/*
*
* The contents of this [class] are subject to the Netscape Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1999 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*/
package org.exist.util;
/**
* Byte to text encoder using base 64 encoding. To create a base 64
* encoding of a byte stream call {@link #translate} for every
* sequence of bytes and {@link #getCharArray} to mark closure of
* the byte stream and retrieve the text presentation.
*
* @author Based on code from the Mozilla Directory SDK
*/
public final class Base64Encoder {
private FastStringBuffer out = new FastStringBuffer(256);
private int buf = 0; // a 24-bit quantity
private int buf_bytes = 0; // how many octets are set in it
private char line[] = new char[74]; // output buffer
private int line_length = 0; // output buffer fill pointer
//static private final byte crlf[] = "\r\n".getBytes();
private static final char map[] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', // 0-7
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', // 8-15
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', // 16-23
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', // 24-31
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', // 32-39
'o', 'p', 'q', 'r', 's', 't', 'u', 'v', // 40-47
'w', 'x', 'y', 'z', '0', '1', '2', '3', // 48-55
'4', '5', '6', '7', '8', '9', '+', '/', // 56-63
};
private void encode_token() {
int i = line_length;
line[i] = map[0x3F & (buf >> 18)]; // sextet 1 (octet 1)
line[i + 1] = map[0x3F & (buf >> 12)]; // sextet 2 (octet 1 and 2)
line[i + 2] = map[0x3F & (buf >> 6)]; // sextet 3 (octet 2 and 3)
line[i + 3] = map[0x3F & buf]; // sextet 4 (octet 3)
line_length += 4;
buf = 0;
buf_bytes = 0;
}
private void encode_partial_token() {
int i = line_length;
line[i] = map[0x3F & (buf >> 18)]; // sextet 1 (octet 1)
line[i + 1] = map[0x3F & (buf >> 12)]; // sextet 2 (octet 1 and 2)
if (buf_bytes == 1)
line[i + 2] = '=';
else
line[i + 2] = map[0x3F & (buf >> 6)]; // sextet 3 (octet 2 and 3)
if (buf_bytes <= 2)
line[i + 3] = '=';
else
line[i + 3] = map[0x3F & buf]; // sextet 4 (octet 3)
line_length += 4;
buf = 0;
buf_bytes = 0;
}
private void flush_line() {
out.append(line, 0, line_length);
line_length = 0;
}
/**
* Given a sequence of input bytes, produces a sequence of output bytes
* using the base64 encoding. If there are bytes in `out' already, the
* new bytes are appended, so the caller should do `out.setLength(0)'
* first if that's desired.
*/
public final void translate(byte[] in) {
int in_length = in.length;
for (int i = 0; i < in_length; i++) {
if (buf_bytes == 0)
buf = (buf & 0x00FFFF) | (in[i] << 16);
else if (buf_bytes == 1)
buf = (buf & 0xFF00FF) | ((in[i] << 8) & 0x00FFFF);
else
buf = (buf & 0xFFFF00) | (in[i] & 0x0000FF);
if ((++buf_bytes) == 3) {
encode_token();
if (line_length >= 72) {
flush_line();
}
}
if (i == (in_length - 1)) {
if ((buf_bytes > 0) && (buf_bytes < 3))
encode_partial_token();
if (line_length > 0)
flush_line();
}
}
for (int i = 0; i < line.length; i++)
line[i] = 0;
}
public char[] getCharArray() {
char[] ch;
if (buf_bytes != 0)
encode_partial_token();
flush_line();
for (int i = 0; i < line.length; i++)
line[i] = 0;
ch = new char[out.length()];
if (out.length() > 0)
out.getChars(0, out.length(), ch, 0);
return ch;
}
public void reset() {
out.setLength(0);
}
}