Java ASCII to Binary ascii2bin(byte[] ascii, int offset, int len, byte[] binary)

Description

asciibin

License

Open Source License

Declaration

public static boolean ascii2bin(byte[] ascii, int offset, int len, byte[] binary) 

Method Source Code

//package com.java2s;
/*// w ww  .ja va 2s.c o  m
 * Copyright (c) 2010-2012 TMate Software Ltd
 *  
 * 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; version 2 of the License.
 *
 * 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.
 *
 * For information on how to redistribute this software under
 * the terms of a license other than GNU General Public License
 * contact TMate Software at support@hg4j.com
 */

public class Main {
    public static boolean ascii2bin(byte[] ascii, int offset, int len, byte[] binary) {
        assert len % 2 == 0;
        assert binary.length >= len >>> 1;

        boolean zeroBytes = true;
        for (int i = 0, j = offset; i < len >>> 1; i++) {
            int b = ascii[j++] & 0xCF; // -0x30 to get decimal digit out from their char, and to uppercase if a letter 
            int hiNibble = b > 64 ? b - 55 : b;
            b = ascii[j++] & 0xCF;
            int lowNibble = b > 64 ? b - 55 : b;
            if (hiNibble >= 16 || lowNibble >= 16) {
                throw new IllegalArgumentException(
                        String.format("Characters '%c%c' (%1$d and %2$d) at index %d are not valid hex digits",
                                ascii[j - 2], ascii[j - 1], j - 2));
            }
            b = (((hiNibble << 4) | lowNibble) & 0xFF);
            binary[i] = (byte) b;
            zeroBytes = zeroBytes && b == 0;
        }
        return zeroBytes;
    }
}

Related

1. AsciiToBinary(String asciiString)
2. asciiToRawQuality(char quality)