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| 1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file | |
| 2 // for details. All rights reserved. Use of this source code is governed by a | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 part of dart.io; | |
| 6 | |
| 7 /** | |
| 8 * Exposes ZLib options for input parameters. | |
| 9 * | |
| 10 * See http://www.zlib.net/manual.html for more documentation. | |
| 11 */ | |
| 12 abstract class ZLibOption { | |
| 13 /// Minimal value for [ZLibCodec.windowBits], [ZLibEncoder.windowBits] | |
| 14 /// and [ZLibDecoder.windowBits]. | |
| 15 static const int MIN_WINDOW_BITS = 8; | |
| 16 /// Maximal value for [ZLibCodec.windowBits], [ZLibEncoder.windowBits] | |
| 17 /// and [ZLibDecoder.windowBits]. | |
| 18 static const int MAX_WINDOW_BITS = 15; | |
| 19 /// Default value for [ZLibCodec.windowBits], [ZLibEncoder.windowBits] | |
| 20 /// and [ZLibDecoder.windowBits]. | |
| 21 static const int DEFAULT_WINDOW_BITS = 15; | |
| 22 | |
| 23 /// Minimal value for [ZLibCodec.level], [ZLibEncoder.level] | |
| 24 /// and [ZLibDecoder.level]. | |
| 25 static const int MIN_LEVEL = -1; | |
| 26 /// Maximal value for [ZLibCodec.level], [ZLibEncoder.level] | |
| 27 /// and [ZLibDecoder.level]. | |
| 28 static const int MAX_LEVEL = 9; | |
| 29 /// Default value for [ZLibCodec.level], [ZLibEncoder.level] | |
| 30 /// and [ZLibDecoder.level]. | |
| 31 static const int DEFAULT_LEVEL = 6; | |
| 32 | |
| 33 /// Minimal value for [ZLibCodec.memLevel], [ZLibEncoder.memLevel] | |
| 34 /// and [ZLibDecoder.memLevel]. | |
| 35 static const int MIN_MEM_LEVEL = 1; | |
| 36 /// Maximal value for [ZLibCodec.memLevel], [ZLibEncoder.memLevel] | |
| 37 /// and [ZLibDecoder.memLevel]. | |
| 38 static const int MAX_MEM_LEVEL = 9; | |
| 39 /// Default value for [ZLibCodec.memLevel], [ZLibEncoder.memLevel] | |
| 40 /// and [ZLibDecoder.memLevel]. | |
| 41 static const int DEFAULT_MEM_LEVEL = 8; | |
| 42 | |
| 43 | |
| 44 /// Recommended strategy for data produced by a filter (or predictor) | |
| 45 static const int STRATEGY_FILTERED = 1; | |
| 46 /// Use this strategy to force Huffman encoding only (no string match) | |
| 47 static const int STRATEGY_HUFFMAN_ONLY = 2; | |
| 48 /// Use this strategy to limit match distances to one (run-length encoding) | |
| 49 static const int STRATEGY_RLE = 3; | |
| 50 /// This strategy prevents the use of dynamic Huffman codes, allowing for a | |
| 51 /// simpler decoder | |
| 52 static const int STRATEGY_FIXED = 4; | |
| 53 /// Recommended strategy for normal data | |
| 54 static const int STRATEGY_DEFAULT = 0; | |
| 55 } | |
| 56 | |
| 57 /** | |
| 58 * An instance of the default implementation of the [ZLibCodec]. | |
| 59 */ | |
| 60 const ZLibCodec ZLIB = const ZLibCodec._default(); | |
| 61 | |
| 62 /** | |
| 63 * The [ZLibCodec] encodes raw bytes to ZLib compressed bytes and decodes ZLib | |
| 64 * compressed bytes to raw bytes. | |
| 65 */ | |
| 66 class ZLibCodec extends Codec<List<int>, List<int>> { | |
| 67 /** | |
| 68 * When true, `GZip` frames will be added to the compressed data. | |
| 69 */ | |
| 70 final bool gzip; | |
| 71 | |
| 72 /** | |
| 73 * The compression-[level] can be set in the range of `-1..9`, with `6` being | |
| 74 * the default compression level. Levels above `6` will have higher | |
| 75 * compression rates at the cost of more CPU and memory usage. Levels below | |
| 76 * `6` will use less CPU and memory at the cost of lower compression rates. | |
| 77 */ | |
| 78 final int level; | |
| 79 | |
| 80 /** | |
| 81 * Specifies how much memory should be allocated for the internal compression | |
| 82 * state. `1` uses minimum memory but is slow and reduces compression ratio; | |
| 83 * `9` uses maximum memory for optimal speed. The default value is `8`. | |
| 84 * | |
| 85 * The memory requirements for deflate are (in bytes): | |
| 86 * | |
| 87 * (1 << (windowBits + 2)) + (1 << (memLevel + 9)) | |
| 88 * that is: 128K for windowBits = 15 + 128K for memLevel = 8 (default values) | |
| 89 */ | |
| 90 final int memLevel; | |
| 91 | |
| 92 /** | |
| 93 * Tunes the compression algorithm. Use the value STRATEGY_DEFAULT for normal | |
| 94 * data, STRATEGY_FILTERED for data produced by a filter (or predictor), | |
| 95 * STRATEGY_HUFFMAN_ONLY to force Huffman encoding only (no string match), or | |
| 96 * STRATEGY_RLE to limit match distances to one (run-length encoding). | |
| 97 */ | |
| 98 final int strategy; | |
| 99 | |
| 100 /** | |
| 101 * Base two logarithm of the window size (the size of the history buffer). It | |
| 102 * should be in the range 8..15. Larger values result in better compression at | |
| 103 * the expense of memory usage. The default value is 15 | |
| 104 */ | |
| 105 final int windowBits; | |
| 106 | |
| 107 /** | |
| 108 * When true, deflate generates raw data with no zlib header or trailer, and | |
| 109 * will not compute an adler32 check value | |
| 110 */ | |
| 111 final bool raw; | |
| 112 | |
| 113 /** | |
| 114 * Initial compression dictionary. | |
| 115 * | |
| 116 * It should consist of strings (byte sequences) that are likely to be | |
| 117 * encountered later in the data to be compressed, with the most commonly used | |
| 118 * strings preferably put towards the end of the dictionary. Using a | |
| 119 * dictionary is most useful when the data to be compressed is short and can | |
| 120 * be predicted with good accuracy; the data can then be compressed better | |
| 121 * than with the default empty dictionary. | |
| 122 */ | |
| 123 final List<int> dictionary; | |
| 124 | |
| 125 ZLibCodec({this.level: ZLibOption.DEFAULT_LEVEL, | |
| 126 this.windowBits: ZLibOption.DEFAULT_WINDOW_BITS, | |
| 127 this.memLevel: ZLibOption.DEFAULT_MEM_LEVEL, | |
| 128 this.strategy: ZLibOption.STRATEGY_DEFAULT, | |
| 129 this.dictionary: null, | |
| 130 this.raw: false, | |
| 131 this.gzip: false}) { | |
| 132 _validateZLibeLevel(level); | |
| 133 _validateZLibMemLevel(memLevel); | |
| 134 _validateZLibStrategy(strategy); | |
| 135 _validateZLibWindowBits(windowBits); | |
| 136 } | |
| 137 | |
| 138 const ZLibCodec._default() | |
| 139 : level = ZLibOption.DEFAULT_LEVEL, | |
| 140 windowBits = ZLibOption.DEFAULT_WINDOW_BITS, | |
| 141 memLevel = ZLibOption.DEFAULT_MEM_LEVEL, | |
| 142 strategy = ZLibOption.STRATEGY_DEFAULT, | |
| 143 raw = false, | |
| 144 gzip = false, | |
| 145 dictionary = null; | |
| 146 | |
| 147 /** | |
| 148 * Get a [ZLibEncoder] for encoding to `ZLib` compressed data. | |
| 149 */ | |
| 150 ZLibEncoder get encoder => | |
| 151 new ZLibEncoder(gzip: false, level: level, windowBits: windowBits, | |
| 152 memLevel: memLevel, strategy: strategy, | |
| 153 dictionary: dictionary, raw: raw); | |
| 154 | |
| 155 /** | |
| 156 * Get a [ZLibDecoder] for decoding `ZLib` compressed data. | |
| 157 */ | |
| 158 ZLibDecoder get decoder => | |
| 159 new ZLibDecoder(windowBits: windowBits, dictionary: dictionary, raw: raw); | |
| 160 } | |
| 161 | |
| 162 | |
| 163 /** | |
| 164 * An instance of the default implementation of the [GZipCodec]. | |
| 165 */ | |
| 166 const GZipCodec GZIP = const GZipCodec._default(); | |
| 167 | |
| 168 | |
| 169 /** | |
| 170 * The [GZipCodec] encodes raw bytes to GZip compressed bytes and decodes GZip | |
| 171 * compressed bytes to raw bytes. | |
| 172 * | |
| 173 * The difference between [ZLibCodec] and [GZipCodec] is that the [GZipCodec] | |
| 174 * wraps the `ZLib` compressed bytes in `GZip` frames. | |
| 175 */ | |
| 176 class GZipCodec extends Codec<List<int>, List<int>> { | |
| 177 /** | |
| 178 * When true, `GZip` frames will be added to the compressed data. | |
| 179 */ | |
| 180 final bool gzip; | |
| 181 | |
| 182 /** | |
| 183 * The compression-[level] can be set in the range of `-1..9`, with `6` being | |
| 184 * the default compression level. Levels above `6` will have higher | |
| 185 * compression rates at the cost of more CPU and memory usage. Levels below | |
| 186 * `6` will use less CPU and memory at the cost of lower compression rates. | |
| 187 */ | |
| 188 final int level; | |
| 189 | |
| 190 /** | |
| 191 * Specifies how much memory should be allocated for the internal compression | |
| 192 * state. `1` uses minimum memory but is slow and reduces compression ratio; | |
| 193 * `9` uses maximum memory for optimal speed. The default value is `8`. | |
| 194 * | |
| 195 * The memory requirements for deflate are (in bytes): | |
| 196 * | |
| 197 * (1 << (windowBits + 2)) + (1 << (memLevel + 9)) | |
| 198 * that is: 128K for windowBits = 15 + 128K for memLevel = 8 (default values) | |
| 199 */ | |
| 200 final int memLevel; | |
| 201 | |
| 202 /** | |
| 203 * Tunes the compression algorithm. Use the value | |
| 204 * [ZLibOption.STRATEGY_DEFAULT] for normal data, | |
| 205 * [ZLibOption.STRATEGY_FILTERED] for data produced by a filter | |
| 206 * (or predictor), [ZLibOption.STRATEGY_HUFFMAN_ONLY] to force Huffman | |
| 207 * encoding only (no string match), or [ZLibOption.STRATEGY_RLE] to limit | |
| 208 * match distances to one (run-length encoding). | |
| 209 */ | |
| 210 final int strategy; | |
| 211 | |
| 212 /** | |
| 213 * Base two logarithm of the window size (the size of the history buffer). It | |
| 214 * should be in the range `8..15`. Larger values result in better compression | |
| 215 * at the expense of memory usage. The default value is `15` | |
| 216 */ | |
| 217 final int windowBits; | |
| 218 | |
| 219 /** | |
| 220 * Initial compression dictionary. | |
| 221 * | |
| 222 * It should consist of strings (byte sequences) that are likely to be | |
| 223 * encountered later in the data to be compressed, with the most commonly used | |
| 224 * strings preferably put towards the end of the dictionary. Using a | |
| 225 * dictionary is most useful when the data to be compressed is short and can | |
| 226 * be predicted with good accuracy; the data can then be compressed better | |
| 227 * than with the default empty dictionary. | |
| 228 */ | |
| 229 final List<int> dictionary; | |
| 230 | |
| 231 /** | |
| 232 * When true, deflate generates raw data with no zlib header or trailer, and | |
| 233 * will not compute an adler32 check value | |
| 234 */ | |
| 235 final bool raw; | |
| 236 | |
| 237 GZipCodec({this.level: ZLibOption.DEFAULT_LEVEL, | |
| 238 this.windowBits: ZLibOption.DEFAULT_WINDOW_BITS, | |
| 239 this.memLevel: ZLibOption.DEFAULT_MEM_LEVEL, | |
| 240 this.strategy: ZLibOption.STRATEGY_DEFAULT, | |
| 241 this.dictionary: null, | |
| 242 this.raw: false, | |
| 243 this.gzip: true}) { | |
| 244 _validateZLibeLevel(level); | |
| 245 _validateZLibMemLevel(memLevel); | |
| 246 _validateZLibStrategy(strategy); | |
| 247 _validateZLibWindowBits(windowBits); | |
| 248 } | |
| 249 | |
| 250 const GZipCodec._default() | |
| 251 : level = ZLibOption.DEFAULT_LEVEL, | |
| 252 windowBits = ZLibOption.DEFAULT_WINDOW_BITS, | |
| 253 memLevel = ZLibOption.DEFAULT_MEM_LEVEL, | |
| 254 strategy = ZLibOption.STRATEGY_DEFAULT, | |
| 255 raw = false, | |
| 256 gzip = true, | |
| 257 dictionary = null; | |
| 258 | |
| 259 /** | |
| 260 * Get a [ZLibEncoder] for encoding to `GZip` compressed data. | |
| 261 */ | |
| 262 ZLibEncoder get encoder => | |
| 263 new ZLibEncoder(gzip: true, level: level, windowBits: windowBits, | |
| 264 memLevel: memLevel, strategy: strategy, | |
| 265 dictionary: dictionary, raw: raw); | |
| 266 | |
| 267 /** | |
| 268 * Get a [ZLibDecoder] for decoding `GZip` compressed data. | |
| 269 */ | |
| 270 ZLibDecoder get decoder => | |
| 271 new ZLibDecoder(windowBits: windowBits, dictionary: dictionary, raw: raw); | |
| 272 } | |
| 273 | |
| 274 /** | |
| 275 * The [ZLibEncoder] encoder is used by [ZLibCodec] and [GZipCodec] to compress | |
| 276 * data. | |
| 277 */ | |
| 278 class ZLibEncoder extends Converter<List<int>, List<int>> { | |
| 279 /** | |
| 280 * When true, `GZip` frames will be added to the compressed data. | |
| 281 */ | |
| 282 final bool gzip; | |
| 283 | |
| 284 /** | |
| 285 * The compression-[level] can be set in the range of `-1..9`, with `6` being | |
| 286 * the default compression level. Levels above `6` will have higher | |
| 287 * compression rates at the cost of more CPU and memory usage. Levels below | |
| 288 * `6` will use less CPU and memory at the cost of lower compression rates. | |
| 289 */ | |
| 290 final int level; | |
| 291 | |
| 292 /** | |
| 293 * Specifies how much memory should be allocated for the internal compression | |
| 294 * state. `1` uses minimum memory but is slow and reduces compression ratio; | |
| 295 * `9` uses maximum memory for optimal speed. The default value is `8`. | |
| 296 * | |
| 297 * The memory requirements for deflate are (in bytes): | |
| 298 * | |
| 299 * (1 << (windowBits + 2)) + (1 << (memLevel + 9)) | |
| 300 * that is: 128K for windowBits = 15 + 128K for memLevel = 8 (default values) | |
| 301 */ | |
| 302 final int memLevel; | |
| 303 | |
| 304 /** | |
| 305 * Tunes the compression algorithm. Use the value | |
| 306 * [ZLibOption.STRATEGY_DEFAULT] for normal data, | |
| 307 * [ZLibOption.STRATEGY_FILTERED] for data produced by a filter | |
| 308 * (or predictor), [ZLibOption.STRATEGY_HUFFMAN_ONLY] to force Huffman | |
| 309 * encoding only (no string match), or [ZLibOption.STRATEGY_RLE] to limit | |
| 310 * match distances to one (run-length encoding). | |
| 311 */ | |
| 312 final int strategy; | |
| 313 | |
| 314 /** | |
| 315 * Base two logarithm of the window size (the size of the history buffer). It | |
| 316 * should be in the range `8..15`. Larger values result in better compression | |
| 317 * at the expense of memory usage. The default value is `15` | |
| 318 */ | |
| 319 final int windowBits; | |
| 320 | |
| 321 /** | |
| 322 * Initial compression dictionary. | |
| 323 * | |
| 324 * It should consist of strings (byte sequences) that are likely to be | |
| 325 * encountered later in the data to be compressed, with the most commonly used | |
| 326 * strings preferably put towards the end of the dictionary. Using a | |
| 327 * dictionary is most useful when the data to be compressed is short and can | |
| 328 * be predicted with good accuracy; the data can then be compressed better | |
| 329 * than with the default empty dictionary. | |
| 330 */ | |
| 331 final List<int> dictionary; | |
| 332 | |
| 333 | |
| 334 /** | |
| 335 * When true, deflate generates raw data with no zlib header or trailer, and | |
| 336 * will not compute an adler32 check value | |
| 337 */ | |
| 338 final bool raw; | |
| 339 | |
| 340 ZLibEncoder({this.gzip: false, | |
| 341 this.level: ZLibOption.DEFAULT_LEVEL, | |
| 342 this.windowBits: ZLibOption.DEFAULT_WINDOW_BITS, | |
| 343 this.memLevel: ZLibOption.DEFAULT_MEM_LEVEL, | |
| 344 this.strategy: ZLibOption.STRATEGY_DEFAULT, | |
| 345 this.dictionary: null, | |
| 346 this.raw: false}) { | |
| 347 _validateZLibeLevel(level); | |
| 348 _validateZLibMemLevel(memLevel); | |
| 349 _validateZLibStrategy(strategy); | |
| 350 _validateZLibWindowBits(windowBits); | |
| 351 } | |
| 352 | |
| 353 /** | |
| 354 * Convert a list of bytes using the options given to the ZLibEncoder | |
| 355 * constructor. | |
| 356 */ | |
| 357 List<int> convert(List<int> bytes) { | |
| 358 _BufferSink sink = new _BufferSink(); | |
| 359 startChunkedConversion(sink)..add(bytes)..close(); | |
| 360 return sink.builder.takeBytes(); | |
| 361 } | |
| 362 | |
| 363 /** | |
| 364 * Start a chunked conversion using the options given to the [ZLibEncoder] | |
| 365 * constructor. While it accepts any [Sink] taking [List<int>]'s, | |
| 366 * the optimal sink to be passed as [sink] is a [ByteConversionSink]. | |
| 367 */ | |
| 368 ByteConversionSink startChunkedConversion(Sink<List<int>> sink) { | |
| 369 if (sink is! ByteConversionSink) { | |
| 370 sink = new ByteConversionSink.from(sink); | |
| 371 } | |
| 372 return new _ZLibEncoderSink(sink, gzip, level, windowBits, memLevel, | |
| 373 strategy, dictionary, raw); | |
| 374 } | |
| 375 } | |
| 376 | |
| 377 | |
| 378 /** | |
| 379 * The [ZLibDecoder] is used by [ZLibCodec] and [GZipCodec] to decompress data. | |
| 380 */ | |
| 381 class ZLibDecoder extends Converter<List<int>, List<int>> { | |
| 382 /** | |
| 383 * Base two logarithm of the window size (the size of the history buffer). It | |
| 384 * should be in the range `8..15`. Larger values result in better compression | |
| 385 * at the expense of memory usage. The default value is `15`. | |
| 386 */ | |
| 387 final int windowBits; | |
| 388 | |
| 389 /** | |
| 390 * Initial compression dictionary. | |
| 391 * | |
| 392 * It should consist of strings (byte sequences) that are likely to be | |
| 393 * encountered later in the data to be compressed, with the most commonly used | |
| 394 * strings preferably put towards the end of the dictionary. Using a | |
| 395 * dictionary is most useful when the data to be compressed is short and can | |
| 396 * be predicted with good accuracy; the data can then be compressed better | |
| 397 * than with the default empty dictionary. | |
| 398 */ | |
| 399 final List<int> dictionary; | |
| 400 | |
| 401 /** | |
| 402 * When true, deflate generates raw data with no zlib header or trailer, and | |
| 403 * will not compute an adler32 check value | |
| 404 */ | |
| 405 final bool raw; | |
| 406 | |
| 407 ZLibDecoder({this.windowBits: ZLibOption.DEFAULT_WINDOW_BITS, | |
| 408 this.dictionary: null, this.raw: false}) { | |
| 409 _validateZLibWindowBits(windowBits); | |
| 410 } | |
| 411 | |
| 412 /** | |
| 413 * Convert a list of bytes using the options given to the [ZLibDecoder] | |
| 414 * constructor. | |
| 415 */ | |
| 416 List<int> convert(List<int> bytes) { | |
| 417 _BufferSink sink = new _BufferSink(); | |
| 418 startChunkedConversion(sink)..add(bytes)..close(); | |
| 419 return sink.builder.takeBytes(); | |
| 420 } | |
| 421 | |
| 422 /** | |
| 423 * Start a chunked conversion. While it accepts any [Sink] | |
| 424 * taking [List<int>]'s, the optimal sink to be passed as [sink] is a | |
| 425 * [ByteConversionSink]. | |
| 426 */ | |
| 427 ByteConversionSink startChunkedConversion(Sink<List<int>> sink) { | |
| 428 if (sink is! ByteConversionSink) { | |
| 429 sink = new ByteConversionSink.from(sink); | |
| 430 } | |
| 431 return new _ZLibDecoderSink(sink, windowBits, dictionary, raw); | |
| 432 } | |
| 433 } | |
| 434 | |
| 435 | |
| 436 class _BufferSink extends ByteConversionSink { | |
| 437 final BytesBuilder builder = new BytesBuilder(copy: false); | |
| 438 | |
| 439 void add(List<int> chunk) { | |
| 440 builder.add(chunk); | |
| 441 } | |
| 442 | |
| 443 void addSlice(List<int> chunk, int start, int end, bool isLast) { | |
| 444 if (chunk is Uint8List) { | |
| 445 Uint8List list = chunk; | |
| 446 builder.add(new Uint8List.view(list.buffer, start, end - start)); | |
| 447 } else { | |
| 448 builder.add(chunk.sublist(start, end)); | |
| 449 } | |
| 450 } | |
| 451 | |
| 452 void close() {} | |
| 453 } | |
| 454 | |
| 455 | |
| 456 class _ZLibEncoderSink extends _FilterSink { | |
| 457 _ZLibEncoderSink(ByteConversionSink sink, bool gzip, int level, | |
| 458 int windowBits, int memLevel, int strategy, | |
| 459 List<int> dictionary, bool raw) | |
| 460 : super(sink, _Filter._newZLibDeflateFilter(gzip, level, windowBits, | |
| 461 memLevel, strategy, | |
| 462 dictionary, raw)); | |
| 463 } | |
| 464 | |
| 465 class _ZLibDecoderSink extends _FilterSink { | |
| 466 _ZLibDecoderSink(ByteConversionSink sink, int windowBits, | |
| 467 List<int> dictionary, bool raw) | |
| 468 : super(sink, _Filter._newZLibInflateFilter(windowBits, dictionary, raw)); | |
| 469 } | |
| 470 | |
| 471 | |
| 472 class _FilterSink extends ByteConversionSink { | |
| 473 final _Filter _filter; | |
| 474 final ByteConversionSink _sink; | |
| 475 bool _closed = false; | |
| 476 bool _empty = true; | |
| 477 | |
| 478 _FilterSink(this._sink, this._filter); | |
| 479 | |
| 480 void add(List<int> data) { | |
| 481 addSlice(data, 0, data.length, false); | |
| 482 } | |
| 483 | |
| 484 void addSlice(List<int> data, int start, int end, bool isLast) { | |
| 485 if (_closed) return; | |
| 486 if (end == null) throw new ArgumentError.notNull("end"); | |
| 487 RangeError.checkValidRange(start, end, data.length); | |
| 488 try { | |
| 489 _empty = false; | |
| 490 _BufferAndStart bufferAndStart = | |
| 491 _ensureFastAndSerializableByteData(data, start, end); | |
| 492 _filter.process(bufferAndStart.buffer, | |
| 493 bufferAndStart.start, | |
| 494 end - (start - bufferAndStart.start)); | |
| 495 var out; | |
| 496 while ((out = _filter.processed(flush: false)) != null) { | |
| 497 _sink.add(out); | |
| 498 } | |
| 499 } catch (e) { | |
| 500 _closed = true; | |
| 501 rethrow; | |
| 502 } | |
| 503 | |
| 504 if (isLast) close(); | |
| 505 } | |
| 506 | |
| 507 void close() { | |
| 508 if (_closed) return; | |
| 509 // Be sure to send process an empty chunk of data. Without this, the empty | |
| 510 // message would not have a GZip frame (if compressed with GZip). | |
| 511 if (_empty) _filter.process(const [], 0, 0); | |
| 512 try { | |
| 513 var out; | |
| 514 while ((out = _filter.processed(end: true)) != null) { | |
| 515 _sink.add(out); | |
| 516 } | |
| 517 } catch (e) { | |
| 518 _closed = true; | |
| 519 throw e; | |
| 520 } | |
| 521 _closed = true; | |
| 522 _sink.close(); | |
| 523 } | |
| 524 } | |
| 525 | |
| 526 | |
| 527 /** | |
| 528 * Private helper-class to handle native filters. | |
| 529 */ | |
| 530 abstract class _Filter { | |
| 531 /** | |
| 532 * Call to process a chunk of data. A call to [process] should only be made | |
| 533 * when [processed] returns [:null:]. | |
| 534 */ | |
| 535 void process(List<int> data, int start, int end); | |
| 536 | |
| 537 /** | |
| 538 * Get a chunk of processed data. When there are no more data available, | |
| 539 * [processed] will return [:null:]. Set [flush] to [:false:] for non-final | |
| 540 * calls to improve performance of some filters. | |
| 541 * | |
| 542 * The last call to [processed] should have [end] set to [:true:]. This will | |
| 543 * make sure an 'end' packet is written on the stream. | |
| 544 */ | |
| 545 List<int> processed({bool flush: true, bool end: false}); | |
| 546 | |
| 547 external static _Filter _newZLibDeflateFilter(bool gzip, int level, | |
| 548 int windowBits, int memLevel, | |
| 549 int strategy, | |
| 550 List<int> dictionary, bool raw); | |
| 551 | |
| 552 external static _Filter _newZLibInflateFilter(int windowBits, | |
| 553 List<int> dictionary, bool raw); | |
| 554 } | |
| 555 | |
| 556 void _validateZLibWindowBits(int windowBits) { | |
| 557 if (ZLibOption.MIN_WINDOW_BITS > windowBits || | |
| 558 ZLibOption.MAX_WINDOW_BITS < windowBits) { | |
| 559 throw new RangeError.range(windowBits, ZLibOption.MIN_WINDOW_BITS, | |
| 560 ZLibOption.MAX_WINDOW_BITS); | |
| 561 } | |
| 562 } | |
| 563 | |
| 564 void _validateZLibeLevel(int level) { | |
| 565 if (ZLibOption.MIN_LEVEL > level || | |
| 566 ZLibOption.MAX_LEVEL < level) { | |
| 567 throw new RangeError.range(level, ZLibOption.MIN_LEVEL, | |
| 568 ZLibOption.MAX_LEVEL); | |
| 569 } | |
| 570 } | |
| 571 | |
| 572 void _validateZLibMemLevel(int memLevel) { | |
| 573 if (ZLibOption.MIN_MEM_LEVEL > memLevel || | |
| 574 ZLibOption.MAX_MEM_LEVEL < memLevel) { | |
| 575 throw new RangeError.range(memLevel, ZLibOption.MIN_MEM_LEVEL, | |
| 576 ZLibOption.MAX_MEM_LEVEL); | |
| 577 } | |
| 578 } | |
| 579 | |
| 580 void _validateZLibStrategy(int strategy) { | |
| 581 const strategies = const <int>[ZLibOption.STRATEGY_FILTERED, | |
| 582 ZLibOption.STRATEGY_HUFFMAN_ONLY, ZLibOption.STRATEGY_RLE, | |
| 583 ZLibOption.STRATEGY_FIXED, ZLibOption.STRATEGY_DEFAULT]; | |
| 584 if (strategies.indexOf(strategy) == -1) { | |
| 585 throw new ArgumentError("Unsupported 'strategy'"); | |
| 586 } | |
| 587 } | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 2698353003:
unfork DDC's copy of most SDK libraries (Closed)
