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19 package org.apache.commons.compress.compressors.snappy;
20
21 import java.io.IOException;
22 import java.io.InputStream;
23 import java.io.PushbackInputStream;
24 import java.util.Arrays;
25
26 import org.apache.commons.codec.digest.PureJavaCrc32C;
27 import org.apache.commons.compress.compressors.CompressorInputStream;
28 import org.apache.commons.compress.utils.ByteUtils;
29 import org.apache.commons.compress.utils.IOUtils;
30 import org.apache.commons.compress.utils.InputStreamStatistics;
31 import org.apache.commons.io.input.BoundedInputStream;
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42
43 public class FramedSnappyCompressorInputStream extends CompressorInputStream implements InputStreamStatistics {
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47
48 static final long MASK_OFFSET = 0xa282ead8L;
49
50 private static final int STREAM_IDENTIFIER_TYPE = 0xff;
51 static final int COMPRESSED_CHUNK_TYPE = 0;
52 private static final int UNCOMPRESSED_CHUNK_TYPE = 1;
53 private static final int PADDING_CHUNK_TYPE = 0xfe;
54 private static final int MIN_UNSKIPPABLE_TYPE = 2;
55 private static final int MAX_UNSKIPPABLE_TYPE = 0x7f;
56 private static final int MAX_SKIPPABLE_TYPE = 0xfd;
57
58
59 static final byte[] SZ_SIGNATURE = {
60 (byte) STREAM_IDENTIFIER_TYPE,
61 6, 0, 0,
62 's', 'N', 'a', 'P', 'p', 'Y' };
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75 public static boolean matches(final byte[] signature, final int length) {
76
77 if (length < SZ_SIGNATURE.length) {
78 return false;
79 }
80
81 byte[] shortenedSig = signature;
82 if (signature.length > SZ_SIGNATURE.length) {
83 shortenedSig = Arrays.copyOf(signature, SZ_SIGNATURE.length);
84 }
85
86 return Arrays.equals(shortenedSig, SZ_SIGNATURE);
87 }
88
89 static long unmask(long x) {
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92 x -= MASK_OFFSET;
93 x &= 0xffffFFFFL;
94 return (x >> 17 | x << 15) & 0xffffFFFFL;
95 }
96
97 private long unreadBytes;
98
99 private final BoundedInputStream countingStream;
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102 private final PushbackInputStream inputStream;
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104
105 private final FramedSnappyDialect dialect;
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107 private SnappyCompressorInputStream currentCompressedChunk;
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110 private final byte[] oneByte = new byte[1];
111 private boolean endReached;
112 private boolean inUncompressedChunk;
113 private int uncompressedBytesRemaining;
114 private long expectedChecksum = -1;
115
116 private final int blockSize;
117
118 private final PureJavaCrc32C checksum = new PureJavaCrc32C();
119
120 private final ByteUtils.ByteSupplier supplier = this::readOneByte;
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129 public FramedSnappyCompressorInputStream(final InputStream in) throws IOException {
130 this(in, FramedSnappyDialect.STANDARD);
131 }
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140 public FramedSnappyCompressorInputStream(final InputStream in, final FramedSnappyDialect dialect) throws IOException {
141 this(in, SnappyCompressorInputStream.DEFAULT_BLOCK_SIZE, dialect);
142 }
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154 public FramedSnappyCompressorInputStream(final InputStream in, final int blockSize, final FramedSnappyDialect dialect) throws IOException {
155 if (blockSize <= 0) {
156 throw new IllegalArgumentException("blockSize must be bigger than 0");
157 }
158 countingStream = BoundedInputStream.builder().setInputStream(in).get();
159 this.inputStream = new PushbackInputStream(countingStream, 1);
160 this.blockSize = blockSize;
161 this.dialect = dialect;
162 if (dialect.hasStreamIdentifier()) {
163 readStreamIdentifier();
164 }
165 }
166
167
168 @Override
169 public int available() throws IOException {
170 if (inUncompressedChunk) {
171 return Math.min(uncompressedBytesRemaining, inputStream.available());
172 }
173 if (currentCompressedChunk != null) {
174 return currentCompressedChunk.available();
175 }
176 return 0;
177 }
178
179
180 @Override
181 public void close() throws IOException {
182 try {
183 org.apache.commons.io.IOUtils.close(currentCompressedChunk);
184 currentCompressedChunk = null;
185 } finally {
186 inputStream.close();
187 }
188 }
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193 @Override
194 public long getCompressedCount() {
195 return countingStream.getCount() - unreadBytes;
196 }
197
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199 @Override
200 public int read() throws IOException {
201 return read(oneByte, 0, 1) == -1 ? -1 : oneByte[0] & 0xFF;
202 }
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205 @Override
206 public int read(final byte[] b, final int off, final int len) throws IOException {
207 if (len == 0) {
208 return 0;
209 }
210 int read = readOnce(b, off, len);
211 if (read == -1) {
212 readNextBlock();
213 if (endReached) {
214 return -1;
215 }
216 read = readOnce(b, off, len);
217 }
218 return read;
219 }
220
221 private long readCrc() throws IOException {
222 final byte[] b = new byte[4];
223 final int read = IOUtils.readFully(inputStream, b);
224 count(read);
225 if (read != 4) {
226 throw new IOException("Premature end of stream");
227 }
228 return ByteUtils.fromLittleEndian(b);
229 }
230
231 private void readNextBlock() throws IOException {
232 verifyLastChecksumAndReset();
233 inUncompressedChunk = false;
234 final int type = readOneByte();
235 if (type == -1) {
236 endReached = true;
237 } else if (type == STREAM_IDENTIFIER_TYPE) {
238 inputStream.unread(type);
239 unreadBytes++;
240 pushedBackBytes(1);
241 readStreamIdentifier();
242 readNextBlock();
243 } else if (type == PADDING_CHUNK_TYPE || type > MAX_UNSKIPPABLE_TYPE && type <= MAX_SKIPPABLE_TYPE) {
244 skipBlock();
245 readNextBlock();
246 } else if (type >= MIN_UNSKIPPABLE_TYPE && type <= MAX_UNSKIPPABLE_TYPE) {
247 throw new IOException("Unskippable chunk with type " + type + " (hex " + Integer.toHexString(type) + ") detected.");
248 } else if (type == UNCOMPRESSED_CHUNK_TYPE) {
249 inUncompressedChunk = true;
250 uncompressedBytesRemaining = readSize() - 4 ;
251 if (uncompressedBytesRemaining < 0) {
252 throw new IOException("Found illegal chunk with negative size");
253 }
254 expectedChecksum = unmask(readCrc());
255 } else if (type == COMPRESSED_CHUNK_TYPE) {
256 final boolean expectChecksum = dialect.usesChecksumWithCompressedChunks();
257 final long size = readSize() - (expectChecksum ? 4L : 0L);
258 if (size < 0) {
259 throw new IOException("Found illegal chunk with negative size");
260 }
261 if (expectChecksum) {
262 expectedChecksum = unmask(readCrc());
263 } else {
264 expectedChecksum = -1;
265 }
266
267 currentCompressedChunk = new SnappyCompressorInputStream(BoundedInputStream.builder()
268 .setInputStream(inputStream)
269 .setMaxCount(size)
270 .setPropagateClose(false)
271 .get(),
272 blockSize);
273
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275 count(currentCompressedChunk.getBytesRead());
276 } else {
277
278 throw new IOException("Unknown chunk type " + type + " detected.");
279 }
280 }
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287 private int readOnce(final byte[] b, final int off, final int len) throws IOException {
288 int read = -1;
289 if (inUncompressedChunk) {
290 final int amount = Math.min(uncompressedBytesRemaining, len);
291 if (amount == 0) {
292 return -1;
293 }
294 read = inputStream.read(b, off, amount);
295 if (read != -1) {
296 uncompressedBytesRemaining -= read;
297 count(read);
298 }
299 } else if (currentCompressedChunk != null) {
300 final long before = currentCompressedChunk.getBytesRead();
301 read = currentCompressedChunk.read(b, off, len);
302 if (read == -1) {
303 currentCompressedChunk.close();
304 currentCompressedChunk = null;
305 } else {
306 count(currentCompressedChunk.getBytesRead() - before);
307 }
308 }
309 if (read > 0) {
310 checksum.update(b, off, read);
311 }
312 return read;
313 }
314
315 private int readOneByte() throws IOException {
316 final int b = inputStream.read();
317 if (b != -1) {
318 count(1);
319 return b & 0xFF;
320 }
321 return -1;
322 }
323
324 private int readSize() throws IOException {
325 return (int) ByteUtils.fromLittleEndian(supplier, 3);
326 }
327
328 private void readStreamIdentifier() throws IOException {
329 final byte[] b = new byte[10];
330 final int read = IOUtils.readFully(inputStream, b);
331 count(read);
332 if (10 != read || !matches(b, 10)) {
333 throw new IOException("Not a framed Snappy stream");
334 }
335 }
336
337 private void skipBlock() throws IOException {
338 final int size = readSize();
339 if (size < 0) {
340 throw new IOException("Found illegal chunk with negative size");
341 }
342 final long read = org.apache.commons.io.IOUtils.skip(inputStream, size);
343 count(read);
344 if (read != size) {
345 throw new IOException("Premature end of stream");
346 }
347 }
348
349 private void verifyLastChecksumAndReset() throws IOException {
350 if (expectedChecksum >= 0 && expectedChecksum != checksum.getValue()) {
351 throw new IOException("Checksum verification failed");
352 }
353 expectedChecksum = -1;
354 checksum.reset();
355 }
356
357 }