Package jnr.ffi.byref

Class ByteByReference

java.lang.Object

java.lang.Number

jnr.ffi.byref.AbstractNumberReference<java.lang.Byte>

jnr.ffi.byref.ByteByReference

All Implemented Interfaces:

java.io.Serializable, ByReference<java.lang.Byte>

public final class ByteByReference
extends AbstractNumberReference<java.lang.Byte>

ByteByReference is used when the address of a primitive byte value must be passed as a parameter to a function.

For example, the following C code,

 
 extern void get_a(char *ap);

 int foo(void) {
     char a;
     // pass a reference to 'a' so get_a() can fill it out
     get_a(&a);

     return a;
 }
 
 

Would be declared in java as

 
 interface Lib {
     void get_a(@Out ByteByReference ap);
 }
 
 

and used like this

 ByteByReference ap = new ByteByReference();
 lib.get_a(ap);
 System.out.printf("a from lib=%d\n", a.byteValue());
 

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
ByteByReference()	Creates a new reference to a byte value initialized to zero.
ByteByReference(byte value)	Creates a new reference to a byte value
ByteByReference(java.lang.Byte value)	Creates a new reference to a byte value

Method Summary

Modifier and Type	Method	Description
void	fromNative(Runtime runtime, Pointer buffer, long offset)	Copies the Byte value from native memory
int	nativeSize(Runtime runtime)	Gets the native size of type of reference in bytes.
void	toNative(Runtime runtime, Pointer buffer, long offset)	Copies the Byte value to native memory

Methods inherited from class jnr.ffi.byref.AbstractNumberReference

byteValue, checkNull, doubleValue, floatValue, getValue, intValue, longValue, shortValue

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ByteByReference

public ByteByReference()

Creates a new reference to a byte value initialized to zero.

ByteByReference

public ByteByReference(java.lang.Byte value)

Creates a new reference to a byte value

Parameters:

value - the initial native value

ByteByReference

public ByteByReference(byte value)

Creates a new reference to a byte value

Parameters:

value - the initial native value

Method Detail

toNative

public void toNative(Runtime runtime,
                     Pointer buffer,
                     long offset)

Copies the Byte value to native memory

Parameters:

runtime - The current runtime.

buffer - the native memory buffer

offset - The offset of the field.

fromNative

public void fromNative(Runtime runtime,
                       Pointer buffer,
                       long offset)

Copies the Byte value from native memory

Parameters:

runtime - The current runtime.

buffer - the native memory buffer.

offset - The offset of the field.

nativeSize

public final int nativeSize(Runtime runtime)

Gets the native size of type of reference in bytes.

Parameters:

runtime - The current runtime.

Returns:

the size of a byte in bytes