/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @author Alexander Y. Kleymenov
*/
package org.apache.harmony.misc;
/**
* This class implements Base64 encoding/decoding functionality
* as specified in RFC 2045 (http://www.ietf.org/rfc/rfc2045.txt).
*/
public class Base64 {
public static byte[] decode(byte[] in) {
return decode(in, in.length);
}
public static byte[] decode(byte[] in, int len) {
int length = len / 4 * 3;
byte[] out = new byte[length];
int pad = 0, index = 0, j = 0, bits = 0;
byte[] bytes = new byte[4];
byte chr;
for (int i=0; i<len; i++) {
if (in[i] == '\n' || in[i] =='\r') {
continue;
}
chr = in[i];
// char ASCII value
// + 43 62
// / 47 63
// 0 48 52
// . . .
// 9 57 61 (ASCII + 4)
// = 61 pad
// A 65 0
// . . .
// Z 90 25 (ASCII - 65)
// a 97 26
// . . .
// z 122 51 (ASCII - 71)
if (chr == '+') {
bits = 62;
} else if (chr == '/') {
bits = 63;
} else if ((chr >= '0') && (chr <= '9')) {
bits = chr + 4;
} else if (chr == '=') {
bits = 0;
pad ++;
} else if ((chr >= 'A') && (chr <= 'Z')) {
bits = chr - 65;
} else if ((chr >= 'a') && (chr <= 'z')) {
bits = chr - 71;
} else {
return null;
}
bytes[j%4] = (byte) bits;
if (j%4 == 3) {
out[index++] = (byte) (bytes[0] << 2 | bytes[1] >> 4);
if (pad != 2) {
out[index++] = (byte) (bytes[1] << 4 | bytes[2] >> 2);
if (pad != 1) {
out[index++] = (byte) (bytes[2] << 6 | bytes[3]);
}
}
}
j++;
}
byte[] result = new byte[index];
System.arraycopy(out, 0, result, 0, index);
return result;
}
private static final byte[] map = new byte[]
{'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', '+', '/'};
public static String encode(byte[] in) {
int length = in.length * 4 / 3;
length += length / 76 + 3; // for crlr
byte[] out = new byte[length];
int index = 0, i, crlr = 0, end = in.length - in.length%3;
for (i=0; i<end; i+=3) {
out[index++] = map[(in[i] & 0xff) >> 2];
out[index++] = map[((in[i] & 0x03) << 4)
| ((in[i+1] & 0xff) >> 4)];
out[index++] = map[((in[i+1] & 0x0f) << 2)
| ((in[i+2] & 0xff) >> 6)];
out[index++] = map[(in[i+2] & 0x3f)];
if (((index - crlr)%76 == 0) && (index != 0)) {
out[index++] = '\n';
crlr++;
//out[index++] = '\r';
//crlr++;
}
}
switch (in.length % 3) {
case 1:
out[index++] = map[(in[end] & 0xff) >> 2];
out[index++] = map[(in[end] & 0x03) << 4];
out[index++] = '=';
out[index++] = '=';
break;
case 2:
out[index++] = map[(in[end] & 0xff) >> 2];
out[index++] = map[((in[end] & 0x03) << 4)
| ((in[end+1] & 0xff) >> 4)];
out[index++] = map[((in[end+1] & 0x0f) << 2)];
out[index++] = '=';
break;
}
return new String(out, 0, index);
}
}
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