001/* 002 * ==================================================================== 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, 014 * software distributed under the License is distributed on an 015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 016 * KIND, either express or implied. See the License for the 017 * specific language governing permissions and limitations 018 * under the License. 019 * ==================================================================== 020 * 021 * This software consists of voluntary contributions made by many 022 * individuals on behalf of the Apache Software Foundation. For more 023 * information on the Apache Software Foundation, please see 024 * <http://www.apache.org/>. 025 * 026 */ 027package org.apache.http.client.entity; 028 029import java.io.IOException; 030import java.io.InputStream; 031import java.io.PushbackInputStream; 032import java.util.zip.Inflater; 033import java.util.zip.InflaterInputStream; 034import java.util.zip.ZipException; 035 036/** 037 * Deflate input stream. This class includes logic needed for various Rfc's in order 038 * to reasonably implement the "deflate" compression style. 039 */ 040public class DeflateInputStream extends InputStream { 041 042 private final InputStream sourceStream; 043 044 public DeflateInputStream(final InputStream wrapped) throws IOException { 045 046 final PushbackInputStream pushback = new PushbackInputStream(wrapped, 2); 047 final int i1 = pushback.read(); 048 final int i2 = pushback.read(); 049 if (i1 == -1 || i2 == -1) { 050 throw new ZipException("Unexpected end of stream"); 051 } 052 053 pushback.unread(i2); 054 pushback.unread(i1); 055 056 boolean nowrap = true; 057 final int b1 = i1 & 0xFF; 058 final int compressionMethod = b1 & 0xF; 059 final int compressionInfo = b1 >> 4 & 0xF; 060 final int b2 = i2 & 0xFF; 061 if (compressionMethod == 8 && compressionInfo <= 7 && ((b1 << 8) | b2) % 31 == 0) { 062 nowrap = false; 063 } 064 sourceStream = new DeflateStream(pushback, new Inflater(nowrap)); 065 } 066 067 /** 068 * Read a byte. 069 */ 070 @Override 071 public int read() throws IOException { 072 return sourceStream.read(); 073 } 074 075 /** 076 * Read lots of bytes. 077 */ 078 @Override 079 public int read(final byte[] b) throws IOException { 080 return sourceStream.read(b); 081 } 082 083 /** 084 * Read lots of specific bytes. 085 */ 086 @Override 087 public int read(final byte[] b, final int off, final int len) throws IOException { 088 return sourceStream.read(b, off, len); 089 } 090 091 /** 092 * Skip 093 */ 094 @Override 095 public long skip(final long n) throws IOException { 096 return sourceStream.skip(n); 097 } 098 099 /** 100 * Get available. 101 */ 102 @Override 103 public int available() throws IOException { 104 return sourceStream.available(); 105 } 106 107 /** 108 * Mark. 109 */ 110 @Override 111 public void mark(final int readLimit) { 112 sourceStream.mark(readLimit); 113 } 114 115 /** 116 * Reset. 117 */ 118 @Override 119 public void reset() throws IOException { 120 sourceStream.reset(); 121 } 122 123 /** 124 * Check if mark is supported. 125 */ 126 @Override 127 public boolean markSupported() { 128 return sourceStream.markSupported(); 129 } 130 131 /** 132 * Close. 133 */ 134 @Override 135 public void close() throws IOException { 136 sourceStream.close(); 137 } 138 139 static class DeflateStream extends InflaterInputStream { 140 141 private boolean closed = false; 142 143 public DeflateStream(final InputStream in, final Inflater inflater) { 144 super(in, inflater); 145 } 146 147 @Override 148 public void close() throws IOException { 149 if (closed) { 150 return; 151 } 152 closed = true; 153 inf.end(); 154 super.close(); 155 } 156 157 } 158 159} 160