asciihexinterpreter.java

java pos,你可以直接编译运行,

/*
 * Copyright (c) 2000 jPOS.org.  All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
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 * 2. Redistributions in binary form must reproduce the above copyright
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 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *    "This product includes software developed by the jPOS project 
 *    (http://www.jpos.org/)". Alternately, this acknowledgment may 
 *    appear in the software itself, if and wherever such third-party 
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the jPOS Project.  For more
 * information please see <http://www.jpos.org/>.
 */

package org.jpos.iso;

/**
 * Implements Hex Interpreter. The Hex digits are stored in ASCII.
 * 
 * @author joconnor
 * @version $Revision: 1.2 $ $Date: 2003/11/05 09:00:53 $
 */
public class AsciiHexInterpreter implements BinaryInterpreter
{
    /** An instance of this Interpreter. Only one needed for the whole system */
    public static final AsciiHexInterpreter INSTANCE = new AsciiHexInterpreter();

    /** 0-15 to ASCII hex digit lookup table. */
    private static final byte[] HEX_ASCII = new byte[] {
              0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
              0x38, 0x39, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46
    };

    /**
     * Converts the binary data into ASCII hex digits.
     * @see org.jpos.iso.BinaryInterpreter#interpret(byte[], byte[], int)
     */
    public void interpret(byte[] data, byte[] b, int offset)
    {
        for (int i = 0; i < data.length; i++) {
            b[offset + i * 2] = HEX_ASCII[(data[i] & 0xF0) >> 4];
            b[offset + i * 2 + 1] = HEX_ASCII[data[i] & 0x0F];
        }
    }

    /**
     * Converts the ASCII hex digits into binary data.
     * @see org.jpos.iso.BinaryInterpreter#uninterpret(byte[], int, int)
     */
    public byte[] uninterpret(byte[] rawData, int offset, int length)
    {
        byte[] ret = new byte[length];
        for (int i = 0; i < length; i++)
        {
            byte hi = rawData[offset + i * 2];
            byte lo = rawData[offset + i * 2 + 1];
            int h = hi > 0x40 ? 10 + hi - 0x41 : hi - 0x30;
            int l = lo > 0x40 ? 10 + lo - 0x41 : lo - 0x30;
            ret[i] = (byte)(h << 4 | l);
        }
        return ret;
    }

    /**
     * Returns double nBytes because the hex representation of 1 byte needs 2 hex digits.
     * 
     * @see org.jpos.iso.BinaryInterpreter#getPackedLength(int)
     */
    public int getPackedLength(int nBytes)
    {
        return nBytes * 2;
    }
}