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

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

void	marshal(Pointer buffer, long offset) Copies the Byte value to native memory
int	nativeSize(Runtime runtime) Gets the native size of type of reference in bytes.
void	unmarshal(Pointer buffer, long offset) Copies the Byte value from 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

marshal

public void marshal(Pointer buffer,
                    long offset)

Copies the Byte value to native memory

Parameters:

buffer - the native memory buffer

unmarshal

public void unmarshal(Pointer buffer,
                      long offset)

Copies the Byte value from native memory

Parameters:

buffer - the native memory buffer.

nativeSize

public final int nativeSize(Runtime runtime)

Gets the native size of type of reference in bytes.

Returns:

the size of a byte in bytes