/*
*
*
* Copyright 1990-2009 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* 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 version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package com.sun.j2me.pim.formats;
import java.io.ByteArrayOutputStream;
/**
* Converter to and from Base64 encoding. Base64 encoding is defined in
* RFC 2045.
*
*/
public class Base64Encoding {
/** Constants for conversion of binary data to Base64. From RFC 2045. */
private static char[] BASE64_CHARS = {
'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',
'+', '/'
};
/**
* Constants for conversion of Base64 data to binary. The inverse
* of the above table.
*/
private static byte[] BASE64_BYTES = {
-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, 0, -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, 26, -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
};
/**
* Converts a BASE64 string to a byte array.
*
* @param sdata the string to be converted
* @return the byte array content of the string
*/
public static byte[] fromBase64(String sdata) {
if (sdata == null || sdata.length() < 2) {
return new byte[0];
}
ByteArrayOutputStream out = new ByteArrayOutputStream();
// copy the string to an array, and pad the end of the data with
// '=' characters.
int length = sdata.length();
char[] data = new char[length + 2];
sdata.getChars(0, length, data, 0);
data[length] = '=';
data[length + 1] = '=';
for (int i = nextCharIndex(data, 0); i < data.length; ) {
int char0 = data[i = nextCharIndex(data, i)];
if (char0 == '=') {
break;
}
int char1 = data[i = nextCharIndex(data, i + 1)];
if (char1 == '=') {
// stop here. this is not a valid Base64 fragment
break;
}
int char2 = data[i = nextCharIndex(data, i + 1)];
int char3 = data[i = nextCharIndex(data, i + 1)];
i = nextCharIndex(data, i + 1);
out.write(BASE64_BYTES[char0] << 2 | BASE64_BYTES[char1] >> 4);
if (char2 == '=') {
// only one byte
} else {
int value = BASE64_BYTES[char1] << 4 | BASE64_BYTES[char2] >> 2;
out.write(value & 0xff);
if (char3 == '=') {
// only 2 bytes
} else {
value = BASE64_BYTES[char2] << 6 | BASE64_BYTES[char3];
out.write(value & 0xff);
}
}
}
return out.toByteArray();
}
/**
* Gets the index of the first character in the given array that
* contains valid Base64 data. Starts searching from the given
* index "i".
* @param data input buffer
* @param i starting offset in the input buffer
* @return offset of first BASE64 char
*/
private static int nextCharIndex(char[] data, int i) {
while (i < data.length &&
(data[i] > 0x7f || BASE64_BYTES[data[i]] == -1)) {
i ++;
}
return i;
}
/**
* Converts a byte array to a BASE64 string.
* @param data the binary data to be converted
* @param lineLength the length of lines to be created
* @param indent the number of blank spaces to write at the beginning
* of each line
* @return BASE64 string
*/
public static String toBase64(byte[] data, int lineLength, int indent) {
StringBuffer sb = new StringBuffer();
for (int j = 0; j < indent; j++)
sb.append(' ');
for (int i = 0, charsInLine = 0; i < data.length; ) {
int byte0 = ((int) data[i++]) & 0xff;
int byte1 = (i < data.length) ? ((int) data[i++]) & 0xff : 0x100;
int byte2 = (i < data.length) ? ((int) data[i++]) & 0xff : 0x100;
sb.append(BASE64_CHARS[ byte0 >> 2 ]);
if (byte1 == 0x100) {
sb.append(BASE64_CHARS[ (byte0 << 4) & 0x30]);
sb.append("==");
} else {
sb.append(BASE64_CHARS[ (byte0 << 4 | byte1 >> 4) & 0x3f]);
if (byte2 == 0x100) {
sb.append(BASE64_CHARS[ (byte1 << 2) & 0x3f]);
sb.append('=');
} else {
sb.append(BASE64_CHARS[ (byte1 << 2 | byte2 >> 6) & 0x3f]);
sb.append(BASE64_CHARS[ byte2 & 0x3f ]);
}
}
charsInLine += 4;
if (charsInLine + 4 > lineLength && i < data.length) {
charsInLine = 0;
sb.append("\r\n");
for (int j = 0; j < indent; j++) {
sb.append(' ');
}
}
}
return sb.toString();
}
}