source: other-projects/trunk/gs3-release-maker/tasks/sshtaskdef/src/mindbright/util/Base64.java@ 14627

/******************************************************************************
 *
 * Copyright (c) 1998,99 by Mindbright Technology AB, Stockholm, Sweden.
 *                 www.mindbright.se, [email protected]
 *
 * 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.
 *
 *****************************************************************************
 * $Author: mats $
 * $Date: 2000/04/18 07:37:44 $
 * $Name: rel1-2-1 $
 *****************************************************************************/
package mindbright.util;

public final class Base64 {

    private final static int[] fromBase64 = {
    -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, 62, -1, -1, -1, 63,
    52, 53, 54, 55, 56, 57, 58, 59,
    60, 61, -1, -1, -1, -1, -1, -1,
    -1,  0,  1,  2,  3,  4,  5,  6,
    7,  8,  9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22,
    23, 24, 25, -1, -1, -1, -1, -1,
    -1, 26, 27, 28, 29, 30, 31, 32,
    33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48,
    49, 50, 51, -1, -1, -1, -1, -1
    };

    private final static byte[] toBase64 = {
    // 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
       65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80,
    // 'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
       81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 97, 98, 99,100,101,102,
    // 'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
       103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,
    // 'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/'
       119,120,121,122, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 43, 47, (byte)'='
    };

    private final static int PAD_CHAR = 64;

    public static byte[] encode(byte[] data) {
    return encode(data, 0, data.length);
    }

    public static byte[] encode(byte[] data, int offset, int length) {
    byte[] encoded;
    int x1, x2, x3, x4;
    int i, j, r, n;

    r       = length % 3;
    n       = offset + (length - r);
    encoded = new byte[((length / 3) * 4) + (r != 0 ? 4 : 0)];

    for(i = offset, j = 0; i < n; i += 3, j += 4) {
        x1 = (data[i] & 0xfc) >> 2;
        x2 = (((data[i    ] & 0x03) << 4) | ((data[i + 1] & 0xf0) >> 4));
        x3 = (((data[i + 1] & 0x0f) << 2) | ((data[i + 2] & 0xc0) >> 6));
        x4 = (data[i + 2] & 0x3f);
        encoded[j    ] = toBase64[x1];
        encoded[j + 1] = toBase64[x2];
        encoded[j + 2] = toBase64[x3];
        encoded[j + 3] = toBase64[x4];
    }

    if(r != 0) {
        x1 = (data[i] & 0xfc) >> 2;
        x2 = (data[i] & 0x03) << 4;
        x3 = PAD_CHAR;
        x4 = PAD_CHAR;
        if(r == 2) {
        x2 |= ((data[i + 1] & 0xf0) >> 4);
        x3 = (data[i + 1] & 0x0f) << 2;
        }
        encoded[j++] = toBase64[x1];
        encoded[j++] = toBase64[x2];
        encoded[j++] = toBase64[x3];
        encoded[j++] = toBase64[x4];
    }

    return encoded;
    }

    public static byte[] decode(byte[] data) {
    return decode(data, 0, data.length);
    }

    public static byte[] decode(byte[] encoded, int offset, int length) {
    byte[] data;
    int i, j, n, v = 0, c, bits = 0;

    n    = offset + length;
    data = new byte[(length * 3) / 4];

    for(i = offset, j = 0; i < n; i++) {
        c = fromBase64[encoded[i]];
        if(c < 0) {
        if(encoded[i] == toBase64[PAD_CHAR])
            break;
        continue;
        }
        v = (v << 6) | c;
        bits += 6;
        if(bits >= 8) {
        bits -= 8;
        data[j++] = (byte) ((v >> bits) & 0xff);
        }
    }

    if(data.length > j) {
        byte[] tmp = new byte[j];
        System.arraycopy(data, 0, tmp, 0, j);
        data = tmp;
    }

    return data;
    }

}