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| 1 | +/* | |
| 2 | + * Copyright (c) 1995, 2000, Oracle and/or its affiliates. All rights reserved. | |
| 3 | + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 | + * | |
| 5 | + * This code is free software; you can redistribute it and/or modify it | |
| 6 | + * under the terms of the GNU General Public License version 2 only, as | |
| 7 | + * published by the Free Software Foundation. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | +package sun.misc; | |
| 26 | + | |
| 27 | +import java.io.OutputStream; | |
| 28 | +import java.io.PushbackInputStream; | |
| 29 | +import java.io.PrintStream; | |
| 30 | + | |
| 31 | +/** | |
| 32 | + * This class implements a BASE64 Character decoder as specified in RFC1521. | |
| 33 | + * | |
| 34 | + * This RFC is part of the MIME specification which is published by the | |
| 35 | + * Internet Engineering Task Force (IETF). Unlike some other encoding | |
| 36 | + * schemes there is nothing in this encoding that tells the decoder | |
| 37 | + * where a buffer starts or stops, so to use it you will need to isolate | |
| 38 | + * your encoded data into a single chunk and then feed them this decoder. | |
| 39 | + * The simplest way to do that is to read all of the encoded data into a | |
| 40 | + * string and then use: | |
| 41 | + * <pre> | |
| 42 | + * byte mydata[]; | |
| 43 | + * BASE64Decoder base64 = new BASE64Decoder(); | |
| 44 | + * | |
| 45 | + * mydata = base64.decodeBuffer(bufferString); | |
| 46 | + * </pre> | |
| 47 | + * This will decode the String in <i>bufferString</i> and give you an array | |
| 48 | + * of bytes in the array <i>myData</i>. | |
| 49 | + * | |
| 50 | + * On errors, this class throws a CEFormatException with the following detail | |
| 51 | + * strings: | |
| 52 | + * <pre> | |
| 53 | + * "BASE64Decoder: Not enough bytes for an atom." | |
| 54 | + * </pre> | |
| 55 | + * | |
| 56 | + * @author Chuck McManis | |
| 57 | + * @see CharacterEncoder | |
| 58 | + * @see BASE64Decoder | |
| 59 | + */ | |
| 60 | + | |
| 61 | +public class BASE64Decoder extends CharacterDecoder { | |
| 62 | + | |
| 63 | + /** This class has 4 bytes per atom */ | |
| 64 | + protected int bytesPerAtom() { | |
| 65 | + return (4); | |
| 66 | + } | |
| 67 | + | |
| 68 | + /** Any multiple of 4 will do, 72 might be common */ | |
| 69 | + protected int bytesPerLine() { | |
| 70 | + return (72); | |
| 71 | + } | |
| 72 | + | |
| 73 | + /** | |
| 74 | + * This character array provides the character to value map | |
| 75 | + * based on RFC1521. | |
| 76 | + */ | |
| 77 | + private final static char pem_array[] = { | |
| 78 | + // 0 1 2 3 4 5 6 7 | |
| 79 | + 'A','B','C','D','E','F','G','H', // 0 | |
| 80 | + 'I','J','K','L','M','N','O','P', // 1 | |
| 81 | + 'Q','R','S','T','U','V','W','X', // 2 | |
| 82 | + 'Y','Z','a','b','c','d','e','f', // 3 | |
| 83 | + 'g','h','i','j','k','l','m','n', // 4 | |
| 84 | + 'o','p','q','r','s','t','u','v', // 5 | |
| 85 | + 'w','x','y','z','0','1','2','3', // 6 | |
| 86 | + '4','5','6','7','8','9','+','/' // 7 | |
| 87 | + }; | |
| 88 | + | |
| 89 | + private final static byte pem_convert_array[] = new byte[256]; | |
| 90 | + | |
| 91 | + static { | |
| 92 | + for (int i = 0; i < 255; i++) { | |
| 93 | + pem_convert_array[i] = -1; | |
| 94 | + } | |
| 95 | + for (int i = 0; i < pem_array.length; i++) { | |
| 96 | + pem_convert_array[pem_array[i]] = (byte) i; | |
| 97 | + } | |
| 98 | + } | |
| 99 | + | |
| 100 | + byte decode_buffer[] = new byte[4]; | |
| 101 | + | |
| 102 | + /** | |
| 103 | + * Decode one BASE64 atom into 1, 2, or 3 bytes of data. | |
| 104 | + */ | |
| 105 | + protected void decodeAtom(PushbackInputStream inStream, OutputStream outStream, int rem) | |
| 106 | + throws java.io.IOException | |
| 107 | + { | |
| 108 | + int i; | |
| 109 | + byte a = -1, b = -1, c = -1, d = -1; | |
| 110 | + | |
| 111 | + if (rem < 2) { | |
| 112 | + throw new CEFormatException("BASE64Decoder: Not enough bytes for an atom."); | |
| 113 | + } | |
| 114 | + do { | |
| 115 | + i = inStream.read(); | |
| 116 | + if (i == -1) { | |
| 117 | + throw new CEStreamExhausted(); | |
| 118 | + } | |
| 119 | + } while (i == '\n' || i == '\r'); | |
| 120 | + decode_buffer[0] = (byte) i; | |
| 121 | + | |
| 122 | + i = readFully(inStream, decode_buffer, 1, rem-1); | |
| 123 | + if (i == -1) { | |
| 124 | + throw new CEStreamExhausted(); | |
| 125 | + } | |
| 126 | + | |
| 127 | + if (rem > 3 && decode_buffer[3] == '=') { | |
| 128 | + rem = 3; | |
| 129 | + } | |
| 130 | + if (rem > 2 && decode_buffer[2] == '=') { | |
| 131 | + rem = 2; | |
| 132 | + } | |
| 133 | + switch (rem) { | |
| 134 | + case 4: | |
| 135 | + d = pem_convert_array[decode_buffer[3] & 0xff]; | |
| 136 | + // NOBREAK | |
| 137 | + case 3: | |
| 138 | + c = pem_convert_array[decode_buffer[2] & 0xff]; | |
| 139 | + // NOBREAK | |
| 140 | + case 2: | |
| 141 | + b = pem_convert_array[decode_buffer[1] & 0xff]; | |
| 142 | + a = pem_convert_array[decode_buffer[0] & 0xff]; | |
| 143 | + break; | |
| 144 | + } | |
| 145 | + | |
| 146 | + switch (rem) { | |
| 147 | + case 2: | |
| 148 | + outStream.write( (byte)(((a << 2) & 0xfc) | ((b >>> 4) & 3)) ); | |
| 149 | + break; | |
| 150 | + case 3: | |
| 151 | + outStream.write( (byte) (((a << 2) & 0xfc) | ((b >>> 4) & 3)) ); | |
| 152 | + outStream.write( (byte) (((b << 4) & 0xf0) | ((c >>> 2) & 0xf)) ); | |
| 153 | + break; | |
| 154 | + case 4: | |
| 155 | + outStream.write( (byte) (((a << 2) & 0xfc) | ((b >>> 4) & 3)) ); | |
| 156 | + outStream.write( (byte) (((b << 4) & 0xf0) | ((c >>> 2) & 0xf)) ); | |
| 157 | + outStream.write( (byte) (((c << 6) & 0xc0) | (d & 0x3f)) ); | |
| 158 | + break; | |
| 159 | + } | |
| 160 | + return; | |
| 161 | + } | |
| 162 | +} | |