Sereal::Encoder(3pm) User Contributed Perl Documentation Sereal::Encoder(3pm)
NAME
Sereal::Encoder - Fast, compact, powerful binary serialization
SYNOPSIS
use Sereal::Encoder qw(encode_sereal sereal_encode_with_object);
my $encoder = Sereal::Encoder->new({...options...});
my $out = $encoder->encode($structure);
# alternatively the functional interface:
$out = sereal_encode_with_object($encoder, $structure);
# much slower functional interface with no persistent objects:
$out = encode_sereal($structure, {... options ...});
DESCRIPTION
This library implements an efficient, compact-output, and feature-rich
serializer using a binary protocol called Sereal. Its sister module
Sereal::Decoder implements a decoder for this format. The two are
released separately to allow for independent and safer upgrading. If
you care greatly about performance, consider reading the
Sereal::Performance documentation after finishing this document.
The Sereal protocol version emitted by this encoder implementation is
currently protocol version 4 by default.
The protocol specification and many other bits of documentation can be
found in the github repository. Right now, the specification is at
<https://github.com/Sereal/Sereal/blob/master/sereal_spec.pod>, there
is a discussion of the design objectives in
<https://github.com/Sereal/Sereal/blob/master/README.pod>, and the
output of our benchmarks can be seen at
<https://github.com/Sereal/Sereal/wiki/Sereal-Comparison-Graphs>. For
more information on getting the best performance out of Sereal, have a
look at the "PERFORMANCE" section below.
CLASS METHODS
new
Constructor. Optionally takes a hash reference as first parameter. This
hash reference may contain any number of options that influence the
behaviour of the encoder.
Currently, the following options are recognized, none of them are on by
default.
compress
If this option provided and true, compression of the document body is
enabled. As of Sereal version 4, three different compression
techniques are supported and can be enabled by setting "compress" to
the respective named constants (exportable from the "Sereal::Encoder"
module): Snappy (named constant: "SRL_SNAPPY"), Zlib ("SRL_ZLIB") and
Zstd ("SRL_ZSTD"). For your convenience, there is also a
"SRL_UNCOMPRESSED" constant.
If this option is set, then the Snappy-related options below are
ignored. They are otherwise recognized for compatibility only.
compress_threshold
The size threshold (in bytes) of the uncompressed output below which
compression is not even attempted even if enabled. Defaults to one
kilobyte (1024 bytes). Set this to 0 and "compress" to a
non-"SRL_UNCOMPRESSED" value to always attempt to compress. Note that
the document will not be compressed if the resulting size will be
bigger than the original size (even if "compress_threshold" is 0).
compress_level
If Zlib or Zstd compressions are used, then this option will set a
compression level: Zlib uses range from 1 (fastest) to 9 (best).
Defaults to 6. Zstd uses range from 1 (fastest) to 22 (best). Default
is 3.
snappy
See also the "compress" option. This option is provided only for
compatibility with Sereal V1.
If set, the main payload of the Sereal document will be compressed
using Google's Snappy algorithm. This can yield anywhere from no effect
to significant savings on output size at rather low run time cost. If
in doubt, test with your data whether this helps or not.
The decoder (version 0.04 and up) will know how to handle Snappy-
compressed Sereal documents transparently.
Note: The "snappy_incr" and "snappy" options are identical in Sereal
protocol v2 and up (so by default). If using an older protocol version
(see "protocol_version" and "use_protocol_v1" options below) to emit
Sereal V1 documents, this emits non-incrementally decodable documents.
See "snappy_incr" in those cases.
snappy_incr
See also the "compress" option. This option is provided only for
compatibility with Sereal V1.
Same as the "snappy" option for default operation (that is in Sereal v2
or up).
In Sereal V1, enables a version of the Snappy protocol which is
suitable for incremental parsing of packets. See also the "snappy"
option above for more details.
snappy_threshold
See also the "compress" option. This option is provided only for
compatibility with Sereal V1.
This option is a synonym for the "compress_threshold" option, but only
if Snappy compression is enabled.
croak_on_bless
If this option is set, then the encoder will refuse to serialize
blessed references and throw an exception instead.
This can be important because blessed references can mean executing a
destructor on a remote system or generally executing code based on
data.
See also "no_bless_objects" to skip the blessing of objects. When both
flags are set, "croak_on_bless" has a higher precedence then
"no_bless_objects".
freeze_callbacks
This option was introduced in Sereal v2 and needs a Sereal v2 decoder.
If this option is set, the encoder will check for and possibly invoke
the "FREEZE" method on any object in the input data. An object that was
serialized using its "FREEZE" method will have its corresponding "THAW"
class method called during deserialization. The exact semantics are
documented below under "FREEZE/THAW CALLBACK MECHANISM".
Beware that using this functionality means a significant slowdown for
object serialization. Even when serializing objects without a "FREEZE"
method, the additional method look up will cost a small amount of
runtime. Yes, "Sereal::Encoder" is so fast that this may make a
difference.
no_bless_objects
If this option is set, then the encoder will serialize blessed
references without the bless information and provide plain data
structures instead.
See also the "croak_on_bless" option above for more details.
undef_unknown
If set, unknown/unsupported data structures will be encoded as "undef"
instead of throwing an exception.
Mutually exclusive with "stringify_unknown". See also "warn_unknown"
below.
stringify_unknown
If set, unknown/unsupported data structures will be stringified and
encoded as that string instead of throwing an exception. The
stringification may cause a warning to be emitted by perl.
Mutually exclusive with "undef_unknown". See also "warn_unknown"
below.
warn_unknown
Only has an effect if "undef_unknown" or "stringify_unknown" are
enabled.
If set to a positive integer, any unknown/unsupported data structure
encountered will emit a warning. If set to a negative integer, it will
warn for unsupported data structures just the same as for a positive
value with one exception: For blessed, unsupported items that have
string overloading, we silently stringify without warning.
max_recursion_depth
"Sereal::Encoder" is recursive. If you pass it a Perl data structure
that is deeply nested, it will eventually exhaust the C stack.
Therefore, there is a limit on the depth of recursion that is accepted.
It defaults to 10000 nested calls. You may choose to override this
value with the "max_recursion_depth" option. Beware that setting it too
high can cause hard crashes, so only do that if you KNOW that it is
safe to do so.
Do note that the setting is somewhat approximate. Setting it to 10000
may break at somewhere between 9997 and 10003 nested structures
depending on their types.
canonical
Enable all options which are related to producing canonical output, so
that two strucutures with similar contents produce the same serialized
form.
See the caveats elsewhere in this document about producing canonical
output.
Currently sets the default for the following parameters:
"canonical_refs" and "sort_keys". If the option is explicitly set then
this setting is ignored. More options may be added in the future.
You are warned that use of this option may incur additional performance
penalties in a future release by enabling other options than those
listed here.
canonical_refs
Normally "Sereal::Encoder" will ARRAYREF and HASHREF tags when the item
contains less than 16 items, and and is not referenced more than once.
This flag will override this optimization and use a standard REFN ARRAY
style tag output. This is primarily useful for producing canonical
output and for testing Sereal itself.
See "CANONICAL REPRESENTATION" for why you might want to use this, and
for the various caveats involved.
sort_keys
Normally "Sereal::Encoder" will output hashes in whatever order is
convenient, generally that used by perl to actually store the hash, or
whatever order was returned by a tied hash.
If this option is enabled then the Encoder will sort the keys before
outputting them. It uses more memory, and is quite a bit slower than
the default.
Generally speaking this should mean that a hash and a copy should
produce the same output. Nevertheless the user is warned that Perl has
a way of "morphing" variables on use, and some of its rules are a
little arcane (for instance utf8 keys), and so two hashes that might
appear to be the same might still produce different output as far as
Sereal is concerned.
As of 3.006_007 (prerelease candidate for 3.007) the sort order has
been changed to the following: order by length of keys (in bytes)
ascending, then by byte order of the raw underlying string, then by
utf8ness, with non-utf8 first. This order was chosen because it is the
most efficient to implement, both in terms of memory and time. This
sort order is enabled when sort_keys is set to 1.
You may also produce output in Perl "cmp" order, by setting sort_keys
to 2. And for backwards compatibility you may also produce output in
reverse Perl "cmp" order by setting sort_keys to 3. Prior to 3.006_007
this was the only sort order possible, although it was not explicitly
defined what it was.
Note that comparatively speaking both of the "cmp" sort orders are slow
and memory inefficient. Unless you have a really good reason stick to
the default which is fast and as lean as possible.
Unless you are concerned with "cross process canonical representation"
then it doesn't matter what option you choose.
See "CANONICAL REPRESENTATION" for why you might want to use this, and
for the various caveats involved.
no_shared_hashkeys
When the "no_shared_hashkeys" option is set to a true value, then the
encoder will disable the detection and elimination of repeated hash
keys. This only has an effect for serializing structures containing
hashes. By skipping the detection of repeated hash keys, performance
goes up a bit, but the size of the output can potentially be much
larger.
Do not disable this unless you have a reason to.
dedupe_strings
If this is option is enabled/true then Sereal will use a hash to encode
duplicates of strings during serialization efficiently using (internal)
backreferences. This has a performance and memory penalty during
encoding so it defaults to off. On the other hand, data structures
with many duplicated strings will see a significant reduction in the
size of the encoded form. Currently only strings longer than 3
characters will be deduped, however this may change in the future.
Note that Sereal will perform certain types of deduping automatically
even without this option. In particular class names and hash keys (see
also the "no_shared_hashkeys" setting) are deduped regardless of this
option. Only enable this if you have good reason to believe that there
are many duplicated strings as values in your data structure.
Use of this option does not require an upgraded decoder (this option
was added in Sereal::Encoder 0.32). The deduping is performed in such a
way that older decoders should handle it just fine. In other words,
the output of a Sereal decoder should not depend on whether this option
was used during encoding. See also below: aliased_dedupe_strings.
aliased_dedupe_strings
This is an advanced option that should be used only after fully
understanding its ramifications.
This option enables a mode of operation that is similar to
dedupe_strings and if both options are set, aliased_dedupe_strings
takes precedence.
The behaviour of aliased_dedupe_strings differs from dedupe_strings in
that the duplicate occurrences of strings are emitted as Perl language
level aliases instead of as Sereal-internal backreferences. This means
that using this option actually produces a different output data
structure when decoding. The upshot is that with this option, the
application using (decoding) the data may save a lot of memory in some
situations but at the cost of potential action at a distance due to the
aliasing.
Beware: The test suite currently does not cover this option as well as
it probably should. Patches welcome.
use_standard_double
This option can be used to force Perls built with uselongdouble or
quadmath to use DOUBLE instead of the native floating point. This can
be helpful interoperating with Perls which do not support larger sized
floats. Note that "uselongdouble" means different things in different
places, so this option may be helpful for such builds. We do not enable
this option by default for backwards compatibility reasons, and because
doing so would lose precision.
protocol_version
Specifies the version of the Sereal protocol to emit. Valid are
integers between 1 and the current version. If not specified, the most
recent protocol version will be used. See also "use_protocol_v1":
It is strongly advised to use the latest protocol version outside of
migration periods.
use_protocol_v1
This option is deprecated in favour of the "protocol_version" option
(see above).
If set, the encoder will emit Sereal documents following protocol
version 1. This is strongly discouraged except for temporary
compatibility/migration purposes.
INSTANCE METHODS
encode
Given a Perl data structure, serializes that data structure and returns
a binary string that can be turned back into the original data
structure by Sereal::Decoder. The method expects a data structure to
serialize as first argument, optionally followed by a header data
structure.
A header is intended for embedding small amounts of meta data, such as
routing information, in a document that allows users to avoid
deserializing main body needlessly.
encode_to_file
Sereal::Encoder->encode_to_file($file,$data,$append);
$encoder->encode_to_file($file,$data,$append);
Encode the data specified and write it the named file. If $append is
true then the written data is appended to any existing data, otherwise
any existing data will be overwritten. Dies if any errors occur during
writing the encoded data.
EXPORTABLE FUNCTIONS
sereal_encode_with_object
The functional interface that is equivalent to using "encode". Takes an
encoder object reference as first argument, followed by a data
structure and optional header to serialize.
This functional interface is marginally faster than the OO interface
since it avoids method resolution overhead and, on sufficiently modern
Perl versions, can usually avoid subroutine call overhead.
encode_sereal
The functional interface that is equivalent to using "new" and
"encode". Expects a data structure to serialize as first argument,
optionally followed by a hash reference of options (see documentation
for "new()").
This function cannot be used for encoding a data structure with a
header. See "encode_sereal_with_header_data".
This functional interface is significantly slower than the OO interface
since it cannot reuse the encoder object.
encode_sereal_with_header_data
The functional interface that is equivalent to using "new" and
"encode". Expects a data structure and a header to serialize as first
and second arguments, optionally followed by a hash reference of
options (see documentation for "new()").
This functional interface is significantly slower than the OO interface
since it cannot reuse the encoder object.
PERFORMANCE
See Sereal::Performance for detailed considerations on performance
tuning. Let it just be said that:
If you care about performance at all, then use
"sereal_encode_with_object" or the OO interface instead of
"encode_sereal". It's a significant difference in performance if you
are serializing small data structures.
The exact performance in time and space depends heavily on the data
structure to be serialized. Often there is a trade-off between space
and time. If in doubt, do your own testing and most importantly ALWAYS
TEST WITH REAL DATA. If you care purely about speed at the expense of
output size, you can use the "no_shared_hashkeys" option for a small
speed-up. If you need smaller output at the cost of higher CPU load and
more memory used during encoding/decoding, try the "dedupe_strings"
option and enable Snappy compression.
For ready-made comparison scripts, see the author_tools/bench.pl and
author_tools/dbench.pl programs that are part of this distribution.
Suffice to say that this library is easily competitive in both time and
space efficiency with the best alternatives.
FREEZE/THAW CALLBACK MECHANISM
Some objects do not lend themselves naturally to naive perl
datastructure level serialization. For instance XS code might use a
hidden structure that would not get serialized, or an object may
contain volatile data like a filehandle that would not be reconstituted
properly. To support cases like this "Sereal" supports a FREEZE and
THAW api. When objects are serialized their FREEZE method is asked for
a replacement representation, and when objects are deserialized their
THAW method is asked to convert that replacement back to something
useful.
This mechanism is enabled using the "freeze_callbacks" option of the
encoder. It is inspired by the equivalent mechanism in CBOR::XS. The
general mechanism is documented in the A GENERIC OBJECT SERIALIATION
PROTOCOL section of Types::Serialiser. Similar to CBOR using "CBOR",
Sereal uses the string "Sereal" as a serializer identifier for the
callbacks.
Here is a contrived example of a class implementing the "FREEZE" /
"THAW" mechanism.
package
File;
use Moo;
has 'path' => (is => 'ro');
has 'fh' => (is => 'rw');
# open file handle if necessary and return it
sub get_fh {
my $self = shift;
# This could also be done with fancier Moo(se) syntax
my $fh = $self->fh;
if (not $fh) {
open $fh, "<", $self->path or die $!;
$self->fh($fh);
}
return $fh;
}
sub FREEZE {
my ($self, $serializer) = @_;
# Could switch on $serializer here: JSON, CBOR, Sereal, ...
# But this case is so simple that it will work with ALL of them.
# Do not try to serialize our file handle! Path will be enough
# to recreate.
return $self->path;
}
sub THAW {
my ($class, $serializer, $data) = @_;
# Turn back into object.
return $class->new(path => $data);
}
Why is the "FREEZE"/"THAW" mechanism important here? Our contrived
"File" class may contain a file handle which can't be serialized. So
"FREEZE" not only returns just the path (which is more compact than
encoding the actual object contents), but it strips the file handle
which can be lazily reopened on the other side of the
serialization/deserialization pipe. But this example also shows that a
naive implementation can easily end up with subtle bugs. A file handle
itself has state (position in file, etc). Thus the deserialization in
the above example won't accurately reproduce the original state. It
can't, of course, if it's deserialized in a different environment
anyway.
THREAD-SAFETY
"Sereal::Encoder" is thread-safe on Perl's 5.8.7 and higher. This means
"thread-safe" in the sense that if you create a new thread, all
"Sereal::Encoder" objects will become a reference to undef in the new
thread. This might change in a future release to become a full clone of
the encoder object.
CANONICAL REPRESENTATION
You might want to compare two data structures by comparing their
serialized byte strings. For that to work reliably the serialization
must take extra steps to ensure that identical data structures are
encoded into identical serialized byte strings (a so-called "canonical
representation").
Unfortunately in Perl there is no such thing as a "canonical
representation". Most people are interested in "structural
equivalence" but even that is less well defined than most people think.
For instance in the following example:
my $array1= [ 0, 0 ];
my $array2= do {
my $zero= 0;
sub{ \@_ }->($zero,$zero);
};
the question of whether $array1 is structurally equivalent to $array2
is a subjective one. Sereal for instance would NOT consider them
equivalent but "Test::Deep" would. There are many examples of this in
Perl. Simply stringifying a number technically changes the scalar.
Storable would notice this, but Sereal generally would not.
Despite this as of 3.002 the Sereal encoder supports a "canonical"
option which will make a "best effort" attempt at producing a canonical
representation of a data structure. This mode is actually a
combination of several other modes which may also be enabled
independently, and as and when we add new options to the encoder that
would assist in this regard then the "canonical" will also enable them.
These options may come with a performance penalty so care should be
taken to read the Changes file and test the performance implications
when upgrading a system that uses this option.
It is important to note that using canonical representation to
determine if two data structures are different is subject to false-
positives. If two Sereal encodings are identical you can generally
assume that the two data structures are functionally equivalent from
the point of view of normal Perl code (XS code might disagree). However
if two Sereal encodings differ the data structures may actually be
functionally equivalent. In practice it seems the the false-positive
rate is low, but your milage may vary.
Some of the issues with producing a true canonical representation are
outlined below:
Sereal doesn't order the hash keys by default.
This can be enabled via the "sort_keys", which is itself enabled by
"canonical" option.
Sereal output is sensitive to refcounts
This can be somewhat mitigated by the use of "canonical_refs", see
above.
There are multiple valid Sereal documents that you can produce for the
same Perl data structure.
Just sorting hash keys is not enough. Some of the reasons are
outlined below. These issues are especially relevant when
considering language interoperability.
PAD bytes
A trivial example is PAD bytes which mean nothing and are
skipped. They mostly exist for encoder optimizations to prevent
certain nasty backtracking situations from becoming O(n) at the
cost of one byte of output. An explicit canonical mode would
have to outlaw them (or add more of them) and thus require a
much more complicated implementation of refcount/weakref
handing in the encoder while at the same time causing some
operations to go from O(1) to a full memcpy of everything after
the point of where we backtracked to. Nasty.
COPY tag
Another example is COPY. The COPY tag indicates that the next
element is an identical copy of a previous element (which is
itself forbidden from including COPY's other than for class
names). COPY is purely internal. The Perl/XS implementation
uses it to share hash keys and class names. One could use it
for other strings (theoretically), but doesn't for time-
efficiency reasons. We'd have to outlaw the use of this
(significant) optimization of canonicalization.
REF representation
Sereal represents a reference to an array as a sequence of tags
which, in its simplest form, reads REF, ARRAY $array_length
TAG1 TAG2 .... The separation of "REF" and "ARRAY" is
necessary to properly implement all of Perl's referencing and
aliasing semantics correctly. Quite frequently, however, your
array is only referenced once and plainly so. If it's also at
most 15 elements long, Sereal optimizes all of the "REF" and
"ARRAY" tags, as well as the length into a special one byte
ARRAYREF tag. This is a very significant optimization for
common cases. This, however, does mean that most arrays up to
15 elements could be represented in two different, yet
perfectly valid forms. ARRAYREF would have to be outlawed for a
properly canonical form. The exact same logic applies to HASH
vs. HASHREF. This behavior can be overridden by the
"canonical_refs" option, which disables use of HASHREF and
ARRAYREF.
Numeric representation
Similar to how Sereal can represent arrays and hashes in a full
and a compact form. For small integers (between -16 and +15
inclusive), Sereal emits only one byte including the encoding
of the type of data. For larger integers, it can use either
variants (positive only) or zigzag encoding, which can also
represent negative numbers. For a canonical mode, the space
optimizations would have to be turned off and it would have to
be explicitly specified whether variant or zigzag encoding is
to be used for encoding positive integers.
Perl may choose to retain multiple representations of a scalar.
Specifically, it can convert integers, floating point numbers,
and strings on the fly and will aggressively cache the results.
Normally, it remembers which of the representations can be
considered canonical, that means, which can be used to recreate
the others reliably. For example, 0 and "0" can both be
considered canonical since they naturally transform into each
other. Beyond intrinsic ambiguity, there are ways to trick Perl
into allowing a single scalar to have distinct string, integer,
and floating point representations that are all flagged as
canonical, but can't be transformed into each other. These are
the so-called dualvars. Sereal cannot represent dualvars (and
that's a good thing).
Floating point values can appear to be the same but serialize
to different byte strings due to insignificant 'noise' in the
floating point representation. Sereal supports different
floating point precisions and will generally choose the most
compact that can represent your floating point number
correctly.
There's also a few cases where Sereal will produce different
documents for values that you might think are the same thing,
because if you e.g. compared them with "eq" or "==" in perl itself
would think they were equivalent. However for the purposes of
serialization they're not the same value.
A good example of these cases is where Test::Deep and Sereal's
canonical mode differ. We have tests for some of these cases in
t/030_canonical_vs_test_deep.t. Here's the issues we've noticed so
far:
Sereal considers ASCII strings with the UTF-8 flag to be different
from the same string without the UTF-8 flag
Consider:
my $language_code = "en";
v.s.:
my $language_code = "en";
utf8::upgrade($en);
Sereal's canonical mode will encode these strings differently,
as it should, since the UTF-8 flag will be passed along on
interpolation.
But this can be confusing if you're just getting some user-
supplied ASCII strings that you may inadvertently toggle the
UTF-8 flag on, e.g. because you're comparing an ASCII value in
a database to a value submitted in a UTF-8 web form.
Sereal will encode strings that look like numbers as strings,
unless they've been used in numeric context
I.e. these values will be encoded differently, respectively:
my $IV_x = "12345";
my $IV_y = "12345" + 0;
my $NV_x = "12.345";
my $NV_y = "12.345" + 0;
But as noted above something like Test::Deep will consider
these to be the same thing.
We might produce certain aggressive flags to the canonical mode in
the future to deal with this. For the cases noted above some
combination of turning the UTF-8 flag on on all strings, or
stripping it from strings that have it but are ASCII-only would
"work", similarly we could scan strings to see if they match
"looks_like_number()" and if so numify them.
This would produce output that either would be a lot bigger (having
to encode all numbers as strings), or would be more expensive to
generate (having to scan strings for numeric or non-ASCII context),
and for some cases like the UTF-8 flag munging wouldn't be suitable
for general use outside of canonicialization.
Often, people don't actually care about "canonical" in the strict sense
required for real identity checking. They just require a best-effort
sort of thing for caching. But it's a slippery slope!
In a nutshell, the "canonical" option may be sufficient for an
application which is simply serializing a cache key, and thus there's
little harm in an occasional false-negative, but think carefully before
applying Sereal in other use-cases.
KNOWN ISSUES
Strings Or Numbers
Perl does not make a strong distinction between strings and
numbers, and from an internal point of view it can be difficult to
tell what the "right" representation is for a given variable.
Sereal tries to not be lossy. So if it detects that the string
value of a var, and the numeric value are different it will
generally round trip the *string* value. This means that "special"
strings often used in Perl function returns, like "0 but true", and
"0e0", will round trip in a way that their normal Perl semantics
are preserved. However this also means that "non canonical" values,
like " 100 ", which will numify as 100 without warnings, will round
trip as their string values.
Perl also has some operators, the binary operators, ^, | and &,
which do different things depending on whether their arguments had
been used in numeric context as the following examples show:
perl -le'my $x="1"; $i=int($x); print unpack "H*", $x ^ "1"'
30
perl -le'my $x="1"; print unpack "H*", $x ^ "1"'
00
perl -le'my $x=" 1 "; $i=int($x); print unpack "H*", $x ^ "1"'
30
perl -le'my $x=" 1 "; print unpack "H*", $x ^ "1"'
113120
Sereal currently cannot round trip this property properly.
An extreme case of this problem is that of "dualvars", which can be
created using the Scalar::Util::dualvar() function. This function
allows one to create variables which have string and integer values
which are completely unrelated to each other. Sereal currently
will choose the *string* value when it detects these items.
It is possible that a future release of the protocol will fix these
issues.
Booleans
As of Perl 5.36 and protocol version 5 Sereal now supports
booleans. The new tags SRL_HDR_YES and SRL_HDR_NO now represent
perl bools, the old special variables that SRL_HDR_TRUE and
SRL_HDR_FALSE may still be generated, but beyond being readonly
these are equivalent to SRL_HDR_YES and SRL_HDR_NO.
BUGS, CONTACT AND SUPPORT
For reporting bugs, please use the github bug tracker at
<http://github.com/Sereal/Sereal/issues>.
For support and discussion of Sereal, there are two Google Groups:
Announcements around Sereal (extremely low volume):
<https://groups.google.com/forum/?fromgroups#!forum/sereal-announce>
Sereal development list:
<https://groups.google.com/forum/?fromgroups#!forum/sereal-dev>
AUTHORS AND CONTRIBUTORS
Yves Orton <demerphq@gmail.com>
Damian Gryski
Steffen Mueller <smueller@cpan.org>
Rafaël Garcia-Suarez
Ævar Arnfjörð Bjarmason <avar@cpan.org>
Tim Bunce
Daniel Dragan <bulkdd@cpan.org> (Windows support and bugfixes)
Zefram
Borislav Nikolov
Ivan Kruglov <ivan.kruglov@yahoo.com>
Some inspiration and code was taken from Marc Lehmann's excellent
JSON::XS module due to obvious overlap in problem domain. Thank you!
ACKNOWLEDGMENT
This module was originally developed for Booking.com. With approval
from Booking.com, this module was generalized and published on CPAN,
for which the authors would like to express their gratitude.
COPYRIGHT AND LICENSE
Copyright (C) 2012, 2013, 2014 by Steffen Mueller Copyright (C) 2012,
2013, 2014 by Yves Orton
The license for the code in this distribution is the following, with
the exceptions listed below:
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
Except portions taken from Marc Lehmann's code for the JSON::XS module,
which is licensed under the same terms as this module.
Also except the code for Snappy compression library, whose license is
reproduced below and which, to the best of our knowledge, is compatible
with this module's license. The license for the enclosed Snappy code
is:
Copyright 2011, Google Inc.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
* Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
perl v5.36.0 2023-02-10 Sereal::Encoder(3pm)
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