ioutilities.java

Java Communicating Agents是一个用于开发网络反应式信息agent的框架

/*
 * $Source: /home/data/cvsroot/src/jacomma/icm/io/imp/IOUtilities.java,v $
 * $Revision: 1.7 $
 * $Date: 2000/10/28 20:09:07 $
 *
 * This file is part of the jacomma framework
 * Copyright (c) 2000 	Dimitrios Vyzovitis
 *			mailto:[e-mail]
 *			
 *
 *			
 *			
 *			
 *
 *	This library is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU Library General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This library 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 Library General Public License for more details.
 *
 *	You should have received a copy of the GNU Library General Public License
 *	along with this library; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, 
 *	Boston, MA  02111-1307  USA
 */

package jacomma.icm.io.imp;

/**
 * TBA
 **/
public final class IOUtilities {

	static final double byte_h = Math.log( 2 ) * 8;

	public static int decodeLength( byte[] array ) {
		return new java.math.BigInteger( 1, array ).intValue();
	}

	public static int decodeInt( byte[] array ) {
		return new java.math.BigInteger( array ).intValue();
	}
	
	public static long decodeLong( byte[] array ) {
		return new java.math.BigInteger( array ).longValue();
	}

	public static byte[] encodeLength( byte code, int length ) {
		return encodeLength( code, length, 
							 (int)Math.ceil( Math.log( length + 1 ) / byte_h ) );
	}

	public static byte[] encodeLength( byte code, int length, int bytes ) {
		byte[] res = new byte[bytes + 1];
		res[0] = (byte)(code | bytes);
		for ( int i = 1; i < res.length; i++ ) {
			res[i] = (byte)((length >> (8 * (bytes - i))) & 0xff);
		}
		
		return res;
	}

	public static byte[] encodeLength( byte code, long length ) {
		return encodeLength( code, length, 
							 (int)Math.ceil( Math.log( length + 1 ) / byte_h ) );
	}

	public static byte[] encodeLength( byte code, long length, int bytes ) {
		byte[] res = new byte[bytes + 1];
		res[0] = (byte)(code | bytes);
		for ( int i = 1; i < res.length; i++ ) {
			res[i] = (byte)((length >> (8 * (bytes - i))) & 0xff);
		}
		
		return res;
	}


	public static String toHexString( byte b ) {
		StringBuffer buf = new StringBuffer();
		return toHexString( b, buf ).toString();
	}
	
	public static StringBuffer toHexString( byte b, StringBuffer buf ) {
		buf.append( "0x" )
			.append( _forDigit( (b >> 4) & 0xf ) )
			.append( _forDigit( b & 0xf ) );
		return buf;
	}

	static String _forDigit( int b ) {
		switch ( b ) {
		case 15: return "f";
		case 14: return "e";
		case 13: return "d";
		case 12: return "c";
		case 11: return "b";
		case 10: return "a";
		default: return String.valueOf( b );
		}
	}

	public static String toHexString( byte[] ba ) {
		StringBuffer buf = new StringBuffer();
		for ( int i = 0; i < ba.length; i++ ) {
			toHexString( ba[i], buf ).append( " " );
		}
		
		return buf.toString().trim();			
	}


}