Jerome Poichet | 7c99785 | 2014-05-20 10:50:05 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
| 3 | * contributor license agreements. See the NOTICE file distributed with |
| 4 | * this work for additional information regarding copyright ownership. |
| 5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
| 6 | * (the "License"); you may not use this file except in compliance with |
| 7 | * the License. You may obtain a copy of the License at |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | */ |
| 17 | |
| 18 | /* |
| 19 | * NOTE: This class copied from the Android Open Source Project: |
| 20 | * dalvik/libcore/luni/src/main/java/org/apache/harmony/luni/util/Base64.java |
| 21 | */ |
| 22 | |
| 23 | /** |
| 24 | * @author Alexander Y. Kleymenov |
| 25 | * @version $Revision$ |
| 26 | */ |
| 27 | |
| 28 | package com.google.polo.wire.json; |
| 29 | |
| 30 | import java.io.UnsupportedEncodingException; |
| 31 | |
| 32 | /** |
| 33 | * This class implements Base64 encoding/decoding functionality |
| 34 | * as specified in RFC 2045 (http://www.ietf.org/rfc/rfc2045.txt). |
| 35 | */ |
| 36 | public class Base64 { |
| 37 | |
| 38 | public static byte[] decode(byte[] in) { |
| 39 | return decode(in, in.length); |
| 40 | } |
| 41 | |
| 42 | public static byte[] decode(byte[] in, int len) { |
| 43 | // approximate output length |
| 44 | int length = len / 4 * 3; |
| 45 | // return an empty array on emtpy or short input without padding |
| 46 | if (length == 0) { |
| 47 | return new byte[0]; |
| 48 | } |
| 49 | // temporary array |
| 50 | byte[] out = new byte[length]; |
| 51 | // number of padding characters ('=') |
| 52 | int pad = 0; |
| 53 | byte chr; |
| 54 | // compute the number of the padding characters |
| 55 | // and adjust the length of the input |
| 56 | for (;;len--) { |
| 57 | chr = in[len-1]; |
| 58 | // skip the neutral characters |
| 59 | if ((chr == '\n') || (chr == '\r') || |
| 60 | (chr == ' ') || (chr == '\t')) { |
| 61 | continue; |
| 62 | } |
| 63 | if (chr == '=') { |
| 64 | pad++; |
| 65 | } else { |
| 66 | break; |
| 67 | } |
| 68 | } |
| 69 | // index in the output array |
| 70 | int out_index = 0; |
| 71 | // index in the input array |
| 72 | int in_index = 0; |
| 73 | // holds the value of the input character |
| 74 | int bits = 0; |
| 75 | // holds the value of the input quantum |
| 76 | int quantum = 0; |
| 77 | for (int i=0; i<len; i++) { |
| 78 | chr = in[i]; |
| 79 | // skip the neutral characters |
| 80 | if ((chr == '\n') || (chr == '\r') || |
| 81 | (chr == ' ') || (chr == '\t')) { |
| 82 | continue; |
| 83 | } |
| 84 | if ((chr >= 'A') && (chr <= 'Z')) { |
| 85 | // char ASCII value |
| 86 | // A 65 0 |
| 87 | // Z 90 25 (ASCII - 65) |
| 88 | bits = chr - 65; |
| 89 | } else if ((chr >= 'a') && (chr <= 'z')) { |
| 90 | // char ASCII value |
| 91 | // a 97 26 |
| 92 | // z 122 51 (ASCII - 71) |
| 93 | bits = chr - 71; |
| 94 | } else if ((chr >= '0') && (chr <= '9')) { |
| 95 | // char ASCII value |
| 96 | // 0 48 52 |
| 97 | // 9 57 61 (ASCII + 4) |
| 98 | bits = chr + 4; |
| 99 | } else if (chr == '+') { |
| 100 | bits = 62; |
| 101 | } else if (chr == '/') { |
| 102 | bits = 63; |
| 103 | } else { |
| 104 | return null; |
| 105 | } |
| 106 | // append the value to the quantum |
| 107 | quantum = (quantum << 6) | (byte) bits; |
| 108 | if (in_index%4 == 3) { |
| 109 | // 4 characters were read, so make the output: |
| 110 | out[out_index++] = (byte) ((quantum & 0x00FF0000) >> 16); |
| 111 | out[out_index++] = (byte) ((quantum & 0x0000FF00) >> 8); |
| 112 | out[out_index++] = (byte) (quantum & 0x000000FF); |
| 113 | } |
| 114 | in_index++; |
| 115 | } |
| 116 | if (pad > 0) { |
| 117 | // adjust the quantum value according to the padding |
| 118 | quantum = quantum << (6*pad); |
| 119 | // make output |
| 120 | out[out_index++] = (byte) ((quantum & 0x00FF0000) >> 16); |
| 121 | if (pad == 1) { |
| 122 | out[out_index++] = (byte) ((quantum & 0x0000FF00) >> 8); |
| 123 | } |
| 124 | } |
| 125 | // create the resulting array |
| 126 | byte[] result = new byte[out_index]; |
| 127 | System.arraycopy(out, 0, result, 0, out_index); |
| 128 | return result; |
| 129 | } |
| 130 | |
| 131 | private static final byte[] map = new byte[] |
| 132 | {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', |
| 133 | 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', |
| 134 | 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', |
| 135 | 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', |
| 136 | '4', '5', '6', '7', '8', '9', '+', '/'}; |
| 137 | |
| 138 | public static String encode(byte[] in, String charsetName) throws UnsupportedEncodingException { |
| 139 | int length = in.length * 4 / 3; |
| 140 | length += length / 76 + 3; // for crlr |
| 141 | byte[] out = new byte[length]; |
| 142 | int index = 0, i, crlr = 0, end = in.length - in.length%3; |
| 143 | for (i=0; i<end; i+=3) { |
| 144 | out[index++] = map[(in[i] & 0xff) >> 2]; |
| 145 | out[index++] = map[((in[i] & 0x03) << 4) |
| 146 | | ((in[i+1] & 0xff) >> 4)]; |
| 147 | out[index++] = map[((in[i+1] & 0x0f) << 2) |
| 148 | | ((in[i+2] & 0xff) >> 6)]; |
| 149 | out[index++] = map[(in[i+2] & 0x3f)]; |
| 150 | if (((index - crlr)%76 == 0) && (index != 0)) { |
| 151 | out[index++] = '\n'; |
| 152 | crlr++; |
| 153 | //out[index++] = '\r'; |
| 154 | //crlr++; |
| 155 | } |
| 156 | } |
| 157 | switch (in.length % 3) { |
| 158 | case 1: |
| 159 | out[index++] = map[(in[end] & 0xff) >> 2]; |
| 160 | out[index++] = map[(in[end] & 0x03) << 4]; |
| 161 | out[index++] = '='; |
| 162 | out[index++] = '='; |
| 163 | break; |
| 164 | case 2: |
| 165 | out[index++] = map[(in[end] & 0xff) >> 2]; |
| 166 | out[index++] = map[((in[end] & 0x03) << 4) |
| 167 | | ((in[end+1] & 0xff) >> 4)]; |
| 168 | out[index++] = map[((in[end+1] & 0x0f) << 2)]; |
| 169 | out[index++] = '='; |
| 170 | break; |
| 171 | } |
| 172 | return new String(out, 0, index, charsetName); |
| 173 | } |
| 174 | } |
| 175 | |