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 * @author Alexander Y. Kleymenov 20 */ 21 22 package com.squareup.okhttp.internal; 23 24 import java.io.UnsupportedEncodingException; 25 26 import static com.squareup.okhttp.internal.Util.EMPTY_BYTE_ARRAY; 27 28 /** 29 * <a href="http://www.ietf.org/rfc/rfc2045.txt">Base64</a> encoder/decoder. 30 * In violation of the RFC, this encoder doesn't wrap lines at 76 columns. 31 */ 32 public final class Base64 { 33 private Base64() { 34 } 35 36 public static byte[] decode(byte[] in) { 37 return decode(in, in.length); 38 } 39 40 public static byte[] decode(byte[] in, int len) { 41 // approximate output length 42 int length = len / 4 * 3; 43 // return an empty array on empty or short input without padding 44 if (length == 0) { 45 return EMPTY_BYTE_ARRAY; 46 } 47 // temporary array 48 byte[] out = new byte[length]; 49 // number of padding characters ('=') 50 int pad = 0; 51 byte chr; 52 // compute the number of the padding characters 53 // and adjust the length of the input 54 for (; ; len--) { 55 chr = in[len - 1]; 56 // skip the neutral characters 57 if ((chr == '\n') || (chr == '\r') || (chr == ' ') || (chr == '\t')) { 58 continue; 59 } 60 if (chr == '=') { 61 pad++; 62 } else { 63 break; 64 } 65 } 66 // index in the output array 67 int outIndex = 0; 68 // index in the input array 69 int inIndex = 0; 70 // holds the value of the input character 71 int bits = 0; 72 // holds the value of the input quantum 73 int quantum = 0; 74 for (int i = 0; i < len; i++) { 75 chr = in[i]; 76 // skip the neutral characters 77 if ((chr == '\n') || (chr == '\r') || (chr == ' ') || (chr == '\t')) { 78 continue; 79 } 80 if ((chr >= 'A') && (chr <= 'Z')) { 81 // char ASCII value 82 // A 65 0 83 // Z 90 25 (ASCII - 65) 84 bits = chr - 65; 85 } else if ((chr >= 'a') && (chr <= 'z')) { 86 // char ASCII value 87 // a 97 26 88 // z 122 51 (ASCII - 71) 89 bits = chr - 71; 90 } else if ((chr >= '0') && (chr <= '9')) { 91 // char ASCII value 92 // 0 48 52 93 // 9 57 61 (ASCII + 4) 94 bits = chr + 4; 95 } else if (chr == '+') { 96 bits = 62; 97 } else if (chr == '/') { 98 bits = 63; 99 } else { 100 return null; 101 } 102 // append the value to the quantum 103 quantum = (quantum << 6) | (byte) bits; 104 if (inIndex % 4 == 3) { 105 // 4 characters were read, so make the output: 106 out[outIndex++] = (byte) (quantum >> 16); 107 out[outIndex++] = (byte) (quantum >> 8); 108 out[outIndex++] = (byte) quantum; 109 } 110 inIndex++; 111 } 112 if (pad > 0) { 113 // adjust the quantum value according to the padding 114 quantum = quantum << (6 * pad); 115 // make output 116 out[outIndex++] = (byte) (quantum >> 16); 117 if (pad == 1) { 118 out[outIndex++] = (byte) (quantum >> 8); 119 } 120 } 121 // create the resulting array 122 byte[] result = new byte[outIndex]; 123 System.arraycopy(out, 0, result, 0, outIndex); 124 return result; 125 } 126 127 private static final byte[] MAP = new byte[] { 128 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 129 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 130 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', 131 '5', '6', '7', '8', '9', '+', '/' 132 }; 133 134 public static String encode(byte[] in) { 135 int length = (in.length + 2) * 4 / 3; 136 byte[] out = new byte[length]; 137 int index = 0, end = in.length - in.length % 3; 138 for (int i = 0; i < end; i += 3) { 139 out[index++] = MAP[(in[i] & 0xff) >> 2]; 140 out[index++] = MAP[((in[i] & 0x03) << 4) | ((in[i + 1] & 0xff) >> 4)]; 141 out[index++] = MAP[((in[i + 1] & 0x0f) << 2) | ((in[i + 2] & 0xff) >> 6)]; 142 out[index++] = MAP[(in[i + 2] & 0x3f)]; 143 } 144 switch (in.length % 3) { 145 case 1: 146 out[index++] = MAP[(in[end] & 0xff) >> 2]; 147 out[index++] = MAP[(in[end] & 0x03) << 4]; 148 out[index++] = '='; 149 out[index++] = '='; 150 break; 151 case 2: 152 out[index++] = MAP[(in[end] & 0xff) >> 2]; 153 out[index++] = MAP[((in[end] & 0x03) << 4) | ((in[end + 1] & 0xff) >> 4)]; 154 out[index++] = MAP[((in[end + 1] & 0x0f) << 2)]; 155 out[index++] = '='; 156 break; 157 } 158 try { 159 return new String(out, 0, index, "US-ASCII"); 160 } catch (UnsupportedEncodingException e) { 161 throw new AssertionError(e); 162 } 163 } 164 } 165
