/*
* eXist Open Source Native XML Database
* Copyright (C) 2000-04, Wolfgang Meier (wolfgang@exist-db.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* $Id$
*/
package org.exist.util;
/**
* A collection of static methods to write integer values from/to a
* byte array.
*
*@author Wolfgang Meier <wolfgang@exist-db.org>
*/
public class ByteConversion {
/**
* Read an integer value from the specified byte array, starting at start.
*/
public final static int byteToInt( final byte data[], final int start ) {
return ( data[start] & 0xff ) |
( ( data[start + 1] & 0xff ) << 8 ) |
( ( data[start + 2] & 0xff ) << 16 ) |
( ( data[start + 3] & 0xff ) << 24 );
}
/**
* Read a long value from the specified byte array, starting at start.
*/
public final static long byteToLong( final byte[] data, final int start ) {
return ( ( ( (long) data[start] ) & 0xffL ) << 56 ) |
( ( ( (long) data[start + 1] ) & 0xffL ) << 48 ) |
( ( ( (long) data[start + 2] ) & 0xffL ) << 40 ) |
( ( ( (long) data[start + 3] ) & 0xffL ) << 32 ) |
( ( ( (long) data[start + 4] ) & 0xffL ) << 24 ) |
( ( ( (long) data[start + 5] ) & 0xffL ) << 16 ) |
( ( ( (long) data[start + 6] ) & 0xffL ) << 8 ) |
( ( (long) data[start + 7] ) & 0xffL );
}
/**
* Read a short value from the specified byte array, starting at start.
*/
public final static short byteToShort( final byte[] data, final int start ) {
return (short) ( ( ( data[start + 1] & 0xff ) << 8 ) |
( data[start] & 0xff ) );
}
/**
* Write an int value to the specified byte array. The first byte is written
* into the location specified by start.
*
*@param v the value
*@param data the byte array to write into
*@param start the offset
*@return the byte array
*/
public final static byte[] intToByte( final int v, final byte[] data, final int start ) {
data[start] = (byte) ( ( v >>> 0 ) & 0xff );
data[start + 1] = (byte) ( ( v >>> 8 ) & 0xff );
data[start + 2] = (byte) ( ( v >>> 16 ) & 0xff );
data[start + 3] = (byte) ( ( v >>> 24 ) & 0xff );
return data;
}
/**
* Write a long value to the specified byte array. The first byte is written
* into the location specified by start.
*
*@param v the value
*@param data the byte array to write into
*@param start the offset
*@return the byte array
*/
public final static byte[] longToByte( final long v, final byte[] data, final int start ) {
data[start + 7] = (byte) ( ( v >>> 0 ) & 0xff );
data[start + 6] = (byte) ( ( v >>> 8 ) & 0xff );
data[start + 5] = (byte) ( ( v >>> 16 ) & 0xff );
data[start + 4] = (byte) ( ( v >>> 24 ) & 0xff );
data[start + 3] = (byte) ( ( v >>> 32 ) & 0xff );
data[start + 2] = (byte) ( ( v >>> 40 ) & 0xff );
data[start + 1] = (byte) ( ( v >>> 48 ) & 0xff );
data[start] = (byte) ( ( v >>> 56 ) & 0xff );
return data;
}
/**
* Write an int value to a newly allocated byte array.
*
*@param v the value
*@return the byte array
*/
public final static byte[] longToByte( final long v ) {
byte[] data = new byte[8];
data[7] = (byte) ( ( v >>> 0 ) & 0xff );
data[6] = (byte) ( ( v >>> 8 ) & 0xff );
data[5] = (byte) ( ( v >>> 16 ) & 0xff );
data[4] = (byte) ( ( v >>> 24 ) & 0xff );
data[3] = (byte) ( ( v >>> 32 ) & 0xff );
data[2] = (byte) ( ( v >>> 40 ) & 0xff );
data[1] = (byte) ( ( v >>> 48 ) & 0xff );
data[0] = (byte) ( ( v >>> 56 ) & 0xff );
return data;
}
/**
* Write a short value to the specified byte array. The first byte is written
* into the location specified by start.
*
*@param v the value
*@param data the byte array to write into
*@param start the offset
*@return the byte array
*/
public final static byte[] shortToByte( final short v, final byte[] data, final int start ) {
data[start] = (byte) ( ( v >>> 0 ) & 0xff );
data[start + 1] = (byte) ( ( v >>> 8 ) & 0xff );
return data;
}
/**
* Write a short value to a newly allocated byte array.
*
*@param v the value
*@return the byte array
*/
public final static byte[] shortToByte( final short v ) {
byte[] data = new byte[2];
data[0] = (byte) ( ( v >>> 0 ) & 0xff );
data[1] = (byte) ( ( v >>> 8 ) & 0xff );
return data;
}
}