Re: java.nio.ByteBuffer problem.

[Bryce McKinlay <bryce at mckinlay dot net dot nz>]

On Friday, Sep 19, 2003, at 09:24 Pacific/Auckland, Rutger Ovidius 
wrote:

> Is this supported with gcj?  All I get are 0's.
>
> gcc version 3.3.1 (mingw special 20030804-1)

I tried this example with the current CVS libgcj. It gets more than 
0's, but the result is incorrect as the current ByteBuffer 
implementation only supports ByteOrder.BIG_ENDIAN (ie Java byte order) 
- note the comments in ByteBufferImpl.java which claim it only supports 
LITTLE_ENDIAN are incorrect.

It wouldn't be too hard to go through and add cases to the existing 
code to handle little endian as well, but I'm thinking there would be a 
lot to be gained by optimizing much of the buffer stuff, such as 
ByteBuffer.putInt() etc, with CNI methods. Anyone else want to comment 
on this? Michael?

Regards

Bryce.



> import java.nio.ByteBuffer;
> import java.nio.ByteOrder;
>
> public class Main {
>
> public static void main (String [] args) {
>
> 	ByteBuffer bb = ByteBuffer.allocate(4);
> 	bb.order( ByteOrder.LITTLE_ENDIAN );
> 	bb.putInt(1111);  // any #..
>
> 	System.out.println(toHexString(bb.array()));
> }
>
> public static String toHexString ( byte[] b )
> {
> 	StringBuffer sb = new StringBuffer( b.length * 2 );
> 	for ( int i=0 ; i<b.length ; i++ )
> 	{
> 	sb.append( hexChar [ ( b[ i] & 0xf0 ) >>> 4 ] ) ;
> 	sb.append( hexChar [ b[ i] & 0x0f ] ) ;
> 	}
> 	return sb.toString() ;
> }
>
> static char[] hexChar =
> {
> '0' , '1' , '2' , '3' ,
> '4' , '5' , '6' , '7' ,
> '8' , '9' , 'a' , 'b' ,
> 'c' , 'd' , 'e' , 'f' }
> ;
>
> }