001/* 002 * SVG Salamander 003 * Copyright (c) 2004, Mark McKay 004 * All rights reserved. 005 * 006 * Redistribution and use in source and binary forms, with or 007 * without modification, are permitted provided that the following 008 * conditions are met: 009 * 010 * - Redistributions of source code must retain the above 011 * copyright notice, this list of conditions and the following 012 * disclaimer. 013 * - Redistributions in binary form must reproduce the above 014 * copyright notice, this list of conditions and the following 015 * disclaimer in the documentation and/or other materials 016 * provided with the distribution. 017 * 018 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 019 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 020 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 021 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 022 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 023 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 025 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 026 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 027 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 028 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 029 * OF THE POSSIBILITY OF SUCH DAMAGE. 030 * 031 * Mark McKay can be contacted at mark@kitfox.com. Salamander and other 032 * projects can be found at http://www.kitfox.com 033 * 034 * Created on July 23, 2007 035 */ 036 037package com.kitfox.svg.util; 038 039import java.io.FilterInputStream; 040import java.io.IOException; 041import java.io.InputStream; 042import java.util.HashMap; 043 044/** 045 * 046 * @author kitfox 047 */ 048public class Base64InputStream extends FilterInputStream implements Base64Consts 049{ 050 static final HashMap<Byte, Integer> lookup64 = new HashMap<Byte, Integer>(); 051 static { 052 byte[] ch = BASE64_CHARS.getBytes(); 053 for (int i = 0; i < ch.length; i++) 054 { 055 lookup64.put(new Byte(ch[i]), new Integer(i)); 056 } 057 } 058 059 int buf; 060 int charsInBuf; 061 062 /** Creates a new instance of Base64InputStream */ 063 public Base64InputStream(InputStream in) 064 { 065 super(in); 066 } 067 068 @Override 069 public int read(byte[] b, int off, int len) throws IOException 070 { 071 for (int i = 0; i < len; ++i) 072 { 073 int val = read(); 074 if (val == -1) 075 { 076 return i == 0 ? -1 : i; 077 } 078 b[off + i] = (byte)val; 079 } 080 return len; 081 } 082 083 084 @Override 085 public int read() throws IOException 086 { 087 if (charsInBuf == 0) 088 { 089 fillBuffer(); 090 if (charsInBuf == 0) 091 { 092 return -1; 093 } 094 } 095 096 return (buf >> (--charsInBuf * 8)) & 0xff; 097 } 098 099 private void fillBuffer() throws IOException 100 { 101 //Read next 4 characters 102 int bitsRead = 0; 103 while (bitsRead < 24) 104 { 105 int val = in.read(); 106 if (val == -1 || val == '=') break; 107 108 Integer lval = (Integer)lookup64.get(new Byte((byte)val)); 109 if (lval == null) continue; 110 111 buf = buf << 6 | lval.byteValue(); 112 bitsRead += 6; 113 } 114 115 switch (bitsRead) 116 { 117 case 6: 118 { 119 throw new RuntimeException("Invalid termination of base64 encoding."); 120 } 121 case 12: 122 { 123 buf >>= 4; 124 bitsRead = 8; 125 break; 126 } 127 case 18: 128 { 129 buf >>= 2; 130 bitsRead = 16; 131 break; 132 } 133 case 0: 134 case 24: 135 { 136 break; 137 } 138 default: 139 { 140 assert false : "Should never encounter other bit counts"; 141 } 142 } 143 144 charsInBuf = bitsRead / 8; 145 } 146}