value given by the parameter From. Then (for both forms)
returns, in the parameter Item, the value of the element whose
position in the given file is specified by the current index of
the file; finally, increases the current index by one.
4 The exception Mode_Error is propagated if the mode of the given
file is Out_File. The exception End_Error is propagated if the
index to be used exceeds the size of the external file. The
exception Data_Error can be propagated if the element read cannot
be interpreted as a value of the subtype Element_Type (see A.13).
5 procedure Write(File : in File_Type; Item : in Element_Type;
To : in Positive_Count);
procedure Write(File : in File_Type; Item : in Element_Type);
6 Operates on a file of mode Inout_File or Out_File. In the case of
the first form, sets the index of the given file to the index
value given by the parameter To. Then (for both forms) gives the
value of the parameter Item to the element whose position in the
given file is specified by the current index of the file; finally,
increases the current index by one.
7 The exception Mode_Error is propagated if the mode of the given
file is In_File. The exception Use_Error is propagated if the
capacity of the external file is exceeded.
8 procedure Set_Index(File : in File_Type; To : in Positive_Count);
9 Operates on a file of any mode. Sets the current index of the
given file to the given index value (which may exceed the current
size of the file).
10 function Index(File : in File_Type) return Positive_Count;
11 Operates on a file of any mode. Returns the current index of the
given file.
12 function Size(File : in File_Type) return Count;
13 Operates on a file of any mode. Returns the current size of the
external file that is associated with the given file.
14 function End_Of_File(File : in File_Type) return Boolean;
15 Operates on a file of mode In_File or Inout_File. Returns True if
the current index exceeds the size of the external file; otherwise
returns False.
16 The exception Mode_Error is propagated if the mode of the given
file is Out_File.
NOTES
17 20 Append_File mode is not supported for the generic package
Direct_IO.
A.9 The Generic Package Storage_IO
1 The generic package Storage_IO provides for reading from and writing to an
in-memory buffer. This generic package supports the construction of
user-defined input-output packages.
Static Semantics
2 The generic library package Storage_IO has the following declaration:
3 with Ada.IO_Exceptions;
with System.Storage_Elements;
generic
type Element_Type is private;
package Ada.Storage_IO is
pragma Preelaborate(Storage_IO);
4 Buffer_Size : constant System.Storage_Elements.Storage_Count :=
implementation-defined;
subtype Buffer_Type is
System.Storage_Elements.Storage_Array(1..Buffer_Size);
5 -- Input and output operations
6 procedure Read (Buffer : in Buffer_Type; Item : out Element_Type);
7 procedure Write(Buffer : out Buffer_Type; Item : in Element_Type);
8 -- Exceptions
9 Data_Error : exception renames IO_Exceptions.Data_Error;
end Ada.Storage_IO;
10 In each instance, the constant Buffer_Size has a value that is the size
(in storage elements) of the buffer required to represent the content of an
object of subtype Element_Type, including any implicit levels of indirection
used by the implementation. The Read and Write procedures of Storage_IO
correspond to the Read and Write procedures of Direct_IO (see A.8.4), but with
the content of the Item parameter being read from or written into the
specified Buffer, rather than an external file.
NOTES
11 21 A buffer used for Storage_IO holds only one element at a time; an
external file used for Direct_IO holds a sequence of elements.
A.10 Text Input-Output
Static Semantics
1 This clause describes the package Text_IO, which provides facilities for
input and output in human-readable form. Each file is read or written
sequentially, as a sequence of characters grouped into lines, and as a
sequence of lines grouped into pages. The specification of the package is
given below in subclause A.10.1.
2 The facilities for file management given above, in subclauses A.8.2 and
A.8.3, are available for text input-output. In place of Read and Write,
however, there are procedures Get and Put that input values of suitable types
from text files, and output values to them. These values are provided to the
Put procedures, and returned by the Get procedures, in a parameter Item.
Several overloaded procedures of these names exist, for different types of
Item. These Get procedures analyze the input sequences of characters based on
lexical elements (see Section 2) and return the corresponding values; the Put
procedures output the given values as appropriate lexical elements. Procedures
Get and Put are also available that input and output individual characters
treated as character values rather than as lexical elements. Related to
character input are procedures to look ahead at the next character without
reading it, and to read a character "immediately" without waiting for an
end-of-line to signal availability.
3 In addition to the procedures Get and Put for numeric and enumeration
types of Item that operate on text files, analogous procedures are provided
that read from and write to a parameter of type String. These procedures
perform the same analysis and composition of character sequences as their
counterparts which have a file parameter.
4 For all Get and Put procedures that operate on text files, and for many
other subprograms, there are forms with and without a file parameter. Each
such Get procedure operates on an input file, and each such Put procedure
operates on an output file. If no file is specified, a default input file or a
default output file is used.
5 At the beginning of program execution the default input and output files
are the so-called standard input file and standard output file. These files
are open, have respectively the current modes In_File and Out_File, and are
associated with two implementation-defined external files. Procedures are
provided to change the current default input file and the current default
output file.
6 At the beginning of program execution a default file for program-dependent
error-related text output is the so-called standard error file. This file is
open, has the current mode Out_File, and is associated with an
implementation-defined external file. A procedure is provided to change the
current default error file.
7 From a logical point of view, a text file is a sequence of pages, a page
is a sequence of lines, and a line is a sequence of characters; the end of a
line is marked by a line terminator; the end of a page is marked by the
combination of a line terminator immediately followed by a page terminator;
and the end of a file is marked by the combination of a line terminator
immediately followed by a page terminator and then a file terminator.
Terminators are generated during output; either by calls of procedures
provided expressly for that purpose; or implicitly as part of other
operations, for example, when a bounded line length, a bounded page length, or
both, have been specified for a file.
8 The actual nature of terminators is not defined by the language and hence
depends on the implementation. Although terminators are recognized or
generated by certain of the procedures that follow, they are not necessarily
implemented as characters or as sequences of characters. Whether they are
characters (and if so which ones) in any particular implementation need not
concern a user who neither explicitly outputs nor explicitly inputs control
characters. The effect of input (Get) or output (Put) of control characters
(other than horizontal tabulation) is not specified by the language.
9 The characters of a line are numbered, starting from one; the number of a
character is called its column number. For a line terminator, a column number
is also defined: it is one more than the number of characters in the line. The
lines of a page, and the pages of a file, are similarly numbered. The current
column number is the column number of the next character or line terminator to
be transferred. The current line number is the number of the current line. The
current page number is the number of the current page. These numbers are
values of the subtype Positive_Count of the type Count (by convention, the
value zero of the type Count is used to indicate special conditions).
10 type Count is range 0 .. implementation-defined;
subtype Positive_Count is Count range 1 .. Count'Last;
11 For an output file or an append file, a maximum line length can be
specified and a maximum page length can be specified. If a value to be output
cannot fit on the current line, for a specified maximum line length, then a
new line is automatically started before the value is output; if, further,
this new line cannot fit on the current page, for a specified maximum page
length, then a new page is automatically started before the value is output.
Functions are provided to determine the maximum line length and the maximum
page length. When a file is opened with mode Out_File or Append_File, both
values are zero: by convention, this means that the line lengths and page
lengths are unbounded. (Consequently, output consists of a single line if the
subprograms for explicit control of line and page structure are not used.) The
constant Unbounded is provided for this purpose.
A.10.1 The Package Text_IO
Static Semantics
1 The library package Text_IO has the following declaration:
2 with Ada.IO_Exceptions;
package Ada.Text_IO is
3 type File_Type is limited private;
4 type File_Mode is (In_File, Out_File, Append_File);
5 type Count is range 0 .. implementation-defined;
subtype Positive_Count is Count range 1 .. Count'Last;
Unbounded : constant Count := 0; -- line and page length
6 subtype Field is Integer range 0 .. implementation-defined;
subtype Number_Base is Integer range 2 .. 16;
7 type Type_Set is (Lower_Case, Upper_Case);
8 -- File Management
9 procedure Create (File : in out File_Type;
Mode : in File_Mode := Out_File;
Name : in String := "";
Form : in String := "");
10 procedure Open (File : in out File_Type;
Mode : in File_Mode;
Name : in String;
Form : in String := "");
11 procedure Close (File : in out File_Type);
procedure Delete (File : in out File_Type);
procedure Reset (File : in out File_Type; Mode : in File_Mode);
procedure Reset (File : in out File_Type);
12 function Mode (File : in File_Type) return File_Mode;
function Name (File : in File_Type) return String;
function Form (File : in File_Type) return String;
13 function Is_Open(File : in File_Type) return Boolean;
14 -- Control of default input and output files
15 procedure Set_Input (File : in File_Type);
procedure Set_Output(File : in File_Type);
procedure Set_Error (File : in File_Type);
16 function Standard_Input return File_Type;
function Standard_Output return File_Type;
function Standard_Error return File_Type;
17 function Current_Input return File_Type;
function Current_Output return File_Type;
function Current_Error return File_Type;
18 type File_Access is access constant File_Type;
19 function Standard_Input return File_Access;
function Standard_Output return File_Access;
function Standard_Error return File_Access;
20 function Current_Input return File_Access;
function Current_Output return File_Access;
function Current_Error return File_Access;
21/1 --Buffer control
procedure Flush (File : in File_Type);
procedure Flush;
22 -- Specification of line and page lengths
23 procedure Set_Line_Length(File : in File_Type; To : in Count);
procedure Set_Line_Length(To : in Count);
24 procedure Set_Page_Length(File : in File_Type; To : in Count);
procedure Set_Page_Length(To : in Count);
25 function Line_Length(File : in File_Type) return Count;
function Line_Length return Count;
26 function Page_Length(File : in File_Type) return Count;
function Page_Length return Count;
27 -- Column, Line, and Page Control
28 procedure New_Line (File : in File_Type;
Spacing : in Positive_Count := 1);
procedure New_Line (Spacing : in Positive_Count := 1);
29 procedure Skip_Line (File : in File_Type;
Spacing : in Positive_Count := 1);
procedure Skip_Line (Spacing : in Positive_Count := 1);
30 function End_Of_Line(File : in File_Type) return Boolean;
function End_Of_Line return Boolean;
31 procedure New_Page (File : in File_Type);
procedure New_Page;
32 procedure Skip_Page (File : in File_Type);
procedure Skip_Page;
33 function End_Of_Page(File : in File_Type) return Boolean;
function End_Of_Page return Boolean;
34 function End_Of_File(File : in File_Type) return Boolean;
function End_Of_File return Boolean;
35 procedure Set_Col (File : in File_Type; To : in Positive_Count);
procedure Set_Col (To : in Positive_Count);
36 procedure Set_Line(File : in File_Type; To : in Positive_Count);
procedure Set_Line(To : in Positive_Count);
37 function Col (File : in File_Type) return Positive_Count;
function Col return Positive_Count;
38 function Line(File : in File_Type) return Positive_Count;
function Line return Positive_Count;
39 function Page(File : in File_Type) return Positive_Count;
function Page return Positive_Count;
40 -- Character Input-Output
41 procedure Get(File : in File_Type; Item : out Character);
procedure Get(Item : out Character);
42 procedure Put(File : in File_Type; Item : in Character);
procedure Put(Item : in Character);
43 procedure Look_Ahead (File : in File_Type;
Item : out Character;
End_Of_Line : out Boolean);
procedure Look_Ahead (Item : out Character;
End_Of_Line : out Boolean);
44 procedure Get_Immediate(File : in File_Type;
Item : out Character);
procedure Get_Immediate(Item : out Character);
45 procedure Get_Immediate(File : in File_Type;
Item : out Character;
Available : out Boolean);
procedure Get_Immediate(Item : out Character;
Available : out Boolean);
46 -- String Input-Output
47 procedure Get(File : in File_Type; Item : out String);
procedure Get(Item : out String);
48 procedure Put(File : in File_Type; Item : in String);
procedure Put(Item : in String);
49 procedure Get_Line(File : in File_Type;
Item : out String;
Last : out Natural);
procedure Get_Line(Item : out String; Last : out Natural);
49.1/2 function Get_Line(File : in File_Type) return String;
function Get_Line return String;
50 procedure Put_Line(File : in File_Type; Item : in String);
procedure Put_Line(Item : in String);
51 -- Generic packages for Input-Output of Integer Types
52 generic
type Num is range <>;
package Integer_IO is
53 Default_Width : Field := Num'Width;
Default_Base : Number_Base := 10;
54 procedure Get(File : in File_Type;
Item : out Num;
Width : in Field := 0);
procedure Get(Item : out Num;
Width : in Field := 0);
55 procedure Put(File : in File_Type;
Item : in Num;
Width : in Field := Default_Width;
Base : in Number_Base := Default_Base);
procedure Put(Item : in Num;
Width : in Field := Default_Width;
Base : in Number_Base := Default_Base);
procedure Get(From : in String;
Item : out Num;
Last : out Positive);
procedure Put(To : out String;
Item : in Num;
Base : in Number_Base := Default_Base);
56 end Integer_IO;
57 generic
type Num is mod <>;
package Modular_IO is
58 Default_Width : Field := Num'Width;
Default_Base : Number_Base := 10;
59 procedure Get(File : in File_Type;
Item : out Num;
Width : in Field := 0);
procedure Get(Item : out Num;
Width : in Field := 0);
60 procedure Put(File : in File_Type;
Item : in Num;
Width : in Field := Default_Width;
Base : in Number_Base := Default_Base);
procedure Put(Item : in Num;
Width : in Field := Default_Width;
Base : in Number_Base := Default_Base);
procedure Get(From : in String;
Item : out Num;
Last : out Positive);
procedure Put(To : out String;
Item : in Num;
Base : in Number_Base := Default_Base);
61 end Modular_IO;
62 -- Generic packages for Input-Output of Real Types
63 generic
type Num is digits <>;
package Float_IO is
64 Default_Fore : Field := 2;
Default_Aft : Field := Num'Digits-1;
Default_Exp : Field := 3;
65 procedure Get(File : in File_Type;
Item : out Num;
Width : in Field := 0);
procedure Get(Item : out Num;
Width : in Field := 0);
66 procedure Put(File : in File_Type;
Item : in Num;
Fore : in Field := Default_Fore;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
procedure Put(Item : in Num;
Fore : in Field := Default_Fore;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
67 procedure Get(From : in String;
Item : out Num;
Last : out Positive);
procedure Put(To : out String;
Item : in Num;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
end Float_IO;
68 generic
type Num is delta <>;
package Fixed_IO is
69 Default_Fore : Field := Num'Fore;
Default_Aft : Field := Num'Aft;
Default_Exp : Field := 0;
70 procedure Get(File : in File_Type;
Item : out Num;
Width : in Field := 0);
procedure Get(Item : out Num;
Width : in Field := 0);
71 procedure Put(File : in File_Type;
Item : in Num;
Fore : in Field := Default_Fore;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
procedure Put(Item : in Num;
Fore : in Field := Default_Fore;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
72 procedure Get(From : in String;
Item : out Num;
Last : out Positive);
procedure Put(To : out String;
Item : in Num;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
end Fixed_IO;
73 generic
type Num is delta <> digits <>;
package Decimal_IO is
74 Default_Fore : Field := Num'Fore;
Default_Aft : Field := Num'Aft;
Default_Exp : Field := 0;
75 procedure Get(File : in File_Type;
Item : out Num;
Width : in Field := 0);
procedure Get(Item : out Num;
Width : in Field := 0);
76 procedure Put(File : in File_Type;
Item : in Num;
Fore : in Field := Default_Fore;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
procedure Put(Item : in Num;
Fore : in Field := Default_Fore;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
77 procedure Get(From : in String;
Item : out Num;
Last : out Positive);
procedure Put(To : out String;
Item : in Num;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
end Decimal_IO;
78 -- Generic package for Input-Output of Enumeration Types
79 generic
type Enum is (<>);
package Enumeration_IO is
80 Default_Width : Field := 0;
Default_Setting : Type_Set := Upper_Case;
81 procedure Get(File : in File_Type;
Item : out Enum);
procedure Get(Item : out Enum);
82 procedure Put(File : in File_Type;
Item : in Enum;
Width : in Field := Default_Width;
Set : in Type_Set := Default_Setting);
procedure Put(Item : in Enum;
Width : in Field := Default_Width;
Set : in Type_Set := Default_Setting);
83 procedure Get(From : in String;
Item : out Enum;
Last : out Positive);
procedure Put(To : out String;
Item : in Enum;
Set : in Type_Set := Default_Setting);
end Enumeration_IO;
84 -- Exceptions
85 Status_Error : exception renames IO_Exceptions.Status_Error;
Mode_Error : exception renames IO_Exceptions.Mode_Error;
Name_Error : exception renames IO_Exceptions.Name_Error;
Use_Error : exception renames IO_Exceptions.Use_Error;
Device_Error : exception renames IO_Exceptions.Device_Error;
End_Error : exception renames IO_Exceptions.End_Error;
Data_Error : exception renames IO_Exceptions.Data_Error;
Layout_Error : exception renames IO_Exceptions.Layout_Error;
private
... -- not specified by the language
end Ada.Text_IO;
86/2 The type File_Type needs finalization (see 7.6).
A.10.2 Text File Management
Static Semantics
1 The only allowed file modes for text files are the modes In_File,
Out_File, and Append_File. The subprograms given in subclause A.8.2 for the
control of external files, and the function End_Of_File given in subclause
A.8.3 for sequential input-output, are also available for text files. There is
also a version of End_Of_File that refers to the current default input file.
For text files, the procedures have the following additional effects:
2 * For the procedures Create and Open: After a file with mode Out_File or
Append_File is opened, the page length and line length are unbounded
(both have the conventional value zero). After a file (of any mode) is
opened, the current column, current line, and current page numbers are
set to one. If the mode is Append_File, it is implementation defined
whether a page terminator will separate preexisting text in the file
from the new text to be written.
3 * For the procedure Close: If the file has the current mode Out_File or
Append_File, has the effect of calling New_Page, unless the current
page is already terminated; then outputs a file terminator.
4 * For the procedure Reset: If the file has the current mode Out_File or
Append_File, has the effect of calling New_Page, unless the current
page is already terminated; then outputs a file terminator. The
current column, line, and page numbers are set to one, and the line
and page lengths to Unbounded. If the new mode is Append_File, it is
implementation defined whether a page terminator will separate
preexisting text in the file from the new text to be written.
5 The exception Mode_Error is propagated by the procedure Reset upon an
attempt to change the mode of a file that is the current default input file,
the current default output file, or the current default error file.
NOTES
6 22 An implementation can define the Form parameter of Create and Open
to control effects including the following:
7 * the interpretation of line and column numbers for an interactive
file, and
8 * the interpretation of text formats in a file created by a foreign
program.
A.10.3 Default Input, Output, and Error Files
Static Semantics
1 The following subprograms provide for the control of the particular
default files that are used when a file parameter is omitted from a Get, Put,
or other operation of text input-output described below, or when
application-dependent error-related text is to be output.
2 procedure Set_Input(File : in File_Type);
3 Operates on a file of mode In_File. Sets the current default input
file to File.
4 The exception Status_Error is propagated if the given file is not
open. The exception Mode_Error is propagated if the mode of the
given file is not In_File.
5 procedure Set_Output(File : in File_Type);
procedure Set_Error (File : in File_Type);
6 Each operates on a file of mode Out_File or Append_File.
Set_Output sets the current default output file to File. Set_Error
sets the current default error file to File. The exception
Status_Error is propagated if the given file is not open. The
exception Mode_Error is propagated if the mode of the given file
is not Out_File or Append_File.
7 function Standard_Input return File_Type;
function Standard_Input return File_Access;
8 Returns the standard input file (see A.10), or an access value
designating the standard input file, respectively.
9 function Standard_Output return File_Type;
function Standard_Output return File_Access;
10 Returns the standard output file (see A.10) or an access value
designating the standard output file, respectively.
11 function Standard_Error return File_Type;
function Standard_Error return File_Access;
12/1 Returns the standard error file (see A.10), or an access value
designating the standard error file, respectively.
13 The Form strings implicitly associated with the opening of Standard_Input,
Standard_Output, and Standard_Error at the start of program execution are
implementation defined.
14 function Current_Input return File_Type;
function Current_Input return File_Access;
15 Returns the current default input file, or an access value
designating the current default input file, respectively.
16 function Current_Output return File_Type;
function Current_Output return File_Access;
17 Returns the current default output file, or an access value
designating the current default output file, respectively.
18 function Current_Error return File_Type;
function Current_Error return File_Access;
19 Returns the current default error file, or an access value
designating the current default error file, respectively.
20/1 procedure Flush (File : in File_Type);
procedure Flush;
21 The effect of Flush is the same as the corresponding subprogram in
Streams.Stream_IO (see A.12.1). If File is not explicitly
specified, Current_Output is used.
Erroneous Execution
22/1 The execution of a program is erroneous if it invokes an operation on a
current default input, default output, or default error file, and if the
corresponding file object is closed or no longer exists.
23/1 This paragraph was deleted.
NOTES
24 23 The standard input, standard output, and standard error files
cannot be opened, closed, reset, or deleted, because the parameter
File of the corresponding procedures has the mode in out.
25 24 The standard input, standard output, and standard error files are
different file objects, but not necessarily different external files.
A.10.4 Specification of Line and Page Lengths
Static Semantics
1 The subprograms described in this subclause are concerned with the line
and page structure of a file of mode Out_File or Append_File. They operate
either on the file given as the first parameter, or, in the absence of such a
file parameter, on the current default output file. They provide for output of
text with a specified maximum line length or page length. In these cases, line
and page terminators are output implicitly and automatically when needed. When
line and page lengths are unbounded (that is, when they have the conventional
value zero), as in the case of a newly opened file, new lines and new pages
are only started when explicitly called for.
2 In all cases, the exception Status_Error is propagated if the file to be
used is not open; the exception Mode_Error is propagated if the mode of the
file is not Out_File or Append_File.
3 procedure Set_Line_Length(File : in File_Type; To : in Count);
procedure Set_Line_Length(To : in Count);
4 Sets the maximum line length of the specified output or append
file to the number of characters specified by To. The value zero
for To specifies an unbounded line length.
5 The exception Use_Error is propagated if the specified line length
is inappropriate for the associated external file.
6 procedure Set_Page_Length(File : in File_Type; To : in Count);
procedure Set_Page_Length(To : in Count);
7 Sets the maximum page length of the specified output or append
file to the number of lines specified by To. The value zero for To
specifies an unbounded page length.
8 The exception Use_Error is propagated if the specified page length
is inappropriate for the associated external file.
9 function Line_Length(File : in File_Type) return Count;
function Line_Length return Count;
10 Returns the maximum line length currently set for the specified
output or append file, or zero if the line length is unbounded.
11 function Page_Length(File : in File_Type) return Count;
function Page_Length return Count;
12 Returns the maximum page length currently set for the specified
output or append file, or zero if the page length is unbounded.
A.10.5 Operations on Columns, Lines, and Pages
Static Semantics
1 The subprograms described in this subclause provide for explicit control
of line and page structure; they operate either on the file given as the first
parameter, or, in the absence of such a file parameter, on the appropriate
(input or output) current default file. The exception Status_Error is
propagated by any of these subprograms if the file to be used is not open.
2 procedure New_Line(File : in File_Type; Spacing : in Positive_Count := 1);
procedure New_Line(Spacing : in Positive_Count := 1);
3 Operates on a file of mode Out_File or Append_File.
4 For a Spacing of one: Outputs a line terminator and sets the
current column number to one. Then increments the current line
number by one, except in the case that the current line number is
already greater than or equal to the maximum page length, for a
bounded page length; in that case a page terminator is output, the
current page number is incremented by one, and the current line
number is set to one.
5 For a Spacing greater than one, the above actions are performed
Spacing times.
6 The exception Mode_Error is propagated if the mode is not Out_File
or Append_File.
7 procedure Skip_Line(File : in File_Type; Spacing : in Positive_Count := 1);
procedure Skip_Line(Spacing : in Positive_Count := 1);
8 Operates on a file of mode In_File.
9 For a Spacing of one: Reads and discards all characters until a
line terminator has been read, and then sets the current column
number to one. If the line terminator is not immediately followed
by a page terminator, the current line number is incremented by
one. Otherwise, if the line terminator is immediately followed by
a page terminator, then the page terminator is skipped, the
current page number is incremented by one, and the current line
number is set to one.
10 For a Spacing greater than one, the above actions are performed
Spacing times.
11 The exception Mode_Error is propagated if the mode is not In_File.
The exception End_Error is propagated if an attempt is made to
read a file terminator.
12 function End_Of_Line(File : in File_Type) return Boolean;
function End_Of_Line return Boolean;
13 Operates on a file of mode In_File. Returns True if a line
terminator or a file terminator is next; otherwise returns False.
14 The exception Mode_Error is propagated if the mode is not In_File.
15 procedure New_Page(File : in File_Type);
procedure New_Page;
16 Operates on a file of mode Out_File or Append_File. Outputs a line
terminator if the current line is not terminated, or if the
current page is empty (that is, if the current column and line
numbers are both equal to one). Then outputs a page terminator,
which terminates the current page. Adds one to the current page
number and sets the current column and line numbers to one.
17 The exception Mode_Error is propagated if the mode is not Out_File
or Append_File.
18 procedure Skip_Page(File : in File_Type);
procedure Skip_Page;
19 Operates on a file of mode In_File. Reads and discards all
characters and line terminators until a page terminator has been
read. Then adds one to the current page number, and sets the
current column and line numbers to one.
20 The exception Mode_Error is propagated if the mode is not In_File.
The exception End_Error is propagated if an attempt is made to
read a file terminator.
21 function End_Of_Page(File : in File_Type) return Boolean;
function End_Of_Page return Boolean;
22 Operates on a file of mode In_File. Returns True if the
combination of a line terminator and a page terminator is next, or
if a file terminator is next; otherwise returns False.
23 The exception Mode_Error is propagated if the mode is not In_File.
24 function End_Of_File(File : in File_Type) return Boolean;
function End_Of_File return Boolean;
25 Operates on a file of mode In_File. Returns True if a file
terminator is next, or if the combination of a line, a page, and a
file terminator is next; otherwise returns False.
26 The exception Mode_Error is propagated if the mode is not In_File.
27 The following subprograms provide for the control of the current position
of reading or writing in a file. In all cases, the default file is the current
output file.
28 procedure Set_Col(File : in File_Type; To : in Positive_Count);
procedure Set_Col(To : in Positive_Count);
29 If the file mode is Out_File or Append_File:
30 * If the value specified by To is greater than the current
column number, outputs spaces, adding one to the current
column number after each space, until the current column
number equals the specified value. If the value specified by
To is equal to the current column number, there is no effect.
If the value specified by To is less than the current column
number, has the effect of calling New_Line (with a spacing of
one), then outputs (To - 1) spaces, and sets the current
column number to the specified value.
31 * The exception Layout_Error is propagated if the value
specified by To exceeds Line_Length when the line length is
bounded (that is, when it does not have the conventional value
zero).
32 If the file mode is In_File:
33 * Reads (and discards) individual characters, line terminators,
and page terminators, until the next character to be read has
a column number that equals the value specified by To; there
is no effect if the current column number already equals this
value. Each transfer of a character or terminator maintains
the current column, line, and page numbers in the same way as
a Get procedure (see A.10.6). (Short lines will be skipped
until a line is reached that has a character at the specified
column position.)
34 * The exception End_Error is propagated if an attempt is made to
read a file terminator.
35 procedure Set_Line(File : in File_Type; To : in Positive_Count);
procedure Set_Line(To : in Positive_Count);
36 If the file mode is Out_File or Append_File:
37 * If the value specified by To is greater than the current line
number, has the effect of repeatedly calling New_Line (with a
spacing of one), until the current line number equals the
specified value. If the value specified by To is equal to the
current line number, there is no effect. If the value
specified by To is less than the current line number, has the
effect of calling New_Page followed by a call of New_Line with
a spacing equal to (To - 1).
38 * The exception Layout_Error is propagated if the value
specified by To exceeds Page_Length when the page length is
bounded (that is, when it does not have the conventional value
zero).
39 If the mode is In_File:
40 * Has the effect of repeatedly calling Skip_Line (with a spacing
of one), until the current line number equals the value
specified by To; there is no effect if the current line number
already equals this value. (Short pages will be skipped until
a page is reached that has a line at the specified line
position.)
41 * The exception End_Error is propagated if an attempt is made to
read a file terminator.
42 function Col(File : in File_Type) return Positive_Count;
function Col return Positive_Count;
43 Returns the current column number.
44 The exception Layout_Error is propagated if this number exceeds
Count'Last.
45 function Line(File : in File_Type) return Positive_Count;
function Line return Positive_Count;
46 Returns the current line number.
47 The exception Layout_Error is propagated if this number exceeds
Count'Last.
48 function Page(File : in File_Type) return Positive_Count;
function Page return Positive_Count;
49 Returns the current page number.
50 The exception Layout_Error is propagated if this number exceeds
Count'Last.
51 The column number, line number, or page number are allowed to exceed
Count'Last (as a consequence of the input or output of sufficiently many
characters, lines, or pages). These events do not cause any exception to be
propagated. However, a call of Col, Line, or Page propagates the exception
Layout_Error if the corresponding number exceeds Count'Last.
NOTES
52 25 A page terminator is always skipped whenever the preceding line
terminator is skipped. An implementation may represent the combination
of these terminators by a single character, provided that it is
properly recognized on input.
A.10.6 Get and Put Procedures
Static Semantics
1 The procedures Get and Put for items of the type Character, String,
numeric types, and enumeration types are described in subsequent subclauses.
Features of these procedures that are common to most of these types are
described in this subclause. The Get and Put procedures for items of type
Character and String deal with individual character values; the Get and Put
procedures for numeric and enumeration types treat the items as lexical
elements.
2 All procedures Get and Put have forms with a file parameter, written
first. Where this parameter is omitted, the appropriate (input or output)
current default file is understood to be specified. Each procedure Get
operates on a file of mode In_File. Each procedure Put operates on a file of
mode Out_File or Append_File.
3 All procedures Get and Put maintain the current column, line, and page
numbers of the specified file: the effect of each of these procedures upon
these numbers is the result of the effects of individual transfers of
characters and of individual output or skipping of terminators. Each transfer
of a character adds one to the current column number. Each output of a line
terminator sets the current column number to one and adds one to the current
line number. Each output of a page terminator sets the current column and line
numbers to one and adds one to the current page number. For input, each
skipping of a line terminator sets the current column number to one and adds
one to the current line number; each skipping of a page terminator sets the
current column and line numbers to one and adds one to the current page
number. Similar considerations apply to the procedures Get_Line, Put_Line, and
Set_Col.
4 Several Get and Put procedures, for numeric and enumeration types, have
format parameters which specify field lengths; these parameters are of the
nonnegative subtype Field of the type Integer.
5/2 Input-output of enumeration values uses the syntax of the corresponding
lexical elements. Any Get procedure for an enumeration type begins by skipping
any leading blanks, or line or page terminators. A blank is defined as a space
or a horizontal tabulation character. Next, characters are input only so long
as the sequence input is an initial sequence of an identifier or of a
character literal (in particular, input ceases when a line terminator is
encountered). The character or line terminator that causes input to cease
remains available for subsequent input.
6 For a numeric type, the Get procedures have a format parameter called
Width. If the value given for this parameter is zero, the Get procedure
proceeds in the same manner as for enumeration types, but using the syntax of
numeric literals instead of that of enumeration literals. If a nonzero value
is given, then exactly Width characters are input, or the characters up to a
line terminator, whichever comes first; any skipped leading blanks are
included in the count. The syntax used for numeric literals is an extended
syntax that allows a leading sign (but no intervening blanks, or line or page
terminators) and that also allows (for real types) an integer literal as well
as forms that have digits only before the point or only after the point.
7 Any Put procedure, for an item of a numeric or an enumeration type,
outputs the value of the item as a numeric literal, identifier, or character
literal, as appropriate. This is preceded by leading spaces if required by the
format parameters Width or Fore (as described in later subclauses), and then a
minus sign for a negative value; for an enumeration type, the spaces follow
instead of leading. The format given for a Put procedure is overridden if it
is insufficiently wide, by using the minimum needed width.
8 Two further cases arise for Put procedures for numeric and enumeration
types, if the line length of the specified output file is bounded (that is, if
it does not have the conventional value zero). If the number of characters to
be output does not exceed the maximum line length, but is such that they
cannot fit on the current line, starting from the current column, then (in
effect) New_Line is called (with a spacing of one) before output of the item.
Otherwise, if the number of characters exceeds the maximum line length, then
the exception Layout_Error is propagated and nothing is output.
9 The exception Status_Error is propagated by any of the procedures Get,
Get_Line, Put, and Put_Line if the file to be used is not open. The exception
Mode_Error is propagated by the procedures Get and Get_Line if the mode of the
file to be used is not In_File; and by the procedures Put and Put_Line, if the
mode is not Out_File or Append_File.
10 The exception End_Error is propagated by a Get procedure if an attempt is
made to skip a file terminator. The exception Data_Error is propagated by a
Get procedure if the sequence finally input is not a lexical element
corresponding to the type, in particular if no characters were input; for this
test, leading blanks are ignored; for an item of a numeric type, when a sign
is input, this rule applies to the succeeding numeric literal. The exception
Layout_Error is propagated by a Put procedure that outputs to a parameter of
type String, if the length of the actual string is insufficient for the output
of the item.
Examples
11 In the examples, here and in subclauses A.10.8 and A.10.9, the string
quotes and the lower case letter b are not transferred: they are shown only to
reveal the layout and spaces.
12 N : Integer;
...
Get(N);
13 -- Characters at input Sequence input
Value of N
-- bb-12535b -12535 -12535
-- bb12_535e1b 12_535e1 125350
-- bb12_535e; 12_535e
(none) Data_Error raised
14 Example of overridden width parameter:
15 Put(Item => -23, Width => 2); -- "-23"
A.10.7 Input-Output of Characters and Strings
Static Semantics
1 For an item of type Character the following procedures are provided:
2 procedure Get(File : in File_Type; Item : out Character);
procedure Get(Item : out Character);
3 After skipping any line terminators and any page terminators,
reads the next character from the specified input file and returns
the value of this character in the out parameter Item.
4 The exception End_Error is propagated if an attempt is made to
skip a file terminator.
5 procedure Put(File : in File_Type; Item : in Character);
procedure Put(Item : in Character);
6 If the line length of the specified output file is bounded (that
is, does not have the conventional value zero), and the current
column number exceeds it, has the effect of calling New_Line with
a spacing of one. Then, or otherwise, outputs the given character
to the file.
7 procedure Look_Ahead (File : in File_Type;
Item : out Character;
End_Of_Line : out Boolean);
procedure Look_Ahead (Item : out Character;
End_Of_Line : out Boolean);
8/1 Mode_Error is propagated if the mode of the file is not In_File.
Sets End_Of_Line to True if at end of line, including if at end of
page or at end of file; in each of these cases the value of Item
is not specified. Otherwise End_Of_Line is set to False and Item
is set to the next character (without consuming it) from the file.
9 procedure Get_Immediate(File : in File_Type;
Item : out Character);
procedure Get_Immediate(Item : out Character);
10 Reads the next character, either control or graphic, from the
specified File or the default input file. Mode_Error is propagated
if the mode of the file is not In_File. End_Error is propagated if
at the end of the file. The current column, line and page numbers
for the file are not affected.
11 procedure Get_Immediate(File : in File_Type;
Item : out Character;
Available : out Boolean);
procedure Get_Immediate(Item : out Character;
Available : out Boolean);
12 If a character, either control or graphic, is available from the
specified File or the default input file, then the character is
read; Available is True and Item contains the value of this
character. If a character is not available, then Available is
False and the value of Item is not specified. Mode_Error is
propagated if the mode of the file is not In_File. End_Error is
propagated if at the end of the file. The current column, line and
page numbers for the file are not affected.
13/2 For an item of type String the following subprograms are provided:
14 procedure Get(File : in File_Type; Item : out String);
procedure Get(Item : out String);
15 Determines the length of the given string and attempts that number
of Get operations for successive characters of the string (in
particular, no operation is performed if the string is null).
16 procedure Put(File : in File_Type; Item : in String);
procedure Put(Item : in String);
17 Determines the length of the given string and attempts that number
of Put operations for successive characters of the string (in
particular, no operation is performed if the string is null).
17.1/2 function Get_Line(File : in File_Type) return String;
function Get_Line return String;
17.2/2 Returns a result string constructed by reading successive
characters from the specified input file, and assigning them to
successive characters of the result string. The result string has
a lower bound of 1 and an upper bound of the number of characters
read. Reading stops when the end of the line is met; Skip_Line is
then (in effect) called with a spacing of 1.
17.3/2 Constraint_Error is raised if the length of the line exceeds
Positive'Last; in this case, the line number and page number are
unchanged, and the column number is unspecified but no less than
it was before the call. The exception End_Error is propagated if
an attempt is made to skip a file terminator.
18 procedure Get_Line(File : in File_Type;
Item : out String;
Last : out Natural);
procedure Get_Line(Item : out String; Last : out Natural);
19 Reads successive characters from the specified input file and
assigns them to successive characters of the specified string.
Reading stops if the end of the string is met. Reading also stops
if the end of the line is met before meeting the end of the
string; in this case Skip_Line is (in effect) called with a
spacing of 1. The values of characters not assigned are not
specified.
20 If characters are read, returns in Last the index value such that
Item(Last) is the last character assigned (the index of the first
character assigned is Item'First). If no characters are read,
returns in Last an index value that is one less than Item'First.
The exception End_Error is propagated if an attempt is made to
skip a file terminator.
21 procedure Put_Line(File : in File_Type; Item : in String);
procedure Put_Line(Item : in String);
22 Calls the procedure Put for the given string, and then the
procedure New_Line with a spacing of one.
Implementation Advice
23 The Get_Immediate procedures should be implemented with unbuffered input.
For a device such as a keyboard, input should be "available" if a key has
already been typed, whereas for a disk file, input should always be available
except at end of file. For a file associated with a keyboard-like device, any
line-editing features of the underlying operating system should be disabled
during the execution of Get_Immediate.
NOTES
24 26 Get_Immediate can be used to read a single key from the keyboard
"immediately"; that is, without waiting for an end of line. In a call
of Get_Immediate without the parameter Available, the caller will wait
until a character is available.
25 27 In a literal string parameter of Put, the enclosing string bracket
characters are not output. Each doubled string bracket character in
the enclosed string is output as a single string bracket character, as
a consequence of the rule for string literals (see 2.6).
26 28 A string read by Get or written by Put can extend over several
lines. An implementation is allowed to assume that certain external
files do not contain page terminators, in which case Get_Line and
Skip_Line can return as soon as a line terminator is read.
A.10.8 Input-Output for Integer Types
Static Semantics
1 The following procedures are defined in the generic packages Integer_IO
and Modular_IO, which have to be instantiated for the appropriate signed
integer or modular type respectively (indicated by Num in the specifications).
2 Values are output as decimal or based literals, without low line
characters or exponent, and, for Integer_IO, preceded by a minus sign if
negative. The format (which includes any leading spaces and minus sign) can be
specified by an optional field width parameter. Values of widths of fields in
output formats are of the nonnegative integer subtype Field. Values of bases
are of the integer subtype Number_Base.
3 subtype Number_Base is Integer range 2 .. 16;
4 The default field width and base to be used by output procedures are
defined by the following variables that are declared in the generic packages
Integer_IO and Modular_IO:
5 Default_Width : Field := Num'Width;
Default_Base : Number_Base := 10;
6 The following procedures are provided:
7 procedure Get(File : in File_Type; Item : out Num; Width : in Field := 0);
procedure Get(Item : out Num; Width : in Field := 0);
8 If the value of the parameter Width is zero, skips any leading
blanks, line terminators, or page terminators, then reads a plus
sign if present or (for a signed type only) a minus sign if
present, then reads the longest possible sequence of characters
matching the syntax of a numeric literal without a point. If a
nonzero value of Width is supplied, then exactly Width characters
are input, or the characters (possibly none) up to a line
terminator, whichever comes first; any skipped leading blanks are
included in the count.
9 Returns, in the parameter Item, the value of type Num that
corresponds to the sequence input.
10 The exception Data_Error is propagated if the sequence of
characters read does not form a legal integer literal or if the
value obtained is not of the subtype Num (for Integer_IO) or is
not in the base range of Num (for Modular_IO).
11 procedure Put(File : in File_Type;
Item : in Num;
Width : in Field := Default_Width;
Base : in Number_Base := Default_Base);
procedure Put(Item : in Num;
Width : in Field := Default_Width;
Base : in Number_Base := Default_Base);
12 Outputs the value of the parameter Item as an integer literal,
with no low lines, no exponent, and no leading zeros (but a single
zero for the value zero), and a preceding minus sign for a
negative value.
13 If the resulting sequence of characters to be output has fewer
than Width characters, then leading spaces are first output to
make up the difference.
14 Uses the syntax for decimal literal if the parameter Base has the
value ten (either explicitly or through Default_Base); otherwise,
uses the syntax for based literal, with any letters in upper case.
15 procedure Get(From : in String; Item : out Num; Last : out Positive);
16 Reads an integer value from the beginning of the given string,
following the same rules as the Get procedure that reads an
integer value from a file, but treating the end of the string as a
file terminator. Returns, in the parameter Item, the value of type
Num that corresponds to the sequence input. Returns in Last the
index value such that From(Last) is the last character read.
17 The exception Data_Error is propagated if the sequence input does
not have the required syntax or if the value obtained is not of
the subtype Num.
18 procedure Put(To : out String;
Item : in Num;
Base : in Number_Base := Default_Base);
19 Outputs the value of the parameter Item to the given string,
following the same rule as for output to a file, using the length
of the given string as the value for Width.
20 Integer_Text_IO is a library package that is a nongeneric equivalent to
Text_IO.Integer_IO for the predefined type Integer:
21 with Ada.Text_IO;
package Ada.Integer_Text_IO is new Ada.Text_IO.Integer_IO(Integer);
22 For each predefined signed integer type, a nongeneric equivalent to
Text_IO.Integer_IO is provided, with names such as Ada.Long_Integer_Text_IO.
Implementation Permissions
23 The nongeneric equivalent packages may, but need not, be actual
instantiations of the generic package for the appropriate predefined type.
NOTES
24 29 For Modular_IO, execution of Get propagates Data_Error if the
sequence of characters read forms an integer literal outside the range
0..Num'Last.
Examples
25/1 This paragraph was deleted.
26 package Int_IO is new Integer_IO(Small_Int); use Int_IO;
-- default format used at instantiation,
-- Default_Width = 4, Default_Base = 10
27 Put(126); -- "b126"
Put(-126, 7); -- "bbb-126"
Put(126, Width => 13, Base => 2); -- "bbb2#1111110#"
A.10.9 Input-Output for Real Types
Static Semantics
1 The following procedures are defined in the generic packages Float_IO,
Fixed_IO, and Decimal_IO, which have to be instantiated for the appropriate
floating point, ordinary fixed point, or decimal fixed point type respectively
(indicated by Num in the specifications).
2 Values are output as decimal literals without low line characters. The
format of each value output consists of a Fore field, a decimal point, an Aft
field, and (if a nonzero Exp parameter is supplied) the letter E and an Exp
field. The two possible formats thus correspond to:
3 Fore . Aft
4 and to:
5 Fore . Aft E Exp
6 without any spaces between these fields. The Fore field may include
leading spaces, and a minus sign for negative values. The Aft field includes
only decimal digits (possibly with trailing zeros). The Exp field includes the
sign (plus or minus) and the exponent (possibly with leading zeros).
7 For floating point types, the default lengths of these fields are defined
by the following variables that are declared in the generic package Float_IO:
8 Default_Fore : Field := 2;
Default_Aft : Field := Num'Digits-1;
Default_Exp : Field := 3;
9 For ordinary or decimal fixed point types, the default lengths of these
fields are defined by the following variables that are declared in the generic
packages Fixed_IO and Decimal_IO, respectively:
10 Default_Fore : Field := Num'Fore;
Default_Aft : Field := Num'Aft;
Default_Exp : Field := 0;
11 The following procedures are provided:
12 procedure Get(File : in File_Type; Item : out Num; Width : in Field := 0);
procedure Get(Item : out Num; Width : in Field := 0);
13 If the value of the parameter Width is zero, skips any leading
blanks, line terminators, or page terminators, then reads the
longest possible sequence of characters matching the syntax of any
of the following (see 2.4):
14 * [+|-]numeric_literal
15 * [+|-]numeral.[exponent]
16 * [+|-].numeral[exponent]
17 * [+|-]base#based_numeral.#[exponent]
18 * [+|-]base#.based_numeral#[exponent]
19 If a nonzero value of Width is supplied, then exactly Width
characters are input, or the characters (possibly none) up to a
line terminator, whichever comes first; any skipped leading blanks
are included in the count.
20 Returns in the parameter Item the value of type Num that
corresponds to the sequence input, preserving the sign (positive
if none has been specified) of a zero value if Num is a floating
point type and Num'Signed_Zeros is True.
21 The exception Data_Error is propagated if the sequence input does
not have the required syntax or if the value obtained is not of
the subtype Num.
22 procedure Put(File : in File_Type;
Item : in Num;
Fore : in Field := Default_Fore;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
procedure Put(Item : in Num;
Fore : in Field := Default_Fore;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
23 Outputs the value of the parameter Item as a decimal literal with
the format defined by Fore, Aft and Exp. If the value is negative,
or if Num is a floating point type where Num'Signed_Zeros is True
and the value is a negatively signed zero, then a minus sign is
included in the integer part. If Exp has the value zero, then the
integer part to be output has as many digits as are needed to
represent the integer part of the value of Item, overriding Fore
if necessary, or consists of the digit zero if the value of Item
has no integer part.
24 If Exp has a value greater than zero, then the integer part to be
output has a single digit, which is nonzero except for the value
0.0 of Item.
25 In both cases, however, if the integer part to be output has fewer
than Fore characters, including any minus sign, then leading
spaces are first output to make up the difference. The number of
digits of the fractional part is given by Aft, or is one if Aft
equals zero. The value is rounded; a value of exactly one half in
the last place is rounded away from zero.
26 If Exp has the value zero, there is no exponent part. If Exp has a
value greater than zero, then the exponent part to be output has
as many digits as are needed to represent the exponent part of the
value of Item (for which a single digit integer part is used), and
includes an initial sign (plus or minus). If the exponent part to
be output has fewer than Exp characters, including the sign, then
leading zeros precede the digits, to make up the difference. For
the value 0.0 of Item, the exponent has the value zero.
27 procedure Get(From : in String; Item : out Num; Last : out Positive);
28 Reads a real value from the beginning of the given string,
following the same rule as the Get procedure that reads a real
value from a file, but treating the end of the string as a file
terminator. Returns, in the parameter Item, the value of type Num
that corresponds to the sequence input. Returns in Last the index
value such that From(Last) is the last character read.
29 The exception Data_Error is propagated if the sequence input does
not have the required syntax, or if the value obtained is not of
the subtype Num.
30 procedure Put(To : out String;
Item : in Num;
Aft : in Field := Default_Aft;
Exp : in Field := Default_Exp);
31 Outputs the value of the parameter Item to the given string,
following the same rule as for output to a file, using a value for
Fore such that the sequence of characters output exactly fills the
string, including any leading spaces.
32 Float_Text_IO is a library package that is a nongeneric equivalent to
Text_IO.Float_IO for the predefined type Float:
33 with Ada.Text_IO;
package Ada.Float_Text_IO is new Ada.Text_IO.Float_IO(Float);
34 For each predefined floating point type, a nongeneric equivalent to
Text_IO.Float_IO is provided, with names such as Ada.Long_Float_Text_IO.
Implementation Permissions
35 An implementation may extend Get and Put for floating point types to
support special values such as infinities and NaNs.
36 The implementation of Put need not produce an output value with greater
accuracy than is supported for the base subtype. The additional accuracy, if
any, of the value produced by Put when the number of requested digits in the
integer and fractional parts exceeds the required accuracy is implementation
defined.
37 The nongeneric equivalent packages may, but need not, be actual
instantiations of the generic package for the appropriate predefined type.
NOTES
38 30 For an item with a positive value, if output to a string exactly
fills the string without leading spaces, then output of the
corresponding negative value will propagate Layout_Error.
39 31 The rules for the Value attribute (see 3.5) and the rules for Get
are based on the same set of formats.
Examples
40/1 This paragraph was deleted.
41 package Real_IO is new Float_IO(Real); use Real_IO;
-- default format used at instantiation, Default_Exp = 3
42 X : Real := -123.4567; -- digits 8 (see 3.5.7)
43 Put(X); -- default format "-
1.2345670E+02"
Put(X, Fore => 5, Aft => 3, Exp => 2); -- "bbb-
1.235E+2"
Put(X, 5, 3, 0); -- "b-
123.457"
A.10.10 Input-Output for Enumeration Types
Static Semantics
1 The following procedures are defined in the generic package
Enumeration_IO, which has to be instantiated for the appropriate enumeration
type (indicated by Enum in the specification).
2 Values are output using either upper or lower case letters for
identifiers. This is specified by the parameter Set, which is of the
enumeration type Type_Set.
3 type Type_Set is (Lower_Case, Upper_Case);
4 The format (which includes any trailing spaces) can be specified by an
optional field width parameter. The default field width and letter case are
defined by the following variables that are declared in the generic package
Enumeration_IO:
5 Default_Width : Field := 0;
Default_Setting : Type_Set := Upper_Case;
6 The following procedures are provided:
7 procedure Get(File : in File_Type; Item : out Enum);
procedure Get(Item : out Enum);
8 After skipping any leading blanks, line terminators, or page
terminators, reads an identifier according to the syntax of this
lexical element (lower and upper case being considered
equivalent), or a character literal according to the syntax of
this lexical element (including the apostrophes). Returns, in the
parameter Item, the value of type Enum that corresponds to the
sequence input.
9 The exception Data_Error is propagated if the sequence input does
not have the required syntax, or if the identifier or character
literal does not correspond to a value of the subtype Enum.
10 procedure Put(File : in File_Type;
Item : in Enum;
Width : in Field := Default_Width;
Set : in Type_Set := Default_Setting);
procedure Put(Item : in Enum;
Width : in Field := Default_Width;
Set : in Type_Set := Default_Setting);
11 Outputs the value of the parameter Item as an enumeration literal
(either an identifier or a character literal). The optional
parameter Set indicates whether lower case or upper case is used
for identifiers; it has no effect for character literals. If the
sequence of characters produced has fewer than Width characters,
then trailing spaces are finally output to make up the difference.
If Enum is a character type, the sequence of characters produced
is as for Enum'Image(Item), as modified by the Width and Set
parameters.
12 procedure Get(From : in String; Item : out Enum; Last : out Positive);
13 Reads an enumeration value from the beginning of the given string,
following the same rule as the Get procedure that reads an
enumeration value from a file, but treating the end of the string
as a file terminator. Returns, in the parameter Item, the value of
type Enum that corresponds to the sequence input. Returns in Last
the index value such that From(Last) is the last character read.
14 The exception Data_Error is propagated if the sequence input does
not have the required syntax, or if the identifier or character
literal does not correspond to a value of the subtype Enum.
15 procedure Put(To : out String;
Item : in Enum;
Set : in Type_Set := Default_Setting);
16 Outputs the value of the parameter Item to the given string,
following the same rule as for output to a file, using the length
of the given string as the value for Width.
17/1 Although the specification of the generic package Enumeration_IO would
allow instantiation for an integer type, this is not the intended purpose of
this generic package, and the effect of such instantiations is not defined by
the language.
NOTES
18 32 There is a difference between Put defined for characters, and for
enumeration values. Thus
19 Ada.Text_IO.Put('A'); -- outputs the character A
20 package Char_IO is new Ada.Text_IO.Enumeration_IO(Character);
Char_IO.Put('A'); -- outputs the character 'A', between apostrophes
21 33 The type Boolean is an enumeration type, hence Enumeration_IO can
be instantiated for this type.
A.10.11 Input-Output for Bounded Strings
1/2 The package Text_IO.Bounded_IO provides input-output in human-readable
form for Bounded_Strings.
Static Semantics
2/2 The generic library package Text_IO.Bounded_IO has the following
declaration:
3/2 with Ada.Strings.Bounded;
generic
with package Bounded is
new Ada.Strings.Bounded.Generic_Bounded_Length (<>);
package Ada.Text_IO.Bounded_IO is
4/2 procedure Put
(File : in File_Type;
Item : in Bounded.Bounded_String);
5/2 procedure Put
(Item : in Bounded.Bounded_String);
6/2 procedure Put_Line
(File : in File_Type;
Item : in Bounded.Bounded_String);
7/2 procedure Put_Line
(Item : in Bounded.Bounded_String);
8/2 function Get_Line
(File : in File_Type)
return Bounded.Bounded_String;
9/2 function Get_Line
return Bounded.Bounded_String;
10/2 procedure Get_Line
(File : in File_Type; Item : out Bounded.Bounded_String);
11/2 procedure Get_Line
(Item : out Bounded.Bounded_String);
12/2 end Ada.Text_IO.Bounded_IO;
13/2 For an item of type Bounded_String, the following subprograms are
provided:
14/2 procedure Put
(File : in File_Type;
Item : in Bounded.Bounded_String);
15/2 Equivalent to Text_IO.Put (File, Bounded.To_String(Item));
16/2 procedure Put
(Item : in Bounded.Bounded_String);
17/2 Equivalent to Text_IO.Put (Bounded.To_String(Item));
18/2 procedure Put_Line
(File : in File_Type;
Item : in Bounded.Bounded_String);
19/2 Equivalent to Text_IO.Put_Line (File, Bounded.To_String(Item));
20/2 procedure Put_Line
(Item : in Bounded.Bounded_String);
21/2 Equivalent to Text_IO.Put_Line (Bounded.To_String(Item));
22/2 function Get_Line
(File : in File_Type)
return Bounded.Bounded_String;
23/2 Returns Bounded.To_Bounded_String(Text_IO.Get_Line(File));
24/2 function Get_Line
return Bounded.Bounded_String;
25/2 Returns Bounded.To_Bounded_String(Text_IO.Get_Line);
26/2 procedure Get_Line
(File : in File_Type; Item : out Bounded.Bounded_String);
27/2 Equivalent to Item := Get_Line (File);
28/2 procedure Get_Line
(Item : out Bounded.Bounded_String);
29/2 Equivalent to Item := Get_Line;
A.10.12 Input-Output for Unbounded Strings
1/2 The package Text_IO.Unbounded_IO provides input-output in human-readable
form for Unbounded_Strings.
Static Semantics
2/2 The library package Text_IO.Unbounded_IO has the following declaration:
3/2 with Ada.Strings.Unbounded;
package Ada.Text_IO.Unbounded_IO is
4/2 procedure Put
(File : in File_Type;
Item : in Strings.Unbounded.Unbounded_String);
5/2 procedure Put
(Item : in Strings.Unbounded.Unbounded_String);
6/2 procedure Put_Line
(File : in File_Type;
Item : in Strings.Unbounded.Unbounded_String);
7/2 procedure Put_Line
(Item : in Strings.Unbounded.Unbounded_String);
8/2 function Get_Line
(File : in File_Type)
return Strings.Unbounded.Unbounded_String;
9/2 function Get_Line
return Strings.Unbounded.Unbounded_String;
10/2 procedure Get_Line
(File : in File_Type; Item : out Strings.Unbounded.Unbounded_String);
11/2 procedure Get_Line
(Item : out Strings.Unbounded.Unbounded_String);
12/2 end Ada.Text_IO.Unbounded_IO;
13/2 For an item of type Unbounded_String, the following subprograms are
provided:
14/2 procedure Put
(File : in File_Type;
Item : in Strings.Unbounded.Unbounded_String);
15/2 Equivalent to Text_IO.Put (File,
Strings.Unbounded.To_String(Item));
16/2 procedure Put
(Item : in Strings.Unbounded.Unbounded_String);
17/2 Equivalent to Text_IO.Put (Strings.Unbounded.To_String(Item));
18/2 procedure Put_Line
(File : in File_Type;
Item : in Strings.Unbounded.Unbounded_String);
19/2 Equivalent to Text_IO.Put_Line (File,
Strings.Unbounded.To_String(Item));
20/2 procedure Put_Line
(Item : in Strings.Unbounded.Unbounded_String);
21/2 Equivalent to Text_IO.Put_Line (Strings.Unbounded.To_String(Item));
22/2 function Get_Line
(File : in File_Type)
return Strings.Unbounded.Unbounded_String;
23/2 Returns Strings.Unbounded.To_Unbounded_String(Text_IO.Get_Line(File));
24/2 function Get_Line
return Strings.Unbounded.Unbounded_String;
25/2 Returns Strings.Unbounded.To_Unbounded_String(Text_IO.Get_Line);
26/2 procedure Get_Line
(File : in File_Type; Item : out Strings.Unbounded.Unbounded_String);
27/2 Equivalent to Item := Get_Line (File);
28/2 procedure Get_Line
(Item : out Strings.Unbounded.Unbounded_String);
29/2 Equivalent to Item := Get_Line;
A.11 Wide Text Input-Output and Wide Wide Text Input-Output
1/2 The packages Wide_Text_IO and Wide_Wide_Text_IO provide facilities for
input and output in human-readable form. Each file is read or written
sequentially, as a sequence of wide characters (or wide wide characters)
grouped into lines, and as a sequence of lines grouped into pages.
Static Semantics
2/2 The specification of package Wide_Text_IO is the same as that for Text_IO,
except that in each Get, Look_Ahead, Get_Immediate, Get_Line, Put, and
Put_Line subprogram, any occurrence of Character is replaced by
Wide_Character, and any occurrence of String is replaced by Wide_String.
Nongeneric equivalents of Wide_Text_IO.Integer_IO and Wide_Text_IO.Float_IO
are provided (as for Text_IO) for each predefined numeric type, with names
such as Ada.Integer_Wide_Text_IO, Ada.Long_Integer_Wide_Text_IO, Ada.Float_-
Wide_Text_IO, Ada.Long_Float_Wide_Text_IO.
3/2 The specification of package Wide_Wide_Text_IO is the same as that for
Text_IO, except that in each Get, Look_Ahead, Get_Immediate, Get_Line, Put,
and Put_Line subprogram, any occurrence of Character is replaced by
Wide_Wide_Character, and any occurrence of String is replaced by
Wide_Wide_String. Nongeneric equivalents of Wide_Wide_Text_IO.Integer_IO and
Wide_Wide_Text_IO.Float_IO are provided (as for Text_IO) for each predefined
numeric type, with names such as Ada.Integer_Wide_Wide_Text_IO, Ada.Long_-
Integer_Wide_Wide_Text_IO, Ada.Float_Wide_Wide_Text_IO, Ada.Long_Float_-
Wide_Wide_Text_IO.
4/2 The specification of package Wide_Text_IO.Wide_Bounded_IO is the same as
that for Text_IO.Bounded_IO, except that any occurrence of Bounded_String is
replaced by Wide_Bounded_String, and any occurrence of package Bounded is
replaced by Wide_Bounded. The specification of package
Wide_Wide_Text_IO.Wide_Wide_Bounded_IO is the same as that for Text_IO.-
Bounded_IO, except that any occurrence of Bounded_String is replaced by
Wide_Wide_Bounded_String, and any occurrence of package Bounded is replaced by
Wide_Wide_Bounded.
5/2 The specification of package Wide_Text_IO.Wide_Unbounded_IO is the same as
that for Text_IO.Unbounded_IO, except that any occurrence of Unbounded_-
String is replaced by Wide_Unbounded_String, and any occurrence of package
Unbounded is replaced by Wide_Unbounded. The specification of package
Wide_Wide_Text_IO.Wide_Wide_Unbounded_IO is the same as that for
Text_IO.Unbounded_IO, except that any occurrence of Unbounded_String is
replaced by Wide_Wide_Unbounded_String, and any occurrence of package
Unbounded is replaced by Wide_Wide_Unbounded.
A.12 Stream Input-Output
1/2 The packages Streams.Stream_IO, Text_IO.Text_Streams,
Wide_Text_IO.Text_Streams, and Wide_Wide_Text_IO.Text_Streams provide
stream-oriented operations on files.
A.12.1 The Package Streams.Stream_IO
1 The subprograms in the child package Streams.Stream_IO provide control
over stream files. Access to a stream file is either sequential, via a call on
Read or Write to transfer an array of stream elements, or positional (if
supported by the implementation for the given file), by specifying a relative
index for an element. Since a stream file can be converted to a Stream_Access
value, calling stream-oriented attribute subprograms of different element
types with the same Stream_Access value provides heterogeneous input-output.
See 13.13 for a general discussion of streams.
Static Semantics
1.1/1 The elements of a stream file are stream elements. If positioning is
supported for the specified external file, a current index and current size
are maintained for the file as described in A.8. If positioning is not
supported, a current index is not maintained, and the current size is
implementation defined.
2 The library package Streams.Stream_IO has the following declaration:
3 with Ada.IO_Exceptions;
package Ada.Streams.Stream_IO is
4 type Stream_Access is access all Root_Stream_Type'Class;
5 type File_Type is limited private;
6 type File_Mode is (In_File, Out_File, Append_File);
7 type Count is range 0 .. implementation-defined;
subtype Positive_Count is Count range 1 .. Count'Last;
-- Index into file, in stream elements.
8 procedure Create (File : in out File_Type;
Mode : in File_Mode := Out_File;
Name : in String := "";
Form : in String := "");
9 procedure Open (File : in out File_Type;
Mode : in File_Mode;
Name : in String;
Form : in String := "");
10 procedure Close (File : in out File_Type);
procedure Delete (File : in out File_Type);
procedure Reset (File : in out File_Type; Mode : in File_Mode);
procedure Reset (File : in out File_Type);
11 function Mode (File : in File_Type) return File_Mode;
function Name (File : in File_Type) return String;
function Form (File : in File_Type) return String;
12 function Is_Open (File : in File_Type) return Boolean;
function End_Of_File (File : in File_Type) return Boolean;
13 function Stream (File : in File_Type) return Stream_Access;
-- Return stream access for use with T'Input and T'Output
14/1 This paragraph was deleted.
15 -- Read array of stream elements from file
procedure Read (File : in File_Type;
Item : out Stream_Element_Array;
Last : out Stream_Element_Offset;
From : in Positive_Count);
16 procedure Read (File : in File_Type;
Item : out Stream_Element_Array;
Last : out Stream_Element_Offset);
17/1 This paragraph was deleted.
18 -- Write array of stream elements into file
procedure Write (File : in File_Type;
Item : in Stream_Element_Array;
To : in Positive_Count);
19 procedure Write (File : in File_Type;
Item : in Stream_Element_Array);
20/1 This paragraph was deleted.
21 -- Operations on position within file
22 procedure Set_Index(File : in File_Type; To : in Positive_Count);
23 function Index(File : in File_Type) return Positive_Count;
function Size (File : in File_Type) return Count;
24 procedure Set_Mode(File : in out File_Type; Mode : in File_Mode);
25/1 procedure Flush(File : in File_Type);
26 -- exceptions
Status_Error : exception renames IO_Exceptions.Status_Error;
Mode_Error : exception renames IO_Exceptions.Mode_Error;
Name_Error : exception renames IO_Exceptions.Name_Error;
Use_Error : exception renames IO_Exceptions.Use_Error;
Device_Error : exception renames IO_Exceptions.Device_Error;
End_Error : exception renames IO_Exceptions.End_Error;
Data_Error : exception renames IO_Exceptions.Data_Error;
27 private
... -- not specified by the language
end Ada.Streams.Stream_IO;
27.1/2 The type File_Type needs finalization (see 7.6).
28/2 The subprograms given in subclause A.8.2 for the control of external
files (Create, Open, Close, Delete, Reset, Mode, Name, Form, and Is_Open) are
available for stream files.
28.1/2 The End_Of_File function:
28.2/2 * Propagates Mode_Error if the mode of the file is not In_File;
28.3/2 * If positioning is supported for the given external file, the
function returns True if the current index exceeds the size of the
external file; otherwise it returns False;
28.4/2 * If positioning is not supported for the given external file, the
function returns True if no more elements can be read from the given
file; otherwise it returns False.
28.5/2 The Set_Mode procedure sets the mode of the file. If the new mode is
Append_File, the file is positioned to its end; otherwise, the position in the
file is unchanged.
28.6/1 The Flush procedure synchronizes the external file with the internal
file (by flushing any internal buffers) without closing the file or changing
the position. Mode_Error is propagated if the mode of the file is In_File.
29/1 The Stream function returns a Stream_Access result from a File_Type
object, thus allowing the stream-oriented attributes Read, Write, Input, and
Output to be used on the same file for multiple types. Stream propagates
Status_Error if File is not open.
30/2 The procedures Read and Write are equivalent to the corresponding
operations in the package Streams. Read propagates Mode_Error if the mode of
File is not In_File. Write propagates Mode_Error if the mode of File is not
Out_File or Append_File. The Read procedure with a Positive_Count parameter
starts reading at the specified index. The Write procedure with a
Positive_Count parameter starts writing at the specified index. For a file
that supports positioning, Read without a Positive_Count parameter starts
reading at the current index, and Write without a Positive_Count parameter
starts writing at the current index.
30.1/1 The Size function returns the current size of the file.
31/1 The Index function returns the current index.
32 The Set_Index procedure sets the current index to the specified value.
32.1/1 If positioning is supported for the external file, the current index is
maintained as follows:
32.2/1 * For Open and Create, if the Mode parameter is Append_File, the
current index is set to the current size of the file plus one;
otherwise, the current index is set to one.
32.3/1 * For Reset, if the Mode parameter is Append_File, or no Mode
parameter is given and the current mode is Append_File, the current
index is set to the current size of the file plus one; otherwise, the
current index is set to one.
32.4/1 * For Set_Mode, if the new mode is Append_File, the current index is
set to current size plus one; otherwise, the current index is
unchanged.
32.5/1 * For Read and Write without a Positive_Count parameter, the current
index is incremented by the number of stream elements read or written.
32.6/1 * For Read and Write with a Positive_Count parameter, the value of
the current index is set to the value of the Positive_Count parameter
plus the number of stream elements read or written.
33 If positioning is not supported for the given file, then a call of Index
or Set_Index propagates Use_Error. Similarly, a call of Read or Write with a
Positive_Count parameter propagates Use_Error.
Paragraphs 34 through 36 were deleted.
Erroneous Execution
36.1/1 If the File_Type object passed to the Stream function is later closed
or finalized, and the stream-oriented attributes are subsequently called
(explicitly or implicitly) on the Stream_Access value returned by Stream,
execution is erroneous. This rule applies even if the File_Type object was
opened again after it had been closed.
A.12.2 The Package Text_IO.Text_Streams
1 The package Text_IO.Text_Streams provides a function for treating a text
file as a stream.
Static Semantics
2 The library package Text_IO.Text_Streams has the following declaration:
3 with Ada.Streams;
package Ada.Text_IO.Text_Streams is
type Stream_Access is access all Streams.Root_Stream_Type'Class;
4 function Stream (File : in File_Type) return Stream_Access;
end Ada.Text_IO.Text_Streams;
5 The Stream function has the same effect as the corresponding function in
Streams.Stream_IO.
NOTES
6 34 The ability to obtain a stream for a text file allows
Current_Input, Current_Output, and Current_Error to be processed with
the functionality of streams, including the mixing of text and binary
input-output, and the mixing of binary input-output for different
types.
7 35 Performing operations on the stream associated with a text file
does not affect the column, line, or page counts.
A.12.3 The Package Wide_Text_IO.Text_Streams
1 The package Wide_Text_IO.Text_Streams provides a function for treating a
wide text file as a stream.
Static Semantics
2 The library package Wide_Text_IO.Text_Streams has the following
declaration:
3 with Ada.Streams;
package Ada.Wide_Text_IO.Text_Streams is
type Stream_Access is access all Streams.Root_Stream_Type'Class;
4 function Stream (File : in File_Type) return Stream_Access;
end Ada.Wide_Text_IO.Text_Streams;
5 The Stream function has the same effect as the corresponding function in
Streams.Stream_IO.
A.12.4 The Package Wide_Wide_Text_IO.Text_Streams
1/2 The package Wide_Wide_Text_IO.Text_Streams provides a function for
treating a wide wide text file as a stream.
Static Semantics
2/2 The library package Wide_Wide_Text_IO.Text_Streams has the following
declaration:
3/2 with Ada.Streams;
package Ada.Wide_Wide_Text_IO.Text_Streams is
type Stream_Access is access all Streams.Root_Stream_Type'Class;
4/2 function Stream (File : in File_Type) return Stream_Access;
end Ada.Wide_Wide_Text_IO.Text_Streams;
5/2 The Stream function has the same effect as the corresponding function in
Streams.Stream_IO.
A.13 Exceptions in Input-Output
1 The package IO_Exceptions defines the exceptions needed by the predefined
input-output packages.
Static Semantics
2 The library package IO_Exceptions has the following declaration:
3 package Ada.IO_Exceptions is
pragma Pure(IO_Exceptions);
4 Status_Error : exception;
Mode_Error : exception;
Name_Error : exception;
Use_Error : exception;
Device_Error : exception;
End_Error : exception;
Data_Error : exception;
Layout_Error : exception;
5 end Ada.IO_Exceptions;
6 If more than one error condition exists, the corresponding exception that
appears earliest in the following list is the one that is propagated.
7 The exception Status_Error is propagated by an attempt to operate upon a
file that is not open, and by an attempt to open a file that is already open.
8 The exception Mode_Error is propagated by an attempt to read from, or test
for the end of, a file whose current mode is Out_File or Append_File, and also
by an attempt to write to a file whose current mode is In_File. In the case of
Text_IO, the exception Mode_Error is also propagated by specifying a file
whose current mode is Out_File or Append_File in a call of Set_Input,
Skip_Line, End_Of_Line, Skip_Page, or End_Of_Page; and by specifying a file
whose current mode is In_File in a call of Set_Output, Set_Line_Length,
Set_Page_Length, Line_Length, Page_Length, New_Line, or New_Page.
9 The exception Name_Error is propagated by a call of Create or Open if the
string given for the parameter Name does not allow the identification of an
external file. For example, this exception is propagated if the string is
improper, or, alternatively, if either none or more than one external file
corresponds to the string.
10 The exception Use_Error is propagated if an operation is attempted that is
not possible for reasons that depend on characteristics of the external file.
For example, this exception is propagated by the procedure Create, among other
circumstances, if the given mode is Out_File but the form specifies an input
only device, if the parameter Form specifies invalid access rights, or if an
external file with the given name already exists and overwriting is not
allowed.
11 The exception Device_Error is propagated if an input-output operation
cannot be completed because of a malfunction of the underlying system.
12 The exception End_Error is propagated by an attempt to skip (read past)
the end of a file.
13 The exception Data_Error can be propagated by the procedure Read (or by
the Read attribute) if the element read cannot be interpreted as a value of
the required subtype. This exception is also propagated by a procedure Get
(defined in the package Text_IO) if the input character sequence fails to
satisfy the required syntax, or if the value input does not belong to the
range of the required subtype.
14 The exception Layout_Error is propagated (in text input-output) by Col,
Line, or Page if the value returned exceeds Count'Last. The exception
Layout_Error is also propagated on output by an attempt to set column or line
numbers in excess of specified maximum line or page lengths, respectively
(excluding the unbounded cases). It is also propagated by an attempt to Put
too many characters to a string.
Documentation Requirements
15 The implementation shall document the conditions under which Name_Error,
Use_Error and Device_Error are propagated.
Implementation Permissions
16 If the associated check is too complex, an implementation need not
propagate Data_Error as part of a procedure Read (or the Read attribute) if
the value read cannot be interpreted as a value of the required subtype.
Erroneous Execution
17 If the element read by the procedure Read (or by the Read attribute)
cannot be interpreted as a value of the required subtype, but this is not
detected and Data_Error is not propagated, then the resulting value can be
abnormal, and subsequent references to the value can lead to erroneous
execution, as explained in 13.9.1.
A.14 File Sharing
Dynamic Semantics
1 It is not specified by the language whether the same external file can be
associated with more than one file object. If such sharing is supported by the
implementation, the following effects are defined:
2 * Operations on one text file object do not affect the column, line, and
page numbers of any other file object.
3/1 * This paragraph was deleted.
4 * For direct and stream files, the current index is a property of each
file object; an operation on one file object does not affect the
current index of any other file object.
5 * For direct and stream files, the current size of the file is a
property of the external file.
6 All other effects are identical.
A.15 The Package Command_Line
1 The package Command_Line allows a program to obtain the values of its
arguments and to set the exit status code to be returned on normal
termination.
Static Semantics
2 The library package Ada.Command_Line has the following declaration:
3 package Ada.Command_Line is
pragma Preelaborate(Command_Line);
4 function Argument_Count return Natural;
5 function Argument (Number : in Positive) return String;
6 function Command_Name return String;
7 type Exit_Status is implementation-defined integer type;
8 Success : constant Exit_Status;
Failure : constant Exit_Status;
9 procedure Set_Exit_Status (Code : in Exit_Status);
10 private
... -- not specified by the language
end Ada.Command_Line;
11 function Argument_Count return Natural;
12 If the external execution environment supports passing arguments
to a program, then Argument_Count returns the number of arguments
passed to the program invoking the function. Otherwise it returns
0. The meaning of "number of arguments" is implementation defined.
13 function Argument (Number : in Positive) return String;
14 If the external execution environment supports passing arguments
to a program, then Argument returns an implementation-defined
value corresponding to the argument at relative position Number.
If Number is outside the range 1..Argument_Count, then
Constraint_Error is propagated.
15 function Command_Name return String;
16 If the external execution environment supports passing arguments
to a program, then Command_Name returns an implementation-defined
value corresponding to the name of the command invoking the
program; otherwise Command_Name returns the null string.
16.1/1 type Exit_Status is implementation-defined integer type;
17 The type Exit_Status represents the range of exit status values
supported by the external execution environment. The constants
Success and Failure correspond to success and failure,
respectively.
18 procedure Set_Exit_Status (Code : in Exit_Status);
19 If the external execution environment supports returning an exit
status from a program, then Set_Exit_Status sets Code as the
status. Normal termination of a program returns as the exit status
the value most recently set by Set_Exit_Status, or, if no such
value has been set, then the value Success. If a program
terminates abnormally, the status set by Set_Exit_Status is
ignored, and an implementation-defined exit status value is set.
20 If the external execution environment does not support returning
an exit value from a program, then Set_Exit_Status does nothing.
Implementation Permissions
21 An alternative declaration is allowed for package Command_Line if
different functionality is appropriate for the external execution environment.
NOTES
22 36 Argument_Count, Argument, and Command_Name correspond to the C
language's argc, argv[n] (for n>0) and argv[0], respectively.
A.16 The Package Directories
1/2 The package Directories provides operations for manipulating files and
directories, and their names.
Static Semantics
2/2 The library package Directories has the following declaration:
3/2 with Ada.IO_Exceptions;
with Ada.Calendar;
package Ada.Directories is
4/2 -- Directory and file operations:
5/2 function Current_Directory return String;
6/2 procedure Set_Directory (Directory : in String);
7/2 procedure Create_Directory (New_Directory : in String;
Form : in String := "");
8/2 procedure Delete_Directory (Directory : in String);
9/2 procedure Create_Path (New_Directory : in String;
Form : in String := "");
10/2 procedure Delete_Tree (Directory : in String);
11/2 procedure Delete_File (Name : in String);
12/2 procedure Rename (Old_Name, New_Name : in String);
13/2 procedure Copy_File (Source_Name,
Target_Name : in String;
Form : in String := "");
14/2 -- File and directory name operations:
15/2 function Full_Name (Name : in String) return String;
16/2 function Simple_Name (Name : in String) return String;
17/2 function Containing_Directory (Name : in String) return String;
18/2 function Extension (Name : in String) return String;
19/2 function Base_Name (Name : in String) return String;
20/2 function Compose (Containing_Directory : in String := "";
Name : in String;
Extension : in String := "") return String;
21/2 -- File and directory queries:
22/2 type File_Kind is (Directory, Ordinary_File, Special_File);
23/2 type File_Size is range 0 .. implementation-defined;
24/2 function Exists (Name : in String) return Boolean;
25/2 function Kind (Name : in String) return File_Kind;
26/2 function Size (Name : in String) return File_Size;
27/2 function Modification_Time
(Name : in String) return Ada.Calendar.Time;
28/2 -- Directory searching:
29/2 type Directory_Entry_Type is limited private;
30/2 type Filter_Type is array (File_Kind) of Boolean;
31/2 type Search_Type is limited private;
32/2 procedure Start_Search (Search : in out Search_Type;
Directory : in String;
Pattern : in String;
Filter : in Filter_Type := (others => True));
33/2 procedure End_Search (Search : in out Search_Type);
34/2 function More_Entries (Search : in Search_Type) return Boolean;
35/2 procedure Get_Next_Entry (Search : in out Search_Type;
Directory_Entry : out Directory_Entry_Type);
36/2 procedure Search (
Directory : in String;
Pattern : in String;
Filter : in Filter_Type := (others => True);
Process : not null access procedure (
Directory_Entry : in Directory_Entry_Type));
37/2 -- Operations on Directory Entries:
38/2 function Simple_Name (Directory_Entry : in Directory_Entry_Type)
return String;
39/2 function Full_Name (Directory_Entry : in Directory_Entry_Type)
return String;
40/2 function Kind (Directory_Entry : in Directory_Entry_Type)
return File_Kind;
41/2 function Size (Directory_Entry : in Directory_Entry_Type)
return File_Size;
42/2 function Modification_Time
(Directory_Entry : in Directory_Entry_Type)
return Ada.Calendar.Time;
43/2 Status_Error : exception renames Ada.IO_Exceptions.Status_Error;
Name_Error : exception renames Ada.IO_Exceptions.Name_Error;
Use_Error : exception renames Ada.IO_Exceptions.Use_Error;
Device_Error : exception renames Ada.IO_Exceptions.Device_Error;
44/2 private
-- Not specified by the language.
end Ada.Directories;
45/2 External files may be classified as directories, special files, or
ordinary files. A directory is an external file that is a container for files
on the target system. A special file is an external file that cannot be
created or read by a predefined Ada input-output package. External files that
are not special files or directories are called ordinary files.
46/2 A file name is a string identifying an external file. Similarly, a
directory name is a string identifying a directory. The interpretation of file
names and directory names is implementation-defined.
47/2 The full name of an external file is a full specification of the name of
the file. If the external environment allows alternative specifications of the
name (for example, abbreviations), the full name should not use such
alternatives. A full name typically will include the names of all of the
directories that contain the item. The simple name of an external file is the
name of the item, not including any containing directory names. Unless
otherwise specified, a file name or directory name parameter in a call to a
predefined Ada input-output subprogram can be a full name, a simple name, or
any other form of name supported by the implementation.
48/2 The default directory is the directory that is used if a directory or
file name is not a full name (that is, when the name does not fully identify
all of the containing directories).
49/2 A directory entry is a single item in a directory, identifying a single
external file (including directories and special files).
50/2 For each function that returns a string, the lower bound of the returned
value is 1.
51/2 The following file and directory operations are provided:
52/2 function Current_Directory return String;
53/2 Returns the full directory name for the current default directory.
The name returned shall be suitable for a future call to
Set_Directory. The exception Use_Error is propagated if a default
directory is not supported by the external environment.
54/2 procedure Set_Directory (Directory : in String);
55/2 Sets the current default directory. The exception Name_Error is
propagated if the string given as Directory does not identify an
existing directory. The exception Use_Error is propagated if the
external environment does not support making Directory (in the
absence of Name_Error) a default directory.
56/2 procedure Create_Directory (New_Directory : in String;
Form : in String := "");
57/2 Creates a directory with name New_Directory. The Form parameter
can be used to give system-dependent characteristics of the
directory; the interpretation of the Form parameter is
implementation-defined. A null string for Form specifies the use
of the default options of the implementation of the new directory.
The exception Name_Error is propagated if the string given as
New_Directory does not allow the identification of a directory.
The exception Use_Error is propagated if the external environment
does not support the creation of a directory with the given name
(in the absence of Name_Error) and form.
58/2 procedure Delete_Directory (Directory : in String);
59/2 Deletes an existing empty directory with name Directory. The
exception Name_Error is propagated if the string given as
Directory does not identify an existing directory. The exception
Use_Error is propagated if the external environment does not
support the deletion of the directory (or some portion of its
contents) with the given name (in the absence of Name_Error).
60/2 procedure Create_Path (New_Directory : in String;
Form : in String := "");
61/2 Creates zero or more directories with name New_Directory. Each
non-existent directory named by New_Directory is created. For
example, on a typical Unix system, Create_Path ("/usr/me/my");
would create directory "me" in directory "usr", then create
directory "my" in directory "me". The Form parameter can be used
to give system-dependent characteristics of the directory; the
interpretation of the Form parameter is implementation-defined. A
null string for Form specifies the use of the default options of
the implementation of the new directory. The exception Name_Error
is propagated if the string given as New_Directory does not allow
the identification of any directory. The exception Use_Error is
propagated if the external environment does not support the
creation of any directories with the given name (in the absence of
Name_Error) and form.
62/2 procedure Delete_Tree (Directory : in String);
63/2 Deletes an existing directory with name Directory. The directory
and all of its contents (possibly including other directories) are
deleted. The exception Name_Error is propagated if the string
given as Directory does not identify an existing directory. The
exception Use_Error is propagated if the external environment does
not support the deletion of the directory or some portion of its
contents with the given name (in the absence of Name_Error). If
Use_Error is propagated, it is unspecified whether a portion of
the contents of the directory is deleted.
64/2 procedure Delete_File (Name : in String);
65/2 Deletes an existing ordinary or special file with name Name. The
exception Name_Error is propagated if the string given as Name
does not identify an existing ordinary or special external file.
The exception Use_Error is propagated if the external environment
does not support the deletion of the file with the given name (in
the absence of Name_Error).
66/2 procedure Rename (Old_Name, New_Name : in String);
67/2 Renames an existing external file (including directories) with
name Old_Name to New_Name. The exception Name_Error is propagated
if the string given as Old_Name does not identify an existing
external file. The exception Use_Error is propagated if the
external environment does not support the renaming of the file
with the given name (in the absence of Name_Error). In particular,
Use_Error is propagated if a file or directory already exists with
name New_Name.
68/2 procedure Copy_File (Source_Name,
Target_Name : in String;
Form : in String);
69/2 Copies the contents of the existing external file with name
Source_Name to an external file with name Target_Name. The
resulting external file is a duplicate of the source external
file. The Form parameter can be used to give system-dependent
characteristics of the resulting external file; the interpretation
of the Form parameter is implementation-defined. Exception
Name_Error is propagated if the string given as Source_Name does
not identify an existing external ordinary or special file, or if
the string given as Target_Name does not allow the identification
of an external file. The exception Use_Error is propagated if the
external environment does not support creating the file with the
name given by Target_Name and form given by Form, or copying of
the file with the name given by Source_Name (in the absence of
Name_Error).
70/2 The following file and directory name operations are provided:
71/2 function Full_Name (Name : in String) return String;
72/2 Returns the full name corresponding to the file name specified by
Name. The exception Name_Error is propagated if the string given
as Name does not allow the identification of an external file
(including directories and special files).
73/2 function Simple_Name (Name : in String) return String;
74/2 Returns the simple name portion of the file name specified by
Name. The exception Name_Error is propagated if the string given
as Name does not allow the identification of an external file
(including directories and special files).
75/2 function Containing_Directory (Name : in String) return String;
76/2 Returns the name of the containing directory of the external file
(including directories) identified by Name. (If more than one
directory can contain Name, the directory name returned is
implementation-defined.) The exception Name_Error is propagated if
the string given as Name does not allow the identification of an
external file. The exception Use_Error is propagated if the
external file does not have a containing directory.
77/2 function Extension (Name : in String) return String;
78/2 Returns the extension name corresponding to Name. The extension
name is a portion of a simple name (not including any separator
characters), typically used to identify the file class. If the
external environment does not have extension names, then the null
string is returned. The exception Name_Error is propagated if the
string given as Name does not allow the identification of an
external file.
79/2 function Base_Name (Name : in String) return String;
80/2 Returns the base name corresponding to Name. The base name is the
remainder of a simple name after removing any extension and
extension separators. The exception Name_Error is propagated if
the string given as Name does not allow the identification of an
external file (including directories and special files).
81/2 function Compose (Containing_Directory : in String := "";
Name : in String;
Extension : in String := "") return String;
82/2 Returns the name of the external file with the specified
Containing_Directory, Name, and Extension. If Extension is the
null string, then Name is interpreted as a simple name; otherwise
Name is interpreted as a base name. The exception Name_Error is
propagated if the string given as Containing_Directory is not null
and does not allow the identification of a directory, or if the
string given as Extension is not null and is not a possible
extension, or if the string given as Name is not a possible simple
name (if Extension is null) or base name (if Extension is
non-null).
83/2 The following file and directory queries and types are provided:
84/2 type File_Kind is (Directory, Ordinary_File, Special_File);
85/2 The type File_Kind represents the kind of file represented by an
external file or directory.
86/2 type File_Size is range 0 .. implementation-defined;
87/2 The type File_Size represents the size of an external file.
88/2 function Exists (Name : in String) return Boolean;
89/2 Returns True if an external file represented by Name exists, and
False otherwise. The exception Name_Error is propagated if the
string given as Name does not allow the identification of an
external file (including directories and special files).
90/2 function Kind (Name : in String) return File_Kind;
91/2 Returns the kind of external file represented by Name. The
exception Name_Error is propagated if the string given as Name
does not allow the identification of an existing external file.
92/2 function Size (Name : in String) return File_Size;
93/2 Returns the size of the external file represented by Name. The
size of an external file is the number of stream elements
contained in the file. If the external file is not an ordinary
file, the result is implementation-defined. The exception
Name_Error is propagated if the string given as Name does not
allow the identification of an existing external file. The
exception Constraint_Error is propagated if the file size is not a
value of type File_Size.
94/2 function Modification_Time (Name : in String) return Ada.Calendar.Time;
95/2 Returns the time that the external file represented by Name was
most recently modified. If the external file is not an ordinary
file, the result is implementation-defined. The exception
Name_Error is propagated if the string given as Name does not
allow the identification of an existing external file. The
exception Use_Error is propagated if the external environment does
not support reading the modification time of the file with the
name given by Name (in the absence of Name_Error).
96/2 The following directory searching operations and types are provided:
97/2 type Directory_Entry_Type is limited private;
98/2 The type Directory_Entry_Type represents a single item in a
directory. These items can only be created by the Get_Next_Entry
procedure in this package. Information about the item can be
obtained from the functions declared in this package. A
default-initialized object of this type is invalid; objects
returned from Get_Next_Entry are valid.
99/2 type Filter_Type is array (File_Kind) of Boolean;
100/2 The type Filter_Type specifies which directory entries are
provided from a search operation. If the Directory component is
True, directory entries representing directories are provided. If
the Ordinary_File component is True, directory entries
representing ordinary files are provided. If the Special_File
component is True, directory entries representing special files
are provided.
101/2 type Search_Type is limited private;
102/2 The type Search_Type contains the state of a directory search. A
default-initialized Search_Type object has no entries available
(function More_Entries returns False). Type Search_Type needs
finalization (see 7.6).
103/2 procedure Start_Search (Search : in out Search_Type;
Directory : in String;
Pattern : in String;
Filter : in Filter_Type := (others => True));
104/2 Starts a search in the directory named by Directory for entries
matching Pattern. Pattern represents a pattern for matching file
names. If Pattern is null, all items in the directory are matched;
otherwise, the interpretation of Pattern is
implementation-defined. Only items that match Filter will be
returned. After a successful call on Start_Search, the object
Search may have entries available, but it may have no entries
available if no files or directories match Pattern and Filter. The
exception Name_Error is propagated if the string given by
Directory does not identify an existing directory, or if Pattern
does not allow the identification of any possible external file or
directory. The exception Use_Error is propagated if the external
environment does not support the searching of the directory with
the given name (in the absence of Name_Error). When Start_Search
propagates Name_Error or Use_Error, the object Search will have no
entries available.
105/2 procedure End_Search (Search : in out Search_Type);
106/2 Ends the search represented by Search. After a successful call on
End_Search, the object Search will have no entries available.
107/2 function More_Entries (Search : in Search_Type) return Boolean;
108/2 Returns True if more entries are available to be returned by a
call to Get_Next_Entry for the specified search object, and False
otherwise.
109/2 procedure Get_Next_Entry (Search : in out Search_Type;
Directory_Entry : out Directory_Entry_Type);
110/2 Returns the next Directory_Entry for the search described by
Search that matches the pattern and filter. If no further matches
are available, Status_Error is raised. It is
implementation-defined as to whether the results returned by this
routine are altered if the contents of the directory are altered
while the Search object is valid (for example, by another
program). The exception Use_Error is propagated if the external
environment does not support continued searching of the directory
represented by Search.
111/2 procedure Search (
Directory : in String;
Pattern : in String;
Filter : in Filter_Type := (others => True);
Process : not null access procedure (
Directory_Entry : in Directory_Entry_Type));
112/2 Searches in the directory named by Directory for entries matching
Pattern. The subprogram designated by Process is called with each
matching entry in turn. Pattern represents a pattern for matching
file names. If Pattern is null, all items in the directory are
matched; otherwise, the interpretation of Pattern is
implementation-defined. Only items that match Filter will be
returned. The exception Name_Error is propagated if the string
given by Directory does not identify an existing directory, or if
Pattern does not allow the identification of any possible external
file or directory. The exception Use_Error is propagated if the
external environment does not support the searching of the
directory with the given name (in the absence of Name_Error).
113/2 function Simple_Name (Directory_Entry : in Directory_Entry_Type)
return String;
114/2 Returns the simple external name of the external file (including
directories) represented by Directory_Entry. The format of the
name returned is implementation-defined. The exception
Status_Error is propagated if Directory_Entry is invalid.
115/2 function Full_Name (Directory_Entry : in Directory_Entry_Type)
return String;
116/2 Returns the full external name of the external file (including
directories) represented by Directory_Entry. The format of the
name returned is implementation-defined. The exception
Status_Error is propagated if Directory_Entry is invalid.
117/2 function Kind (Directory_Entry : in Directory_Entry_Type)
return File_Kind;
118/2 Returns the kind of external file represented by Directory_Entry.
The exception Status_Error is propagated if Directory_Entry is
invalid.
119/2 function Size (Directory_Entry : in Directory_Entry_Type)
return File_Size;
120/2 Returns the size of the external file represented by
Directory_Entry. The size of an external file is the number of
stream elements contained in the file. If the external file
represented by Directory_Entry is not an ordinary file, the result
is implementation-defined. The exception Status_Error is
propagated if Directory_Entry is invalid. The exception
Constraint_Error is propagated if the file size is not a value of
type File_Size.
121/2 function Modification_Time (Directory_Entry : in Directory_Entry_Type)
return Ada.Calendar.Time;
122/2 Returns the time that the external file represented by
Directory_Entry was most recently modified. If the external file
represented by Directory_Entry is not an ordinary file, the result
is implementation-defined. The exception Status_Error is
propagated if Directory_Entry is invalid. The exception Use_Error
is propagated if the external environment does not support reading
the modification time of the file represented by Directory_Entry.
Implementation Requirements
123/2 For Copy_File, if Source_Name identifies an existing external ordinary
file created by a predefined Ada input-output package, and Target_Name and
Form can be used in the Create operation of that input-output package with
mode Out_File without raising an exception, then Copy_File shall not propagate
Use_Error.
Implementation Advice
124/2 If other information about a file (such as the owner or creation date)
is available in a directory entry, the implementation should provide functions
in a child package Directories.Information to retrieve it.
125/2 Start_Search and Search should raise Use_Error if Pattern is malformed,
but not if it could represent a file in the directory but does not actually do
so.
126/2 Rename should be supported at least when both New_Name and Old_Name are
simple names and New_Name does not identify an existing external file.
NOTES
127/2 37 The operations Containing_Directory, Full_Name, Simple_Name,
Base_Name, Extension, and Compose operate on file names, not external
files. The files identified by these operations do not need to exist.
Name_Error is raised only if the file name is malformed and cannot
possibly identify a file. Of these operations, only the result of
Full_Name depends on the current default directory; the result of the
others depends only on their parameters.
128/2 38 Using access types, values of Search_Type and Directory_Entry_Type
can be saved and queried later. However, another task or application
can modify or delete the file represented by a Directory_Entry_Type
value or the directory represented by a Search_Type value; such a
value can only give the information valid at the time it is created.
Therefore, long-term storage of these values is not recommended.
129/2 39 If the target system does not support directories inside of
directories, then Kind will never return Directory and
Containing_Directory will always raise Use_Error.
130/2 40 If the target system does not support creation or deletion of
directories, then Create_Directory, Create_Path, Delete_Directory, and
Delete_Tree will always propagate Use_Error.
131/2 41 To move a file or directory to a different location, use Rename.
Most target systems will allow renaming of files from one directory to
another. If the target file or directory might already exist, it
should be deleted first.
A.17 The Package Environment_Variables
1/2 The package Environment_Variables allows a program to read or modify
environment variables. Environment variables are name-value pairs, where both
the name and value are strings. The definition of what constitutes an
environment variable, and the meaning of the name and value, are
implementation defined.
Static Semantics
2/2 The library package Environment_Variables has the following declaration:
3/2 package Ada.Environment_Variables is
pragma Preelaborate(Environment_Variables);
4/2 function Value (Name : in String) return String;
5/2 function Exists (Name : in String) return Boolean;
6/2 procedure Set (Name : in String; Value : in String);
7/2 procedure Clear (Name : in String);
procedure Clear;
8/2 procedure Iterate (
Process : not null access procedure (Name, Value : in String));
9/2 end Ada.Environment_Variables;
10/2 function Value (Name : in String) return String;
11/2 If the external execution environment supports environment
variables, then Value returns the value of the environment
variable with the given name. If no environment variable with the
given name exists, then Constraint_Error is propagated. If the
execution environment does not support environment variables, then
Program_Error is propagated.
12/2 function Exists (Name : in String) return Boolean;
13/2 If the external execution environment supports environment
variables and an environment variable with the given name
currently exists, then Exists returns True; otherwise it returns
False.
14/2 procedure Set (Name : in String; Value : in String);
15/2 If the external execution environment supports environment
variables, then Set first clears any existing environment variable
with the given name, and then defines a single new environment
variable with the given name and value. Otherwise Program_Error is
propagated.
16/2 If implementation-defined circumstances prohibit the definition of
an environment variable with the given name and value, then
Constraint_Error is propagated.
17/2 It is implementation defined whether there exist values for which
the call Set(Name, Value) has the same effect as Clear (Name).
18/2 procedure Clear (Name : in String);
19/2 If the external execution environment supports environment
variables, then Clear deletes all existing environment variable
with the given name. Otherwise Program_Error is propagated.
20/2 procedure Clear;
21/2 If the external execution environment supports environment
variables, then Clear deletes all existing environment variables.
Otherwise Program_Error is propagated.
22/2 procedure Iterate (
Process : not null access procedure (Name, Value : in String));
23/2 If the external execution environment supports environment
variables, then Iterate calls the subprogram designated by Process
for each existing environment variable, passing the name and value
of that environment variable. Otherwise Program_Error is
propagated.
24/2 If several environment variables exist that have the same name,
Process is called once for each such variable.
Bounded (Run-Time) Errors
25/2 It is a bounded error to call Value if more than one environment variable
exists with the given name; the possible outcomes are that:
26/2 * one of the values is returned, and that same value is returned in
subsequent calls in the absence of changes to the environment; or
27/2 * Program_Error is propagated.
Erroneous Execution
28/2 Making calls to the procedures Set or Clear concurrently with calls to
any subprogram of package Environment_Variables, or to any instantiation of
Iterate, results in erroneous execution.
29/2 Making calls to the procedures Set or Clear in the actual subprogram
corresponding to the Process parameter of Iterate results in erroneous
execution.
Documentation Requirements
30/2 An implementation shall document how the operations of this package
behave if environment variables are changed by external mechanisms (for
instance, calling operating system services).
Implementation Permissions
31/2 An implementation running on a system that does not support environment
variables is permitted to define the operations of package
Environment_Variables with the semantics corresponding to the case where the
external execution environment does support environment variables. In this
case, it shall provide a mechanism to initialize a nonempty set of environment
variables prior to the execution of a partition.
Implementation Advice
32/2 If the execution environment supports subprocesses, the currently defined
environment variables should be used to initialize the environment variables
of a subprocess.
33/2 Changes to the environment variables made outside the control of this
package should be reflected immediately in the effect of the operations of
this package. Changes to the environment variables made using this package
should be reflected immediately in the external execution environment. This
package should not perform any buffering of the environment variables.
A.18 Containers
1/2 This clause presents the specifications of the package Containers and
several child packages, which provide facilities for storing collections of
elements.
2/2 A variety of sequence and associative containers are provided. Each
container includes a cursor type. A cursor is a reference to an element within
a container. Many operations on cursors are common to all of the containers. A
cursor referencing an element in a container is considered to be overlapping
with the container object itself.
3/2 Within this clause we provide Implementation Advice for the desired
average or worst case time complexity of certain operations on a container.
This advice is expressed using the Landau symbol O(X). Presuming f is some
function of a length parameter N and t(N) is the time the operation takes (on
average or worst case, as specified) for the length N, a complexity of O(f(N))
means that there exists a finite A such that for any N, t(N)/f(N) < A.
4/2 If the advice suggests that the complexity should be less than O(f(N)),
then for any arbitrarily small positive real D, there should exist a positive
integer M such that for all N > M, t(N)/f(N) < D.
A.18.1 The Package Containers
1/2 The package Containers is the root of the containers subsystem.
Static Semantics
2/2 The library package Containers has the following declaration:
3/2 package Ada.Containers is
pragma Pure(Containers);
4/2 type Hash_Type is mod implementation-defined;
5/2 type Count_Type is range 0 .. implementation-defined;
6/2 end Ada.Containers;
7/2 Hash_Type represents the range of the result of a hash function.
Count_Type represents the (potential or actual) number of elements of a
container.
Implementation Advice
8/2 Hash_Type'Modulus should be at least 2**32. Count_Type'Last should be at
least 2**31-1.
A.18.2 The Package Containers.Vectors
1/2 The language-defined generic package Containers.Vectors provides private
types Vector and Cursor, and a set of operations for each type. A vector
container allows insertion and deletion at any position, but it is
specifically optimized for insertion and deletion at the high end (the end
with the higher index) of the container. A vector container also provides
random access to its elements.
2/2 A vector container behaves conceptually as an array that expands as
necessary as items are inserted. The length of a vector is the number of
elements that the vector contains. The capacity of a vector is the maximum
number of elements that can be inserted into the vector prior to it being
automatically expanded.
3/2 Elements in a vector container can be referred to by an index value of a
generic formal type. The first element of a vector always has its index value
equal to the lower bound of the formal type.
4/2 A vector container may contain empty elements. Empty elements do not have
a specified value.
Static Semantics
5/2 The generic library package Containers.Vectors has the following
declaration:
6/2 generic
type Index_Type is range <>;
type Element_Type is private;
with function "=" (Left, Right : Element_Type)
return Boolean is <>;
package Ada.Containers.Vectors is
pragma Preelaborate(Vectors);
7/2 subtype Extended_Index is
Index_Type'Base range
Index_Type'First-1 ..
Index_Type'Min (Index_Type'Base'Last - 1, Index_Type'Last) + 1;
No_Index : constant Extended_Index := Extended_Index'First;
8/2 type Vector is tagged private;
pragma Preelaborable_Initialization(Vector);
9/2 type Cursor is private;
pragma Preelaborable_Initialization(Cursor);
10/2 Empty_Vector : constant Vector;
11/2 No_Element : constant Cursor;
12/2 function "=" (Left, Right : Vector) return Boolean;
13/2 function To_Vector (Length : Count_Type) return Vector;
14/2 function To_Vector
(New_Item : Element_Type;
Length : Count_Type) return Vector;
15/2 function "&" (Left, Right : Vector) return Vector;
16/2 function "&" (Left : Vector;
Right : Element_Type) return Vector;
17/2 function "&" (Left : Element_Type;
Right : Vector) return Vector;
18/2 function "&" (Left, Right : Element_Type) return Vector;
19/2 function Capacity (Container : Vector) return Count_Type;
20/2 procedure Reserve_Capacity (Container : in out Vector;
Capacity : in Count_Type);
21/2 function Length (Container : Vector) return Count_Type;
22/2 procedure Set_Length (Container : in out Vector;
Length : in Count_Type);
23/2 function Is_Empty (Container : Vector) return Boolean;
24/2 procedure Clear (Container : in out Vector);
25/2 function To_Cursor (Container : Vector;
Index : Extended_Index) return Cursor;
26/2 function To_Index (Position : Cursor) return Extended_Index;
27/2 function Element (Container : Vector;
Index : Index_Type)
return Element_Type;
28/2 function Element (Position : Cursor) return Element_Type;
29/2 procedure Replace_Element (Container : in out Vector;
Index : in Index_Type;
New_Item : in Element_Type);
30/2 procedure Replace_Element (Container : in out Vector;
Position : in Cursor;
New_item : in Element_Type);
31/2 procedure Query_Element
(Container : in Vector;
Index : in Index_Type;
Process : not null access procedure (Element : in Element_Type));
32/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Element : in Element_Type));
33/2 procedure Update_Element
(Container : in out Vector;
Index : in Index_Type;
Process : not null access procedure
(Element : in out Element_Type));
34/2 procedure Update_Element
(Container : in out Vector;
Position : in Cursor;
Process : not null access procedure
(Element : in out Element_Type));
35/2 procedure Move (Target : in out Vector;
Source : in out Vector);
36/2 procedure Insert (Container : in out Vector;
Before : in Extended_Index;
New_Item : in Vector);
37/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
New_Item : in Vector);
38/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
New_Item : in Vector;
Position : out Cursor);
39/2 procedure Insert (Container : in out Vector;
Before : in Extended_Index;
New_Item : in Element_Type;
Count : in Count_Type := 1);
40/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
New_Item : in Element_Type;
Count : in Count_Type := 1);
41/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
New_Item : in Element_Type;
Position : out Cursor;
Count : in Count_Type := 1);
42/2 procedure Insert (Container : in out Vector;
Before : in Extended_Index;
Count : in Count_Type := 1);
43/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
Position : out Cursor;
Count : in Count_Type := 1);
44/2 procedure Prepend (Container : in out Vector;
New_Item : in Vector);
45/2 procedure Prepend (Container : in out Vector;
New_Item : in Element_Type;
Count : in Count_Type := 1);
46/2 procedure Append (Container : in out Vector;
New_Item : in Vector);
47/2 procedure Append (Container : in out Vector;
New_Item : in Element_Type;
Count : in Count_Type := 1);
48/2 procedure Insert_Space (Container : in out Vector;
Before : in Extended_Index;
Count : in Count_Type := 1);
49/2 procedure Insert_Space (Container : in out Vector;
Before : in Cursor;
Position : out Cursor;
Count : in Count_Type := 1);
50/2 procedure Delete (Container : in out Vector;
Index : in Extended_Index;
Count : in Count_Type := 1);
51/2 procedure Delete (Container : in out Vector;
Position : in out Cursor;
Count : in Count_Type := 1);
52/2 procedure Delete_First (Container : in out Vector;
Count : in Count_Type := 1);
53/2 procedure Delete_Last (Container : in out Vector;
Count : in Count_Type := 1);
54/2 procedure Reverse_Elements (Container : in out Vector);
55/2 procedure Swap (Container : in out Vector;
I, J : in Index_Type);
56/2 procedure Swap (Container : in out Vector;
I, J : in Cursor);
57/2 function First_Index (Container : Vector) return Index_Type;
58/2 function First (Container : Vector) return Cursor;
59/2 function First_Element (Container : Vector)
return Element_Type;
60/2 function Last_Index (Container : Vector) return Extended_Index;
61/2 function Last (Container : Vector) return Cursor;
62/2 function Last_Element (Container : Vector)
return Element_Type;
63/2 function Next (Position : Cursor) return Cursor;
64/2 procedure Next (Position : in out Cursor);
65/2 function Previous (Position : Cursor) return Cursor;
66/2 procedure Previous (Position : in out Cursor);
67/2 function Find_Index (Container : Vector;
Item : Element_Type;
Index : Index_Type := Index_Type'First)
return Extended_Index;
68/2 function Find (Container : Vector;
Item : Element_Type;
Position : Cursor := No_Element)
return Cursor;
69/2 function Reverse_Find_Index (Container : Vector;
Item : Element_Type;
Index : Index_Type := Index_Type'Last)
return Extended_Index;
70/2 function Reverse_Find (Container : Vector;
Item : Element_Type;
Position : Cursor := No_Element)
return Cursor;
71/2 function Contains (Container : Vector;
Item : Element_Type) return Boolean;
72/2 function Has_Element (Position : Cursor) return Boolean;
73/2 procedure Iterate
(Container : in Vector;
Process : not null access procedure (Position : in Cursor));
74/2 procedure Reverse_Iterate
(Container : in Vector;
Process : not null access procedure (Position : in Cursor));
75/2 generic
with function "<" (Left, Right : Element_Type)
return Boolean is <>;
package Generic_Sorting is
76/2 function Is_Sorted (Container : Vector) return Boolean;
77/2 procedure Sort (Container : in out Vector);
78/2 procedure Merge (Target : in out Vector;
Source : in out Vector);
79/2 end Generic_Sorting;
80/2 private
81/2 ... -- not specified by the language
82/2 end Ada.Containers.Vectors;
83/2 The actual function for the generic formal function "=" on Element_Type
values is expected to define a reflexive and symmetric relationship and return
the same result value each time it is called with a particular pair of values.
If it behaves in some other manner, the functions defined to use it return an
unspecified value. The exact arguments and number of calls of this generic
formal function by the functions defined to use it are unspecified.
84/2 The type Vector is used to represent vectors. The type Vector needs
finalization (see 7.6).
85/2 Empty_Vector represents the empty vector object. It has a length of 0. If
an object of type Vector is not otherwise initialized, it is initialized to
the same value as Empty_Vector.
86/2 No_Element represents a cursor that designates no element. If an object
of type Cursor is not otherwise initialized, it is initialized to the same
value as No_Element.
87/2 The predefined "=" operator for type Cursor returns True if both cursors
are No_Element, or designate the same element in the same container.
88/2 Execution of the default implementation of the Input, Output, Read, or
Write attribute of type Cursor raises Program_Error.
89/2 No_Index represents a position that does not correspond to any element.
The subtype Extended_Index includes the indices covered by Index_Type plus the
value No_Index and, if it exists, the successor to the Index_Type'Last.
90/2 Some operations of this generic package have access-to-subprogram
parameters. To ensure such operations are well-defined, they guard against
certain actions by the designated subprogram. In particular, some operations
check for "tampering with cursors" of a container because they depend on the
set of elements of the container remaining constant, and others check for "
tampering with elements" of a container because they depend on elements of the
container not being replaced.
91/2 A subprogram is said to tamper with cursors of a vector object V if:
92/2 * it inserts or deletes elements of V, that is, it calls the Insert,
Insert_Space, Clear, Delete, or Set_Length procedures with V as a
parameter; or
93/2 * it finalizes V; or
94/2 * it calls the Move procedure with V as a parameter.
95/2 A subprogram is said to tamper with elements of a vector object V if:
96/2 * it tampers with cursors of V; or
97/2 * it replaces one or more elements of V, that is, it calls the
Replace_Element, Reverse_Elements, or Swap procedures or the Sort or
Merge procedures of an instance of Generic_Sorting with V as a
parameter.
98/2 function "=" (Left, Right : Vector) return Boolean;
99/2 If Left and Right denote the same vector object, then the function
returns True. If Left and Right have different lengths, then the
function returns False. Otherwise, it compares each element in
Left to the corresponding element in Right using the generic
formal equality operator. If any such comparison returns False,
the function returns False; otherwise it returns True. Any
exception raised during evaluation of element equality is
propagated.
100/2 function To_Vector (Length : Count_Type) return Vector;
101/2 Returns a vector with a length of Length, filled with empty
elements.
102/2 function To_Vector
(New_Item : Element_Type;
Length : Count_Type) return Vector;
103/2 Returns a vector with a length of Length, filled with elements
initialized to the value New_Item.
104/2 function "&" (Left, Right : Vector) return Vector;
105/2 Returns a vector comprising the elements of Left followed by the
elements of Right.
106/2 function "&" (Left : Vector;
Right : Element_Type) return Vector;
107/2 Returns a vector comprising the elements of Left followed by the
element Right.
108/2 function "&" (Left : Element_Type;
Right : Vector) return Vector;
109/2 Returns a vector comprising the element Left followed by the
elements of Right.
110/2 function "&" (Left, Right : Element_Type) return Vector;
111/2 Returns a vector comprising the element Left followed by the
element Right.
112/2 function Capacity (Container : Vector) return Count_Type;
113/2 Returns the capacity of Container.
114/2 procedure Reserve_Capacity (Container : in out Vector;
Capacity : in Count_Type);
115/2 Reserve_Capacity allocates new internal data structures such that
the length of the resulting vector can become at least the value
Capacity without requiring an additional call to Reserve_Capacity,
and is large enough to hold the current length of Container.
Reserve_Capacity then copies the elements into the new data
structures and deallocates the old data structures. Any exception
raised during allocation is propagated and Container is not
modified.
116/2 function Length (Container : Vector) return Count_Type;
117/2 Returns the number of elements in Container.
118/2 procedure Set_Length (Container : in out Vector;
Length : in Count_Type);
119/2 If Length is larger than the capacity of Container, Set_Length
calls Reserve_Capacity (Container, Length), then sets the length
of the Container to Length. If Length is greater than the original
length of Container, empty elements are added to Container;
otherwise elements are removed from Container.
120/2 function Is_Empty (Container : Vector) return Boolean;
121/2 Equivalent to Length (Container) = 0.
122/2 procedure Clear (Container : in out Vector);
123/2 Removes all the elements from Container. The capacity of Container
does not change.
124/2 function To_Cursor (Container : Vector;
Index : Extended_Index) return Cursor;
125/2 If Index is not in the range First_Index (Container) .. Last_Index
(Container), then No_Element is returned. Otherwise, a cursor
designating the element at position Index in Container is returned.
126/2 function To_Index (Position : Cursor) return Extended_Index;
127/2 If Position is No_Element, No_Index is returned. Otherwise, the
index (within its containing vector) of the element designated by
Position is returned.
128/2 function Element (Container : Vector;
Index : Index_Type)
return Element_Type;
129/2 If Index is not in the range First_Index (Container) .. Last_Index
(Container), then Constraint_Error is propagated. Otherwise,
Element returns the element at position Index.
130/2 function Element (Position : Cursor) return Element_Type;
131/2 If Position equals No_Element, then Constraint_Error is
propagated. Otherwise, Element returns the element designated by
Position.
132/2 procedure Replace_Element (Container : in out Vector;
Index : in Index_Type;
New_Item : in Element_Type);
133/2 If Index is not in the range First_Index (Container) .. Last_Index
(Container), then Constraint_Error is propagated. Otherwise
Replace_Element assigns the value New_Item to the element at
position Index. Any exception raised during the assignment is
propagated. The element at position Index is not an empty element
after successful call to Replace_Element.
134/2 procedure Replace_Element (Container : in out Vector;
Position : in Cursor;
New_Item : in Element_Type);
135/2 If Position equals No_Element, then Constraint_Error is
propagated; if Position does not designate an element in
Container, then Program_Error is propagated. Otherwise
Replace_Element assigns New_Item to the element designated by
Position. Any exception raised during the assignment is
propagated. The element at Position is not an empty element after
successful call to Replace_Element.
136/2 procedure Query_Element
(Container : in Vector;
Index : in Index_Type;
Process : not null access procedure (Element : in Element_Type));
137/2 If Index is not in the range First_Index (Container) .. Last_Index
(Container), then Constraint_Error is propagated. Otherwise,
Query_Element calls Process.all with the element at position Index
as the argument. Program_Error is propagated if Process.all
tampers with the elements of Container. Any exception raised by
Process.all is propagated.
138/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Element : in Element_Type));
139/2 If Position equals No_Element, then Constraint_Error is
propagated. Otherwise, Query_Element calls Process.all with the
element designated by Position as the argument. Program_Error is
propagated if Process.all tampers with the elements of Container.
Any exception raised by Process.all is propagated.
140/2 procedure Update_Element
(Container : in out Vector;
Index : in Index_Type;
Process : not null access procedure (Element : in out Element_Type));
141/2 If Index is not in the range First_Index (Container) .. Last_Index
(Container), then Constraint_Error is propagated. Otherwise,
Update_Element calls Process.all with the element at position
Index as the argument. Program_Error is propagated if Process.all
tampers with the elements of Container. Any exception raised by
Process.all is propagated.
142/2 If Element_Type is unconstrained and definite, then the actual
Element parameter of Process.all shall be unconstrained.
143/2 The element at position Index is not an empty element after
successful completion of this operation.
144/2 procedure Update_Element
(Container : in out Vector;
Position : in Cursor;
Process : not null access procedure (Element : in out Element_Type));
145/2 If Position equals No_Element, then Constraint_Error is
propagated; if Position does not designate an element in
Container, then Program_Error is propagated. Otherwise
Update_Element calls Process.all with the element designated by
Position as the argument. Program_Error is propagated if
Process.all tampers with the elements of Container. Any exception
raised by Process.all is propagated.
146/2 If Element_Type is unconstrained and definite, then the actual
Element parameter of Process.all shall be unconstrained.
147/2 The element designated by Position is not an empty element after
successful completion of this operation.
148/2 procedure Move (Target : in out Vector;
Source : in out Vector);
149/2 If Target denotes the same object as Source, then Move has no
effect. Otherwise, Move first calls Clear (Target); then, each
element from Source is removed from Source and inserted into
Target in the original order. The length of Source is 0 after a
successful call to Move.
150/2 procedure Insert (Container : in out Vector;
Before : in Extended_Index;
New_Item : in Vector);
151/2 If Before is not in the range First_Index (Container) ..
Last_Index (Container) + 1, then Constraint_Error is propagated.
If Length(New_Item) is 0, then Insert does nothing. Otherwise, it
computes the new length NL as the sum of the current length and
Length (New_Item); if the value of Last appropriate for length NL
would be greater than Index_Type'Last then Constraint_Error is
propagated.
152/2 If the current vector capacity is less than NL, Reserve_Capacity
(Container, NL) is called to increase the vector capacity. Then
Insert slides the elements in the range Before .. Last_Index
(Container) up by Length(New_Item) positions, and then copies the
elements of New_Item to the positions starting at Before. Any
exception raised during the copying is propagated.
153/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
New_Item : in Vector);
154/2 If Before is not No_Element, and does not designate an element in
Container, then Program_Error is propagated. Otherwise, if
Length(New_Item) is 0, then Insert does nothing. If Before is
No_Element, then the call is equivalent to Insert (Container,
Last_Index (Container) + 1, New_Item); otherwise the call is
equivalent to Insert (Container, To_Index (Before), New_Item);
155/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
New_Item : in Vector;
Position : out Cursor);
156/2 If Before is not No_Element, and does not designate an element in
Container, then Program_Error is propagated. If Before equals
No_Element, then let T be Last_Index (Container) + 1; otherwise,
let T be To_Index (Before). Insert (Container, T, New_Item) is
called, and then Position is set to To_Cursor (Container, T).
157/2 procedure Insert (Container : in out Vector;
Before : in Extended_Index;
New_Item : in Element_Type;
Count : in Count_Type := 1);
158/2 Equivalent to Insert (Container, Before, To_Vector (New_Item,
Count));
159/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
New_Item : in Element_Type;
Count : in Count_Type := 1);
160/2 Equivalent to Insert (Container, Before, To_Vector (New_Item,
Count));
161/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
New_Item : in Element_Type;
Position : out Cursor;
Count : in Count_Type := 1);
162/2 Equivalent to Insert (Container, Before, To_Vector (New_Item,
Count), Position);
163/2 procedure Insert (Container : in out Vector;
Before : in Extended_Index;
Count : in Count_Type := 1);
164/2 If Before is not in the range First_Index (Container) ..
Last_Index (Container) + 1, then Constraint_Error is propagated.
If Count is 0, then Insert does nothing. Otherwise, it computes
the new length NL as the sum of the current length and Count; if
the value of Last appropriate for length NL would be greater than
Index_Type'Last then Constraint_Error is propagated.
165/2 If the current vector capacity is less than NL, Reserve_Capacity
(Container, NL) is called to increase the vector capacity. Then
Insert slides the elements in the range Before .. Last_Index
(Container) up by Count positions, and then inserts elements that
are initialized by default (see 3.3.1) in the positions starting
at Before.
166/2 procedure Insert (Container : in out Vector;
Before : in Cursor;
Position : out Cursor;
Count : in Count_Type := 1);
167/2 If Before is not No_Element, and does not designate an element in
Container, then Program_Error is propagated. If Before equals
No_Element, then let T be Last_Index (Container) + 1; otherwise,
let T be To_Index (Before). Insert (Container, T, Count) is
called, and then Position is set to To_Cursor (Container, T).
168/2 procedure Prepend (Container : in out Vector;
New_Item : in Vector;
Count : in Count_Type := 1);
169/2 Equivalent to Insert (Container, First_Index (Container),
New_Item).
170/2 procedure Prepend (Container : in out Vector;
New_Item : in Element_Type;
Count : in Count_Type := 1);
171/2 Equivalent to Insert (Container, First_Index (Container),
New_Item, Count).
172/2 procedure Append (Container : in out Vector;
New_Item : in Vector);
173/2 Equivalent to Insert (Container, Last_Index (Container) + 1,
New_Item).
174/2 procedure Append (Container : in out Vector;
New_Item : in Element_Type;
Count : in Count_Type := 1);
175/2 Equivalent to Insert (Container, Last_Index (Container) + 1,
New_Item, Count).
176/2 procedure Insert_Space (Container : in out Vector;
Before : in Extended_Index;
Count : in Count_Type := 1);
177/2 If Before is not in the range First_Index (Container) ..
Last_Index (Container) + 1, then Constraint_Error is propagated.
If Count is 0, then Insert_Space does nothing. Otherwise, it
computes the new length NL as the sum of the current length and
Count; if the value of Last appropriate for length NL would be
greater than Index_Type'Last then Constraint_Error is propagated.
178/2 If the current vector capacity is less than NL, Reserve_Capacity
(Container, NL) is called to increase the vector capacity. Then
Insert_Space slides the elements in the range Before .. Last_Index
(Container) up by Count positions, and then inserts empty elements
in the positions starting at Before.
179/2 procedure Insert_Space (Container : in out Vector;
Before : in Cursor;
Position : out Cursor;
Count : in Count_Type := 1);
180/2 If Before is not No_Element, and does not designate an element in
Container, then Program_Error is propagated. If Before equals
No_Element, then let T be Last_Index (Container) + 1; otherwise,
let T be To_Index (Before). Insert_Space (Container, T, Count) is
called, and then Position is set to To_Cursor (Container, T).
181/2 procedure Delete (Container : in out Vector;
Index : in Extended_Index;
Count : in Count_Type := 1);
182/2 If Index is not in the range First_Index (Container) .. Last_Index
(Container) + 1, then Constraint_Error is propagated. If Count is
0, Delete has no effect. Otherwise Delete slides the elements (if
any) starting at position Index + Count down to Index. Any
exception raised during element assignment is propagated.
183/2 procedure Delete (Container : in out Vector;
Position : in out Cursor;
Count : in Count_Type := 1);
184/2 If Position equals No_Element, then Constraint_Error is
propagated. If Position does not designate an element in
Container, then Program_Error is propagated. Otherwise, Delete
(Container, To_Index (Position), Count) is called, and then
Position is set to No_Element.
185/2 procedure Delete_First (Container : in out Vector;
Count : in Count_Type := 1);
186/2 Equivalent to Delete (Container, First_Index (Container), Count).
187/2 procedure Delete_Last (Container : in out Vector;
Count : in Count_Type := 1);
188/2 If Length (Container) <= Count then Delete_Last is equivalent to
Clear (Container). Otherwise it is equivalent to Delete
(Container, Index_Type'Val(Index_Type'Pos(Last_Index (Container))
- Count + 1), Count).
189/2 procedure Reverse_Elements (Container : in out List);
190/2 Reorders the elements of Container in reverse order.
191/2 procedure Swap (Container : in out Vector;
I, J : in Index_Type);
192/2 If either I or J is not in the range First_Index (Container) ..
Last_Index (Container), then Constraint_Error is propagated.
Otherwise, Swap exchanges the values of the elements at positions
I and J.
193/2 procedure Swap (Container : in out Vector;
I, J : in Cursor);
194/2 If either I or J is No_Element, then Constraint_Error is
propagated. If either I or J do not designate an element in
Container, then Program_Error is propagated. Otherwise, Swap
exchanges the values of the elements designated by I and J.
195/2 function First_Index (Container : Vector) return Index_Type;
196/2 Returns the value Index_Type'First.
197/2 function First (Container : Vector) return Cursor;
198/2 If Container is empty, First returns No_Element. Otherwise, it
returns a cursor that designates the first element in Container.
199/2 function First_Element (Container : Vector) return Element_Type;
200/2 Equivalent to Element (Container, First_Index (Container)).
201/2 function Last_Index (Container : Vector) return Extended_Index;
202/2 If Container is empty, Last_Index returns No_Index. Otherwise, it
returns the position of the last element in Container.
203/2 function Last (Container : Vector) return Cursor;
204/2 If Container is empty, Last returns No_Element. Otherwise, it
returns a cursor that designates the last element in Container.
205/2 function Last_Element (Container : Vector) return Element_Type;
206/2 Equivalent to Element (Container, Last_Index (Container)).
207/2 function Next (Position : Cursor) return Cursor;
208/2 If Position equals No_Element or designates the last element of
the container, then Next returns the value No_Element. Otherwise,
it returns a cursor that designates the element with index
To_Index (Position) + 1 in the same vector as Position.
209/2 procedure Next (Position : in out Cursor);
210/2 Equivalent to Position := Next (Position).
211/2 function Previous (Position : Cursor) return Cursor;
212/2 If Position equals No_Element or designates the first element of
the container, then Previous returns the value No_Element.
Otherwise, it returns a cursor that designates the element with
index To_Index (Position) - 1 in the same vector as Position.
213/2 procedure Previous (Position : in out Cursor);
214/2 Equivalent to Position := Previous (Position).
215/2 function Find_Index (Container : Vector;
Item : Element_Type;
Index : Index_Type := Index_Type'First)
return Extended_Index;
216/2 Searches the elements of Container for an element equal to Item
(using the generic formal equality operator). The search starts at
position Index and proceeds towards Last_Index (Container). If no
equal element is found, then Find_Index returns No_Index.
Otherwise, it returns the index of the first equal element
encountered.
217/2 function Find (Container : Vector;
Item : Element_Type;
Position : Cursor := No_Element)
return Cursor;
218/2 If Position is not No_Element, and does not designate an element
in Container, then Program_Error is propagated. Otherwise Find
searches the elements of Container for an element equal to Item
(using the generic formal equality operator). The search starts at
the first element if Position equals No_Element, and at the
element designated by Position otherwise. It proceeds towards the
last element of Container. If no equal element is found, then Find
returns No_Element. Otherwise, it returns a cursor designating the
first equal element encountered.
219/2 function Reverse_Find_Index (Container : Vector;
Item : Element_Type;
Index : Index_Type := Index_Type'Last)
return Extended_Index;
220/2 Searches the elements of Container for an element equal to Item
(using the generic formal equality operator). The search starts at
position Index or, if Index is greater than Last_Index
(Container), at position Last_Index (Container). It proceeds
towards First_Index (Container). If no equal element is found,
then Reverse_Find_Index returns No_Index. Otherwise, it returns
the index of the first equal element encountered.
221/2 function Reverse_Find (Container : Vector;
Item : Element_Type;
Position : Cursor := No_Element)
return Cursor;
222/2 If Position is not No_Element, and does not designate an element
in Container, then Program_Error is propagated. Otherwise
Reverse_Find searches the elements of Container for an element
equal to Item (using the generic formal equality operator). The
search starts at the last element if Position equals No_Element,
and at the element designated by Position otherwise. It proceeds
towards the first element of Container. If no equal element is
found, then Reverse_Find returns No_Element. Otherwise, it returns
a cursor designating the first equal element encountered.
223/2 function Contains (Container : Vector;
Item : Element_Type) return Boolean;
224/2 Equivalent to Has_Element (Find (Container, Item)).
225/2 function Has_Element (Position : Cursor) return Boolean;
226/2 Returns True if Position designates an element, and returns False
otherwise.
227/2 procedure Iterate
(Container : in Vector;
Process : not null access procedure (Position : in Cursor));
228/2 Invokes Process.all with a cursor that designates each element in
Container, in index order. Program_Error is propagated if
Process.all tampers with the cursors of Container. Any exception
raised by Process is propagated.
229/2 procedure Reverse_Iterate
(Container : in Vector;
Process : not null access procedure (Position : in Cursor));
230/2 Iterates over the elements in Container as per Iterate, except
that elements are traversed in reverse index order.
231/2 The actual function for the generic formal function "<" of
Generic_Sorting is expected to return the same value each time it is called
with a particular pair of element values. It should define a strict ordering
relationship, that is, be irreflexive, asymmetric, and transitive; it should
not modify Container. If the actual for "<" behaves in some other manner, the
behavior of the subprograms of Generic_Sorting are unspecified. How many times
the subprograms of Generic_Sorting call "<" is unspecified.
232/2 function Is_Sorted (Container : Vector) return Boolean;
233/2 Returns True if the elements are sorted smallest first as
determined by the generic formal "<" operator; otherwise,
Is_Sorted returns False. Any exception raised during evaluation of
"<" is propagated.
234/2 procedure Sort (Container : in out Vector);
235/2 Reorders the elements of Container such that the elements are
sorted smallest first as determined by the generic formal "<"
operator provided. Any exception raised during evaluation of "<"
is propagated.
236/2 procedure Merge (Target : in out Vector;
Source : in out Vector);
237/2 Merge removes elements from Source and inserts them into Target;
afterwards, Target contains the union of the elements that were
initially in Source and Target; Source is left empty. If Target
and Source are initially sorted smallest first, then Target is
ordered smallest first as determined by the generic formal "<"
operator; otherwise, the order of elements in Target is
unspecified. Any exception raised during evaluation of "<" is
propagated.
Bounded (Run-Time) Errors
238/2 Reading the value of an empty element by calling Element, Query_Element,
Update_Element, Swap, Is_Sorted, Sort, Merge, "=", Find, or Reverse_Find is a
bounded error. The implementation may treat the element as having any normal
value (see 13.9.1) of the element type, or raise Constraint_Error or
Program_Error before modifying the vector.
239/2 Calling Merge in an instance of Generic_Sorting with either Source or
Target not ordered smallest first using the provided generic formal "<"
operator is a bounded error. Either Program_Error is raised after Target is
updated as described for Merge, or the operation works as defined.
240/2 A Cursor value is ambiguous if any of the following have occurred since
it was created:
241/2 * Insert, Insert_Space, or Delete has been called on the vector that
contains the element the cursor designates with an index value (or a
cursor designating an element at such an index value) less than or
equal to the index value of the element designated by the cursor; or
242/2 * The vector that contains the element it designates has been passed
to the Sort or Merge procedures of an instance of Generic_Sorting, or
to the Reverse_Elements procedure.
243/2 It is a bounded error to call any subprogram other than "=" or
Has_Element declared in Containers.Vectors with an ambiguous (but not invalid,
see below) cursor parameter. Possible results are:
244/2 * The cursor may be treated as if it were No_Element;
245/2 * The cursor may designate some element in the vector (but not
necessarily the element that it originally designated);
246/2 * Constraint_Error may be raised; or
247/2 * Program_Error may be raised.
Erroneous Execution
248/2 A Cursor value is invalid if any of the following have occurred since it
was created:
249/2 * The vector that contains the element it designates has been
finalized;
250/2 * The vector that contains the element it designates has been used as
the Source or Target of a call to Move; or
251/2 * The element it designates has been deleted.
252/2 The result of "=" or Has_Element is unspecified if it is called with an
invalid cursor parameter. Execution is erroneous if any other subprogram
declared in Containers.Vectors is called with an invalid cursor parameter.
Implementation Requirements
253/2 No storage associated with a vector object shall be lost upon assignment
or scope exit.
254/2 The execution of an assignment_statement for a vector shall have the
effect of copying the elements from the source vector object to the target
vector object.
Implementation Advice
255/2 Containers.Vectors should be implemented similarly to an array. In
particular, if the length of a vector is N, then
256/2 * the worst-case time complexity of Element should be O(log N);
257 * the worst-case time complexity of Append with Count=1 when N is less
than the capacity of the vector should be O(log N); and
258/2 * the worst-case time complexity of Prepend with Count=1 and
Delete_First with Count=1 should be O(N log N).
259/2 The worst-case time complexity of a call on procedure Sort of an
instance of Containers.Vectors.Generic_Sorting should be O(N**2), and the
average time complexity should be better than O(N**2).
260/2 Containers.Vectors.Generic_Sorting.Sort and
Containers.Vectors.Generic_Sorting.Merge should minimize copying of elements.
261/2 Move should not copy elements, and should minimize copying of internal
data structures.
262/2 If an exception is propagated from a vector operation, no storage should
be lost, nor any elements removed from a vector unless specified by the
operation.
NOTES
263/2 42 All elements of a vector occupy locations in the internal array.
If a sparse container is required, a Hashed_Map should be used rather
than a vector.
264/2 43 If Index_Type'Base'First = Index_Type'First an instance of
Ada.Containers.Vectors will raise Constraint_Error. A value below
Index_Type'First is required so that an empty vector has a meaningful
value of Last_Index.
A.18.3 The Package Containers.Doubly_Linked_Lists
1/2 The language-defined generic package Containers.Doubly_Linked_Lists
provides private types List and Cursor, and a set of operations for each type.
A list container is optimized for insertion and deletion at any position.
2/2 A doubly-linked list container object manages a linked list of internal
nodes, each of which contains an element and pointers to the next (successor)
and previous (predecessor) internal nodes. A cursor designates a particular
node within a list (and by extension the element contained in that node). A
cursor keeps designating the same node (and element) as long as the node is
part of the container, even if the node is moved in the container.
3/2 The length of a list is the number of elements it contains.
Static Semantics
4/2 The generic library package Containers.Doubly_Linked_Lists has the
following declaration:
5/2 generic
type Element_Type is private;
with function "=" (Left, Right : Element_Type)
return Boolean is <>;
package Ada.Containers.Doubly_Linked_Lists is
pragma Preelaborate(Doubly_Linked_Lists);
6/2 type List is tagged private;
pragma Preelaborable_Initialization(List);
7/2 type Cursor is private;
pragma Preelaborable_Initialization(Cursor);
8/2 Empty_List : constant List;
9/2 No_Element : constant Cursor;
10/2 function "=" (Left, Right : List) return Boolean;
11/2 function Length (Container : List) return Count_Type;
12/2 function Is_Empty (Container : List) return Boolean;
13/2 procedure Clear (Container : in out List);
14/2 function Element (Position : Cursor)
return Element_Type;
15/2 procedure Replace_Element (Container : in out List;
Position : in Cursor;
New_Item : in Element_Type);
16/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Element : in Element_Type));
17/2 procedure Update_Element
(Container : in out List;
Position : in Cursor;
Process : not null access procedure
(Element : in out Element_Type));
18/2 procedure Move (Target : in out List;
Source : in out List);
19/2 procedure Insert (Container : in out List;
Before : in Cursor;
New_Item : in Element_Type;
Count : in Count_Type := 1);
20/2 procedure Insert (Container : in out List;
Before : in Cursor;
New_Item : in Element_Type;
Position : out Cursor;
Count : in Count_Type := 1);
21/2 procedure Insert (Container : in out List;
Before : in Cursor;
Position : out Cursor;
Count : in Count_Type := 1);
22/2 procedure Prepend (Container : in out List;
New_Item : in Element_Type;
Count : in Count_Type := 1);
23/2 procedure Append (Container : in out List;
New_Item : in Element_Type;
Count : in Count_Type := 1);
24/2 procedure Delete (Container : in out List;
Position : in out Cursor;
Count : in Count_Type := 1);
25/2 procedure Delete_First (Container : in out List;
Count : in Count_Type := 1);
26/2 procedure Delete_Last (Container : in out List;
Count : in Count_Type := 1);
27/2 procedure Reverse_Elements (Container : in out List);
28/2 procedure Swap (Container : in out List;
I, J : in Cursor);
29/2 procedure Swap_Links (Container : in out List;
I, J : in Cursor);
30/2 procedure Splice (Target : in out List;
Before : in Cursor;
Source : in out List);
31/2 procedure Splice (Target : in out List;
Before : in Cursor;
Source : in out List;
Position : in out Cursor);
32/2 procedure Splice (Container: in out List;
Before : in Cursor;
Position : in Cursor);
33/2 function First (Container : List) return Cursor;
34/2 function First_Element (Container : List)
return Element_Type;
35/2 function Last (Container : List) return Cursor;
36/2 function Last_Element (Container : List)
return Element_Type;
37/2 function Next (Position : Cursor) return Cursor;
38/2 function Previous (Position : Cursor) return Cursor;
39/2 procedure Next (Position : in out Cursor);
40/2 procedure Previous (Position : in out Cursor);
41/2 function Find (Container : List;
Item : Element_Type;
Position : Cursor := No_Element)
return Cursor;
42/2 function Reverse_Find (Container : List;
Item : Element_Type;
Position : Cursor := No_Element)
return Cursor;
43/2 function Contains (Container : List;
Item : Element_Type) return Boolean;
44/2 function Has_Element (Position : Cursor) return Boolean;
45/2 procedure Iterate
(Container : in List;
Process : not null access procedure (Position : in Cursor));
46/2 procedure Reverse_Iterate
(Container : in List;
Process : not null access procedure (Position : in Cursor));
47/2 generic
with function "<" (Left, Right : Element_Type)
return Boolean is <>;
package Generic_Sorting is
48/2 function Is_Sorted (Container : List) return Boolean;
49/2 procedure Sort (Container : in out List);
50/2 procedure Merge (Target : in out List;
Source : in out List);
51/2 end Generic_Sorting;
52/2 private
53/2 ... -- not specified by the language
54/2 end Ada.Containers.Doubly_Linked_Lists;
55/2 The actual function for the generic formal function "=" on Element_Type
values is expected to define a reflexive and symmetric relationship and return
the same result value each time it is called with a particular pair of values.
If it behaves in some other manner, the functions Find, Reverse_Find, and "="
on list values return an unspecified value. The exact arguments and number of
calls of this generic formal function by the functions Find, Reverse_Find, and
"=" on list values are unspecified.
56/2 The type List is used to represent lists. The type List needs
finalization (see 7.6).
57/2 Empty_List represents the empty List object. It has a length of 0. If an
object of type List is not otherwise initialized, it is initialized to the
same value as Empty_List.
58/2 No_Element represents a cursor that designates no element. If an object
of type Cursor is not otherwise initialized, it is initialized to the same
value as No_Element.
59/2 The predefined "=" operator for type Cursor returns True if both cursors
are No_Element, or designate the same element in the same container.
60/2 Execution of the default implementation of the Input, Output, Read, or
Write attribute of type Cursor raises Program_Error.
61/2 Some operations of this generic package have access-to-subprogram
parameters. To ensure such operations are well-defined, they guard against
certain actions by the designated subprogram. In particular, some operations
check for "tampering with cursors" of a container because they depend on the
set of elements of the container remaining constant, and others check for "
tampering with elements" of a container because they depend on elements of the
container not being replaced.
62/2 A subprogram is said to tamper with cursors of a list object L if:
63/2 * it inserts or deletes elements of L, that is, it calls the Insert,
Clear, Delete, or Delete_Last procedures with L as a parameter; or
64/2 * it reorders the elements of L, that is, it calls the Splice,
Swap_Links, or Reverse_Elements procedures or the Sort or Merge
procedures of an instance of Generic_Sorting with L as a parameter; or
65/2 * it finalizes L; or
66/2 * it calls the Move procedure with L as a parameter.
67/2 A subprogram is said to tamper with elements of a list object L if:
68/2 * it tampers with cursors of L; or
69/2 * it replaces one or more elements of L, that is, it calls the
Replace_Element or Swap procedures with L as a parameter.
70/2 function "=" (Left, Right : List) return Boolean;
71/2 If Left and Right denote the same list object, then the function
returns True. If Left and Right have different lengths, then the
function returns False. Otherwise, it compares each element in
Left to the corresponding element in Right using the generic
formal equality operator. If any such comparison returns False,
the function returns False; otherwise it returns True. Any
exception raised during evaluation of element equality is
propagated.
72/2 function Length (Container : List) return Count_Type;
73/2 Returns the number of elements in Container.
74/2 function Is_Empty (Container : List) return Boolean;
75/2 Equivalent to Length (Container) = 0.
76/2 procedure Clear (Container : in out List);
77/2 Removes all the elements from Container.
78/2 function Element (Position : Cursor) return Element_Type;
79/2 If Position equals No_Element, then Constraint_Error is
propagated. Otherwise, Element returns the element designated by
Position.
80/2 procedure Replace_Element (Container : in out List;
Position : in Cursor;
New_Item : in Element_Type);
81/2 If Position equals No_Element, then Constraint_Error is
propagated; if Position does not designate an element in
Container, then Program_Error is propagated. Otherwise
Replace_Element assigns the value New_Item to the element
designated by Position.
82/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Element : in Element_Type));
83/2 If Position equals No_Element, then Constraint_Error is
propagated. Otherwise, Query_Element calls Process.all with the
element designated by Position as the argument. Program_Error is
propagated if Process.all tampers with the elements of Container.
Any exception raised by Process.all is propagated.
84/2 procedure Update_Element
(Container : in out List;
Position : in Cursor;
Process : not null access procedure (Element : in out Element_Type));
85/2 If Position equals No_Element, then Constraint_Error is
propagated; if Position does not designate an element in
Container, then Program_Error is propagated. Otherwise
Update_Element calls Process.all with the element designated by
Position as the argument. Program_Error is propagated if
Process.all tampers with the elements of Container. Any exception
raised by Process.all is propagated.
86/2 If Element_Type is unconstrained and definite, then the actual
Element parameter of Process.all shall be unconstrained.
87/2 procedure Move (Target : in out List;
Source : in out List);
88/2 If Target denotes the same object as Source, then Move has no
effect. Otherwise, Move first calls Clear (Target). Then, the
nodes in Source are moved to Target (in the original order). The
length of Target is set to the length of Source, and the length of
Source is set to 0.
89/2 procedure Insert (Container : in out List;
Before : in Cursor;
New_Item : in Element_Type;
Count : in Count_Type := 1);
90/2 If Before is not No_Element, and does not designate an element in
Container, then Program_Error is propagated. Otherwise, Insert
inserts Count copies of New_Item prior to the element designated
by Before. If Before equals No_Element, the new elements are
inserted after the last node (if any). Any exception raised during
allocation of internal storage is propagated, and Container is not
modified.
91/2 procedure Insert (Container : in out List;
Before : in Cursor;
New_Item : in Element_Type;
Position : out Cursor;
Count : in Count_Type := 1);
92/2 If Before is not No_Element, and does not designate an element in
Container, then Program_Error is propagated. Otherwise, Insert
allocates Count copies of New_Item, and inserts them prior to the
element designated by Before. If Before equals No_Element, the new
elements are inserted after the last element (if any). Position
designates the first newly-inserted element. Any exception raised
during allocation of internal storage is propagated, and Container
is not modified.
93/2 procedure Insert (Container : in out List;
Before : in Cursor;
Position : out Cursor;
Count : in Count_Type := 1);
94/2 If Before is not No_Element, and does not designate an element in
Container, then Program_Error is propagated. Otherwise, Insert
inserts Count new elements prior to the element designated by
Before. If Before equals No_Element, the new elements are inserted
after the last node (if any). The new elements are initialized by
default (see 3.3.1). Any exception raised during allocation of
internal storage is propagated, and Container is not modified.
95/2 procedure Prepend (Container : in out List;
New_Item : in Element_Type;
Count : in Count_Type := 1);
96/2 Equivalent to Insert (Container, First (Container), New_Item,
Count).
97/2 procedure Append (Container : in out List;
New_Item : in Element_Type;
Count : in Count_Type := 1);
98/2 Equivalent to Insert (Container, No_Element, New_Item, Count).
99/2 procedure Delete (Container : in out List;
Position : in out Cursor;
Count : in Count_Type := 1);
100/2 If Position equals No_Element, then Constraint_Error is
propagated. If Position does not designate an element in
Container, then Program_Error is propagated. Otherwise Delete
removes (from Container) Count elements starting at the element
designated by Position (or all of the elements starting at
Position if there are fewer than Count elements starting at
Position). Finally, Position is set to No_Element.
101/2 procedure Delete_First (Container : in out List;
Count : in Count_Type := 1);
102/2 Equivalent to Delete (Container, First (Container), Count).
103/2 procedure Delete_Last (Container : in out List;
Count : in Count_Type := 1);
104/2 If Length (Container) <= Count then Delete_Last is equivalent to
Clear (Container). Otherwise it removes the last Count nodes from
Container.
105/2 procedure Reverse_Elements (Container : in out List);
106/2 Reorders the elements of Container in reverse order.
107/2 procedure Swap (Container : in out List;
I, J : in Cursor);
108/2 If either I or J is No_Element, then Constraint_Error is
propagated. If either I or J do not designate an element in
Container, then Program_Error is propagated. Otherwise, Swap
exchanges the values of the elements designated by I and J.
109/2 procedure Swap_Links (Container : in out List;
I, J : in Cursor);
110/2 If either I or J is No_Element, then Constraint_Error is
propagated. If either I or J do not designate an element in
Container, then Program_Error is propagated. Otherwise, Swap_Links
exchanges the nodes designated by I and J.
111/2 procedure Splice (Target : in out List;
Before : in Cursor;
Source : in out List);
112/2 If Before is not No_Element, and does not designate an element in
Target, then Program_Error is propagated. Otherwise, if Source
denotes the same object as Target, the operation has no effect.
Otherwise, Splice reorders elements such that they are removed
from Source and moved to Target, immediately prior to Before. If
Before equals No_Element, the nodes of Source are spliced after
the last node of Target. The length of Target is incremented by
the number of nodes in Source, and the length of Source is set to
0.
113/2 procedure Splice (Target : in out List;
Before : in Cursor;
Source : in out List;
Position : in out Cursor);
114/2 If Position is No_Element then Constraint_Error is propagated. If
Before does not equal No_Element, and does not designate an
element in Target, then Program_Error is propagated. If Position
does not equal No_Element, and does not designate a node in
Source, then Program_Error is propagated. If Source denotes the
same object as Target, then there is no effect if Position equals
Before, else the element designated by Position is moved
immediately prior to Before, or, if Before equals No_Element,
after the last element. In both cases, Position and the length of
Target are unchanged. Otherwise the element designated by Position
is removed from Source and moved to Target, immediately prior to
Before, or, if Before equals No_Element, after the last element of
Target. The length of Target is incremented, the length of Source
is decremented, and Position is updated to represent an element in
Target.
115/2 procedure Splice (Container: in out List;
Before : in Cursor;
Position : in Cursor);
116/2 If Position is No_Element then Constraint_Error is propagated. If
Before does not equal No_Element, and does not designate an
element in Container, then Program_Error is propagated. If
Position does not equal No_Element, and does not designate a node
in Container, then Program_Error is propagated. If Position equals
Before there is no effect. Otherwise, the element designated by
Position is moved immediately prior to Before, or, if Before
equals No_Element, after the last element. The length of Container
is unchanged.
117/2 function First (Container : List) return Cursor;
118/2 If Container is empty, First returns the value No_Element.
Otherwise it returns a cursor that designates the first node in
Container.
119/2 function First_Element (Container : List) return Element_Type;
120/2 Equivalent to Element (First (Container)).
121/2 function Last (Container : List) return Cursor;
122/2 If Container is empty, Last returns the value No_Element.
Otherwise it returns a cursor that designates the last node in
Container.
123/2 function Last_Element (Container : List) return Element_Type;
124/2 Equivalent to Element (Last (Container)).
125/2 function Next (Position : Cursor) return Cursor;
126/2 If Position equals No_Element or designates the last element of
the container, then Next returns the value No_Element. Otherwise,
it returns a cursor that designates the successor of the element
designated by Position.
127/2 function Previous (Position : Cursor) return Cursor;
128/2 If Position equals No_Element or designates the first element of
the container, then Previous returns the value No_Element.
Otherwise, it returns a cursor that designates the predecessor of
the element designated by Position.
129/2 procedure Next (Position : in out Cursor);
130/2 Equivalent to Position := Next (Position).
131/2 procedure Previous (Position : in out Cursor);
132/2 Equivalent to Position := Previous (Position).
133/2 function Find (Container : List;
Item : Element_Type;
Position : Cursor := No_Element)
return Cursor;
134/2 If Position is not No_Element, and does not designate an element
in Container, then Program_Error is propagated. Find searches the
elements of Container for an element equal to Item (using the
generic formal equality operator). The search starts at the
element designated by Position, or at the first element if
Position equals No_Element. It proceeds towards Last (Container).
If no equal element is found, then Find returns No_Element.
Otherwise, it returns a cursor designating the first equal element
encountered.
135/2 function Reverse_Find (Container : List;
Item : Element_Type;
Position : Cursor := No_Element)
return Cursor;
136/2 If Position is not No_Element, and does not designate an element
in Container, then Program_Error is propagated. Find searches the
elements of Container for an element equal to Item (using the
generic formal equality operator). The search starts at the
element designated by Position, or at the last element if Position
equals No_Element. It proceeds towards First (Container). If no
equal element is found, then Reverse_Find returns No_Element.
Otherwise, it returns a cursor designating the first equal element
encountered.
137/2 function Contains (Container : List;
Item : Element_Type) return Boolean;
138/2 Equivalent to Find (Container, Item) /= No_Element.
139/2 function Has_Element (Position : Cursor) return Boolean;
140/2 Returns True if Position designates an element, and returns False
otherwise.
141/2 procedure Iterate
(Container : in List;
Process : not null access procedure (Position : in Cursor));
142/2 Iterate calls Process.all with a cursor that designates each node
in Container, starting with the first node and moving the cursor
as per the Next function. Program_Error is propagated if
Process.all tampers with the cursors of Container. Any exception
raised by Process.all is propagated.
143/2 procedure Reverse_Iterate
(Container : in List;
Process : not null access procedure (Position : in Cursor));
144/2 Iterates over the nodes in Container as per Iterate, except that
elements are traversed in reverse order, starting with the last
node and moving the cursor as per the Previous function.
145/2 The actual function for the generic formal function "<" of
Generic_Sorting is expected to return the same value each time it is called
with a particular pair of element values. It should define a strict ordering
relationship, that is, be irreflexive, asymmetric, and transitive; it should
not modify Container. If the actual for "<" behaves in some other manner, the
behavior of the subprograms of Generic_Sorting are unspecified. How many times
the subprograms of Generic_Sorting call "<" is unspecified.
146/2 function Is_Sorted (Container : List) return Boolean;
147/2 Returns True if the elements are sorted smallest first as
determined by the generic formal "<" operator; otherwise,
Is_Sorted returns False. Any exception raised during evaluation of
"<" is propagated.
148/2 procedure Sort (Container : in out List);
149/2 Reorders the nodes of Container such that the elements are sorted
smallest first as determined by the generic formal "<" operator
provided. The sort is stable. Any exception raised during
evaluation of "<" is propagated.
150/2 procedure Merge (Target : in out List;
Source : in out List);
151/2 Merge removes elements from Source and inserts them into Target;
afterwards, Target contains the union of the elements that were
initially in Source and Target; Source is left empty. If Target
and Source are initially sorted smallest first, then Target is
ordered smallest first as determined by the generic formal "<"
operator; otherwise, the order of elements in Target is
unspecified. Any exception raised during evaluation of "<" is
propagated.
Bounded (Run-Time) Errors
152/2 Calling Merge in an instance of Generic_Sorting with either Source or
Target not ordered smallest first using the provided generic formal "<"
operator is a bounded error. Either Program_Error is raised after Target is
updated as described for Merge, or the operation works as defined.
Erroneous Execution
153/2 A Cursor value is invalid if any of the following have occurred since it
was created:
154/2 * The list that contains the element it designates has been finalized;
155/2 * The list that contains the element it designates has been used as
the Source or Target of a call to Move; or
156/2 * The element it designates has been deleted.
157/2 The result of "=" or Has_Element is unspecified if it is called with an
invalid cursor parameter. Execution is erroneous if any other subprogram
declared in Containers.Doubly_Linked_Lists is called with an invalid cursor
parameter.
Implementation Requirements
158/2 No storage associated with a doubly-linked List object shall be lost
upon assignment or scope exit.
159/2 The execution of an assignment_statement for a list shall have the
effect of copying the elements from the source list object to the target list
object.
Implementation Advice
160/2 Containers.Doubly_Linked_Lists should be implemented similarly to a
linked list. In particular, if N is the length of a list, then the worst-case
time complexity of Element, Insert with Count=1, and Delete with Count=1
should be O(log N).
161/2 The worst-case time complexity of a call on procedure Sort of an
instance of Containers.Doubly_Linked_Lists.Generic_Sorting should be O(N**2),
and the average time complexity should be better than O(N**2).
162/2 Move should not copy elements, and should minimize copying of internal
data structures.
163/2 If an exception is propagated from a list operation, no storage should
be lost, nor any elements removed from a list unless specified by the
operation.
NOTES
164/2 44 Sorting a list never copies elements, and is a stable sort (equal
elements remain in the original order). This is different than sorting
an array or vector, which may need to copy elements, and is probably
not a stable sort.
A.18.4 Maps
1/2 The language-defined generic packages Containers.Hashed_Maps and
Containers.Ordered_Maps provide private types Map and Cursor, and a set of
operations for each type. A map container allows an arbitrary type to be used
as a key to find the element associated with that key. A hashed map uses a
hash function to organize the keys, while an ordered map orders the keys per a
specified relation.
2/2 This section describes the declarations that are common to both kinds of
maps. See A.18.5 for a description of the semantics specific to
Containers.Hashed_Maps and A.18.6 for a description of the semantics specific
to Containers.Ordered_Maps.
Static Semantics
3/2 The actual function for the generic formal function "=" on Element_Type
values is expected to define a reflexive and symmetric relationship and return
the same result value each time it is called with a particular pair of values.
If it behaves in some other manner, the function "=" on map values returns an
unspecified value. The exact arguments and number of calls of this generic
formal function by the function "=" on map values are unspecified.
4/2 The type Map is used to represent maps. The type Map needs finalization
(see 7.6).
5/2 A map contains pairs of keys and elements, called nodes. Map cursors
designate nodes, but also can be thought of as designating an element (the
element contained in the node) for consistency with the other containers.
There exists an equivalence relation on keys, whose definition is different
for hashed maps and ordered maps. A map never contains two or more nodes with
equivalent keys. The length of a map is the number of nodes it contains.
6/2 Each nonempty map has two particular nodes called the first node and the
last node (which may be the same). Each node except for the last node has a
successor node. If there are no other intervening operations, starting with
the first node and repeatedly going to the successor node will visit each node
in the map exactly once until the last node is reached. The exact definition
of these terms is different for hashed maps and ordered maps.
7/2 Some operations of these generic packages have access-to-subprogram
parameters. To ensure such operations are well-defined, they guard against
certain actions by the designated subprogram. In particular, some operations
check for "tampering with cursors" of a container because they depend on the
set of elements of the container remaining constant, and others check for "
tampering with elements" of a container because they depend on elements of the
container not being replaced.
8/2 A subprogram is said to tamper with cursors of a map object M if:
9/2 * it inserts or deletes elements of M, that is, it calls the Insert,
Include, Clear, Delete, or Exclude procedures with M as a parameter; or
10/2 * it finalizes M; or
11/2 * it calls the Move procedure with M as a parameter; or
12/2 * it calls one of the operations defined to tamper with the cursors of
M.
13/2 A subprogram is said to tamper with elements of a map object M if:
14/2 * it tampers with cursors of M; or
15/2 * it replaces one or more elements of M, that is, it calls the Replace
or Replace_Element procedures with M as a parameter.
16/2 Empty_Map represents the empty Map object. It has a length of 0. If an
object of type Map is not otherwise initialized, it is initialized to the same
value as Empty_Map.
17/2 No_Element represents a cursor that designates no node. If an object of
type Cursor is not otherwise initialized, it is initialized to the same value
as No_Element.
18/2 The predefined "=" operator for type Cursor returns True if both cursors
are No_Element, or designate the same element in the same container.
19/2 Execution of the default implementation of the Input, Output, Read, or
Write attribute of type Cursor raises Program_Error.
20/2 function "=" (Left, Right : Map) return Boolean;
21/2 If Left and Right denote the same map object, then the function
returns True. If Left and Right have different lengths, then the
function returns False. Otherwise, for each key K in Left, the
function returns False if:
22/2 * a key equivalent to K is not present in Right; or
23/2 * the element associated with K in Left is not equal to the
element associated with K in Right (using the generic formal
equality operator for elements).
24/2 If the function has not returned a result after checking all of
the keys, it returns True. Any exception raised during evaluation
of key equivalence or element equality is propagated.
25/2 function Length (Container : Map) return Count_Type;
26/2 Returns the number of nodes in Container.
27/2 function Is_Empty (Container : Map) return Boolean;
28/2 Equivalent to Length (Container) = 0.
29/2 procedure Clear (Container : in out Map);
30/2 Removes all the nodes from Container.
31/2 function Key (Position : Cursor) return Key_Type;
32/2 If Position equals No_Element, then Constraint_Error is
propagated. Otherwise, Key returns the key component of the node
designated by Position.
33/2 function Element (Position : Cursor) return Element_Type;
34/2 If Position equals No_Element, then Constraint_Error is
propagated. Otherwise, Element returns the element component of
the node designated by Position.
35/2 procedure Replace_Element (Container : in out Map;
Position : in Cursor;
New_Item : in Element_Type);
36/2 If Position equals No_Element, then Constraint_Error is
propagated; if Position does not designate an element in
Container, then Program_Error is propagated. Otherwise
Replace_Element assigns New_Item to the element of the node
designated by Position.
37/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Key : in Key_Type;
Element : in Element_Type));
38/2 If Position equals No_Element, then Constraint_Error is
propagated. Otherwise, Query_Element calls Process.all with the
key and element from the node designated by Position as the
arguments. Program_Error is propagated if Process.all tampers with
the elements of Container. Any exception raised by Process.all is
propagated.
39/2 procedure Update_Element
(Container : in out Map;
Position : in Cursor;
Process : not null access procedure (Key : in Key_Type;
Element : in out Element_Type));
40/2 If Position equals No_Element, then Constraint_Error is
propagated; if Position does not designate an element in
Container, then Program_Error is propagated. Otherwise
Update_Element calls Process.all with the key and element from the
node designated by Position as the arguments. Program_Error is
propagated if Process.all tampers with the elements of Container.
Any exception raised by Process.all is propagated.
41/2 If Element_Type is unconstrained and definite, then the actual
Element parameter of Process.all shall be unconstrained.
42/2 procedure Move (Target : in out Map;
Source : in out Map);
43/2 If Target denotes the same object as Source, then Move has no
effect. Otherwise, Move first calls Clear (Target). Then, each
node from Source is removed from Source and inserted into Target.
The length of Source is 0 after a successful call to Move.
44/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type;
Position : out Cursor;
Inserted : out Boolean);
45/2 Insert checks if a node with a key equivalent to Key is already
present in Container. If a match is found, Inserted is set to
False and Position designates the element with the matching key.
Otherwise, Insert allocates a new node, initializes it to Key and
New_Item, and adds it to Container; Inserted is set to True and
Position designates the newly-inserted node. Any exception raised
during allocation is propagated and Container is not modified.
46/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
Position : out Cursor;
Inserted : out Boolean);
47/2 Insert inserts Key into Container as per the five-parameter
Insert, with the difference that an element initialized by default
(see 3.3.1) is inserted.
48/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type);
49/2 Insert inserts Key and New_Item into Container as per the
five-parameter Insert, with the difference that if a node with a
key equivalent to Key is already in the map, then Constraint_Error
is propagated.
50/2 procedure Include (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type);
51/2 Include inserts Key and New_Item into Container as per the
five-parameter Insert, with the difference that if a node with a
key equivalent to Key is already in the map, then this operation
assigns Key and New_Item to the matching node. Any exception
raised during assignment is propagated.
52/2 procedure Replace (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type);
53/2 Replace checks if a node with a key equivalent to Key is present
in Container. If a match is found, Replace assigns Key and
New_Item to the matching node; otherwise, Constraint_Error is
propagated.
54/2 procedure Exclude (Container : in out Map;
Key : in Key_Type);
55/2 Exclude checks if a node with a key equivalent to Key is present
in Container. If a match is found, Exclude removes the node from
the map.
56/2 procedure Delete (Container : in out Map;
Key : in Key_Type);
57/2 Delete checks if a node with a key equivalent to Key is present in
Container. If a match is found, Delete removes the node from the
map; otherwise, Constraint_Error is propagated.
58/2 procedure Delete (Container : in out Map;
Position : in out Cursor);
59/2 If Position equals No_Element, then Constraint_Error is
propagated. If Position does not designate an element in
Container, then Program_Error is propagated. Otherwise, Delete
removes the node designated by Position from the map. Position is
set to No_Element on return.
60/2 function First (Container : Map) return Cursor;
61/2 If Length (Container) = 0, then First returns No_Element.
Otherwise, First returns a cursor that designates the first node
in Container.
62/2 function Next (Position : Cursor) return Cursor;
63/2 Returns a cursor that designates the successor of the node
designated by Position. If Position designates the last node, then
No_Element is returned. If Position equals No_Element, then
No_Element is returned.
64/2 procedure Next (Position : in out Cursor);
65/2 Equivalent to Position := Next (Position).
66/2 function Find (Container : Map;
Key : Key_Type) return Cursor;
67/2 If Length (Container) equals 0, then Find returns No_Element.
Otherwise, Find checks if a node with a key equivalent to Key is
present in Container. If a match is found, a cursor designating
the matching node is returned; otherwise, No_Element is returned.
68/2 function Element (Container : Map;
Key : Key_Type) return Element_Type;
69/2 Equivalent to Element (Find (Container, Key)).
70/2 function Contains (Container : Map;
Key : Key_Type) return Boolean;
71/2 Equivalent to Find (Container, Key) /= No_Element.
72/2 function Has_Element (Position : Cursor) return Boolean;
73/2 Returns True if Position designates a node, and returns False
otherwise.
74/2 procedure Iterate
(Container : in Map;
Process : not null access procedure (Position : in Cursor));
75/2 Iterate calls Process.all with a cursor that designates each node
in Container, starting with the first node and moving the cursor
according to the successor relation. Program_Error is propagated
if Process.all tampers with the cursors of Container. Any
exception raised by Process.all is propagated.
Erroneous Execution
76/2 A Cursor value is invalid if any of the following have occurred since it
was created:
77/2 * The map that contains the node it designates has been finalized;
78/2 * The map that contains the node it designates has been used as the
Source or Target of a call to Move; or
79/2 * The node it designates has been deleted from the map.
80/2 The result of "=" or Has_Element is unspecified if these functions are
called with an invalid cursor parameter. Execution is erroneous if any other
subprogram declared in Containers.Hashed_Maps or Containers.Ordered_Maps is
called with an invalid cursor parameter.
Implementation Requirements
81/2 No storage associated with a Map object shall be lost upon assignment or
scope exit.
82/2 The execution of an assignment_statement for a map shall have the effect
of copying the elements from the source map object to the target map object.
Implementation Advice
83/2 Move should not copy elements, and should minimize copying of internal
data structures.
84/2 If an exception is propagated from a map operation, no storage should be
lost, nor any elements removed from a map unless specified by the operation.
A.18.5 The Package Containers.Hashed_Maps
Static Semantics
1/2 The generic library package Containers.Hashed_Maps has the following
declaration:
2/2 generic
type Key_Type is private;
type Element_Type is private;
with function Hash (Key : Key_Type) return Hash_Type;
with function Equivalent_Keys (Left, Right : Key_Type)
return Boolean;
with function "=" (Left, Right : Element_Type)
return Boolean is <>;
package Ada.Containers.Hashed_Maps is
pragma Preelaborate(Hashed_Maps);
3/2 type Map is tagged private;
pragma Preelaborable_Initialization(Map);
4/2 type Cursor is private;
pragma Preelaborable_Initialization(Cursor);
5/2 Empty_Map : constant Map;
6/2 No_Element : constant Cursor;
7/2 function "=" (Left, Right : Map) return Boolean;
8/2 function Capacity (Container : Map) return Count_Type;
9/2 procedure Reserve_Capacity (Container : in out Map;
Capacity : in Count_Type);
10/2 function Length (Container : Map) return Count_Type;
11/2 function Is_Empty (Container : Map) return Boolean;
12/2 procedure Clear (Container : in out Map);
13/2 function Key (Position : Cursor) return Key_Type;
14/2 function Element (Position : Cursor) return Element_Type;
15/2 procedure Replace_Element (Container : in out Map;
Position : in Cursor;
New_Item : in Element_Type);
16/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Key : in Key_Type;
Element : in Element_Type));
17/2 procedure Update_Element
(Container : in out Map;
Position : in Cursor;
Process : not null access procedure
(Key : in Key_Type;
Element : in out Element_Type));
18/2 procedure Move (Target : in out Map;
Source : in out Map);
19/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type;
Position : out Cursor;
Inserted : out Boolean);
20/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
Position : out Cursor;
Inserted : out Boolean);
21/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type);
22/2 procedure Include (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type);
23/2 procedure Replace (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type);
24/2 procedure Exclude (Container : in out Map;
Key : in Key_Type);
25/2 procedure Delete (Container : in out Map;
Key : in Key_Type);
26/2 procedure Delete (Container : in out Map;
Position : in out Cursor);
27/2 function First (Container : Map)
return Cursor;
28/2 function Next (Position : Cursor) return Cursor;
29/2 procedure Next (Position : in out Cursor);
30/2 function Find (Container : Map;
Key : Key_Type)
return Cursor;
31/2 function Element (Container : Map;
Key : Key_Type)
return Element_Type;
32/2 function Contains (Container : Map;
Key : Key_Type) return Boolean;
33/2 function Has_Element (Position : Cursor) return Boolean;
34/2 function Equivalent_Keys (Left, Right : Cursor)
return Boolean;
35/2 function Equivalent_Keys (Left : Cursor;
Right : Key_Type)
return Boolean;
36/2 function Equivalent_Keys (Left : Key_Type;
Right : Cursor)
return Boolean;
37/2 procedure Iterate
(Container : in Map;
Process : not null access procedure (Position : in Cursor));
38/2 private
39/2 ... -- not specified by the language
40/2 end Ada.Containers.Hashed_Maps;
41/2 An object of type Map contains an expandable hash table, which is used to
provide direct access to nodes. The capacity of an object of type Map is the
maximum number of nodes that can be inserted into the hash table prior to it
being automatically expanded.
42/2 Two keys K1 and K2 are defined to be equivalent if Equivalent_Keys (K1,
K2) returns True.
43/2 The actual function for the generic formal function Hash is expected to
return the same value each time it is called with a particular key value. For
any two equivalent key values, the actual for Hash is expected to return the
same value. If the actual for Hash behaves in some other manner, the behavior
of this package is unspecified. Which subprograms of this package call Hash,
and how many times they call it, is unspecified.
44/2 The actual function for the generic formal function Equivalent_Keys on
Key_Type values is expected to return the same value each time it is called
with a particular pair of key values. It should define an equivalence
relationship, that is, be reflexive, symmetric, and transitive. If the actual
for Equivalent_Keys behaves in some other manner, the behavior of this package
is unspecified. Which subprograms of this package call Equivalent_Keys, and
how many times they call it, is unspecified.
45/2 If the value of a key stored in a node of a map is changed other than by
an operation in this package such that at least one of Hash or Equivalent_Keys
give different results, the behavior of this package is unspecified.
46/2 Which nodes are the first node and the last node of a map, and which node
is the successor of a given node, are unspecified, other than the general
semantics described in A.18.4.
47/2 function Capacity (Container : Map) return Count_Type;
48/2 Returns the capacity of Container.
49/2 procedure Reserve_Capacity (Container : in out Map;
Capacity : in Count_Type);
50/2 Reserve_Capacity allocates a new hash table such that the length
of the resulting map can become at least the value Capacity
without requiring an additional call to Reserve_Capacity, and is
large enough to hold the current length of Container.
Reserve_Capacity then rehashes the nodes in Container onto the new
hash table. It replaces the old hash table with the new hash
table, and then deallocates the old hash table. Any exception
raised during allocation is propagated and Container is not
modified.
51/2 Reserve_Capacity tampers with the cursors of Container.
52/2 procedure Clear (Container : in out Map);
53/2 In addition to the semantics described in A.18.4, Clear does not
affect the capacity of Container.
54/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type;
Position : out Cursor;
Inserted : out Boolean);
55/2 In addition to the semantics described in A.18.4, if Length
(Container) equals Capacity (Container), then Insert first calls
Reserve_Capacity to increase the capacity of Container to some
larger value.
56/2 function Equivalent_Keys (Left, Right : Cursor)
return Boolean;
57/2 Equivalent to Equivalent_Keys (Key (Left), Key (Right)).
58/2 function Equivalent_Keys (Left : Cursor;
Right : Key_Type) return Boolean;
59/2 Equivalent to Equivalent_Keys (Key (Left), Right).
60/2 function Equivalent_Keys (Left : Key_Type;
Right : Cursor) return Boolean;
61/2 Equivalent to Equivalent_Keys (Left, Key (Right)).
Implementation Advice
62/2 If N is the length of a map, the average time complexity of the
subprograms Element, Insert, Include, Replace, Delete, Exclude and Find that
take a key parameter should be O(log N). The average time complexity of the
subprograms that take a cursor parameter should be O(1). The average time
complexity of Reserve_Capacity should be O(N).
A.18.6 The Package Containers.Ordered_Maps
Static Semantics
1/2 The generic library package Containers.Ordered_Maps has the following
declaration:
2/2 generic
type Key_Type is private;
type Element_Type is private;
with function "<" (Left, Right : Key_Type) return Boolean is <>;
with function "=" (Left, Right : Element_Type) return Boolean is <>;
package Ada.Containers.Ordered_Maps is
pragma Preelaborate(Ordered_Maps);
3/2 function Equivalent_Keys (Left, Right : Key_Type) return Boolean;
4/2 type Map is tagged private;
pragma Preelaborable_Initialization(Map);
5/2 type Cursor is private;
pragma Preelaborable_Initialization(Cursor);
6/2 Empty_Map : constant Map;
7/2 No_Element : constant Cursor;
8/2 function "=" (Left, Right : Map) return Boolean;
9/2 function Length (Container : Map) return Count_Type;
10/2 function Is_Empty (Container : Map) return Boolean;
11/2 procedure Clear (Container : in out Map);
12/2 function Key (Position : Cursor) return Key_Type;
13/2 function Element (Position : Cursor) return Element_Type;
14/2 procedure Replace_Element (Container : in out Map;
Position : in Cursor;
New_Item : in Element_Type);
15/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Key : in Key_Type;
Element : in Element_Type));
16/2 procedure Update_Element
(Container : in out Map;
Position : in Cursor;
Process : not null access procedure
(Key : in Key_Type;
Element : in out Element_Type));
17/2 procedure Move (Target : in out Map;
Source : in out Map);
18/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type;
Position : out Cursor;
Inserted : out Boolean);
19/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
Position : out Cursor;
Inserted : out Boolean);
20/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type);
21/2 procedure Include (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type);
22/2 procedure Replace (Container : in out Map;
Key : in Key_Type;
New_Item : in Element_Type);
23/2 procedure Exclude (Container : in out Map;
Key : in Key_Type);
24/2 procedure Delete (Container : in out Map;
Key : in Key_Type);
25/2 procedure Delete (Container : in out Map;
Position : in out Cursor);
26/2 procedure Delete_First (Container : in out Map);
27/2 procedure Delete_Last (Container : in out Map);
28/2 function First (Container : Map) return Cursor;
29/2 function First_Element (Container : Map) return Element_Type;
30/2 function First_Key (Container : Map) return Key_Type;
31/2 function Last (Container : Map) return Cursor;
32/2 function Last_Element (Container : Map) return Element_Type;
33/2 function Last_Key (Container : Map) return Key_Type;
34/2 function Next (Position : Cursor) return Cursor;
35/2 procedure Next (Position : in out Cursor);
36/2 function Previous (Position : Cursor) return Cursor;
37/2 procedure Previous (Position : in out Cursor);
38/2 function Find (Container : Map;
Key : Key_Type) return Cursor;
39/2 function Element (Container : Map;
Key : Key_Type) return Element_Type;
40/2 function Floor (Container : Map;
Key : Key_Type) return Cursor;
41/2 function Ceiling (Container : Map;
Key : Key_Type) return Cursor;
42/2 function Contains (Container : Map;
Key : Key_Type) return Boolean;
43/2 function Has_Element (Position : Cursor) return Boolean;
44/2 function "<" (Left, Right : Cursor) return Boolean;
45/2 function ">" (Left, Right : Cursor) return Boolean;
46/2 function "<" (Left : Cursor; Right : Key_Type) return Boolean;
47/2 function ">" (Left : Cursor; Right : Key_Type) return Boolean;
48/2 function "<" (Left : Key_Type; Right : Cursor) return Boolean;
49/2 function ">" (Left : Key_Type; Right : Cursor) return Boolean;
50/2 procedure Iterate
(Container : in Map;
Process : not null access procedure (Position : in Cursor));
51/2 procedure Reverse_Iterate
(Container : in Map;
Process : not null access procedure (Position : in Cursor));
52/2 private
53/2 ... -- not specified by the language
54/2 end Ada.Containers.Ordered_Maps;
55/2 Two keys K1 and K2 are equivalent if both K1 < K2 and K2 < K1 return
False, using the generic formal "<" operator for keys. Function
Equivalent_Keys returns True if Left and Right are equivalent, and False
otherwise.
56/2 The actual function for the generic formal function "<" on Key_Type
values is expected to return the same value each time it is called with a
particular pair of key values. It should define a strict ordering
relationship, that is, be irreflexive, asymmetric, and transitive. If the
actual for "<" behaves in some other manner, the behavior of this package is
unspecified. Which subprograms of this package call "<" and how many times
they call it, is unspecified.
57/2 If the value of a key stored in a map is changed other than by an
operation in this package such that at least one of "<" or "=" give different
results, the behavior of this package is unspecified.
58/2 The first node of a nonempty map is the one whose key is less than the
key of all the other nodes in the map. The last node of a nonempty map is the
one whose key is greater than the key of all the other elements in the map.
The successor of a node is the node with the smallest key that is larger than
the key of the given node. The predecessor of a node is the node with the
largest key that is smaller than the key of the given node. All comparisons
are done using the generic formal "<" operator for keys.
59/2 procedure Delete_First (Container : in out Map);
60/2 If Container is empty, Delete_First has no effect. Otherwise the
node designated by First (Container) is removed from Container.
Delete_First tampers with the cursors of Container.
61/2 procedure Delete_Last (Container : in out Map);
62/2 If Container is empty, Delete_Last has no effect. Otherwise the
node designated by Last (Container) is removed from Container.
Delete_Last tampers with the cursors of Container.
63/2 function First_Element (Container : Map) return Element_Type;
64/2 Equivalent to Element (First (Container)).
65/2 function First_Key (Container : Map) return Key_Type;
66/2 Equivalent to Key (First (Container)).
67/2 function Last (Container : Map) return Cursor;
68/2 Returns a cursor that designates the last node in Container. If
Container is empty, returns No_Element.
69/2 function Last_Element (Container : Map) return Element_Type;
70/2 Equivalent to Element (Last (Container)).
71/2 function Last_Key (Container : Map) return Key_Type;
72/2 Equivalent to Key (Last (Container)).
73/2 function Previous (Position : Cursor) return Cursor;
74/2 If Position equals No_Element, then Previous returns No_Element.
Otherwise Previous returns a cursor designating the node that
precedes the one designated by Position. If Position designates
the first element, then Previous returns No_Element.
75/2 procedure Previous (Position : in out Cursor);
76/2 Equivalent to Position := Previous (Position).
77/2 function Floor (Container : Map;
Key : Key_Type) return Cursor;
78/2 Floor searches for the last node whose key is not greater than
Key, using the generic formal "<" operator for keys. If such a
node is found, a cursor that designates it is returned. Otherwise
No_Element is returned.
79/2 function Ceiling (Container : Map;
Key : Key_Type) return Cursor;
80/2 Ceiling searches for the first node whose key is not less than
Key, using the generic formal "<" operator for keys. If such a
node is found, a cursor that designates it is returned. Otherwise
No_Element is returned.
81/2 function "<" (Left, Right : Cursor) return Boolean;
82/2 Equivalent to Key (Left) < Key (Right).
83/2 function ">" (Left, Right : Cursor) return Boolean;
84/2 Equivalent to Key (Right) < Key (Left).
85/2 function "<" (Left : Cursor; Right : Key_Type) return Boolean;
86/2 Equivalent to Key (Left) < Right.
87/2 function ">" (Left : Cursor; Right : Key_Type) return Boolean;
88/2 Equivalent to Right < Key (Left).
89/2 function "<" (Left : Key_Type; Right : Cursor) return Boolean;
90/2 Equivalent to Left < Key (Right).
91/2 function ">" (Left : Key_Type; Right : Cursor) return Boolean;
92/2 Equivalent to Key (Right) < Left.
93/2 procedure Reverse_Iterate
(Container : in Map;
Process : not null access procedure (Position : in Cursor));
94/2 Iterates over the nodes in Container as per Iterate, with the
difference that the nodes are traversed in predecessor order,
starting with the last node.
Implementation Advice
95/2 If N is the length of a map, then the worst-case time complexity of the
Element, Insert, Include, Replace, Delete, Exclude and Find operations that
take a key parameter should be O((log N)**2) or better. The worst-case time
complexity of the subprograms that take a cursor parameter should be O(1).
A.18.7 Sets
1/2 The language-defined generic packages Containers.Hashed_Sets and
Containers.Ordered_Sets provide private types Set and Cursor, and a set of
operations for each type. A set container allows elements of an arbitrary type
to be stored without duplication. A hashed set uses a hash function to
organize elements, while an ordered set orders its element per a specified
relation.
2/2 This section describes the declarations that are common to both kinds of
sets. See A.18.8 for a description of the semantics specific to
Containers.Hashed_Sets and A.18.9 for a description of the semantics specific
to Containers.Ordered_Sets.
Static Semantics
3/2 The actual function for the generic formal function "=" on Element_Type
values is expected to define a reflexive and symmetric relationship and return
the same result value each time it is called with a particular pair of values.
If it behaves in some other manner, the function "=" on set values returns an
unspecified value. The exact arguments and number of calls of this generic
formal function by the function "=" on set values are unspecified.
4/2 The type Set is used to represent sets. The type Set needs finalization
(see 7.6).
5/2 A set contains elements. Set cursors designate elements. There exists an
equivalence relation on elements, whose definition is different for hashed
sets and ordered sets. A set never contains two or more equivalent elements.
The length of a set is the number of elements it contains.
6/2 Each nonempty set has two particular elements called the first element and
the last element (which may be the same). Each element except for the last
element has a successor element. If there are no other intervening operations,
starting with the first element and repeatedly going to the successor element
will visit each element in the set exactly once until the last element is
reached. The exact definition of these terms is different for hashed sets and
ordered sets.
7/2 Some operations of these generic packages have access-to-subprogram
parameters. To ensure such operations are well-defined, they guard against
certain actions by the designated subprogram. In particular, some operations
check for "tampering with cursors" of a container because they depend on the
set of elements of the container remaining constant, and others check for "
tampering with elements" of a container because they depend on elements of the
container not being replaced.
8/2 A subprogram is said to tamper with cursors of a set object S if:
9/2 * it inserts or deletes elements of S, that is, it calls the Insert,
Include, Clear, Delete, Exclude, or Replace_Element procedures with S
as a parameter; or
10/2 * it finalizes S; or
11/2 * it calls the Move procedure with S as a parameter; or
12/2 * it calls one of the operations defined to tamper with cursors of S.
13/2 A subprogram is said to tamper with elements of a set object S if:
14/2 * it tampers with cursors of S.
15/2 Empty_Set represents the empty Set object. It has a length of 0. If an
object of type Set is not otherwise initialized, it is initialized to the same
value as Empty_Set.
16/2 No_Element represents a cursor that designates no element. If an object
of type Cursor is not otherwise initialized, it is initialized to the same
value as No_Element.
17/2 The predefined "=" operator for type Cursor returns True if both cursors
are No_Element, or designate the same element in the same container.
18/2 Execution of the default implementation of the Input, Output, Read, or
Write attribute of type Cursor raises Program_Error.
19/2 function "=" (Left, Right : Set) return Boolean;
20/2 If Left and Right denote the same set object, then the function
returns True. If Left and Right have different lengths, then the
function returns False. Otherwise, for each element E in Left, the
function returns False if an element equal to E (using the generic
formal equality operator) is not present in Right. If the function
has not returned a result after checking all of the elements, it
returns True. Any exception raised during evaluation of element
equality is propagated.
21/2 function Equivalent_Sets (Left, Right : Set) return Boolean;
22/2 If Left and Right denote the same set object, then the function
returns True. If Left and Right have different lengths, then the
function returns False. Otherwise, for each element E in Left, the
function returns False if an element equivalent to E is not
present in Right. If the function has not returned a result after
checking all of the elements, it returns True. Any exception
raised during evaluation of element equivalence is propagated.
23/2 function To_Set (New_Item : Element_Type) return Set;
24/2 Returns a set containing the single element New_Item.
25/2 function Length (Container : Set) return Count_Type;
26/2 Returns the number of elements in Container.
27/2 function Is_Empty (Container : Set) return Boolean;
28/2 Equivalent to Length (Container) = 0.
29/2 procedure Clear (Container : in out Set);
30/2 Removes all the elements from Container.
31/2 function Element (Position : Cursor) return Element_Type;
32/2 If Position equals No_Element, then Constraint_Error is
propagated. Otherwise, Element returns the element designated by
Position.
33/2 procedure Replace_Element (Container : in out Set;
Position : in Cursor;
New_Item : in Element_Type);
34/2 If Position equals No_Element, then Constraint_Error is
propagated; if Position does not designate an element in
Container, then Program_Error is propagated. If an element
equivalent to New_Item is already present in Container at a
position other than Position, Program_Error is propagated.
Otherwise, Replace_Element assigns New_Item to the element
designated by Position. Any exception raised by the assignment is
propagated.
35/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Element : in Element_Type));
36/2 If Position equals No_Element, then Constraint_Error is
propagated. Otherwise, Query_Element calls Process.all with the
element designated by Position as the argument. Program_Error is
propagated if Process.all tampers with the elements of Container.
Any exception raised by Process.all is propagated.
37/2 procedure Move (Target : in out Set;
Source : in out Set);
38/2 If Target denotes the same object as Source, then Move has no
effect. Otherwise, Move first clears Target. Then, each element
from Source is removed from Source and inserted into Target. The
length of Source is 0 after a successful call to Move.
39/2 procedure Insert (Container : in out Set;
New_Item : in Element_Type;
Position : out Cursor;
Inserted : out Boolean);
40/2 Insert checks if an element equivalent to New_Item is already
present in Container. If a match is found, Inserted is set to
False and Position designates the matching element. Otherwise,
Insert adds New_Item to Container; Inserted is set to True and
Position designates the newly-inserted element. Any exception
raised during allocation is propagated and Container is not
modified.
41/2 procedure Insert (Container : in out Set;
New_Item : in Element_Type);
42/2 Insert inserts New_Item into Container as per the four-parameter
Insert, with the difference that if an element equivalent to
New_Item is already in the set, then Constraint_Error is
propagated.
43/2 procedure Include (Container : in out Set;
New_Item : in Element_Type);
44/2 Include inserts New_Item into Container as per the four-parameter
Insert, with the difference that if an element equivalent to
New_Item is already in the set, then it is replaced. Any exception
raised during assignment is propagated.
45/2 procedure Replace (Container : in out Set;
New_Item : in Element_Type);
46/2 Replace checks if an element equivalent to New_Item is already in
the set. If a match is found, that element is replaced with
New_Item; otherwise, Constraint_Error is propagated.
47/2 procedure Exclude (Container : in out Set;
Item : in Element_Type);
48/2 Exclude checks if an element equivalent to Item is present in
Container. If a match is found, Exclude removes the element from
the set.
49/2 procedure Delete (Container : in out Set;
Item : in Element_Type);
50/2 Delete checks if an element equivalent to Item is present in
Container. If a match is found, Delete removes the element from
the set; otherwise, Constraint_Error is propagated.
51/2 procedure Delete (Container : in out Set;
Position : in out Cursor);
52/2 If Position equals No_Element, then Constraint_Error is
propagated. If Position does not designate an element in
Container, then Program_Error is propagated. Otherwise, Delete
removes the element designated by Position from the set. Position
is set to No_Element on return.
53/2 procedure Union (Target : in out Set;
Source : in Set);
54/2 Union inserts into Target the elements of Source that are not
equivalent to some element already in Target.
55/2 function Union (Left, Right : Set) return Set;
56/2 Returns a set comprising all of the elements of Left, and the
elements of Right that are not equivalent to some element of Left.
57/2 procedure Intersection (Target : in out Set;
Source : in Set);
58/2 Union deletes from Target the elements of Target that are not
equivalent to some element of Source.
59/2 function Intersection (Left, Right : Set) return Set;
60/2 Returns a set comprising all the elements of Left that are
equivalent to the some element of Right.
61/2 procedure Difference (Target : in out Set;
Source : in Set);
62/2 If Target denotes the same object as Source, then Difference
clears Target. Otherwise, it deletes from Target the elements that
are equivalent to some element of Source.
63/2 function Difference (Left, Right : Set) return Set;
64/2 Returns a set comprising the elements of Left that are not
equivalent to some element of Right.
65/2 procedure Symmetric_Difference (Target : in out Set;
Source : in Set);
66/2 If Target denotes the same object as Source, then
Symmetric_Difference clears Target. Otherwise, it deletes from
Target the elements that are equivalent to some element of Source,
and inserts into Target the elements of Source that are not
equivalent to some element of Target.
67/2 function Symmetric_Difference (Left, Right : Set) return Set;
68/2 Returns a set comprising the elements of Left that are not
equivalent to some element of Right, and the elements of Right
that are not equivalent to some element of Left.
69/2 function Overlap (Left, Right : Set) return Boolean;
70/2 If an element of Left is equivalent to some element of Right, then
Overlap returns True. Otherwise it returns False.
71/2 function Is_Subset (Subset : Set;
Of_Set : Set) return Boolean;
72/2 If an element of Subset is not equivalent to some element of
Of_Set, then Is_Subset returns False. Otherwise it returns True.
73/2 function First (Container : Set) return Cursor;
74/2 If Length (Container) = 0, then First returns No_Element.
Otherwise, First returns a cursor that designates the first
element in Container.
75/2 function Next (Position : Cursor) return Cursor;
76/2 Returns a cursor that designates the successor of the element
designated by Position. If Position designates the last element,
then No_Element is returned. If Position equals No_Element, then
No_Element is returned.
77/2 procedure Next (Position : in out Cursor);
78/2 Equivalent to Position := Next (Position).
79/2 Equivalent to Find (Container, Item) /= No_Element.
80/2 function Find (Container : Set;
Item : Element_Type) return Cursor;
81/2 If Length (Container) equals 0, then Find returns No_Element.
Otherwise, Find checks if an element equivalent to Item is present
in Container. If a match is found, a cursor designating the
matching element is returned; otherwise, No_Element is returned.
82/2 function Contains (Container : Set;
Item : Element_Type) return Boolean;
83/2 function Has_Element (Position : Cursor) return Boolean;
84/2 Returns True if Position designates an element, and returns False
otherwise.
85/2 procedure Iterate
(Container : in Set;
Process : not null access procedure (Position : in Cursor));
86/2 Iterate calls Process.all with a cursor that designates each
element in Container, starting with the first element and moving
the cursor according to the successor relation. Program_Error is
propagated if Process.all tampers with the cursors of Container.
Any exception raised by Process.all is propagated.
87/2 Both Containers.Hashed_Set and Containers.Ordered_Set declare a nested
generic package Generic_Keys, which provides operations that allow set
manipulation in terms of a key (typically, a portion of an element) instead of
a complete element. The formal function Key of Generic_Keys extracts a key
value from an element. It is expected to return the same value each time it is
called with a particular element. The behavior of Generic_Keys is unspecified
if Key behaves in some other manner.
88/2 A key is expected to unambiguously determine a single equivalence class
for elements. The behavior of Generic_Keys is unspecified if the formal
parameters of this package behave in some other manner.
89/2 function Key (Position : Cursor) return Key_Type;
90/2 Equivalent to Key (Element (Position)).
91/2 The subprograms in package Generic_Keys named Contains, Find, Element,
Delete, and Exclude, are equivalent to the corresponding subprograms in the
parent package, with the difference that the Key parameter is used to locate
an element in the set.
92/2 procedure Replace (Container : in out Set;
Key : in Key_Type;
New_Item : in Element_Type);
93/2 Equivalent to Replace_Element (Container, Find (Container, Key),
New_Item).
94/2 procedure Update_Element_Preserving_Key
(Container : in out Set;
Position : in Cursor;
Process : not null access procedure
(Element : in out Element_Type));
95/2 If Position equals No_Element, then Constraint_Error is
propagated; if Position does not designate an element in
Container, then Program_Error is propagated. Otherwise, Update_-
Element_Preserving_Key uses Key to save the key value K of the
element designated by Position. Update_Element_Preserving_Key then
calls Process.all with that element as the argument. Program_Error
is propagated if Process.all tampers with the elements of
Container. Any exception raised by Process.all is propagated.
After Process.all returns, Update_Element_Preserving_Key checks if
K determines the same equivalence class as that for the new
element; if not, the element is removed from the set and
Program_Error is propagated.
96/2 If Element_Type is unconstrained and definite, then the actual
Element parameter of Process.all shall be unconstrained.
Erroneous Execution
97/2 A Cursor value is invalid if any of the following have occurred since it
was created:
98/2 * The set that contains the element it designates has been finalized;
99/2 * The set that contains the element it designates has been used as the
Source or Target of a call to Move; or
100/2 * The element it designates has been deleted from the set.
101/2 The result of "=" or Has_Element is unspecified if these functions are
called with an invalid cursor parameter. Execution is erroneous if any other
subprogram declared in Containers.Hashed_Sets or Containers.Ordered_Sets is
called with an invalid cursor parameter.
Implementation Requirements
102/2 No storage associated with a Set object shall be lost upon assignment or
scope exit.
103/2 The execution of an assignment_statement for a set shall have the effect
of copying the elements from the source set object to the target set object.
Implementation Advice
104/2 Move should not copy elements, and should minimize copying of internal
data structures.
105/2 If an exception is propagated from a set operation, no storage should be
lost, nor any elements removed from a set unless specified by the operation.
A.18.8 The Package Containers.Hashed_Sets
Static Semantics
1/2 The generic library package Containers.Hashed_Sets has the following
declaration:
2/2 generic
type Element_Type is private;
with function Hash (Element : Element_Type) return Hash_Type;
with function Equivalent_Elements (Left, Right : Element_Type)
return Boolean;
with function "=" (Left, Right : Element_Type) return Boolean is <>;
package Ada.Containers.Hashed_Sets is
pragma Preelaborate(Hashed_Sets);
3/2 type Set is tagged private;
pragma Preelaborable_Initialization(Set);
4/2 type Cursor is private;
pragma Preelaborable_Initialization(Cursor);
5/2 Empty_Set : constant Set;
6/2 No_Element : constant Cursor;
7/2 function "=" (Left, Right : Set) return Boolean;
8/2 function Equivalent_Sets (Left, Right : Set) return Boolean;
9/2 function To_Set (New_Item : Element_Type) return Set;
10/2 function Capacity (Container : Set) return Count_Type;
11/2 procedure Reserve_Capacity (Container : in out Set;
Capacity : in Count_Type);
12/2 function Length (Container : Set) return Count_Type;
13/2 function Is_Empty (Container : Set) return Boolean;
14/2 procedure Clear (Container : in out Set);
15/2 function Element (Position : Cursor) return Element_Type;
16/2 procedure Replace_Element (Container : in out Set;
Position : in Cursor;
New_Item : in Element_Type);
17/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Element : in Element_Type));
18/2 procedure Move (Target : in out Set;
Source : in out Set);
19/2 procedure Insert (Container : in out Set;
New_Item : in Element_Type;
Position : out Cursor;
Inserted : out Boolean);
20/2 procedure Insert (Container : in out Set;
New_Item : in Element_Type);
21/2 procedure Include (Container : in out Set;
New_Item : in Element_Type);
22/2 procedure Replace (Container : in out Set;
New_Item : in Element_Type);
23/2 procedure Exclude (Container : in out Set;
Item : in Element_Type);
24/2 procedure Delete (Container : in out Set;
Item : in Element_Type);
25/2 procedure Delete (Container : in out Set;
Position : in out Cursor);
26/2 procedure Union (Target : in out Set;
Source : in Set);
27/2 function Union (Left, Right : Set) return Set;
28/2 function "or" (Left, Right : Set) return Set renames Union;
29/2 procedure Intersection (Target : in out Set;
Source : in Set);
30/2 function Intersection (Left, Right : Set) return Set;
31/2 function "and" (Left, Right : Set) return Set renames Intersection;
32/2 procedure Difference (Target : in out Set;
Source : in Set);
33/2 function Difference (Left, Right : Set) return Set;
34/2 function "-" (Left, Right : Set) return Set renames Difference;
35/2 procedure Symmetric_Difference (Target : in out Set;
Source : in Set);
36/2 function Symmetric_Difference (Left, Right : Set) return Set;
37/2 function "xor" (Left, Right : Set) return Set
renames Symmetric_Difference;
38/2 function Overlap (Left, Right : Set) return Boolean;
39/2 function Is_Subset (Subset : Set;
Of_Set : Set) return Boolean;
40/2 function First (Container : Set) return Cursor;
41/2 function Next (Position : Cursor) return Cursor;
42/2 procedure Next (Position : in out Cursor);
43/2 function Find (Container : Set;
Item : Element_Type) return Cursor;
44/2 function Contains (Container : Set;
Item : Element_Type) return Boolean;
45/2 function Has_Element (Position : Cursor) return Boolean;
46/2 function Equivalent_Elements (Left, Right : Cursor)
return Boolean;
47/2 function Equivalent_Elements (Left : Cursor;
Right : Element_Type)
return Boolean;
48/2 function Equivalent_Elements (Left : Element_Type;
Right : Cursor)
return Boolean;
49/2 procedure Iterate
(Container : in Set;
Process : not null access procedure (Position : in Cursor));
50/2 generic
type Key_Type (<>) is private;
with function Key (Element : Element_Type) return Key_Type;
with function Hash (Key : Key_Type) return Hash_Type;
with function Equivalent_Keys (Left, Right : Key_Type)
return Boolean;
package Generic_Keys is
51/2 function Key (Position : Cursor) return Key_Type;
52/2 function Element (Container : Set;
Key : Key_Type)
return Element_Type;
53/2 procedure Replace (Container : in out Set;
Key : in Key_Type;
New_Item : in Element_Type);
54/2 procedure Exclude (Container : in out Set;
Key : in Key_Type);
55/2 procedure Delete (Container : in out Set;
Key : in Key_Type);
56/2 function Find (Container : Set;
Key : Key_Type)
return Cursor;
57/2 function Contains (Container : Set;
Key : Key_Type)
return Boolean;
58/2 procedure Update_Element_Preserving_Key
(Container : in out Set;
Position : in Cursor;
Process : not null access procedure
(Element : in out Element_Type));
59/2 end Generic_Keys;
60/2 private
61/2 ... -- not specified by the language
62/2 end Ada.Containers.Hashed_Sets;
63/2 An object of type Set contains an expandable hash table, which is used to
provide direct access to elements. The capacity of an object of type Set is
the maximum number of elements that can be inserted into the hash table prior
to it being automatically expanded.
64/2 Two elements E1 and E2 are defined to be equivalent if
Equivalent_Elements (E1, E2) returns True.
65/2 The actual function for the generic formal function Hash is expected to
return the same value each time it is called with a particular element value.
For any two equivalent elements, the actual for Hash is expected to return the
same value. If the actual for Hash behaves in some other manner, the behavior
of this package is unspecified. Which subprograms of this package call Hash,
and how many times they call it, is unspecified.
66/2 The actual function for the generic formal function Equivalent_Elements
is expected to return the same value each time it is called with a particular
pair of Element values. It should define an equivalence relationship, that is,
be reflexive, symmetric, and transitive. If the actual for Equivalent_Elements
behaves in some other manner, the behavior of this package is unspecified.
Which subprograms of this package call Equivalent_Elements, and how many times
they call it, is unspecified.
67/2 If the value of an element stored in a set is changed other than by an
operation in this package such that at least one of Hash or
Equivalent_Elements give different results, the behavior of this package is
unspecified.
68/2 Which elements are the first element and the last element of a set, and
which element is the successor of a given element, are unspecified, other than
the general semantics described in A.18.7.
69/2 function Capacity (Container : Set) return Count_Type;
70/2 Returns the capacity of Container.
71/2 procedure Reserve_Capacity (Container : in out Set;
Capacity : in Count_Type);
72/2 Reserve_Capacity allocates a new hash table such that the length
of the resulting set can become at least the value Capacity
without requiring an additional call to Reserve_Capacity, and is
large enough to hold the current length of Container.
Reserve_Capacity then rehashes the elements in Container onto the
new hash table. It replaces the old hash table with the new hash
table, and then deallocates the old hash table. Any exception
raised during allocation is propagated and Container is not
modified.
73/2 Reserve_Capacity tampers with the cursors of Container.
74/2 procedure Clear (Container : in out Set);
75/2 In addition to the semantics described in A.18.7, Clear does not
affect the capacity of Container.
76/2 procedure Insert (Container : in out Set;
New_Item : in Element_Type;
Position : out Cursor;
Inserted : out Boolean);
77/2 In addition to the semantics described in A.18.7, if Length
(Container) equals Capacity (Container), then Insert first calls
Reserve_Capacity to increase the capacity of Container to some
larger value.
78/2 function First (Container : Set) return Cursor;
79/2 If Length (Container) = 0, then First returns No_Element.
Otherwise, First returns a cursor that designates the first hashed
element in Container.
80/2 function Equivalent_Elements (Left, Right : Cursor)
return Boolean;
81/2 Equivalent to Equivalent_Elements (Element (Left), Element
(Right)).
82/2 function Equivalent_Elements (Left : Cursor;
Right : Element_Type) return Boolean;
83/2 Equivalent to Equivalent_Elements (Element (Left), Right).
84/2 function Equivalent_Elements (Left : Element_Type;
Right : Cursor) return Boolean;
85/2 Equivalent to Equivalent_Elements (Left, Element (Right)).
86/2 For any element E, the actual function for the generic formal function
Generic_Keys.Hash is expected to be such that Hash (E) = Generic_Keys.Hash
(Key (E)). If the actuals for Key or Generic_Keys.Hash behave in some other
manner, the behavior of Generic_Keys is unspecified. Which subprograms of
Generic_Keys call Generic_Keys.Hash, and how many times they call it, is
unspecified.
87/2 For any two elements E1 and E2, the boolean values Equivalent_Elements
(E1, E2) and Equivalent_Keys (Key (E1), Key (E2)) are expected to be equal. If
the actuals for Key or Equivalent_Keys behave in some other manner, the
behavior of Generic_Keys is unspecified. Which subprograms of Generic_Keys
call Equivalent_Keys, and how many times they call it, is unspecified.
Implementation Advice
88/2 If N is the length of a set, the average time complexity of the
subprograms Insert, Include, Replace, Delete, Exclude and Find that take an
element parameter should be O(log N). The average time complexity of the
subprograms that take a cursor parameter should be O(1). The average time
complexity of Reserve_Capacity should be O(N).
A.18.9 The Package Containers.Ordered_Sets
Static Semantics
1/2 The generic library package Containers.Ordered_Sets has the following
declaration:
2/2 generic
type Element_Type is private;
with function "<" (Left, Right : Element_Type) return Boolean is <>;
with function "=" (Left, Right : Element_Type) return Boolean is <>;
package Ada.Containers.Ordered_Sets is
pragma Preelaborate(Ordered_Sets);
3/2 function Equivalent_Elements
(Left, Right : Element_Type) return Boolean;
4/2 type Set is tagged private;
pragma Preelaborable_Initialization(Set);
5/2 type Cursor is private;
pragma Preelaborable_Initialization(Cursor);
6/2 Empty_Set : constant Set;
7/2 No_Element : constant Cursor;
8/2 function "=" (Left, Right : Set) return Boolean;
9/2 function Equivalent_Sets (Left, Right : Set) return Boolean;
10/2 function To_Set (New_Item : Element_Type) return Set;
11/2 function Length (Container : Set) return Count_Type;
12/2 function Is_Empty (Container : Set) return Boolean;
13/2 procedure Clear (Container : in out Set);
14/2 function Element (Position : Cursor) return Element_Type;
15/2 procedure Replace_Element (Container : in out Set;
Position : in Cursor;
New_Item : in Element_Type);
16/2 procedure Query_Element
(Position : in Cursor;
Process : not null access procedure (Element : in Element_Type));
17/2 procedure Move (Target : in out Set;
Source : in out Set);
18/2 procedure Insert (Container : in out Set;
New_Item : in Element_Type;
Position : out Cursor;
Inserted : out Boolean);
19/2 procedure Insert (Container : in out Set;
New_Item : in Element_Type);
20/2 procedure Include (Container : in out Set;
New_Item : in Element_Type);
21/2 procedure Replace (Container : in out Set;
New_Item : in Element_Type);
22/2 procedure Exclude (Container : in out Set;
Item : in Element_Type);
23/2 procedure Delete (Container : in out Set;
Item : in Element_Type);
24/2 procedure Delete (Container : in out Set;
Position : in out Cursor);
25/2 procedure Delete_First (Container : in out Set);
26/2 procedure Delete_Last (Container : in out Set);
27/2 procedure Union (Target : in out Set;
Source : in Set);
28/2 function Union (Left, Right : Set) return Set;
29/2 function "or" (Left, Right : Set) return Set renames Union;
30/2 procedure Intersection (Target : in out Set;
Source : in Set);
31/2 function Intersection (Left, Right : Set) return Set;
32/2 function "and" (Left, Right : Set) return Set renames Intersection;
33/2 procedure Difference (Target : in out Set;
Source : in Set);
34/2 function Difference (Left, Right : Set) return Set;
35/2 function "-" (Left, Right : Set) return Set renames Difference;
36/2 procedure Symmetric_Difference (Target : in out Set;
Source : in Set);
37/2 function Symmetric_Difference (Left, Right : Set) return Set;
38/2 function "xor" (Left, Right : Set) return Set renames
Symmetric_Difference;
39/2 function Overlap (Left, Right : Set) return Boolean;
40/2 function Is_Subset (Subset : Set;
Of_Set : Set) return Boolean;
41/2 function First (Container : Set) return Cursor;
42/2 function First_Element (Container : Set) return Element_Type;
43/2 function Last (Container : Set) return Cursor;
44/2 function Last_Element (Container : Set) return Element_Type;
45/2 function Next (Position : Cursor) return Cursor;
46/2 procedure Next (Position : in out Cursor);
47/2 function Previous (Position : Cursor) return Cursor;
48/2 procedure Previous (Position : in out Cursor);
49/2 function Find (Container : Set;
Item : Element_Type)
return Cursor;
50/2 function Floor (Container : Set;
Item : Element_Type)
return Cursor;
51/2 function Ceiling (Container : Set;
Item : Element_Type)
return Cursor;
52/2 function Contains (Container : Set;
Item : Element_Type) return Boolean;
53/2 function Has_Element (Position : Cursor) return Boolean;
54/2 function "<" (Left, Right : Cursor) return Boolean;
55/2 function ">" (Left, Right : Cursor) return Boolean;
56/2 function "<" (Left : Cursor; Right : Element_Type)
return Boolean;
57/2 function ">" (Left : Cursor; Right : Element_Type)
return Boolean;
58/2 function "<" (Left : Element_Type; Right : Cursor)
return Boolean;
59/2 function ">" (Left : Element_Type; Right : Cursor)
return Boolean;
60/2 procedure Iterate
(Container : in Set;
Process : not null access procedure (Position : in Cursor));
61/2 procedure Reverse_Iterate
(Container : in Set;
Process : not null access procedure (Position : in Cursor));
62/2 generic
type Key_Type (<>) is private;
with function Key (Element : Element_Type) return Key_Type;
with function "<" (Left, Right : Key_Type)
return Boolean is <>;
package Generic_Keys is
63/2 function Equivalent_Keys (Left, Right : Key_Type)
return Boolean;
64/2 function Key (Position : Cursor) return Key_Type;
65/2 function Element (Container : Set;
Key : Key_Type)
return Element_Type;
66/2 procedure Replace (Container : in out Set;
Key : in Key_Type;
New_Item : in Element_Type);
67/2 procedure Exclude (Container : in out Set;
Key : in Key_Type);
68/2 procedure Delete (Container : in out Set;
Key : in Key_Type);
69/2 function Find (Container : Set;
Key : Key_Type)
return Cursor;
70/2 function Floor (Container : Set;
Key : Key_Type)
return Cursor;
71/2 function Ceiling (Container : Set;
Key : Key_Type)
return Cursor;
72/2 function Contains (Container : Set;
Key : Key_Type) return Boolean;
73/2 procedure Update_Element_Preserving_Key
(Container : in out Set;
Position : in Cursor;
Process : not null access procedure
(Element : in out Element_Type));
74/2 end Generic_Keys;
75/2 private
76/2 ... -- not specified by the language
77/2 end Ada.Containers.Ordered_Sets;
78/2 Two elements E1 and E2 are equivalent if both E1 < E2 and E2 < E1 return
False, using the generic formal "<" operator for elements. Function
Equivalent_Elements returns True if Left and Right are equivalent, and False
otherwise.
79/2 The actual function for the generic formal function "<" on Element_Type
values is expected to return the same value each time it is called with a
particular pair of key values. It should define a strict ordering
relationship, that is, be irreflexive, asymmetric, and transitive. If the
actual for "<" behaves in some other manner, the behavior of this package is
unspecified. Which subprograms of this package call "<" and how many times
they call it, is unspecified.
80/2 If the value of an element stored in a set is changed other than by an
operation in this package such that at least one of "<" or "=" give different
results, the behavior of this package is unspecified.
81/2 The first element of a nonempty set is the one which is less than all the
other elements in the set. The last element of a nonempty set is the one which
is greater than all the other elements in the set. The successor of an element
is the smallest element that is larger than the given element. The predecessor
of an element is the largest element that is smaller than the given element.
All comparisons are done using the generic formal "<" operator for elements.
82/2 procedure Delete_First (Container : in out Set);
83/2 If Container is empty, Delete_First has no effect. Otherwise the
element designated by First (Container) is removed from Container.
Delete_First tampers with the cursors of Container.
84/2 procedure Delete_Last (Container : in out Set);
85/2 If Container is empty, Delete_Last has no effect. Otherwise the
element designated by Last (Container) is removed from Container.
Delete_Last tampers with the cursors of Container.
86/2 function First_Element (Container : Set) return Element_Type;
87/2 Equivalent to Element (First (Container)).
88/2 function Last (Container : Set) return Cursor;
89/2 Returns a cursor that designates the last element in Container. If
Container is empty, returns No_Element.
90/2 function Last_Element (Container : Set) return Element_Type;
91/2 Equivalent to Element (Last (Container)).
92/2 function Previous (Position : Cursor) return Cursor;
93/2 If Position equals No_Element, then Previous returns No_Element.
Otherwise Previous returns a cursor designating the element that
precedes the one designated by Position. If Position designates
the first element, then Previous returns No_Element.
94/2 procedure Previous (Position : in out Cursor);
95/2 Equivalent to Position := Previous (Position).
96/2 function Floor (Container : Set;
Item : Element_Type) return Cursor;
97/2 Floor searches for the last element which is not greater than
Item. If such an element is found, a cursor that designates it is
returned. Otherwise No_Element is returned.
98/2 function Ceiling (Container : Set;
Item : Element_Type) return Cursor;
99/2 Ceiling searches for the first element which is not less than
Item. If such an element is found, a cursor that designates it is
returned. Otherwise No_Element is returned.
100/2 function "<" (Left, Right : Cursor) return Boolean;
101/2 Equivalent to Element (Left) < Element (Right).
102/2 function ">" (Left, Right : Cursor) return Boolean;
103/2 Equivalent to Element (Right) < Element (Left).
104/2 function "<" (Left : Cursor; Right : Element_Type) return Boolean;
105/2 Equivalent to Element (Left) < Right.
106/2 function ">" (Left : Cursor; Right : Element_Type) return Boolean;
107/2 Equivalent to Right < Element (Left).
108/2 function "<" (Left : Element_Type; Right : Cursor) return Boolean;
109/2 Equivalent to Left < Element (Right).
110/2 function ">" (Left : Element_Type; Right : Cursor) return Boolean;
111/2 Equivalent to Element (Right) < Left.
112/2 procedure Reverse_Iterate
(Container : in Set;
Process : not null access procedure (Position : in Cursor));
113/2 Iterates over the elements in Container as per Iterate, with the
difference that the elements are traversed in predecessor order,
starting with the last element.
114/2 For any two elements E1 and E2, the boolean values (E1 < E2) and
(Key(E1) < Key(E2)) are expected to be equal. If the actuals for Key or
Generic_Keys."<" behave in some other manner, the behavior of this package is
unspecified. Which subprograms of this package call Key and Generic_Keys."<",
and how many times the functions are called, is unspecified.
115/2 In addition to the semantics described in A.18.7, the subprograms in
package Generic_Keys named Floor and Ceiling, are equivalent to the
corresponding subprograms in the parent package, with the difference that the
Key subprogram parameter is compared to elements in the container using the
Key and "<" generic formal functions. The function named Equivalent_Keys in
package Generic_Keys returns True if both Left < Right and Right < Left return
False using the generic formal "<" operator, and returns True otherwise.
Implementation Advice
116/2 If N is the length of a set, then the worst-case time complexity of the
Insert, Include, Replace, Delete, Exclude and Find operations that take an
element parameter should be O((log N)**2) or better. The worst-case time
complexity of the subprograms that take a cursor parameter should be O(1).
A.18.10 The Package Containers.Indefinite_Vectors
1/2 The language-defined generic package Containers.Indefinite_Vectors
provides a private type Vector and a set of operations. It provides the same
operations as the package Containers.Vectors (see A.18.2), with the difference
that the generic formal Element_Type is indefinite.
Static Semantics
2/2 The declaration of the generic library package
Containers.Indefinite_Vectors has the same contents as Containers.Vectors
except:
3/2 * The generic formal Element_Type is indefinite.
4/2 * The procedures with the profiles:
5/2 procedure Insert (Container : in out Vector;
Before : in Extended_Index;
Count : in Count_Type := 1);
6 procedure Insert (Container : in out Vector;
Before : in Cursor;
Position : out Cursor;
Count : in Count_Type := 1);
7/2 are omitted.
8/2 * The actual Element parameter of access subprogram Process of
Update_Element may be constrained even if Element_Type is
unconstrained.
A.18.11 The Package Containers.Indefinite_Doubly_Linked_Lists
1/2 The language-defined generic package
Containers.Indefinite_Doubly_Linked_Lists provides private types List and
Cursor, and a set of operations for each type. It provides the same operations
as the package Containers.Doubly_Linked_Lists (see A.18.3), with the
difference that the generic formal Element_Type is indefinite.
Static Semantics
2/2 The declaration of the generic library package Containers.Indefinite_-
Doubly_Linked_Lists has the same contents as Containers.Doubly_Linked_Lists
except:
3/2 * The generic formal Element_Type is indefinite.
4/2 * The procedure with the profile:
5/2 procedure Insert (Container : in out List;
Before : in Cursor;
Position : out Cursor;
Count : in Count_Type := 1);
6/2 is omitted.
7/2 * The actual Element parameter of access subprogram Process of
Update_Element may be constrained even if Element_Type is
unconstrained.
A.18.12 The Package Containers.Indefinite_Hashed_Maps
1/2 The language-defined generic package Containers.Indefinite_Hashed_Maps
provides a map with the same operations as the package Containers.Hashed_Maps
(see A.18.5), with the difference that the generic formal types Key_Type and
Element_Type are indefinite.
Static Semantics
2/2 The declaration of the generic library package
Containers.Indefinite_Hashed_Maps has the same contents as
Containers.Hashed_Maps except:
3/2 * The generic formal Key_Type is indefinite.
4/2 * The generic formal Element_Type is indefinite.
5/2 * The procedure with the profile:
6/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
Position : out Cursor;
Inserted : out Boolean);
7/2 is omitted.
8/2 * The actual Element parameter of access subprogram Process of
Update_Element may be constrained even if Element_Type is
unconstrained.
A.18.13 The Package Containers.Indefinite_Ordered_Maps
1/2 The language-defined generic package Containers.Indefinite_Ordered_Maps
provides a map with the same operations as the package Containers.Ordered_Maps
(see A.18.6), with the difference that the generic formal types Key_Type and
Element_Type are indefinite.
Static Semantics
2/2 The declaration of the generic library package
Containers.Indefinite_Ordered_Maps has the same contents as
Containers.Ordered_Maps except:
3/2 * The generic formal Key_Type is indefinite.
4/2 * The generic formal Element_Type is indefinite.
5/2 * The procedure with the profile:
6/2 procedure Insert (Container : in out Map;
Key : in Key_Type;
Position : out Cursor;
Inserted : out Boolean);
7/2 is omitted.
8/2 * The actual Element parameter of access subprogram Process of
Update_Element may be constrained even if Element_Type is
unconstrained.
A.18.14 The Package Containers.Indefinite_Hashed_Sets
1/2 The language-defined generic package Containers.Indefinite_Hashed_Sets
provides a set with the same operations as the package Containers.Hashed_Sets
(see A.18.8), with the difference that the generic formal type Element_Type is
indefinite.
Static Semantics
2/2 The declaration of the generic library package
Containers.Indefinite_Hashed_Sets has the same contents as
Containers.Hashed_Sets except:
3/2 * The generic formal Element_Type is indefinite.
4/2 * The actual Element parameter of access subprogram Process of Update_-
Element_Preserving_Key may be constrained even if Element_Type is
unconstrained.
A.18.15 The Package Containers.Indefinite_Ordered_Sets
1/2 The language-defined generic package Containers.Indefinite_Ordered_Sets
provides a set with the same operations as the package Containers.Ordered_Sets
(see A.18.9), with the difference that the generic formal type Element_Type is
indefinite.
Static Semantics
2/2 The declaration of the generic library package
Containers.Indefinite_Ordered_Sets has the same contents as
Containers.Ordered_Sets except:
3/2 * The generic formal Element_Type is indefinite.
4/2 * The actual Element parameter of access subprogram Process of Update_-
Element_Preserving_Key may be constrained even if Element_Type is
unconstrained.
A.18.16 Array Sorting
1/2 The language-defined generic procedures Containers.Generic_Array_Sort and
Containers.Generic_Constrained_Array_Sort provide sorting on arbitrary array
types.
Static Semantics
2/2 The generic library procedure Containers.Generic_Array_Sort has the
following declaration:
3/2 generic
type Index_Type is (<>);
type Element_Type is private;
type Array_Type is array (Index_Type range <>) of Element_Type;
with function "<" (Left, Right : Element_Type)
return Boolean is <>;
procedure Ada.Containers.Generic_Array_Sort (Container : in out Array_Type);
pragma Pure(Ada.Containers.Generic_Array_Sort);
4/2 Reorders the elements of Container such that the elements are
sorted smallest first as determined by the generic formal "<"
operator provided. Any exception raised during evaluation of "<"
is propagated.
5/2 The actual function for the generic formal function "<" of
Generic_Array_Sort is expected to return the same value each time
it is called with a particular pair of element values. It should
define a strict ordering relationship, that is, be irreflexive,
asymmetric, and transitive; it should not modify Container. If the
actual for "<" behaves in some other manner, the behavior of the
instance of Generic_Array_Sort is unspecified. How many times
Generic_Array_Sort calls "<" is unspecified.
6/2 The generic library procedure Containers.Generic_Constrained_Array_Sort
has the following declaration:
7/2 generic
type Index_Type is (<>);
type Element_Type is private;
type Array_Type is array (Index_Type) of Element_Type;
with function "<" (Left, Right : Element_Type)
return Boolean is <>;
procedure Ada.Containers.Generic_Constrained_Array_Sort
(Container : in out Array_Type);
pragma Pure(Ada.Containers.Generic_Constrained_Array_Sort);
8/2 Reorders the elements of Container such that the elements are
sorted smallest first as determined by the generic formal "<"
operator provided. Any exception raised during evaluation of "<"
is propagated.
9/2 The actual function for the generic formal function "<" of
Generic_Constrained_Array_Sort is expected to return the same
value each time it is called with a particular pair of element
values. It should define a strict ordering relationship, that is,
be irreflexive, asymmetric, and transitive; it should not modify
Container. If the actual for "<" behaves in some other manner, the
behavior of the instance of Generic_Constrained_Array_Sort is
unspecified. How many times Generic_Constrained_Array_Sort calls
"<" is unspecified.
Implementation Advice
10/2 The worst-case time complexity of a call on an instance of
Containers.Generic_Array_Sort or Containers.Generic_Constrained_Array_Sort
should be O(N**2) or better, and the average time complexity should be better
than O(N**2), where N is the length of the Container parameter.
11/2 Containers.Generic_Array_Sort and
Containers.Generic_Constrained_Array_Sort should minimize copying of elements.
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