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.lz4; 020 021import java.io.IOException; 022import java.io.InputStream; 023import java.util.Arrays; 024import java.util.zip.CheckedInputStream; 025 026import org.apache.commons.compress.compressors.CompressorInputStream; 027import org.apache.commons.compress.utils.BoundedInputStream; 028import org.apache.commons.compress.utils.ByteUtils; 029import org.apache.commons.compress.utils.IOUtils; 030import org.apache.commons.compress.utils.InputStreamStatistics; 031import org.apache.commons.io.input.CountingInputStream; 032 033/** 034 * CompressorInputStream for the LZ4 frame format. 035 * 036 * <p> 037 * Based on the "spec" in the version "1.5.1 (31/03/2015)" 038 * </p> 039 * 040 * @see <a href="https://lz4.github.io/lz4/lz4_Frame_format.html">LZ4 Frame Format Description</a> 041 * @since 1.14 042 * @NotThreadSafe 043 */ 044public class FramedLZ4CompressorInputStream extends CompressorInputStream implements InputStreamStatistics { 045 046 /** Used by FramedLZ4CompressorOutputStream as well. */ 047 static final byte[] LZ4_SIGNATURE = { 4, 0x22, 0x4d, 0x18 }; 048 private static final byte[] SKIPPABLE_FRAME_TRAILER = { 0x2a, 0x4d, 0x18 }; 049 private static final byte SKIPPABLE_FRAME_PREFIX_BYTE_MASK = 0x50; 050 051 static final int VERSION_MASK = 0xC0; 052 static final int SUPPORTED_VERSION = 0x40; 053 static final int BLOCK_INDEPENDENCE_MASK = 0x20; 054 static final int BLOCK_CHECKSUM_MASK = 0x10; 055 static final int CONTENT_SIZE_MASK = 0x08; 056 static final int CONTENT_CHECKSUM_MASK = 0x04; 057 static final int BLOCK_MAX_SIZE_MASK = 0x70; 058 static final int UNCOMPRESSED_FLAG_MASK = 0x80000000; 059 060 private static boolean isSkippableFrameSignature(final byte[] b) { 061 if ((b[0] & SKIPPABLE_FRAME_PREFIX_BYTE_MASK) != SKIPPABLE_FRAME_PREFIX_BYTE_MASK) { 062 return false; 063 } 064 for (int i = 1; i < 4; i++) { 065 if (b[i] != SKIPPABLE_FRAME_TRAILER[i - 1]) { 066 return false; 067 } 068 } 069 return true; 070 } 071 072 /** 073 * Checks if the signature matches what is expected for a .lz4 file. 074 * <p> 075 * .lz4 files start with a four byte signature. 076 * </p> 077 * 078 * @param signature the bytes to check 079 * @param length the number of bytes to check 080 * @return true if this is a .sz stream, false otherwise 081 */ 082 public static boolean matches(final byte[] signature, final int length) { 083 084 if (length < LZ4_SIGNATURE.length) { 085 return false; 086 } 087 088 byte[] shortenedSig = signature; 089 if (signature.length > LZ4_SIGNATURE.length) { 090 shortenedSig = Arrays.copyOf(signature, LZ4_SIGNATURE.length); 091 } 092 093 return Arrays.equals(shortenedSig, LZ4_SIGNATURE); 094 } 095 096 /** Used in no-arg read method. */ 097 private final byte[] oneByte = new byte[1]; 098 private final ByteUtils.ByteSupplier supplier = this::readOneByte; 099 100 private final CountingInputStream inputStream; 101 private final boolean decompressConcatenated; 102 private boolean expectBlockChecksum; 103 private boolean expectBlockDependency; 104 105 private boolean expectContentChecksum; 106 107 private InputStream currentBlock; 108 109 private boolean endReached, inUncompressed; 110 111 /** Used for frame header checksum and content checksum, if present. */ 112 private final org.apache.commons.codec.digest.XXHash32 contentHash = new org.apache.commons.codec.digest.XXHash32(); 113 114 /** Used for block checksum, if present. */ 115 private final org.apache.commons.codec.digest.XXHash32 blockHash = new org.apache.commons.codec.digest.XXHash32(); 116 117 /** Only created if the frame doesn't set the block independence flag. */ 118 private byte[] blockDependencyBuffer; 119 120 /** 121 * Creates a new input stream that decompresses streams compressed using the LZ4 frame format and stops after decompressing the first frame. 122 * 123 * @param in the InputStream from which to read the compressed data 124 * @throws IOException if reading fails 125 */ 126 public FramedLZ4CompressorInputStream(final InputStream in) throws IOException { 127 this(in, false); 128 } 129 130 /** 131 * Creates a new input stream that decompresses streams compressed using the LZ4 frame format. 132 * 133 * @param in the InputStream from which to read the compressed data 134 * @param decompressConcatenated if true, decompress until the end of the input; if false, stop after the first LZ4 frame and leave the input position to 135 * point to the next byte after the frame stream 136 * @throws IOException if reading fails 137 */ 138 public FramedLZ4CompressorInputStream(final InputStream in, final boolean decompressConcatenated) throws IOException { 139 this.inputStream = new CountingInputStream(in); 140 this.decompressConcatenated = decompressConcatenated; 141 init(true); 142 } 143 144 private void appendToBlockDependencyBuffer(final byte[] b, final int off, int len) { 145 len = Math.min(len, blockDependencyBuffer.length); 146 if (len > 0) { 147 final int keep = blockDependencyBuffer.length - len; 148 if (keep > 0) { 149 // move last keep bytes towards the start of the buffer 150 System.arraycopy(blockDependencyBuffer, len, blockDependencyBuffer, 0, keep); 151 } 152 // append new data 153 System.arraycopy(b, off, blockDependencyBuffer, keep, len); 154 } 155 } 156 157 /** {@inheritDoc} */ 158 @Override 159 public void close() throws IOException { 160 try { 161 if (currentBlock != null) { 162 currentBlock.close(); 163 currentBlock = null; 164 } 165 } finally { 166 inputStream.close(); 167 } 168 } 169 170 /** 171 * @since 1.17 172 */ 173 @Override 174 public long getCompressedCount() { 175 return inputStream.getByteCount(); 176 } 177 178 private void init(final boolean firstFrame) throws IOException { 179 if (readSignature(firstFrame)) { 180 readFrameDescriptor(); 181 nextBlock(); 182 } 183 } 184 185 private void maybeFinishCurrentBlock() throws IOException { 186 if (currentBlock != null) { 187 currentBlock.close(); 188 currentBlock = null; 189 if (expectBlockChecksum) { 190 verifyChecksum(blockHash, "block"); 191 blockHash.reset(); 192 } 193 } 194 } 195 196 private void nextBlock() throws IOException { 197 maybeFinishCurrentBlock(); 198 final long len = ByteUtils.fromLittleEndian(supplier, 4); 199 final boolean uncompressed = (len & UNCOMPRESSED_FLAG_MASK) != 0; 200 final int realLen = (int) (len & ~UNCOMPRESSED_FLAG_MASK); 201 if (realLen == 0) { 202 verifyContentChecksum(); 203 if (!decompressConcatenated) { 204 endReached = true; 205 } else { 206 init(false); 207 } 208 return; 209 } 210 InputStream capped = new BoundedInputStream(inputStream, realLen); 211 if (expectBlockChecksum) { 212 capped = new CheckedInputStream(capped, blockHash); 213 } 214 if (uncompressed) { 215 inUncompressed = true; 216 currentBlock = capped; 217 } else { 218 inUncompressed = false; 219 final BlockLZ4CompressorInputStream s = new BlockLZ4CompressorInputStream(capped); 220 if (expectBlockDependency) { 221 s.prefill(blockDependencyBuffer); 222 } 223 currentBlock = s; 224 } 225 } 226 227 /** {@inheritDoc} */ 228 @Override 229 public int read() throws IOException { 230 return read(oneByte, 0, 1) == -1 ? -1 : oneByte[0] & 0xFF; 231 } 232 233 /** {@inheritDoc} */ 234 @Override 235 public int read(final byte[] b, final int off, final int len) throws IOException { 236 if (len == 0) { 237 return 0; 238 } 239 if (endReached) { 240 return -1; 241 } 242 int r = readOnce(b, off, len); 243 if (r == -1) { 244 nextBlock(); 245 if (!endReached) { 246 r = readOnce(b, off, len); 247 } 248 } 249 if (r != -1) { 250 if (expectBlockDependency) { 251 appendToBlockDependencyBuffer(b, off, r); 252 } 253 if (expectContentChecksum) { 254 contentHash.update(b, off, r); 255 } 256 } 257 return r; 258 } 259 260 private void readFrameDescriptor() throws IOException { 261 final int flags = readOneByte(); 262 if (flags == -1) { 263 throw new IOException("Premature end of stream while reading frame flags"); 264 } 265 contentHash.update(flags); 266 if ((flags & VERSION_MASK) != SUPPORTED_VERSION) { 267 throw new IOException("Unsupported version " + (flags >> 6)); 268 } 269 expectBlockDependency = (flags & BLOCK_INDEPENDENCE_MASK) == 0; 270 if (expectBlockDependency) { 271 if (blockDependencyBuffer == null) { 272 blockDependencyBuffer = new byte[BlockLZ4CompressorInputStream.WINDOW_SIZE]; 273 } 274 } else { 275 blockDependencyBuffer = null; 276 } 277 expectBlockChecksum = (flags & BLOCK_CHECKSUM_MASK) != 0; 278 final boolean expectContentSize = (flags & CONTENT_SIZE_MASK) != 0; 279 expectContentChecksum = (flags & CONTENT_CHECKSUM_MASK) != 0; 280 final int bdByte = readOneByte(); 281 if (bdByte == -1) { // max size is irrelevant for this implementation 282 throw new IOException("Premature end of stream while reading frame BD byte"); 283 } 284 contentHash.update(bdByte); 285 if (expectContentSize) { // for now, we don't care, contains the uncompressed size 286 final byte[] contentSize = new byte[8]; 287 final int skipped = IOUtils.readFully(inputStream, contentSize); 288 count(skipped); 289 if (8 != skipped) { 290 throw new IOException("Premature end of stream while reading content size"); 291 } 292 contentHash.update(contentSize, 0, contentSize.length); 293 } 294 final int headerHash = readOneByte(); 295 if (headerHash == -1) { // partial hash of header. 296 throw new IOException("Premature end of stream while reading frame header checksum"); 297 } 298 final int expectedHash = (int) (contentHash.getValue() >> 8 & 0xff); 299 contentHash.reset(); 300 if (headerHash != expectedHash) { 301 throw new IOException("Frame header checksum mismatch"); 302 } 303 } 304 305 private int readOnce(final byte[] b, final int off, final int len) throws IOException { 306 if (inUncompressed) { 307 final int cnt = currentBlock.read(b, off, len); 308 count(cnt); 309 return cnt; 310 } 311 final BlockLZ4CompressorInputStream l = (BlockLZ4CompressorInputStream) currentBlock; 312 final long before = l.getBytesRead(); 313 final int cnt = currentBlock.read(b, off, len); 314 count(l.getBytesRead() - before); 315 return cnt; 316 } 317 318 private int readOneByte() throws IOException { 319 final int b = inputStream.read(); 320 if (b != -1) { 321 count(1); 322 return b & 0xFF; 323 } 324 return -1; 325 } 326 327 private boolean readSignature(final boolean firstFrame) throws IOException { 328 final String garbageMessage = firstFrame ? "Not a LZ4 frame stream" : "LZ4 frame stream followed by garbage"; 329 final byte[] b = new byte[4]; 330 int read = IOUtils.readFully(inputStream, b); 331 count(read); 332 if (0 == read && !firstFrame) { 333 // good LZ4 frame and nothing after it 334 endReached = true; 335 return false; 336 } 337 if (4 != read) { 338 throw new IOException(garbageMessage); 339 } 340 341 read = skipSkippableFrame(b); 342 if (0 == read && !firstFrame) { 343 // good LZ4 frame with only some skippable frames after it 344 endReached = true; 345 return false; 346 } 347 if (4 != read || !matches(b, 4)) { 348 throw new IOException(garbageMessage); 349 } 350 return true; 351 } 352 353 /** 354 * Skips over the contents of a skippable frame as well as skippable frames following it. 355 * <p> 356 * It then tries to read four more bytes which are supposed to hold an LZ4 signature and returns the number of bytes read while storing the bytes in the 357 * given array. 358 * </p> 359 */ 360 private int skipSkippableFrame(final byte[] b) throws IOException { 361 int read = 4; 362 while (read == 4 && isSkippableFrameSignature(b)) { 363 final long len = ByteUtils.fromLittleEndian(supplier, 4); 364 if (len < 0) { 365 throw new IOException("Found illegal skippable frame with negative size"); 366 } 367 final long skipped = org.apache.commons.io.IOUtils.skip(inputStream, len); 368 count(skipped); 369 if (len != skipped) { 370 throw new IOException("Premature end of stream while skipping frame"); 371 } 372 read = IOUtils.readFully(inputStream, b); 373 count(read); 374 } 375 return read; 376 } 377 378 private void verifyChecksum(final org.apache.commons.codec.digest.XXHash32 hash, final String kind) throws IOException { 379 final byte[] checksum = new byte[4]; 380 final int read = IOUtils.readFully(inputStream, checksum); 381 count(read); 382 if (4 != read) { 383 throw new IOException("Premature end of stream while reading " + kind + " checksum"); 384 } 385 final long expectedHash = hash.getValue(); 386 if (expectedHash != ByteUtils.fromLittleEndian(checksum)) { 387 throw new IOException(kind + " checksum mismatch."); 388 } 389 } 390 391 private void verifyContentChecksum() throws IOException { 392 if (expectContentChecksum) { 393 verifyChecksum(contentHash, "content"); 394 } 395 contentHash.reset(); 396 } 397}