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/****************************************************************
* 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. *
****************************************************************/
public class EncodeUtils {
public static final int MASK = 0x3F;
public static final int FIRST_MASK = MASK << 18;
public static final int SECOND_MASK = MASK << 12;
public static final int THIRD_MASK = MASK << 6;
public static final int FORTH_MASK = MASK;
public static final byte[] ENCODING = {'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 final void main(String[] args) throws Exception {
byte[] bytes = {(byte) 0, (byte) 128, (byte) 0};
System.out.println(new String(toBase64(bytes)));
System.out.println(new String(toBase64("Hello, World".getBytes())));
System.out.println(new String(toBase64("Monday".getBytes())));
System.out.println(new String(toBase64("M\u00F6nchengladbach\r\n".getBytes("ISO-8859-1"))));
}
public static byte[] toBase64(byte[] in) {
int inputLength = in.length;
int outputLength = (int) Math.floor((4*inputLength) / 3f) + 3;
outputLength = outputLength + 2 * (int) Math.floor(outputLength / 76f);
byte[] results = new byte[outputLength];
int inputIndex = 0;
int outputIndex = 0;
while (inputLength - inputIndex > 2) {
int one = (toInt(in[inputIndex++]) << 16);
int two = (toInt(in[inputIndex++]) << 8);
int three = toInt(in[inputIndex++]);
int quantum = one | two | three;
int index = (quantum & FIRST_MASK) >> 18;
outputIndex = setResult(results, outputIndex, ENCODING[index]);
index = (quantum & SECOND_MASK) >> 12;
outputIndex = setResult(results, outputIndex, ENCODING[index]);
index = (quantum & THIRD_MASK) >> 6;
outputIndex = setResult(results, outputIndex, ENCODING[index]);
index = (quantum & FORTH_MASK);
outputIndex = setResult(results, outputIndex, ENCODING[index]);
}
switch (inputLength - inputIndex) {
case 1:
int quantum = in[inputIndex++] << 16;
int index = (quantum & FIRST_MASK) >> 18;
outputIndex = setResult(results, outputIndex, ENCODING[index]);
index = (quantum & SECOND_MASK) >> 12;
outputIndex = setResult(results, outputIndex, ENCODING[index]);
outputIndex = setResult(results, outputIndex, (byte) '=');
outputIndex = setResult(results, outputIndex, (byte) '=');
break;
case 2:
quantum = (in[inputIndex++] << 16) + (in[inputIndex++] << 8);
index = (quantum & FIRST_MASK) >> 18;
outputIndex = setResult(results, outputIndex, ENCODING[index]);
index = (quantum & SECOND_MASK) >> 12;
outputIndex = setResult(results, outputIndex, ENCODING[index]);
index = (quantum & THIRD_MASK) >> 6;
outputIndex = setResult(results, outputIndex, ENCODING[index]);
outputIndex = setResult(results, outputIndex, (byte) '=');
break;
}
return results;
}
private static int toInt(byte b) {
return 255 & b;
}
private static int setResult(byte[] results, int outputIndex, byte value) {
results[outputIndex++] = value;
outputIndex = checkLineLength(results, outputIndex);
return outputIndex;
}
private static int checkLineLength(byte[] results, int outputIndex) {
if (outputIndex == 76 || outputIndex > 76 && (outputIndex - 2*Math.floor(outputIndex/76f - 1)) % 76 == 0) {
results[outputIndex++] = '\r';
results[outputIndex++] = '\n';
}
return outputIndex;
}
}
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