1 /* 2 LZ4 HC - High Compression Mode of LZ4 3 Header File 4 Copyright (C) 2011-2020, Yann Collet. 5 BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) 6 7 Redistribution and use in source and binary forms, with or without 8 modification, are permitted provided that the following conditions are 9 met: 10 11 * Redistributions of source code must retain the above copyright 12 notice, this list of conditions and the following disclaimer. 13 * Redistributions in binary form must reproduce the above 14 copyright notice, this list of conditions and the following disclaimer 15 in the documentation and/or other materials provided with the 16 distribution. 17 18 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 You can contact the author at : 31 - LZ4 source repository : https://github.com/lz4/lz4 32 - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c 33 */ 34 #ifndef LZ4_HC_H_19834876238432 35 #define LZ4_HC_H_19834876238432 36 37 #if defined (__cplusplus) 38 extern "C" { 39 #endif 40 41 /* --- Dependency --- */ 42 /* note : lz4hc requires lz4.h/lz4.c for compilation */ 43 #include "lz4.h" /* stddef, LZ4LIB_API, LZ4_DEPRECATED */ 44 45 46 /* --- Useful constants --- */ 47 #define LZ4HC_CLEVEL_MIN 2 48 #define LZ4HC_CLEVEL_DEFAULT 9 49 #define LZ4HC_CLEVEL_OPT_MIN 10 50 #define LZ4HC_CLEVEL_MAX 12 51 52 53 /*-************************************ 54 * Block Compression 55 **************************************/ 56 /*! LZ4_compress_HC() : 57 * Compress data from `src` into `dst`, using the powerful but slower "HC" algorithm. 58 * `dst` must be already allocated. 59 * Compression is guaranteed to succeed if `dstCapacity >= LZ4_compressBound(srcSize)` (see "lz4.h") 60 * Max supported `srcSize` value is LZ4_MAX_INPUT_SIZE (see "lz4.h") 61 * `compressionLevel` : any value between 1 and LZ4HC_CLEVEL_MAX will work. 62 * Values > LZ4HC_CLEVEL_MAX behave the same as LZ4HC_CLEVEL_MAX. 63 * @return : the number of bytes written into 'dst' 64 * or 0 if compression fails. 65 */ 66 LZ4LIB_API int LZ4_compress_HC (const char* src, char* dst, int srcSize, int dstCapacity, int compressionLevel); 67 68 69 /* Note : 70 * Decompression functions are provided within "lz4.h" (BSD license) 71 */ 72 73 74 /*! LZ4_compress_HC_extStateHC() : 75 * Same as LZ4_compress_HC(), but using an externally allocated memory segment for `state`. 76 * `state` size is provided by LZ4_sizeofStateHC(). 77 * Memory segment must be aligned on 8-bytes boundaries (which a normal malloc() should do properly). 78 */ 79 LZ4LIB_API int LZ4_sizeofStateHC(void); 80 LZ4LIB_API int LZ4_compress_HC_extStateHC(void* stateHC, const char* src, char* dst, int srcSize, int maxDstSize, int compressionLevel); 81 82 83 /*! LZ4_compress_HC_destSize() : v1.9.0+ 84 * Will compress as much data as possible from `src` 85 * to fit into `targetDstSize` budget. 86 * Result is provided in 2 parts : 87 * @return : the number of bytes written into 'dst' (necessarily <= targetDstSize) 88 * or 0 if compression fails. 89 * `srcSizePtr` : on success, *srcSizePtr is updated to indicate how much bytes were read from `src` 90 */ 91 LZ4LIB_API int LZ4_compress_HC_destSize(void* stateHC, 92 const char* src, char* dst, 93 int* srcSizePtr, int targetDstSize, 94 int compressionLevel); 95 96 97 /*-************************************ 98 * Streaming Compression 99 * Bufferless synchronous API 100 **************************************/ 101 typedef union LZ4_streamHC_u LZ4_streamHC_t; /* incomplete type (defined later) */ 102 103 /*! LZ4_createStreamHC() and LZ4_freeStreamHC() : 104 * These functions create and release memory for LZ4 HC streaming state. 105 * Newly created states are automatically initialized. 106 * A same state can be used multiple times consecutively, 107 * starting with LZ4_resetStreamHC_fast() to start a new stream of blocks. 108 */ 109 LZ4LIB_API LZ4_streamHC_t* LZ4_createStreamHC(void); 110 LZ4LIB_API int LZ4_freeStreamHC (LZ4_streamHC_t* streamHCPtr); 111 112 /* 113 These functions compress data in successive blocks of any size, 114 using previous blocks as dictionary, to improve compression ratio. 115 One key assumption is that previous blocks (up to 64 KB) remain read-accessible while compressing next blocks. 116 There is an exception for ring buffers, which can be smaller than 64 KB. 117 Ring-buffer scenario is automatically detected and handled within LZ4_compress_HC_continue(). 118 119 Before starting compression, state must be allocated and properly initialized. 120 LZ4_createStreamHC() does both, though compression level is set to LZ4HC_CLEVEL_DEFAULT. 121 122 Selecting the compression level can be done with LZ4_resetStreamHC_fast() (starts a new stream) 123 or LZ4_setCompressionLevel() (anytime, between blocks in the same stream) (experimental). 124 LZ4_resetStreamHC_fast() only works on states which have been properly initialized at least once, 125 which is automatically the case when state is created using LZ4_createStreamHC(). 126 127 After reset, a first "fictional block" can be designated as initial dictionary, 128 using LZ4_loadDictHC() (Optional). 129 Note: In order for LZ4_loadDictHC() to create the correct data structure, 130 it is essential to set the compression level _before_ loading the dictionary. 131 132 Invoke LZ4_compress_HC_continue() to compress each successive block. 133 The number of blocks is unlimited. 134 Previous input blocks, including initial dictionary when present, 135 must remain accessible and unmodified during compression. 136 137 It's allowed to update compression level anytime between blocks, 138 using LZ4_setCompressionLevel() (experimental). 139 140 @dst buffer should be sized to handle worst case scenarios 141 (see LZ4_compressBound(), it ensures compression success). 142 In case of failure, the API does not guarantee recovery, 143 so the state _must_ be reset. 144 To ensure compression success 145 whenever @dst buffer size cannot be made >= LZ4_compressBound(), 146 consider using LZ4_compress_HC_continue_destSize(). 147 148 Whenever previous input blocks can't be preserved unmodified in-place during compression of next blocks, 149 it's possible to copy the last blocks into a more stable memory space, using LZ4_saveDictHC(). 150 Return value of LZ4_saveDictHC() is the size of dictionary effectively saved into 'safeBuffer' (<= 64 KB) 151 152 After completing a streaming compression, 153 it's possible to start a new stream of blocks, using the same LZ4_streamHC_t state, 154 just by resetting it, using LZ4_resetStreamHC_fast(). 155 */ 156 157 LZ4LIB_API void LZ4_resetStreamHC_fast(LZ4_streamHC_t* streamHCPtr, int compressionLevel); /* v1.9.0+ */ 158 LZ4LIB_API int LZ4_loadDictHC (LZ4_streamHC_t* streamHCPtr, const char* dictionary, int dictSize); 159 160 LZ4LIB_API int LZ4_compress_HC_continue (LZ4_streamHC_t* streamHCPtr, 161 const char* src, char* dst, 162 int srcSize, int maxDstSize); 163 164 /*! LZ4_compress_HC_continue_destSize() : v1.9.0+ 165 * Similar to LZ4_compress_HC_continue(), 166 * but will read as much data as possible from `src` 167 * to fit into `targetDstSize` budget. 168 * Result is provided into 2 parts : 169 * @return : the number of bytes written into 'dst' (necessarily <= targetDstSize) 170 * or 0 if compression fails. 171 * `srcSizePtr` : on success, *srcSizePtr will be updated to indicate how much bytes were read from `src`. 172 * Note that this function may not consume the entire input. 173 */ 174 LZ4LIB_API int LZ4_compress_HC_continue_destSize(LZ4_streamHC_t* LZ4_streamHCPtr, 175 const char* src, char* dst, 176 int* srcSizePtr, int targetDstSize); 177 178 LZ4LIB_API int LZ4_saveDictHC (LZ4_streamHC_t* streamHCPtr, char* safeBuffer, int maxDictSize); 179 180 181 /*! LZ4_attach_HC_dictionary() : stable since v1.10.0 182 * This API allows for the efficient re-use of a static dictionary many times. 183 * 184 * Rather than re-loading the dictionary buffer into a working context before 185 * each compression, or copying a pre-loaded dictionary's LZ4_streamHC_t into a 186 * working LZ4_streamHC_t, this function introduces a no-copy setup mechanism, 187 * in which the working stream references the dictionary stream in-place. 188 * 189 * Several assumptions are made about the state of the dictionary stream. 190 * Currently, only streams which have been prepared by LZ4_loadDictHC() should 191 * be expected to work. 192 * 193 * Alternatively, the provided dictionary stream pointer may be NULL, in which 194 * case any existing dictionary stream is unset. 195 * 196 * A dictionary should only be attached to a stream without any history (i.e., 197 * a stream that has just been reset). 198 * 199 * The dictionary will remain attached to the working stream only for the 200 * current stream session. Calls to LZ4_resetStreamHC(_fast) will remove the 201 * dictionary context association from the working stream. The dictionary 202 * stream (and source buffer) must remain in-place / accessible / unchanged 203 * through the lifetime of the stream session. 204 */ 205 LZ4LIB_API void 206 LZ4_attach_HC_dictionary(LZ4_streamHC_t* working_stream, 207 const LZ4_streamHC_t* dictionary_stream); 208 209 210 /*^********************************************** 211 * !!!!!! STATIC LINKING ONLY !!!!!! 212 ***********************************************/ 213 214 /*-****************************************************************** 215 * PRIVATE DEFINITIONS : 216 * Do not use these definitions directly. 217 * They are merely exposed to allow static allocation of `LZ4_streamHC_t`. 218 * Declare an `LZ4_streamHC_t` directly, rather than any type below. 219 * Even then, only do so in the context of static linking, as definitions may change between versions. 220 ********************************************************************/ 221 222 #define LZ4HC_DICTIONARY_LOGSIZE 16 223 #define LZ4HC_MAXD (1<<LZ4HC_DICTIONARY_LOGSIZE) 224 #define LZ4HC_MAXD_MASK (LZ4HC_MAXD - 1) 225 226 #define LZ4HC_HASH_LOG 15 227 #define LZ4HC_HASHTABLESIZE (1 << LZ4HC_HASH_LOG) 228 #define LZ4HC_HASH_MASK (LZ4HC_HASHTABLESIZE - 1) 229 230 231 /* Never ever use these definitions directly ! 232 * Declare or allocate an LZ4_streamHC_t instead. 233 **/ 234 typedef struct LZ4HC_CCtx_internal LZ4HC_CCtx_internal; 235 struct LZ4HC_CCtx_internal 236 { 237 LZ4_u32 hashTable[LZ4HC_HASHTABLESIZE]; 238 LZ4_u16 chainTable[LZ4HC_MAXD]; 239 const LZ4_byte* end; /* next block here to continue on current prefix */ 240 const LZ4_byte* prefixStart; /* Indexes relative to this position */ 241 const LZ4_byte* dictStart; /* alternate reference for extDict */ 242 LZ4_u32 dictLimit; /* below that point, need extDict */ 243 LZ4_u32 lowLimit; /* below that point, no more history */ 244 LZ4_u32 nextToUpdate; /* index from which to continue dictionary update */ 245 short compressionLevel; 246 LZ4_i8 favorDecSpeed; /* favor decompression speed if this flag set, 247 otherwise, favor compression ratio */ 248 LZ4_i8 dirty; /* stream has to be fully reset if this flag is set */ 249 const LZ4HC_CCtx_internal* dictCtx; 250 }; 251 252 #define LZ4_STREAMHC_MINSIZE 262200 /* static size, for inter-version compatibility */ 253 union LZ4_streamHC_u { 254 char minStateSize[LZ4_STREAMHC_MINSIZE]; 255 LZ4HC_CCtx_internal internal_donotuse; 256 }; /* previously typedef'd to LZ4_streamHC_t */ 257 258 /* LZ4_streamHC_t : 259 * This structure allows static allocation of LZ4 HC streaming state. 260 * This can be used to allocate statically on stack, or as part of a larger structure. 261 * 262 * Such state **must** be initialized using LZ4_initStreamHC() before first use. 263 * 264 * Note that invoking LZ4_initStreamHC() is not required when 265 * the state was created using LZ4_createStreamHC() (which is recommended). 266 * Using the normal builder, a newly created state is automatically initialized. 267 * 268 * Static allocation shall only be used in combination with static linking. 269 */ 270 271 /* LZ4_initStreamHC() : v1.9.0+ 272 * Required before first use of a statically allocated LZ4_streamHC_t. 273 * Before v1.9.0 : use LZ4_resetStreamHC() instead 274 */ 275 LZ4LIB_API LZ4_streamHC_t* LZ4_initStreamHC(void* buffer, size_t size); 276 277 278 /*-************************************ 279 * Deprecated Functions 280 **************************************/ 281 /* see lz4.h LZ4_DISABLE_DEPRECATE_WARNINGS to turn off deprecation warnings */ 282 283 /* deprecated compression functions */ 284 LZ4_DEPRECATED("use LZ4_compress_HC() instead") LZ4LIB_API int LZ4_compressHC (const char* source, char* dest, int inputSize); 285 LZ4_DEPRECATED("use LZ4_compress_HC() instead") LZ4LIB_API int LZ4_compressHC_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize); 286 LZ4_DEPRECATED("use LZ4_compress_HC() instead") LZ4LIB_API int LZ4_compressHC2 (const char* source, char* dest, int inputSize, int compressionLevel); 287 LZ4_DEPRECATED("use LZ4_compress_HC() instead") LZ4LIB_API int LZ4_compressHC2_limitedOutput(const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel); 288 LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_compressHC_withStateHC (void* state, const char* source, char* dest, int inputSize); 289 LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_compressHC_limitedOutput_withStateHC (void* state, const char* source, char* dest, int inputSize, int maxOutputSize); 290 LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_compressHC2_withStateHC (void* state, const char* source, char* dest, int inputSize, int compressionLevel); 291 LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_compressHC2_limitedOutput_withStateHC(void* state, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel); 292 LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize); 293 LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC_limitedOutput_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize, int maxOutputSize); 294 295 /* Obsolete streaming functions; degraded functionality; do not use! 296 * 297 * In order to perform streaming compression, these functions depended on data 298 * that is no longer tracked in the state. They have been preserved as well as 299 * possible: using them will still produce a correct output. However, use of 300 * LZ4_slideInputBufferHC() will truncate the history of the stream, rather 301 * than preserve a window-sized chunk of history. 302 */ 303 #if !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION) 304 LZ4_DEPRECATED("use LZ4_createStreamHC() instead") LZ4LIB_API void* LZ4_createHC (const char* inputBuffer); 305 LZ4_DEPRECATED("use LZ4_freeStreamHC() instead") LZ4LIB_API int LZ4_freeHC (void* LZ4HC_Data); 306 #endif 307 LZ4_DEPRECATED("use LZ4_saveDictHC() instead") LZ4LIB_API char* LZ4_slideInputBufferHC (void* LZ4HC_Data); 308 LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC2_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int compressionLevel); 309 LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC2_limitedOutput_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel); 310 LZ4_DEPRECATED("use LZ4_createStreamHC() instead") LZ4LIB_API int LZ4_sizeofStreamStateHC(void); 311 LZ4_DEPRECATED("use LZ4_initStreamHC() instead") LZ4LIB_API int LZ4_resetStreamStateHC(void* state, char* inputBuffer); 312 313 314 /* LZ4_resetStreamHC() is now replaced by LZ4_initStreamHC(). 315 * The intention is to emphasize the difference with LZ4_resetStreamHC_fast(), 316 * which is now the recommended function to start a new stream of blocks, 317 * but cannot be used to initialize a memory segment containing arbitrary garbage data. 318 * 319 * It is recommended to switch to LZ4_initStreamHC(). 320 * LZ4_resetStreamHC() will generate deprecation warnings in a future version. 321 */ 322 LZ4LIB_API void LZ4_resetStreamHC (LZ4_streamHC_t* streamHCPtr, int compressionLevel); 323 324 325 #if defined (__cplusplus) 326 } 327 #endif 328 329 #endif /* LZ4_HC_H_19834876238432 */ 330 331 332 /*-************************************************** 333 * !!!!! STATIC LINKING ONLY !!!!! 334 * Following definitions are considered experimental. 335 * They should not be linked from DLL, 336 * as there is no guarantee of API stability yet. 337 * Prototypes will be promoted to "stable" status 338 * after successful usage in real-life scenarios. 339 ***************************************************/ 340 #ifdef LZ4_HC_STATIC_LINKING_ONLY /* protection macro */ 341 #ifndef LZ4_HC_SLO_098092834 342 #define LZ4_HC_SLO_098092834 343 344 #define LZ4_STATIC_LINKING_ONLY /* LZ4LIB_STATIC_API */ 345 #include "lz4.h" 346 347 #if defined (__cplusplus) 348 extern "C" { 349 #endif 350 351 /*! LZ4_setCompressionLevel() : v1.8.0+ (experimental) 352 * It's possible to change compression level 353 * between successive invocations of LZ4_compress_HC_continue*() 354 * for dynamic adaptation. 355 */ 356 LZ4LIB_STATIC_API void LZ4_setCompressionLevel( 357 LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel); 358 359 /*! LZ4_favorDecompressionSpeed() : v1.8.2+ (experimental) 360 * Opt. Parser will favor decompression speed over compression ratio. 361 * Only applicable to levels >= LZ4HC_CLEVEL_OPT_MIN. 362 */ 363 LZ4LIB_STATIC_API void LZ4_favorDecompressionSpeed( 364 LZ4_streamHC_t* LZ4_streamHCPtr, int favor); 365 366 /*! LZ4_resetStreamHC_fast() : v1.9.0+ 367 * When an LZ4_streamHC_t is known to be in a internally coherent state, 368 * it can often be prepared for a new compression with almost no work, only 369 * sometimes falling back to the full, expensive reset that is always required 370 * when the stream is in an indeterminate state (i.e., the reset performed by 371 * LZ4_resetStreamHC()). 372 * 373 * LZ4_streamHCs are guaranteed to be in a valid state when: 374 * - returned from LZ4_createStreamHC() 375 * - reset by LZ4_resetStreamHC() 376 * - memset(stream, 0, sizeof(LZ4_streamHC_t)) 377 * - the stream was in a valid state and was reset by LZ4_resetStreamHC_fast() 378 * - the stream was in a valid state and was then used in any compression call 379 * that returned success 380 * - the stream was in an indeterminate state and was used in a compression 381 * call that fully reset the state (LZ4_compress_HC_extStateHC()) and that 382 * returned success 383 * 384 * Note: 385 * A stream that was last used in a compression call that returned an error 386 * may be passed to this function. However, it will be fully reset, which will 387 * clear any existing history and settings from the context. 388 */ 389 LZ4LIB_STATIC_API void LZ4_resetStreamHC_fast( 390 LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel); 391 392 /*! LZ4_compress_HC_extStateHC_fastReset() : 393 * A variant of LZ4_compress_HC_extStateHC(). 394 * 395 * Using this variant avoids an expensive initialization step. It is only safe 396 * to call if the state buffer is known to be correctly initialized already 397 * (see above comment on LZ4_resetStreamHC_fast() for a definition of 398 * "correctly initialized"). From a high level, the difference is that this 399 * function initializes the provided state with a call to 400 * LZ4_resetStreamHC_fast() while LZ4_compress_HC_extStateHC() starts with a 401 * call to LZ4_resetStreamHC(). 402 */ 403 LZ4LIB_STATIC_API int LZ4_compress_HC_extStateHC_fastReset ( 404 void* state, 405 const char* src, char* dst, 406 int srcSize, int dstCapacity, 407 int compressionLevel); 408 409 #if defined (__cplusplus) 410 } 411 #endif 412 413 #endif /* LZ4_HC_SLO_098092834 */ 414 #endif /* LZ4_HC_STATIC_LINKING_ONLY */ 415