1adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project/* 2adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Licensed to the Apache Software Foundation (ASF) under one or more 3adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * contributor license agreements. See the NOTICE file distributed with 4adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * this work for additional information regarding copyright ownership. 5adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * The ASF licenses this file to You under the Apache License, Version 2.0 6adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * (the "License"); you may not use this file except in compliance with 7adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * the License. You may obtain a copy of the License at 8adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 9adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 10adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * 11adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * Unless required by applicable law or agreed to in writing, software 12adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 13adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * See the License for the specific language governing permissions and 15adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project * limitations under the License. 16adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 17adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 18adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project/** 19adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project* @author Alexander Y. Kleymenov 20adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project*/ 21adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 2232b2c95c350002f67c8b3e65777161feda766b72Jesse Wilsonpackage libcore.io; 23adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 242a6f23ff8690ac2f025588a360547ce96cde0943Elliott Hughesimport java.nio.charset.StandardCharsets; 256186821cb13f4ac7ff50950c813394367e021eaeJesse Wilsonimport libcore.util.EmptyArray; 26adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 27adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project/** 2832b2c95c350002f67c8b3e65777161feda766b72Jesse Wilson * <a href="http://www.ietf.org/rfc/rfc2045.txt">Base64</a> encoder/decoder. 2932b2c95c350002f67c8b3e65777161feda766b72Jesse Wilson * In violation of the RFC, this encoder doesn't wrap lines at 76 columns. 30adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project */ 3132b2c95c350002f67c8b3e65777161feda766b72Jesse Wilsonpublic final class Base64 { 32b1b8fbeeae579e9f49c41166bb5d9b2e60b75438Elliott Hughes private Base64() { 33b1b8fbeeae579e9f49c41166bb5d9b2e60b75438Elliott Hughes } 34f33eae7e84eb6d3b0f4e86b59605bb3de73009f3Elliott Hughes 35adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public static byte[] decode(byte[] in) { 36adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project return decode(in, in.length); 37adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 38f33eae7e84eb6d3b0f4e86b59605bb3de73009f3Elliott Hughes 39adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project public static byte[] decode(byte[] in, int len) { 40adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // approximate output length 41adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project int length = len / 4 * 3; 42b1b8fbeeae579e9f49c41166bb5d9b2e60b75438Elliott Hughes // return an empty array on empty or short input without padding 43adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project if (length == 0) { 44693eacca9fa67ad79d1b35dbaad61c5ac1ac457cElliott Hughes return EmptyArray.BYTE; 45adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 46adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // temporary array 47adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project byte[] out = new byte[length]; 48adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // number of padding characters ('=') 49adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project int pad = 0; 50adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project byte chr; 51adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // compute the number of the padding characters 52adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // and adjust the length of the input 53adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project for (;;len--) { 54adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project chr = in[len-1]; 55adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // skip the neutral characters 56f33eae7e84eb6d3b0f4e86b59605bb3de73009f3Elliott Hughes if ((chr == '\n') || (chr == '\r') || 57adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project (chr == ' ') || (chr == '\t')) { 58adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project continue; 59adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 60adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project if (chr == '=') { 61adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project pad++; 62adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } else { 63adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project break; 64adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 65adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 66adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // index in the output array 679229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes int outIndex = 0; 68adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // index in the input array 699229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes int inIndex = 0; 70adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // holds the value of the input character 71adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project int bits = 0; 72adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // holds the value of the input quantum 73adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project int quantum = 0; 74adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project for (int i=0; i<len; i++) { 75adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project chr = in[i]; 76adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // skip the neutral characters 77f33eae7e84eb6d3b0f4e86b59605bb3de73009f3Elliott Hughes if ((chr == '\n') || (chr == '\r') || 78adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project (chr == ' ') || (chr == '\t')) { 79adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project continue; 80adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 81adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project if ((chr >= 'A') && (chr <= 'Z')) { 82adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // char ASCII value 83adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // A 65 0 84adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // Z 90 25 (ASCII - 65) 85adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project bits = chr - 65; 86adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } else if ((chr >= 'a') && (chr <= 'z')) { 87adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // char ASCII value 88adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // a 97 26 89adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // z 122 51 (ASCII - 71) 90adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project bits = chr - 71; 91adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } else if ((chr >= '0') && (chr <= '9')) { 92adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // char ASCII value 93adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // 0 48 52 94adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // 9 57 61 (ASCII + 4) 95adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project bits = chr + 4; 96adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } else if (chr == '+') { 97adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project bits = 62; 98adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } else if (chr == '/') { 99adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project bits = 63; 100adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } else { 101adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project return null; 102adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 103adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // append the value to the quantum 104adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project quantum = (quantum << 6) | (byte) bits; 1059229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes if (inIndex%4 == 3) { 106adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // 4 characters were read, so make the output: 1079229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes out[outIndex++] = (byte) (quantum >> 16); 1089229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes out[outIndex++] = (byte) (quantum >> 8); 1099229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes out[outIndex++] = (byte) quantum; 110adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 1119229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes inIndex++; 112adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 113adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project if (pad > 0) { 114adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // adjust the quantum value according to the padding 115adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project quantum = quantum << (6*pad); 116adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // make output 1179229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes out[outIndex++] = (byte) (quantum >> 16); 118adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project if (pad == 1) { 1199229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes out[outIndex++] = (byte) (quantum >> 8); 120adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 121adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 122adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project // create the resulting array 1239229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes byte[] result = new byte[outIndex]; 1249229d47c1288e25ead3a2dc27fac8a4a2ee932a3Elliott Hughes System.arraycopy(out, 0, result, 0, outIndex); 125adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project return result; 126adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 127adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 128adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project private static final byte[] map = new byte[] 129f33eae7e84eb6d3b0f4e86b59605bb3de73009f3Elliott Hughes {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 130f33eae7e84eb6d3b0f4e86b59605bb3de73009f3Elliott Hughes 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 131f33eae7e84eb6d3b0f4e86b59605bb3de73009f3Elliott Hughes 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 132f33eae7e84eb6d3b0f4e86b59605bb3de73009f3Elliott Hughes 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', 133adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project '4', '5', '6', '7', '8', '9', '+', '/'}; 134adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project 13532b2c95c350002f67c8b3e65777161feda766b72Jesse Wilson public static String encode(byte[] in) { 13632b2c95c350002f67c8b3e65777161feda766b72Jesse Wilson int length = (in.length + 2) * 4 / 3; 137adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project byte[] out = new byte[length]; 13832b2c95c350002f67c8b3e65777161feda766b72Jesse Wilson int index = 0, end = in.length - in.length % 3; 13932b2c95c350002f67c8b3e65777161feda766b72Jesse Wilson for (int i = 0; i < end; i += 3) { 140adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project out[index++] = map[(in[i] & 0xff) >> 2]; 141b5bde2fd72189192b52e726a2d606d70c3c8a34bElliott Hughes out[index++] = map[((in[i] & 0x03) << 4) | ((in[i+1] & 0xff) >> 4)]; 142b5bde2fd72189192b52e726a2d606d70c3c8a34bElliott Hughes out[index++] = map[((in[i+1] & 0x0f) << 2) | ((in[i+2] & 0xff) >> 6)]; 143adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project out[index++] = map[(in[i+2] & 0x3f)]; 144adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 145adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project switch (in.length % 3) { 146adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project case 1: 147adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project out[index++] = map[(in[end] & 0xff) >> 2]; 148adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project out[index++] = map[(in[end] & 0x03) << 4]; 149adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project out[index++] = '='; 150adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project out[index++] = '='; 151adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project break; 152adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project case 2: 153adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project out[index++] = map[(in[end] & 0xff) >> 2]; 154b5bde2fd72189192b52e726a2d606d70c3c8a34bElliott Hughes out[index++] = map[((in[end] & 0x03) << 4) | ((in[end+1] & 0xff) >> 4)]; 155f33eae7e84eb6d3b0f4e86b59605bb3de73009f3Elliott Hughes out[index++] = map[((in[end+1] & 0x0f) << 2)]; 156adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project out[index++] = '='; 157adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project break; 158adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 1592a6f23ff8690ac2f025588a360547ce96cde0943Elliott Hughes return new String(out, 0, index, StandardCharsets.US_ASCII); 160adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project } 161adc854b798c1cfe3bfd4c27d68d5cee38ca617daThe Android Open Source Project} 162