/*******************************************************************************
* Copyright © 2011, 2013 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*
*******************************************************************************/
package org.eclipse.edt.compiler.internal.util;
public class EGLOldDecoder {
private static final char[] S_BASE64CHAR = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', '+', '/'
};
private static final char S_BASE64PAD = '=';
private static final byte[] S_DECODETABLE = new byte[128];
static {
for (int i = 0; i < S_DECODETABLE.length; i ++)
S_DECODETABLE[i] = Byte.MAX_VALUE; // 127
for (int i = 0; i < S_BASE64CHAR.length; i ++) // 0 to 63
S_DECODETABLE[S_BASE64CHAR[i]] = (byte)i;
}
public static byte[] decode(String data) {
char[] ibuf = new char[4];
int ibufcount = 0;
byte[] obuf = new byte[data.length()/4*3+3];
int obufcount = 0;
for (int i = 0; i < data.length(); i ++) {
char ch = data.charAt(i);
if (ch == S_BASE64PAD
|| ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
ibuf[ibufcount++] = ch;
if (ibufcount == ibuf.length) {
ibufcount = 0;
obufcount += decode0(ibuf, obuf, obufcount);
}
}
}
if (obufcount == obuf.length)
return obuf;
byte[] ret = new byte[obufcount];
System.arraycopy(obuf, 0, ret, 0, obufcount);
return ret;
}
private static int decode0(char[] ibuf, byte[] obuf, int wp) {
int outlen = 3;
if (ibuf[3] == S_BASE64PAD) outlen = 2;
if (ibuf[2] == S_BASE64PAD) outlen = 1;
int b0 = S_DECODETABLE[ibuf[0]];
int b1 = S_DECODETABLE[ibuf[1]];
int b2 = S_DECODETABLE[ibuf[2]];
int b3 = S_DECODETABLE[ibuf[3]];
switch (outlen) {
case 1:
obuf[wp] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
return 1;
case 2:
obuf[wp++] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
obuf[wp] = (byte)(b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
return 2;
case 3:
obuf[wp++] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
obuf[wp++] = (byte)(b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
obuf[wp] = (byte)(b2 << 6 & 0xc0 | b3 & 0x3f);
return 3;
default:
throw new RuntimeException("Internal Errror"); //$NON-NLS-1$
}
}
}