1/**************************************************************** 2 * Licensed to the Apache Software Foundation (ASF) under one * 3 * or more contributor license agreements. See the NOTICE file * 4 * distributed with this work for additional information * 5 * regarding copyright ownership. The ASF licenses this file * 6 * to you under the Apache License, Version 2.0 (the * 7 * "License"); you may not use this file except in compliance * 8 * with the License. You may obtain a copy of the License at * 9 * * 10 * http://www.apache.org/licenses/LICENSE-2.0 * 11 * * 12 * Unless required by applicable law or agreed to in writing, * 13 * software distributed under the License is distributed on an * 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * 15 * KIND, either express or implied. See the License for the * 16 * specific language governing permissions and limitations * 17 * under the License. * 18 ****************************************************************/ 19 20/** 21 * Modified for Exchange attachment decoding 5/12/11. Changes are bracketed with START EAS CHANGES 22 * and END EAS CHANGES 23 * 24 * Without the included changes, the final bytes of the input stream will be read here and thrown 25 * away; in that case, the WBXML parser will lose information necessary to determine that the 26 * entire stream has been processed correctly. Since inline WBXML text is terminated with a zero 27 * byte, and since zero is not valid Base64, we terminate reading when we find a zero byte, leaving 28 * the remainder of the stream untouched (to be read by the Parser that created the 29 * Base64InputStream. 30 */ 31 32package com.android.exchange.adapter; 33 34import java.io.IOException; 35import java.io.InputStream; 36 37/** 38 * Performs Base-64 decoding on an underlying stream. 39 * 40 * 41 * @version $Id: Base64InputStream.java,v 1.3 2004/11/29 13:15:47 ntherning Exp $ 42 */ 43public class Base64InputStream extends InputStream { 44 private final InputStream s; 45 private int outCount = 0; 46 private int outIndex = 0; 47 private final int[] outputBuffer = new int[3]; 48 private final byte[] inputBuffer = new byte[4]; 49 private boolean done = false; 50 // START EAS CHANGES 51 private boolean padSeen = false; 52 // END EAS CHANGES 53 54 public Base64InputStream(InputStream s) { 55 this.s = s; 56 } 57 58 /** 59 * Closes the underlying stream. 60 * 61 * @throws IOException on I/O errors. 62 */ 63 @Override 64 public void close() throws IOException { 65 s.close(); 66 } 67 68 @Override 69 public int read() throws IOException { 70 if (outIndex == outCount) { 71 fillBuffer(); 72 if (outIndex == outCount) { 73 return -1; 74 } 75 } 76 77 return outputBuffer[outIndex++]; 78 } 79 80 /** 81 * Retrieve data from the underlying stream, decode it, 82 * and put the results in the byteq. 83 * @throws IOException 84 */ 85 private void fillBuffer() throws IOException { 86 outCount = 0; 87 outIndex = 0; 88 int inCount = 0; 89 90 int i; 91 // "done" is needed for the two successive '=' at the end 92 while (!done) { 93 switch (i = s.read()) { 94 // START EAS CHANGES 95 case 0: 96 // In EAS, a zero will indicate the end of the (inline) base64 string 97 // Stop reading at this point, so that we can continue with WBXML 98 done = true; 99 return; 100 // END EAS CHANGES 101 case -1: 102 // No more input - just return, let outputBuffer drain out, and be done 103 return; 104 case '=': 105 // START EAS CHANGES 106 // Allow for a second '=' before we're really done (we should get a zero next) 107 if (padSeen) { 108 return; 109 } 110 // We've seen a (first) end padding character, flush what's in the buffer 111 padSeen = true; 112 // END EAS CHANGES 113 // PRE-EAS LINE COMMENTED OUT 114 //done = true; 115 decodeAndEnqueue(inCount); 116 return; 117 default: 118 byte sX = TRANSLATION[i]; 119 if (sX < 0) continue; 120 inputBuffer[inCount++] = sX; 121 if (inCount == 4) { 122 decodeAndEnqueue(inCount); 123 return; 124 } 125 break; 126 } 127 } 128 } 129 130 private void decodeAndEnqueue(int len) { 131 int accum = 0; 132 accum |= inputBuffer[0] << 18; 133 accum |= inputBuffer[1] << 12; 134 accum |= inputBuffer[2] << 6; 135 accum |= inputBuffer[3]; 136 137 // There's a bit of duplicated code here because we want to have straight-through operation 138 // for the most common case of len==4 139 if (len == 4) { 140 outputBuffer[0] = (accum >> 16) & 0xFF; 141 outputBuffer[1] = (accum >> 8) & 0xFF; 142 outputBuffer[2] = (accum) & 0xFF; 143 outCount = 3; 144 return; 145 } else if (len == 3) { 146 outputBuffer[0] = (accum >> 16) & 0xFF; 147 outputBuffer[1] = (accum >> 8) & 0xFF; 148 outCount = 2; 149 return; 150 } else { // len == 2 151 outputBuffer[0] = (accum >> 16) & 0xFF; 152 outCount = 1; 153 return; 154 } 155 } 156 157 private static byte[] TRANSLATION = { 158 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x00 */ 159 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x10 */ 160 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, /* 0x20 */ 161 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, /* 0x30 */ 162 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 0x40 */ 163 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 0x50 */ 164 -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60 */ 165 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /* 0x70 */ 166 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x80 */ 167 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x90 */ 168 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xA0 */ 169 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xB0 */ 170 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xC0 */ 171 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xD0 */ 172 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0xE0 */ 173 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 /* 0xF0 */ 174 }; 175} 176