001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.apache.commons.compress.compressors.xz; 020 021import java.io.IOException; 022import java.io.InputStream; 023 024import org.apache.commons.compress.MemoryLimitException; 025import org.tukaani.xz.XZ; 026import org.tukaani.xz.SingleXZInputStream; 027import org.tukaani.xz.XZInputStream; 028 029import org.apache.commons.compress.compressors.CompressorInputStream; 030 031/** 032 * XZ decompressor. 033 * @since 1.4 034 */ 035public class XZCompressorInputStream extends CompressorInputStream { 036 private final InputStream in; 037 038 /** 039 * Checks if the signature matches what is expected for a .xz file. 040 * 041 * @param signature the bytes to check 042 * @param length the number of bytes to check 043 * @return true if signature matches the .xz magic bytes, false otherwise 044 */ 045 public static boolean matches(final byte[] signature, final int length) { 046 if (length < XZ.HEADER_MAGIC.length) { 047 return false; 048 } 049 050 for (int i = 0; i < XZ.HEADER_MAGIC.length; ++i) { 051 if (signature[i] != XZ.HEADER_MAGIC[i]) { 052 return false; 053 } 054 } 055 056 return true; 057 } 058 059 /** 060 * Creates a new input stream that decompresses XZ-compressed data 061 * from the specified input stream. This doesn't support 062 * concatenated .xz files. 063 * 064 * @param inputStream where to read the compressed data 065 * 066 * @throws IOException if the input is not in the .xz format, 067 * the input is corrupt or truncated, the .xz 068 * headers specify options that are not supported 069 * by this implementation, or the underlying 070 * <code>inputStream</code> throws an exception 071 */ 072 public XZCompressorInputStream(final InputStream inputStream) 073 throws IOException { 074 this(inputStream, false); 075 } 076 077 /** 078 * Creates a new input stream that decompresses XZ-compressed data 079 * from the specified input stream. 080 * 081 * @param inputStream where to read the compressed data 082 * @param decompressConcatenated 083 * if true, decompress until the end of the 084 * input; if false, stop after the first .xz 085 * stream and leave the input position to point 086 * to the next byte after the .xz stream 087 * 088 * @throws IOException if the input is not in the .xz format, 089 * the input is corrupt or truncated, the .xz 090 * headers specify options that are not supported 091 * by this implementation, or the underlying 092 * <code>inputStream</code> throws an exception 093 */ 094 public XZCompressorInputStream(final InputStream inputStream, 095 final boolean decompressConcatenated) 096 throws IOException { 097 this(inputStream, decompressConcatenated, -1); 098 } 099 100 /** 101 * Creates a new input stream that decompresses XZ-compressed data 102 * from the specified input stream. 103 * 104 * @param inputStream where to read the compressed data 105 * @param decompressConcatenated 106 * if true, decompress until the end of the 107 * input; if false, stop after the first .xz 108 * stream and leave the input position to point 109 * to the next byte after the .xz stream 110 * @param memoryLimitInKb memory limit used when reading blocks. If 111 * the estimated memory limit is exceeded on {@link #read()}, 112 * a {@link MemoryLimitException} is thrown. 113 * 114 * @throws IOException if the input is not in the .xz format, 115 * the input is corrupt or truncated, the .xz 116 * headers specify options that are not supported 117 * by this implementation, 118 * or the underlying <code>inputStream</code> throws an exception 119 * 120 * @since 1.14 121 */ 122 public XZCompressorInputStream(InputStream inputStream, 123 boolean decompressConcatenated, final int memoryLimitInKb) 124 throws IOException { 125 if (decompressConcatenated) { 126 in = new XZInputStream(inputStream, memoryLimitInKb); 127 } else { 128 in = new SingleXZInputStream(inputStream, memoryLimitInKb); 129 } 130 } 131 132 @Override 133 public int read() throws IOException { 134 try { 135 final int ret = in.read(); 136 count(ret == -1 ? -1 : 1); 137 return ret; 138 } catch (org.tukaani.xz.MemoryLimitException e) { 139 throw new MemoryLimitException(e.getMemoryNeeded(), e.getMemoryLimit(), e); 140 } 141 } 142 143 @Override 144 public int read(final byte[] buf, final int off, final int len) throws IOException { 145 try { 146 final int ret = in.read(buf, off, len); 147 count(ret); 148 return ret; 149 } catch (org.tukaani.xz.MemoryLimitException e) { 150 //convert to commons-compress MemoryLimtException 151 throw new MemoryLimitException(e.getMemoryNeeded(), e.getMemoryLimit(), e); 152 } 153 } 154 155 @Override 156 public long skip(final long n) throws IOException { 157 try { 158 return in.skip(n); 159 } catch (org.tukaani.xz.MemoryLimitException e) { 160 //convert to commons-compress MemoryLimtException 161 throw new MemoryLimitException(e.getMemoryNeeded(), e.getMemoryLimit(), e); 162 } 163 } 164 165 @Override 166 public int available() throws IOException { 167 return in.available(); 168 } 169 170 @Override 171 public void close() throws IOException { 172 in.close(); 173 } 174}