| /* |
| * 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. |
| */ |
| /* |
| * The apr_md5_encode() routine in the APR project's apr_md5.c file uses much |
| * code obtained from the FreeBSD 3.0 MD5 crypt() function, which is licenced |
| * as follows: |
| * ---------------------------------------------------------------------------- |
| * "THE BEER-WARE LICENSE" (Revision 42): |
| * <phk@login.dknet.dk> wrote this file. As long as you retain this notice you |
| * can do whatever you want with this stuff. If we meet some day, and you think |
| * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp |
| * ---------------------------------------------------------------------------- |
| */ |
| package org.apache.shiro.codec; |
| |
| import java.io.IOException; |
| |
| /** |
| * Codec for <a href="http://en.wikipedia.org/wiki/Crypt_(Unix)">Unix Crypt</a>-style encoding. While similar to |
| * Base64, it is not compatible with Base64. |
| * <p/> |
| * This implementation is based on encoding algorithms found in the Apache Portable Runtime library's |
| * <a href="http://svn.apache.org/viewvc/apr/apr/trunk/crypto/apr_md5.c?revision=HEAD&view=markup">apr_md5.c</a> |
| * implementation for its {@code crypt}-style support. The APR team in turn received inspiration for its encoding |
| * implementation based on FreeBSD 3.0's {@code /usr/src/lib/libcrypt/crypt.c} implementation. The |
| * accompanying license headers have been retained at the top of this source file. |
| * <p/> |
| * This file and all that it contains is ASL 2.0 compatible. |
| * |
| * @since 1.2 |
| */ |
| public class H64 { |
| |
| private static final char[] itoa64 = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray(); |
| |
| private static short toShort(byte b) { |
| return (short) (b & 0xff); |
| } |
| |
| private static int toInt(byte[] bytes, int offset, int numBytes) { |
| if (numBytes < 1 || numBytes > 4) { |
| throw new IllegalArgumentException("numBytes must be between 1 and 4."); |
| } |
| int val = toShort(bytes[offset]); //1st byte |
| for (int i = 1; i < numBytes; i++) { //any remaining bytes: |
| short s = toShort(bytes[offset + i]); |
| switch (i) { |
| case 1: val |= s << 8; break; |
| case 2: val |= s << 16; break; |
| case 3: val |= s << 24; break; |
| } |
| } |
| return val; |
| } |
| |
| /** |
| * Appends the specified character into the buffer, rethrowing any encountered |
| * {@link IOException} as an {@link IllegalStateException} (since this method is used for internal |
| * implementation needs and we only ever use StringBuilders, we should never encounter an IOException). |
| * |
| * @param buf the buffer to append to |
| * @param c the character to append. |
| */ |
| private static void append(Appendable buf, char c) { |
| try { |
| buf.append(c); |
| } catch (IOException e) { |
| throw new IllegalStateException("Unable to append character to internal buffer.", e); |
| } |
| } |
| |
| /** |
| * Encodes the specified integer to {@code numChars} H64-compatible characters and appends them into {@code buf}. |
| * |
| * @param value the integer to encode to H64-compatible characters |
| * @param buf the output buffer |
| * @param numChars the number of characters the value should be converted to. 3, 2 or 1. |
| */ |
| private static void encodeAndAppend(int value, Appendable buf, int numChars) { |
| for (int i = 0; i < numChars; i++) { |
| append(buf, itoa64[value & 0x3f]); |
| value >>= 6; |
| } |
| } |
| |
| /** |
| * Encodes the specified bytes to an {@code H64}-encoded String. |
| * |
| * @param bytes |
| * @return |
| */ |
| public static String encodeToString(byte[] bytes) { |
| if (bytes == null || bytes.length == 0) return null; |
| |
| StringBuilder buf = new StringBuilder(); |
| |
| int length = bytes.length; |
| int remainder = length % 3; |
| int i = 0; //starting byte |
| int last3ByteIndex = length - remainder; //last byte whose index is a multiple of 3 |
| |
| for(; i < last3ByteIndex; i += 3) { |
| int twentyFourBit = toInt(bytes, i, 3); |
| encodeAndAppend(twentyFourBit, buf, 4); |
| } |
| if (remainder > 0) { |
| //one or two bytes that we still need to encode: |
| int a = toInt(bytes, i, remainder); |
| encodeAndAppend(a, buf, remainder + 1); |
| } |
| return buf.toString(); |
| } |
| } |