1 /* 2 * LZ4 - Fast LZ compression algorithm 3 * Header File 4 * Copyright (C) 2011-present, Yann Collet. 5 6 BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) 7 8 Redistribution and use in source and binary forms, with or without 9 modification, are permitted provided that the following conditions are 10 met: 11 12 * Redistributions of source code must retain the above copyright 13 notice, this list of conditions and the following disclaimer. 14 * Redistributions in binary form must reproduce the above 15 copyright notice, this list of conditions and the following disclaimer 16 in the documentation and/or other materials provided with the 17 distribution. 18 19 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31 You can contact the author at : 32 - LZ4 homepage : http://www.lz4.org 33 - LZ4 source repository : https://github.com/lz4/lz4 34 */ 35 #if defined (__cplusplus) 36 extern "C" { 37 #endif 38 39 #ifndef LZ4_H_2983827168210 40 #define LZ4_H_2983827168210 41 42 /* --- Dependency --- */ 43 #include <stddef.h> /* size_t */ 44 45 46 /** 47 Introduction 48 49 LZ4 is lossless compression algorithm, providing compression speed at 500 MB/s per core, 50 scalable with multi-cores CPU. It features an extremely fast decoder, with speed in 51 multiple GB/s per core, typically reaching RAM speed limits on multi-core systems. 52 53 The LZ4 compression library provides in-memory compression and decompression functions. 54 Compression can be done in: 55 - a single step (described as Simple Functions) 56 - a single step, reusing a context (described in Advanced Functions) 57 - unbounded multiple steps (described as Streaming compression) 58 59 lz4.h provides block compression functions. It gives full buffer control to user. 60 Decompressing an lz4-compressed block also requires metadata (such as compressed size). 61 Each application is free to encode such metadata in whichever way it wants. 62 63 An additional format, called LZ4 frame specification (doc/lz4_Frame_format.md), 64 take care of encoding standard metadata alongside LZ4-compressed blocks. 65 Frame format is required for interoperability. 66 It is delivered through a companion API, declared in lz4frame.h. 67 */ 68 69 /*^*************************************************************** 70 * Export parameters 71 *****************************************************************/ 72 /* 73 * LZ4_DLL_EXPORT : 74 * Enable exporting of functions when building a Windows DLL 75 * LZ4LIB_VISIBILITY : 76 * Control library symbols visibility. 77 */ 78 #ifndef LZ4LIB_VISIBILITY 79 # if defined(__GNUC__) && (__GNUC__ >= 4) 80 # define LZ4LIB_VISIBILITY __attribute__ ((visibility ("default"))) 81 # else 82 # define LZ4LIB_VISIBILITY 83 # endif 84 #endif 85 #if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1) 86 # define LZ4LIB_API __declspec(dllexport) LZ4LIB_VISIBILITY 87 #elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1) 88 # define LZ4LIB_API __declspec(dllimport) LZ4LIB_VISIBILITY /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/ 89 #else 90 # define LZ4LIB_API LZ4LIB_VISIBILITY 91 #endif 92 93 /*------ Version ------*/ 94 #define LZ4_VERSION_MAJOR 1 /* for breaking interface changes */ 95 #define LZ4_VERSION_MINOR 8 /* for new (non-breaking) interface capabilities */ 96 #define LZ4_VERSION_RELEASE 3 /* for tweaks, bug-fixes, or development */ 97 98 #define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR *100*100 + LZ4_VERSION_MINOR *100 + LZ4_VERSION_RELEASE) 99 100 #define LZ4_LIB_VERSION LZ4_VERSION_MAJOR.LZ4_VERSION_MINOR.LZ4_VERSION_RELEASE 101 #define LZ4_QUOTE(str) #str 102 #define LZ4_EXPAND_AND_QUOTE(str) LZ4_QUOTE(str) 103 #define LZ4_VERSION_STRING LZ4_EXPAND_AND_QUOTE(LZ4_LIB_VERSION) 104 105 LZ4LIB_API int LZ4_versionNumber (void); /**< library version number; useful to check dll version */ 106 LZ4LIB_API const char* LZ4_versionString (void); /**< library version string; unseful to check dll version */ 107 108 109 /*-************************************ 110 * Tuning parameter 111 **************************************/ 112 /*! 113 * LZ4_MEMORY_USAGE : 114 * Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.) 115 * Increasing memory usage improves compression ratio 116 * Reduced memory usage may improve speed, thanks to cache effect 117 * Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache 118 */ 119 #ifndef LZ4_MEMORY_USAGE 120 # define LZ4_MEMORY_USAGE 14 121 #endif 122 123 /*-************************************ 124 * Simple Functions 125 **************************************/ 126 /*! LZ4_compress_default() : 127 Compresses 'srcSize' bytes from buffer 'src' 128 into already allocated 'dst' buffer of size 'dstCapacity'. 129 Compression is guaranteed to succeed if 'dstCapacity' >= LZ4_compressBound(srcSize). 130 It also runs faster, so it's a recommended setting. 131 If the function cannot compress 'src' into a more limited 'dst' budget, 132 compression stops *immediately*, and the function result is zero. 133 Note : as a consequence, 'dst' content is not valid. 134 Note 2 : This function is protected against buffer overflow scenarios (never writes outside 'dst' buffer, nor read outside 'source' buffer). 135 srcSize : max supported value is LZ4_MAX_INPUT_SIZE. 136 dstCapacity : size of buffer 'dst' (which must be already allocated) 137 return : the number of bytes written into buffer 'dst' (necessarily <= dstCapacity) 138 or 0 if compression fails */ 139 LZ4LIB_API int LZ4_compress_default(const char* src, char* dst, int srcSize, int dstCapacity); 140 141 /*! LZ4_decompress_safe() : 142 compressedSize : is the exact complete size of the compressed block. 143 dstCapacity : is the size of destination buffer, which must be already allocated. 144 return : the number of bytes decompressed into destination buffer (necessarily <= dstCapacity) 145 If destination buffer is not large enough, decoding will stop and output an error code (negative value). 146 If the source stream is detected malformed, the function will stop decoding and return a negative result. 147 This function is protected against malicious data packets. 148 */ 149 LZ4LIB_API int LZ4_decompress_safe (const char* src, char* dst, int compressedSize, int dstCapacity); 150 151 152 /*-************************************ 153 * Advanced Functions 154 **************************************/ 155 #define LZ4_MAX_INPUT_SIZE 0x7E000000 /* 2 113 929 216 bytes */ 156 #define LZ4_COMPRESSBOUND(isize) ((unsigned)(isize) > (unsigned)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize)/255) + 16) 157 158 /*! 159 LZ4_compressBound() : 160 Provides the maximum size that LZ4 compression may output in a "worst case" scenario (input data not compressible) 161 This function is primarily useful for memory allocation purposes (destination buffer size). 162 Macro LZ4_COMPRESSBOUND() is also provided for compilation-time evaluation (stack memory allocation for example). 163 Note that LZ4_compress_default() compresses faster when dstCapacity is >= LZ4_compressBound(srcSize) 164 inputSize : max supported value is LZ4_MAX_INPUT_SIZE 165 return : maximum output size in a "worst case" scenario 166 or 0, if input size is incorrect (too large or negative) 167 */ 168 LZ4LIB_API int LZ4_compressBound(int inputSize); 169 170 /*! 171 LZ4_compress_fast() : 172 Same as LZ4_compress_default(), but allows selection of "acceleration" factor. 173 The larger the acceleration value, the faster the algorithm, but also the lesser the compression. 174 It's a trade-off. It can be fine tuned, with each successive value providing roughly +~3% to speed. 175 An acceleration value of "1" is the same as regular LZ4_compress_default() 176 Values <= 0 will be replaced by ACCELERATION_DEFAULT (currently == 1, see lz4.c). 177 */ 178 LZ4LIB_API int LZ4_compress_fast (const char* src, char* dst, int srcSize, int dstCapacity, int acceleration); 179 180 181 /*! 182 LZ4_compress_fast_extState() : 183 Same compression function, just using an externally allocated memory space to store compression state. 184 Use LZ4_sizeofState() to know how much memory must be allocated, 185 and allocate it on 8-bytes boundaries (using malloc() typically). 186 Then, provide this buffer as 'void* state' to compression function. 187 */ 188 LZ4LIB_API int LZ4_sizeofState(void); 189 LZ4LIB_API int LZ4_compress_fast_extState (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration); 190 191 192 /*! LZ4_compress_destSize() : 193 * Reverse the logic : compresses as much data as possible from 'src' buffer 194 * into already allocated buffer 'dst', of size >= 'targetDestSize'. 195 * This function either compresses the entire 'src' content into 'dst' if it's large enough, 196 * or fill 'dst' buffer completely with as much data as possible from 'src'. 197 * note: acceleration parameter is fixed to "default". 198 * 199 * *srcSizePtr : will be modified to indicate how many bytes where read from 'src' to fill 'dst'. 200 * New value is necessarily <= input value. 201 * @return : Nb bytes written into 'dst' (necessarily <= targetDestSize) 202 * or 0 if compression fails. 203 */ 204 LZ4LIB_API int LZ4_compress_destSize (const char* src, char* dst, int* srcSizePtr, int targetDstSize); 205 206 207 /*! LZ4_decompress_fast() : **unsafe!** 208 * This function used to be a bit faster than LZ4_decompress_safe(), 209 * though situation has changed in recent versions, 210 * and now `LZ4_decompress_safe()` can be as fast and sometimes faster than `LZ4_decompress_fast()`. 211 * Moreover, LZ4_decompress_fast() is not protected vs malformed input, as it doesn't perform full validation of compressed data. 212 * As a consequence, this function is no longer recommended, and may be deprecated in future versions. 213 * It's only remaining specificity is that it can decompress data without knowing its compressed size. 214 * 215 * originalSize : is the uncompressed size to regenerate. 216 * `dst` must be already allocated, its size must be >= 'originalSize' bytes. 217 * @return : number of bytes read from source buffer (== compressed size). 218 * If the source stream is detected malformed, the function stops decoding and returns a negative result. 219 * note : This function requires uncompressed originalSize to be known in advance. 220 * The function never writes past the output buffer. 221 * However, since it doesn't know its 'src' size, it may read past the intended input. 222 * Also, because match offsets are not validated during decoding, 223 * reads from 'src' may underflow. 224 * Use this function in trusted environment **only**. 225 */ 226 LZ4LIB_API int LZ4_decompress_fast (const char* src, char* dst, int originalSize); 227 228 /*! LZ4_decompress_safe_partial() : 229 * Decompress an LZ4 compressed block, of size 'srcSize' at position 'src', 230 * into destination buffer 'dst' of size 'dstCapacity'. 231 * Up to 'targetOutputSize' bytes will be decoded. 232 * The function stops decoding on reaching this objective, 233 * which can boost performance when only the beginning of a block is required. 234 * 235 * @return : the number of bytes decoded in `dst` (necessarily <= dstCapacity) 236 * If source stream is detected malformed, function returns a negative result. 237 * 238 * Note : @return can be < targetOutputSize, if compressed block contains less data. 239 * 240 * Note 2 : this function features 2 parameters, targetOutputSize and dstCapacity, 241 * and expects targetOutputSize <= dstCapacity. 242 * It effectively stops decoding on reaching targetOutputSize, 243 * so dstCapacity is kind of redundant. 244 * This is because in a previous version of this function, 245 * decoding operation would not "break" a sequence in the middle. 246 * As a consequence, there was no guarantee that decoding would stop at exactly targetOutputSize, 247 * it could write more bytes, though only up to dstCapacity. 248 * Some "margin" used to be required for this operation to work properly. 249 * This is no longer necessary. 250 * The function nonetheless keeps its signature, in an effort to not break API. 251 */ 252 LZ4LIB_API int LZ4_decompress_safe_partial (const char* src, char* dst, int srcSize, int targetOutputSize, int dstCapacity); 253 254 255 /*-********************************************* 256 * Streaming Compression Functions 257 ***********************************************/ 258 typedef union LZ4_stream_u LZ4_stream_t; /* incomplete type (defined later) */ 259 260 /*! LZ4_createStream() and LZ4_freeStream() : 261 * LZ4_createStream() will allocate and initialize an `LZ4_stream_t` structure. 262 * LZ4_freeStream() releases its memory. 263 */ 264 LZ4LIB_API LZ4_stream_t* LZ4_createStream(void); 265 LZ4LIB_API int LZ4_freeStream (LZ4_stream_t* streamPtr); 266 267 /*! LZ4_resetStream() : 268 * An LZ4_stream_t structure can be allocated once and re-used multiple times. 269 * Use this function to start compressing a new stream. 270 */ 271 LZ4LIB_API void LZ4_resetStream (LZ4_stream_t* streamPtr); 272 273 /*! LZ4_loadDict() : 274 * Use this function to load a static dictionary into LZ4_stream_t. 275 * Any previous data will be forgotten, only 'dictionary' will remain in memory. 276 * Loading a size of 0 is allowed, and is the same as reset. 277 * @return : dictionary size, in bytes (necessarily <= 64 KB) 278 */ 279 LZ4LIB_API int LZ4_loadDict (LZ4_stream_t* streamPtr, const char* dictionary, int dictSize); 280 281 /*! LZ4_compress_fast_continue() : 282 * Compress 'src' content using data from previously compressed blocks, for better compression ratio. 283 * 'dst' buffer must be already allocated. 284 * If dstCapacity >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster. 285 * 286 * @return : size of compressed block 287 * or 0 if there is an error (typically, cannot fit into 'dst'). 288 * 289 * Note 1 : Each invocation to LZ4_compress_fast_continue() generates a new block. 290 * Each block has precise boundaries. 291 * It's not possible to append blocks together and expect a single invocation of LZ4_decompress_*() to decompress them together. 292 * Each block must be decompressed separately, calling LZ4_decompress_*() with associated metadata. 293 * 294 * Note 2 : The previous 64KB of source data is __assumed__ to remain present, unmodified, at same address in memory! 295 * 296 * Note 3 : When input is structured as a double-buffer, each buffer can have any size, including < 64 KB. 297 * Make sure that buffers are separated, by at least one byte. 298 * This construction ensures that each block only depends on previous block. 299 * 300 * Note 4 : If input buffer is a ring-buffer, it can have any size, including < 64 KB. 301 * 302 * Note 5 : After an error, the stream status is invalid, it can only be reset or freed. 303 */ 304 LZ4LIB_API int LZ4_compress_fast_continue (LZ4_stream_t* streamPtr, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration); 305 306 /*! LZ4_saveDict() : 307 * If last 64KB data cannot be guaranteed to remain available at its current memory location, 308 * save it into a safer place (char* safeBuffer). 309 * This is schematically equivalent to a memcpy() followed by LZ4_loadDict(), 310 * but is much faster, because LZ4_saveDict() doesn't need to rebuild tables. 311 * @return : saved dictionary size in bytes (necessarily <= maxDictSize), or 0 if error. 312 */ 313 LZ4LIB_API int LZ4_saveDict (LZ4_stream_t* streamPtr, char* safeBuffer, int maxDictSize); 314 315 316 /*-********************************************** 317 * Streaming Decompression Functions 318 * Bufferless synchronous API 319 ************************************************/ 320 typedef union LZ4_streamDecode_u LZ4_streamDecode_t; /* tracking context */ 321 322 /*! LZ4_createStreamDecode() and LZ4_freeStreamDecode() : 323 * creation / destruction of streaming decompression tracking context. 324 * A tracking context can be re-used multiple times. 325 */ 326 LZ4LIB_API LZ4_streamDecode_t* LZ4_createStreamDecode(void); 327 LZ4LIB_API int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream); 328 329 /*! LZ4_setStreamDecode() : 330 * An LZ4_streamDecode_t context can be allocated once and re-used multiple times. 331 * Use this function to start decompression of a new stream of blocks. 332 * A dictionary can optionally be set. Use NULL or size 0 for a reset order. 333 * Dictionary is presumed stable : it must remain accessible and unmodified during next decompression. 334 * @return : 1 if OK, 0 if error 335 */ 336 LZ4LIB_API int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize); 337 338 /*! LZ4_decoderRingBufferSize() : v1.8.2 339 * Note : in a ring buffer scenario (optional), 340 * blocks are presumed decompressed next to each other 341 * up to the moment there is not enough remaining space for next block (remainingSize < maxBlockSize), 342 * at which stage it resumes from beginning of ring buffer. 343 * When setting such a ring buffer for streaming decompression, 344 * provides the minimum size of this ring buffer 345 * to be compatible with any source respecting maxBlockSize condition. 346 * @return : minimum ring buffer size, 347 * or 0 if there is an error (invalid maxBlockSize). 348 */ 349 LZ4LIB_API int LZ4_decoderRingBufferSize(int maxBlockSize); 350 #define LZ4_DECODER_RING_BUFFER_SIZE(mbs) (65536 + 14 + (mbs)) /* for static allocation; mbs presumed valid */ 351 352 /*! LZ4_decompress_*_continue() : 353 * These decoding functions allow decompression of consecutive blocks in "streaming" mode. 354 * A block is an unsplittable entity, it must be presented entirely to a decompression function. 355 * Decompression functions only accepts one block at a time. 356 * The last 64KB of previously decoded data *must* remain available and unmodified at the memory position where they were decoded. 357 * If less than 64KB of data has been decoded, all the data must be present. 358 * 359 * Special : if decompression side sets a ring buffer, it must respect one of the following conditions : 360 * - Decompression buffer size is _at least_ LZ4_decoderRingBufferSize(maxBlockSize). 361 * maxBlockSize is the maximum size of any single block. It can have any value > 16 bytes. 362 * In which case, encoding and decoding buffers do not need to be synchronized. 363 * Actually, data can be produced by any source compliant with LZ4 format specification, and respecting maxBlockSize. 364 * - Synchronized mode : 365 * Decompression buffer size is _exactly_ the same as compression buffer size, 366 * and follows exactly same update rule (block boundaries at same positions), 367 * and decoding function is provided with exact decompressed size of each block (exception for last block of the stream), 368 * _then_ decoding & encoding ring buffer can have any size, including small ones ( < 64 KB). 369 * - Decompression buffer is larger than encoding buffer, by a minimum of maxBlockSize more bytes. 370 * In which case, encoding and decoding buffers do not need to be synchronized, 371 * and encoding ring buffer can have any size, including small ones ( < 64 KB). 372 * 373 * Whenever these conditions are not possible, 374 * save the last 64KB of decoded data into a safe buffer where it can't be modified during decompression, 375 * then indicate where this data is saved using LZ4_setStreamDecode(), before decompressing next block. 376 */ 377 LZ4LIB_API int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* src, char* dst, int srcSize, int dstCapacity); 378 LZ4LIB_API int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* src, char* dst, int originalSize); 379 380 381 /*! LZ4_decompress_*_usingDict() : 382 * These decoding functions work the same as 383 * a combination of LZ4_setStreamDecode() followed by LZ4_decompress_*_continue() 384 * They are stand-alone, and don't need an LZ4_streamDecode_t structure. 385 * Dictionary is presumed stable : it must remain accessible and unmodified during next decompression. 386 */ 387 LZ4LIB_API int LZ4_decompress_safe_usingDict (const char* src, char* dst, int srcSize, int dstCapcity, const char* dictStart, int dictSize); 388 LZ4LIB_API int LZ4_decompress_fast_usingDict (const char* src, char* dst, int originalSize, const char* dictStart, int dictSize); 389 390 391 /*^********************************************** 392 * !!!!!! STATIC LINKING ONLY !!!!!! 393 ***********************************************/ 394 395 /*-************************************ 396 * Unstable declarations 397 ************************************** 398 * Declarations in this section should be considered unstable. 399 * Use at your own peril, etc., etc. 400 * They may be removed in the future. 401 * Their signatures may change. 402 **************************************/ 403 404 #ifdef LZ4_STATIC_LINKING_ONLY 405 406 /*! LZ4_resetStream_fast() : 407 * Use this, like LZ4_resetStream(), to prepare a context for a new chain of 408 * calls to a streaming API (e.g., LZ4_compress_fast_continue()). 409 * 410 * Note: 411 * Using this in advance of a non- streaming-compression function is redundant, 412 * and potentially bad for performance, since they all perform their own custom 413 * reset internally. 414 * 415 * Differences from LZ4_resetStream(): 416 * When an LZ4_stream_t is known to be in a internally coherent state, 417 * it can often be prepared for a new compression with almost no work, only 418 * sometimes falling back to the full, expensive reset that is always required 419 * when the stream is in an indeterminate state (i.e., the reset performed by 420 * LZ4_resetStream()). 421 * 422 * LZ4_streams are guaranteed to be in a valid state when: 423 * - returned from LZ4_createStream() 424 * - reset by LZ4_resetStream() 425 * - memset(stream, 0, sizeof(LZ4_stream_t)), though this is discouraged 426 * - the stream was in a valid state and was reset by LZ4_resetStream_fast() 427 * - the stream was in a valid state and was then used in any compression call 428 * that returned success 429 * - the stream was in an indeterminate state and was used in a compression 430 * call that fully reset the state (e.g., LZ4_compress_fast_extState()) and 431 * that returned success 432 * 433 * When a stream isn't known to be in a valid state, it is not safe to pass to 434 * any fastReset or streaming function. It must first be cleansed by the full 435 * LZ4_resetStream(). 436 */ 437 LZ4LIB_API void LZ4_resetStream_fast (LZ4_stream_t* streamPtr); 438 439 /*! LZ4_compress_fast_extState_fastReset() : 440 * A variant of LZ4_compress_fast_extState(). 441 * 442 * Using this variant avoids an expensive initialization step. It is only safe 443 * to call if the state buffer is known to be correctly initialized already 444 * (see above comment on LZ4_resetStream_fast() for a definition of "correctly 445 * initialized"). From a high level, the difference is that this function 446 * initializes the provided state with a call to something like 447 * LZ4_resetStream_fast() while LZ4_compress_fast_extState() starts with a 448 * call to LZ4_resetStream(). 449 */ 450 LZ4LIB_API int LZ4_compress_fast_extState_fastReset (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration); 451 452 /*! LZ4_attach_dictionary() : 453 * This is an experimental API that allows for the efficient use of a 454 * static dictionary many times. 455 * 456 * Rather than re-loading the dictionary buffer into a working context before 457 * each compression, or copying a pre-loaded dictionary's LZ4_stream_t into a 458 * working LZ4_stream_t, this function introduces a no-copy setup mechanism, 459 * in which the working stream references the dictionary stream in-place. 460 * 461 * Several assumptions are made about the state of the dictionary stream. 462 * Currently, only streams which have been prepared by LZ4_loadDict() should 463 * be expected to work. 464 * 465 * Alternatively, the provided dictionary stream pointer may be NULL, in which 466 * case any existing dictionary stream is unset. 467 * 468 * If a dictionary is provided, it replaces any pre-existing stream history. 469 * The dictionary contents are the only history that can be referenced and 470 * logically immediately precede the data compressed in the first subsequent 471 * compression call. 472 * 473 * The dictionary will only remain attached to the working stream through the 474 * first compression call, at the end of which it is cleared. The dictionary 475 * stream (and source buffer) must remain in-place / accessible / unchanged 476 * through the completion of the first compression call on the stream. 477 */ 478 LZ4LIB_API void LZ4_attach_dictionary(LZ4_stream_t *working_stream, const LZ4_stream_t *dictionary_stream); 479 480 #endif 481 482 /*-************************************ 483 * Private definitions 484 ************************************** 485 * Do not use these definitions. 486 * They are exposed to allow static allocation of `LZ4_stream_t` and `LZ4_streamDecode_t`. 487 * Using these definitions will expose code to API and/or ABI break in future versions of the library. 488 **************************************/ 489 #define LZ4_HASHLOG (LZ4_MEMORY_USAGE-2) 490 #define LZ4_HASHTABLESIZE (1 << LZ4_MEMORY_USAGE) 491 #define LZ4_HASH_SIZE_U32 (1 << LZ4_HASHLOG) /* required as macro for static allocation */ 492 493 #if defined(__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) 494 #include <stdint.h> 495 496 typedef struct LZ4_stream_t_internal LZ4_stream_t_internal; 497 struct LZ4_stream_t_internal { 498 uint32_t hashTable[LZ4_HASH_SIZE_U32]; 499 uint32_t currentOffset; 500 uint16_t initCheck; 501 uint16_t tableType; 502 const uint8_t* dictionary; 503 const LZ4_stream_t_internal* dictCtx; 504 uint32_t dictSize; 505 }; 506 507 typedef struct { 508 const uint8_t* externalDict; 509 size_t extDictSize; 510 const uint8_t* prefixEnd; 511 size_t prefixSize; 512 } LZ4_streamDecode_t_internal; 513 514 #else 515 516 typedef struct LZ4_stream_t_internal LZ4_stream_t_internal; 517 struct LZ4_stream_t_internal { 518 unsigned int hashTable[LZ4_HASH_SIZE_U32]; 519 unsigned int currentOffset; 520 unsigned short initCheck; 521 unsigned short tableType; 522 const unsigned char* dictionary; 523 const LZ4_stream_t_internal* dictCtx; 524 unsigned int dictSize; 525 }; 526 527 typedef struct { 528 const unsigned char* externalDict; 529 size_t extDictSize; 530 const unsigned char* prefixEnd; 531 size_t prefixSize; 532 } LZ4_streamDecode_t_internal; 533 534 #endif 535 536 /*! 537 * LZ4_stream_t : 538 * information structure to track an LZ4 stream. 539 * init this structure before first use. 540 * note : only use in association with static linking ! 541 * this definition is not API/ABI safe, 542 * it may change in a future version ! 543 */ 544 #define LZ4_STREAMSIZE_U64 ((1 << (LZ4_MEMORY_USAGE-3)) + 4) 545 #define LZ4_STREAMSIZE (LZ4_STREAMSIZE_U64 * sizeof(unsigned long long)) 546 union LZ4_stream_u { 547 unsigned long long table[LZ4_STREAMSIZE_U64]; 548 LZ4_stream_t_internal internal_donotuse; 549 } ; /* previously typedef'd to LZ4_stream_t */ 550 551 552 /*! 553 * LZ4_streamDecode_t : 554 * information structure to track an LZ4 stream during decompression. 555 * init this structure using LZ4_setStreamDecode (or memset()) before first use 556 * note : only use in association with static linking ! 557 * this definition is not API/ABI safe, 558 * and may change in a future version ! 559 */ 560 #define LZ4_STREAMDECODESIZE_U64 4 561 #define LZ4_STREAMDECODESIZE (LZ4_STREAMDECODESIZE_U64 * sizeof(unsigned long long)) 562 union LZ4_streamDecode_u { 563 unsigned long long table[LZ4_STREAMDECODESIZE_U64]; 564 LZ4_streamDecode_t_internal internal_donotuse; 565 } ; /* previously typedef'd to LZ4_streamDecode_t */ 566 567 568 /*-************************************ 569 * Obsolete Functions 570 **************************************/ 571 572 /*! Deprecation warnings 573 Should deprecation warnings be a problem, 574 it is generally possible to disable them, 575 typically with -Wno-deprecated-declarations for gcc 576 or _CRT_SECURE_NO_WARNINGS in Visual. 577 Otherwise, it's also possible to define LZ4_DISABLE_DEPRECATE_WARNINGS */ 578 #ifdef LZ4_DISABLE_DEPRECATE_WARNINGS 579 # define LZ4_DEPRECATED(message) /* disable deprecation warnings */ 580 #else 581 # define LZ4_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) 582 # if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */ 583 # define LZ4_DEPRECATED(message) [[deprecated(message)]] 584 # elif (LZ4_GCC_VERSION >= 405) || defined(__clang__) 585 # define LZ4_DEPRECATED(message) __attribute__((deprecated(message))) 586 # elif (LZ4_GCC_VERSION >= 301) 587 # define LZ4_DEPRECATED(message) __attribute__((deprecated)) 588 # elif defined(_MSC_VER) 589 # define LZ4_DEPRECATED(message) __declspec(deprecated(message)) 590 # else 591 # pragma message("WARNING: You need to implement LZ4_DEPRECATED for this compiler") 592 # define LZ4_DEPRECATED(message) 593 # endif 594 #endif /* LZ4_DISABLE_DEPRECATE_WARNINGS */ 595 596 /* Obsolete compression functions */ 597 LZ4_DEPRECATED("use LZ4_compress_default() instead") LZ4LIB_API int LZ4_compress (const char* source, char* dest, int sourceSize); 598 LZ4_DEPRECATED("use LZ4_compress_default() instead") LZ4LIB_API int LZ4_compress_limitedOutput (const char* source, char* dest, int sourceSize, int maxOutputSize); 599 LZ4_DEPRECATED("use LZ4_compress_fast_extState() instead") LZ4LIB_API int LZ4_compress_withState (void* state, const char* source, char* dest, int inputSize); 600 LZ4_DEPRECATED("use LZ4_compress_fast_extState() instead") LZ4LIB_API int LZ4_compress_limitedOutput_withState (void* state, const char* source, char* dest, int inputSize, int maxOutputSize); 601 LZ4_DEPRECATED("use LZ4_compress_fast_continue() instead") LZ4LIB_API int LZ4_compress_continue (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize); 602 LZ4_DEPRECATED("use LZ4_compress_fast_continue() instead") LZ4LIB_API int LZ4_compress_limitedOutput_continue (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize, int maxOutputSize); 603 604 /* Obsolete decompression functions */ 605 LZ4_DEPRECATED("use LZ4_decompress_fast() instead") LZ4LIB_API int LZ4_uncompress (const char* source, char* dest, int outputSize); 606 LZ4_DEPRECATED("use LZ4_decompress_safe() instead") LZ4LIB_API int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize); 607 608 /* Obsolete streaming functions; degraded functionality; do not use! 609 * 610 * In order to perform streaming compression, these functions depended on data 611 * that is no longer tracked in the state. They have been preserved as well as 612 * possible: using them will still produce a correct output. However, they don't 613 * actually retain any history between compression calls. The compression ratio 614 * achieved will therefore be no better than compressing each chunk 615 * independently. 616 */ 617 LZ4_DEPRECATED("Use LZ4_createStream() instead") LZ4LIB_API void* LZ4_create (char* inputBuffer); 618 LZ4_DEPRECATED("Use LZ4_createStream() instead") LZ4LIB_API int LZ4_sizeofStreamState(void); 619 LZ4_DEPRECATED("Use LZ4_resetStream() instead") LZ4LIB_API int LZ4_resetStreamState(void* state, char* inputBuffer); 620 LZ4_DEPRECATED("Use LZ4_saveDict() instead") LZ4LIB_API char* LZ4_slideInputBuffer (void* state); 621 622 /* Obsolete streaming decoding functions */ 623 LZ4_DEPRECATED("use LZ4_decompress_safe_usingDict() instead") LZ4LIB_API int LZ4_decompress_safe_withPrefix64k (const char* src, char* dst, int compressedSize, int maxDstSize); 624 LZ4_DEPRECATED("use LZ4_decompress_fast_usingDict() instead") LZ4LIB_API int LZ4_decompress_fast_withPrefix64k (const char* src, char* dst, int originalSize); 625 626 #endif /* LZ4_H_2983827168210 */ 627 628 629 #if defined (__cplusplus) 630 } 631 #endif 632