| /**************************************************************** |
| * 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. * |
| ****************************************************************/ |
| |
| package org.apache.james.mime4j; |
| |
| |
| 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; |
| } |
| } |