1 /* 2 LZ4F - LZ4-Frame library 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 35 /* LZ4F is a stand-alone API able to create and decode LZ4 frames 36 * conformant with specification v1.6.1 in doc/lz4_Frame_format.md . 37 * Generated frames are compatible with `lz4` CLI. 38 * 39 * LZ4F also offers streaming capabilities. 40 * 41 * lz4.h is not required when using lz4frame.h, 42 * except to extract common constants such as LZ4_VERSION_NUMBER. 43 * */ 44 45 #ifndef LZ4F_H_09782039843 46 #define LZ4F_H_09782039843 47 48 #if defined (__cplusplus) 49 extern "C" { 50 #endif 51 52 /* --- Dependency --- */ 53 #include <stddef.h> /* size_t */ 54 55 56 /** 57 * Introduction 58 * 59 * lz4frame.h implements LZ4 frame specification: see doc/lz4_Frame_format.md . 60 * LZ4 Frames are compatible with `lz4` CLI, 61 * and designed to be interoperable with any system. 62 **/ 63 64 /*-*************************************************************** 65 * Compiler specifics 66 *****************************************************************/ 67 /* LZ4_DLL_EXPORT : 68 * Enable exporting of functions when building a Windows DLL 69 * LZ4FLIB_VISIBILITY : 70 * Control library symbols visibility. 71 */ 72 #ifndef LZ4FLIB_VISIBILITY 73 # if defined(__GNUC__) && (__GNUC__ >= 4) 74 # define LZ4FLIB_VISIBILITY __attribute__ ((visibility ("default"))) 75 # else 76 # define LZ4FLIB_VISIBILITY 77 # endif 78 #endif 79 #if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1) 80 # define LZ4FLIB_API __declspec(dllexport) LZ4FLIB_VISIBILITY 81 #elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1) 82 # define LZ4FLIB_API __declspec(dllimport) LZ4FLIB_VISIBILITY 83 #else 84 # define LZ4FLIB_API LZ4FLIB_VISIBILITY 85 #endif 86 87 #ifdef LZ4F_DISABLE_DEPRECATE_WARNINGS 88 # define LZ4F_DEPRECATE(x) x 89 #else 90 # if defined(_MSC_VER) 91 # define LZ4F_DEPRECATE(x) x /* __declspec(deprecated) x - only works with C++ */ 92 # elif defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 6)) 93 # define LZ4F_DEPRECATE(x) x __attribute__((deprecated)) 94 # else 95 # define LZ4F_DEPRECATE(x) x /* no deprecation warning for this compiler */ 96 # endif 97 #endif 98 99 100 /*-************************************ 101 * Error management 102 **************************************/ 103 typedef size_t LZ4F_errorCode_t; 104 105 LZ4FLIB_API unsigned LZ4F_isError(LZ4F_errorCode_t code); /**< tells when a function result is an error code */ 106 LZ4FLIB_API const char* LZ4F_getErrorName(LZ4F_errorCode_t code); /**< return error code string; for debugging */ 107 108 109 /*-************************************ 110 * Frame compression types 111 ************************************* */ 112 /* #define LZ4F_ENABLE_OBSOLETE_ENUMS // uncomment to enable obsolete enums */ 113 #ifdef LZ4F_ENABLE_OBSOLETE_ENUMS 114 # define LZ4F_OBSOLETE_ENUM(x) , LZ4F_DEPRECATE(x) = LZ4F_##x 115 #else 116 # define LZ4F_OBSOLETE_ENUM(x) 117 #endif 118 119 /* The larger the block size, the (slightly) better the compression ratio, 120 * though there are diminishing returns. 121 * Larger blocks also increase memory usage on both compression and decompression sides. 122 */ 123 typedef enum { 124 LZ4F_default=0, 125 LZ4F_max64KB=4, 126 LZ4F_max256KB=5, 127 LZ4F_max1MB=6, 128 LZ4F_max4MB=7 129 LZ4F_OBSOLETE_ENUM(max64KB) 130 LZ4F_OBSOLETE_ENUM(max256KB) 131 LZ4F_OBSOLETE_ENUM(max1MB) 132 LZ4F_OBSOLETE_ENUM(max4MB) 133 } LZ4F_blockSizeID_t; 134 135 /* Linked blocks sharply reduce inefficiencies when using small blocks, 136 * they compress better. 137 * However, some LZ4 decoders are only compatible with independent blocks */ 138 typedef enum { 139 LZ4F_blockLinked=0, 140 LZ4F_blockIndependent 141 LZ4F_OBSOLETE_ENUM(blockLinked) 142 LZ4F_OBSOLETE_ENUM(blockIndependent) 143 } LZ4F_blockMode_t; 144 145 typedef enum { 146 LZ4F_noContentChecksum=0, 147 LZ4F_contentChecksumEnabled 148 LZ4F_OBSOLETE_ENUM(noContentChecksum) 149 LZ4F_OBSOLETE_ENUM(contentChecksumEnabled) 150 } LZ4F_contentChecksum_t; 151 152 typedef enum { 153 LZ4F_noBlockChecksum=0, 154 LZ4F_blockChecksumEnabled 155 } LZ4F_blockChecksum_t; 156 157 typedef enum { 158 LZ4F_frame=0, 159 LZ4F_skippableFrame 160 LZ4F_OBSOLETE_ENUM(skippableFrame) 161 } LZ4F_frameType_t; 162 163 #ifdef LZ4F_ENABLE_OBSOLETE_ENUMS 164 typedef LZ4F_blockSizeID_t blockSizeID_t; 165 typedef LZ4F_blockMode_t blockMode_t; 166 typedef LZ4F_frameType_t frameType_t; 167 typedef LZ4F_contentChecksum_t contentChecksum_t; 168 #endif 169 170 /*! LZ4F_frameInfo_t : 171 * makes it possible to set or read frame parameters. 172 * Structure must be first init to 0, using memset() or LZ4F_INIT_FRAMEINFO, 173 * setting all parameters to default. 174 * It's then possible to update selectively some parameters */ 175 typedef struct { 176 LZ4F_blockSizeID_t blockSizeID; /* max64KB, max256KB, max1MB, max4MB; 0 == default (LZ4F_max64KB) */ 177 LZ4F_blockMode_t blockMode; /* LZ4F_blockLinked, LZ4F_blockIndependent; 0 == default (LZ4F_blockLinked) */ 178 LZ4F_contentChecksum_t contentChecksumFlag; /* 1: add a 32-bit checksum of frame's decompressed data; 0 == default (disabled) */ 179 LZ4F_frameType_t frameType; /* read-only field : LZ4F_frame or LZ4F_skippableFrame */ 180 unsigned long long contentSize; /* Size of uncompressed content ; 0 == unknown */ 181 unsigned dictID; /* Dictionary ID, sent by compressor to help decoder select correct dictionary; 0 == no dictID provided */ 182 LZ4F_blockChecksum_t blockChecksumFlag; /* 1: each block followed by a checksum of block's compressed data; 0 == default (disabled) */ 183 } LZ4F_frameInfo_t; 184 185 #define LZ4F_INIT_FRAMEINFO { LZ4F_max64KB, LZ4F_blockLinked, LZ4F_noContentChecksum, LZ4F_frame, 0ULL, 0U, LZ4F_noBlockChecksum } /* v1.8.3+ */ 186 187 /*! LZ4F_preferences_t : 188 * makes it possible to supply advanced compression instructions to streaming interface. 189 * Structure must be first init to 0, using memset() or LZ4F_INIT_PREFERENCES, 190 * setting all parameters to default. 191 * All reserved fields must be set to zero. */ 192 typedef struct { 193 LZ4F_frameInfo_t frameInfo; 194 int compressionLevel; /* 0: default (fast mode); values > LZ4HC_CLEVEL_MAX count as LZ4HC_CLEVEL_MAX; values < 0 trigger "fast acceleration" */ 195 unsigned autoFlush; /* 1: always flush; reduces usage of internal buffers */ 196 unsigned favorDecSpeed; /* 1: parser favors decompression speed vs compression ratio. Only works for high compression modes (>= LZ4HC_CLEVEL_OPT_MIN) */ /* v1.8.2+ */ 197 unsigned reserved[3]; /* must be zero for forward compatibility */ 198 } LZ4F_preferences_t; 199 200 #define LZ4F_INIT_PREFERENCES { LZ4F_INIT_FRAMEINFO, 0, 0u, 0u, { 0u, 0u, 0u } } /* v1.8.3+ */ 201 202 203 /*-********************************* 204 * Simple compression function 205 ***********************************/ 206 207 /*! LZ4F_compressFrame() : 208 * Compress srcBuffer content into an LZ4-compressed frame. 209 * It's a one shot operation, all input content is consumed, and all output is generated. 210 * 211 * Note : it's a stateless operation (no LZ4F_cctx state needed). 212 * In order to reduce load on the allocator, LZ4F_compressFrame(), by default, 213 * uses the stack to allocate space for the compression state and some table. 214 * If this usage of the stack is too much for your application, 215 * consider compiling `lz4frame.c` with compile-time macro LZ4F_HEAPMODE set to 1 instead. 216 * All state allocations will use the Heap. 217 * It also means each invocation of LZ4F_compressFrame() will trigger several internal alloc/free invocations. 218 * 219 * @dstCapacity MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr). 220 * @preferencesPtr is optional : one can provide NULL, in which case all preferences are set to default. 221 * @return : number of bytes written into dstBuffer. 222 * or an error code if it fails (can be tested using LZ4F_isError()) 223 */ 224 LZ4FLIB_API size_t LZ4F_compressFrame(void* dstBuffer, size_t dstCapacity, 225 const void* srcBuffer, size_t srcSize, 226 const LZ4F_preferences_t* preferencesPtr); 227 228 /*! LZ4F_compressFrameBound() : 229 * Returns the maximum possible compressed size with LZ4F_compressFrame() given srcSize and preferences. 230 * `preferencesPtr` is optional. It can be replaced by NULL, in which case, the function will assume default preferences. 231 * Note : this result is only usable with LZ4F_compressFrame(). 232 * It may also be relevant to LZ4F_compressUpdate() _only if_ no flush() operation is ever performed. 233 */ 234 LZ4FLIB_API size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr); 235 236 237 /*! LZ4F_compressionLevel_max() : 238 * @return maximum allowed compression level (currently: 12) 239 */ 240 LZ4FLIB_API int LZ4F_compressionLevel_max(void); /* v1.8.0+ */ 241 242 243 /*-*********************************** 244 * Advanced compression functions 245 *************************************/ 246 typedef struct LZ4F_cctx_s LZ4F_cctx; /* incomplete type */ 247 typedef LZ4F_cctx* LZ4F_compressionContext_t; /* for compatibility with older APIs, prefer using LZ4F_cctx */ 248 249 typedef struct { 250 unsigned stableSrc; /* 1 == src content will remain present on future calls to LZ4F_compress(); skip copying src content within tmp buffer */ 251 unsigned reserved[3]; 252 } LZ4F_compressOptions_t; 253 254 /*--- Resource Management ---*/ 255 256 #define LZ4F_VERSION 100 /* This number can be used to check for an incompatible API breaking change */ 257 LZ4FLIB_API unsigned LZ4F_getVersion(void); 258 259 /*! LZ4F_createCompressionContext() : 260 * The first thing to do is to create a compressionContext object, 261 * which will keep track of operation state during streaming compression. 262 * This is achieved using LZ4F_createCompressionContext(), which takes as argument a version, 263 * and a pointer to LZ4F_cctx*, to write the resulting pointer into. 264 * @version provided MUST be LZ4F_VERSION. It is intended to track potential version mismatch, notably when using DLL. 265 * The function provides a pointer to a fully allocated LZ4F_cctx object. 266 * @cctxPtr MUST be != NULL. 267 * If @return != zero, context creation failed. 268 * A created compression context can be employed multiple times for consecutive streaming operations. 269 * Once all streaming compression jobs are completed, 270 * the state object can be released using LZ4F_freeCompressionContext(). 271 * Note1 : LZ4F_freeCompressionContext() is always successful. Its return value can be ignored. 272 * Note2 : LZ4F_freeCompressionContext() works fine with NULL input pointers (do nothing). 273 **/ 274 LZ4FLIB_API LZ4F_errorCode_t LZ4F_createCompressionContext(LZ4F_cctx** cctxPtr, unsigned version); 275 LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_cctx* cctx); 276 277 278 /*---- Compression ----*/ 279 280 #define LZ4F_HEADER_SIZE_MIN 7 /* LZ4 Frame header size can vary, depending on selected parameters */ 281 #define LZ4F_HEADER_SIZE_MAX 19 282 283 /* Size in bytes of a block header in little-endian format. Highest bit indicates if block data is uncompressed */ 284 #define LZ4F_BLOCK_HEADER_SIZE 4 285 286 /* Size in bytes of a block checksum footer in little-endian format. */ 287 #define LZ4F_BLOCK_CHECKSUM_SIZE 4 288 289 /* Size in bytes of the content checksum. */ 290 #define LZ4F_CONTENT_CHECKSUM_SIZE 4 291 292 /*! LZ4F_compressBegin() : 293 * will write the frame header into dstBuffer. 294 * dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes. 295 * `prefsPtr` is optional : NULL can be provided to set all preferences to default. 296 * @return : number of bytes written into dstBuffer for the header 297 * or an error code (which can be tested using LZ4F_isError()) 298 */ 299 LZ4FLIB_API size_t LZ4F_compressBegin(LZ4F_cctx* cctx, 300 void* dstBuffer, size_t dstCapacity, 301 const LZ4F_preferences_t* prefsPtr); 302 303 /*! LZ4F_compressBound() : 304 * Provides minimum dstCapacity required to guarantee success of 305 * LZ4F_compressUpdate(), given a srcSize and preferences, for a worst case scenario. 306 * When srcSize==0, LZ4F_compressBound() provides an upper bound for LZ4F_flush() and LZ4F_compressEnd() instead. 307 * Note that the result is only valid for a single invocation of LZ4F_compressUpdate(). 308 * When invoking LZ4F_compressUpdate() multiple times, 309 * if the output buffer is gradually filled up instead of emptied and re-used from its start, 310 * one must check if there is enough remaining capacity before each invocation, using LZ4F_compressBound(). 311 * @return is always the same for a srcSize and prefsPtr. 312 * prefsPtr is optional : when NULL is provided, preferences will be set to cover worst case scenario. 313 * tech details : 314 * @return if automatic flushing is not enabled, includes the possibility that internal buffer might already be filled by up to (blockSize-1) bytes. 315 * It also includes frame footer (ending + checksum), since it might be generated by LZ4F_compressEnd(). 316 * @return doesn't include frame header, as it was already generated by LZ4F_compressBegin(). 317 */ 318 LZ4FLIB_API size_t LZ4F_compressBound(size_t srcSize, const LZ4F_preferences_t* prefsPtr); 319 320 /*! LZ4F_compressUpdate() : 321 * LZ4F_compressUpdate() can be called repetitively to compress as much data as necessary. 322 * Important rule: dstCapacity MUST be large enough to ensure operation success even in worst case situations. 323 * This value is provided by LZ4F_compressBound(). 324 * If this condition is not respected, LZ4F_compress() will fail (result is an errorCode). 325 * After an error, the state is left in a UB state, and must be re-initialized or freed. 326 * If previously an uncompressed block was written, buffered data is flushed 327 * before appending compressed data is continued. 328 * `cOptPtr` is optional : NULL can be provided, in which case all options are set to default. 329 * @return : number of bytes written into `dstBuffer` (it can be zero, meaning input data was just buffered). 330 * or an error code if it fails (which can be tested using LZ4F_isError()) 331 */ 332 LZ4FLIB_API size_t LZ4F_compressUpdate(LZ4F_cctx* cctx, 333 void* dstBuffer, size_t dstCapacity, 334 const void* srcBuffer, size_t srcSize, 335 const LZ4F_compressOptions_t* cOptPtr); 336 337 /*! LZ4F_flush() : 338 * When data must be generated and sent immediately, without waiting for a block to be completely filled, 339 * it's possible to call LZ4_flush(). It will immediately compress any data buffered within cctx. 340 * `dstCapacity` must be large enough to ensure the operation will be successful. 341 * `cOptPtr` is optional : it's possible to provide NULL, all options will be set to default. 342 * @return : nb of bytes written into dstBuffer (can be zero, when there is no data stored within cctx) 343 * or an error code if it fails (which can be tested using LZ4F_isError()) 344 * Note : LZ4F_flush() is guaranteed to be successful when dstCapacity >= LZ4F_compressBound(0, prefsPtr). 345 */ 346 LZ4FLIB_API size_t LZ4F_flush(LZ4F_cctx* cctx, 347 void* dstBuffer, size_t dstCapacity, 348 const LZ4F_compressOptions_t* cOptPtr); 349 350 /*! LZ4F_compressEnd() : 351 * To properly finish an LZ4 frame, invoke LZ4F_compressEnd(). 352 * It will flush whatever data remained within `cctx` (like LZ4_flush()) 353 * and properly finalize the frame, with an endMark and a checksum. 354 * `cOptPtr` is optional : NULL can be provided, in which case all options will be set to default. 355 * @return : nb of bytes written into dstBuffer, necessarily >= 4 (endMark), 356 * or an error code if it fails (which can be tested using LZ4F_isError()) 357 * Note : LZ4F_compressEnd() is guaranteed to be successful when dstCapacity >= LZ4F_compressBound(0, prefsPtr). 358 * A successful call to LZ4F_compressEnd() makes `cctx` available again for another compression task. 359 */ 360 LZ4FLIB_API size_t LZ4F_compressEnd(LZ4F_cctx* cctx, 361 void* dstBuffer, size_t dstCapacity, 362 const LZ4F_compressOptions_t* cOptPtr); 363 364 365 /*-********************************* 366 * Decompression functions 367 ***********************************/ 368 typedef struct LZ4F_dctx_s LZ4F_dctx; /* incomplete type */ 369 typedef LZ4F_dctx* LZ4F_decompressionContext_t; /* compatibility with previous API versions */ 370 371 typedef struct { 372 unsigned stableDst; /* pledges that last 64KB decompressed data is present right before @dstBuffer pointer. 373 * This optimization skips internal storage operations. 374 * Once set, this pledge must remain valid up to the end of current frame. */ 375 unsigned skipChecksums; /* disable checksum calculation and verification, even when one is present in frame, to save CPU time. 376 * Setting this option to 1 once disables all checksums for the rest of the frame. */ 377 unsigned reserved1; /* must be set to zero for forward compatibility */ 378 unsigned reserved0; /* idem */ 379 } LZ4F_decompressOptions_t; 380 381 382 /* Resource management */ 383 384 /*! LZ4F_createDecompressionContext() : 385 * Create an LZ4F_dctx object, to track all decompression operations. 386 * @version provided MUST be LZ4F_VERSION. 387 * @dctxPtr MUST be valid. 388 * The function fills @dctxPtr with the value of a pointer to an allocated and initialized LZ4F_dctx object. 389 * The @return is an errorCode, which can be tested using LZ4F_isError(). 390 * dctx memory can be released using LZ4F_freeDecompressionContext(); 391 * Result of LZ4F_freeDecompressionContext() indicates current state of decompressionContext when being released. 392 * That is, it should be == 0 if decompression has been completed fully and correctly. 393 */ 394 LZ4FLIB_API LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_dctx** dctxPtr, unsigned version); 395 LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* dctx); 396 397 398 /*-*********************************** 399 * Streaming decompression functions 400 *************************************/ 401 402 #define LZ4F_MAGICNUMBER 0x184D2204U 403 #define LZ4F_MAGIC_SKIPPABLE_START 0x184D2A50U 404 #define LZ4F_MIN_SIZE_TO_KNOW_HEADER_LENGTH 5 405 406 /*! LZ4F_headerSize() : v1.9.0+ 407 * Provide the header size of a frame starting at `src`. 408 * `srcSize` must be >= LZ4F_MIN_SIZE_TO_KNOW_HEADER_LENGTH, 409 * which is enough to decode the header length. 410 * @return : size of frame header 411 * or an error code, which can be tested using LZ4F_isError() 412 * note : Frame header size is variable, but is guaranteed to be 413 * >= LZ4F_HEADER_SIZE_MIN bytes, and <= LZ4F_HEADER_SIZE_MAX bytes. 414 */ 415 LZ4FLIB_API size_t LZ4F_headerSize(const void* src, size_t srcSize); 416 417 /*! LZ4F_getFrameInfo() : 418 * This function extracts frame parameters (max blockSize, dictID, etc.). 419 * Its usage is optional: user can also invoke LZ4F_decompress() directly. 420 * 421 * Extracted information will fill an existing LZ4F_frameInfo_t structure. 422 * This can be useful for allocation and dictionary identification purposes. 423 * 424 * LZ4F_getFrameInfo() can work in the following situations : 425 * 426 * 1) At the beginning of a new frame, before any invocation of LZ4F_decompress(). 427 * It will decode header from `srcBuffer`, 428 * consuming the header and starting the decoding process. 429 * 430 * Input size must be large enough to contain the full frame header. 431 * Frame header size can be known beforehand by LZ4F_headerSize(). 432 * Frame header size is variable, but is guaranteed to be >= LZ4F_HEADER_SIZE_MIN bytes, 433 * and not more than <= LZ4F_HEADER_SIZE_MAX bytes. 434 * Hence, blindly providing LZ4F_HEADER_SIZE_MAX bytes or more will always work. 435 * It's allowed to provide more input data than the header size, 436 * LZ4F_getFrameInfo() will only consume the header. 437 * 438 * If input size is not large enough, 439 * aka if it's smaller than header size, 440 * function will fail and return an error code. 441 * 442 * 2) After decoding has been started, 443 * it's possible to invoke LZ4F_getFrameInfo() anytime 444 * to extract already decoded frame parameters stored within dctx. 445 * 446 * Note that, if decoding has barely started, 447 * and not yet read enough information to decode the header, 448 * LZ4F_getFrameInfo() will fail. 449 * 450 * The number of bytes consumed from srcBuffer will be updated in *srcSizePtr (necessarily <= original value). 451 * LZ4F_getFrameInfo() only consumes bytes when decoding has not yet started, 452 * and when decoding the header has been successful. 453 * Decompression must then resume from (srcBuffer + *srcSizePtr). 454 * 455 * @return : a hint about how many srcSize bytes LZ4F_decompress() expects for next call, 456 * or an error code which can be tested using LZ4F_isError(). 457 * note 1 : in case of error, dctx is not modified. Decoding operation can resume from beginning safely. 458 * note 2 : frame parameters are *copied into* an already allocated LZ4F_frameInfo_t structure. 459 */ 460 LZ4FLIB_API size_t 461 LZ4F_getFrameInfo(LZ4F_dctx* dctx, 462 LZ4F_frameInfo_t* frameInfoPtr, 463 const void* srcBuffer, size_t* srcSizePtr); 464 465 /*! LZ4F_decompress() : 466 * Call this function repetitively to regenerate data compressed in `srcBuffer`. 467 * 468 * The function requires a valid dctx state. 469 * It will read up to *srcSizePtr bytes from srcBuffer, 470 * and decompress data into dstBuffer, of capacity *dstSizePtr. 471 * 472 * The nb of bytes consumed from srcBuffer will be written into *srcSizePtr (necessarily <= original value). 473 * The nb of bytes decompressed into dstBuffer will be written into *dstSizePtr (necessarily <= original value). 474 * 475 * The function does not necessarily read all input bytes, so always check value in *srcSizePtr. 476 * Unconsumed source data must be presented again in subsequent invocations. 477 * 478 * `dstBuffer` can freely change between each consecutive function invocation. 479 * `dstBuffer` content will be overwritten. 480 * 481 * Note: if `LZ4F_getFrameInfo()` is called before `LZ4F_decompress()`, srcBuffer must be updated to reflect 482 * the number of bytes consumed after reading the frame header. Failure to update srcBuffer before calling 483 * `LZ4F_decompress()` will cause decompression failure or, even worse, successful but incorrect decompression. 484 * See the `LZ4F_getFrameInfo()` docs for details. 485 * 486 * @return : an hint of how many `srcSize` bytes LZ4F_decompress() expects for next call. 487 * Schematically, it's the size of the current (or remaining) compressed block + header of next block. 488 * Respecting the hint provides some small speed benefit, because it skips intermediate buffers. 489 * This is just a hint though, it's always possible to provide any srcSize. 490 * 491 * When a frame is fully decoded, @return will be 0 (no more data expected). 492 * When provided with more bytes than necessary to decode a frame, 493 * LZ4F_decompress() will stop reading exactly at end of current frame, and @return 0. 494 * 495 * If decompression failed, @return is an error code, which can be tested using LZ4F_isError(). 496 * After a decompression error, the `dctx` context is not resumable. 497 * Use LZ4F_resetDecompressionContext() to return to clean state. 498 * 499 * After a frame is fully decoded, dctx can be used again to decompress another frame. 500 */ 501 LZ4FLIB_API size_t 502 LZ4F_decompress(LZ4F_dctx* dctx, 503 void* dstBuffer, size_t* dstSizePtr, 504 const void* srcBuffer, size_t* srcSizePtr, 505 const LZ4F_decompressOptions_t* dOptPtr); 506 507 508 /*! LZ4F_resetDecompressionContext() : added in v1.8.0 509 * In case of an error, the context is left in "undefined" state. 510 * In which case, it's necessary to reset it, before re-using it. 511 * This method can also be used to abruptly stop any unfinished decompression, 512 * and start a new one using same context resources. */ 513 LZ4FLIB_API void LZ4F_resetDecompressionContext(LZ4F_dctx* dctx); /* always successful */ 514 515 516 /********************************** 517 * Dictionary compression API 518 *********************************/ 519 520 /* A Dictionary is useful for the compression of small messages (KB range). 521 * It dramatically improves compression efficiency. 522 * 523 * LZ4 can ingest any input as dictionary, though only the last 64 KB are useful. 524 * Better results are generally achieved by using Zstandard's Dictionary Builder 525 * to generate a high-quality dictionary from a set of samples. 526 * 527 * The same dictionary will have to be used on the decompression side 528 * for decoding to be successful. 529 * To help identify the correct dictionary at decoding stage, 530 * the frame header allows optional embedding of a dictID field. 531 */ 532 533 /*! LZ4F_compressBegin_usingDict() : stable since v1.10 534 * Inits dictionary compression streaming, and writes the frame header into dstBuffer. 535 * @dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes. 536 * @prefsPtr is optional : one may provide NULL as argument, 537 * however, it's the only way to provide dictID in the frame header. 538 * @dictBuffer must outlive the compression session. 539 * @return : number of bytes written into dstBuffer for the header, 540 * or an error code (which can be tested using LZ4F_isError()) 541 * NOTE: The LZ4Frame spec allows each independent block to be compressed with the dictionary, 542 * but this entry supports a more limited scenario, where only the first block uses the dictionary. 543 * This is still useful for small data, which only need one block anyway. 544 * For larger inputs, one may be more interested in LZ4F_compressFrame_usingCDict() below. 545 */ 546 LZ4FLIB_API size_t 547 LZ4F_compressBegin_usingDict(LZ4F_cctx* cctx, 548 void* dstBuffer, size_t dstCapacity, 549 const void* dictBuffer, size_t dictSize, 550 const LZ4F_preferences_t* prefsPtr); 551 552 /*! LZ4F_decompress_usingDict() : stable since v1.10 553 * Same as LZ4F_decompress(), using a predefined dictionary. 554 * Dictionary is used "in place", without any preprocessing. 555 ** It must remain accessible throughout the entire frame decoding. */ 556 LZ4FLIB_API size_t 557 LZ4F_decompress_usingDict(LZ4F_dctx* dctxPtr, 558 void* dstBuffer, size_t* dstSizePtr, 559 const void* srcBuffer, size_t* srcSizePtr, 560 const void* dict, size_t dictSize, 561 const LZ4F_decompressOptions_t* decompressOptionsPtr); 562 563 /***************************************** 564 * Bulk processing dictionary compression 565 *****************************************/ 566 567 /* Loading a dictionary has a cost, since it involves construction of tables. 568 * The Bulk processing dictionary API makes it possible to share this cost 569 * over an arbitrary number of compression jobs, even concurrently, 570 * markedly improving compression latency for these cases. 571 * 572 * Note that there is no corresponding bulk API for the decompression side, 573 * because dictionary does not carry any initialization cost for decompression. 574 * Use the regular LZ4F_decompress_usingDict() there. 575 */ 576 typedef struct LZ4F_CDict_s LZ4F_CDict; 577 578 /*! LZ4_createCDict() : stable since v1.10 579 * When compressing multiple messages / blocks using the same dictionary, it's recommended to initialize it just once. 580 * LZ4_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay. 581 * LZ4_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only. 582 * @dictBuffer can be released after LZ4_CDict creation, since its content is copied within CDict. */ 583 LZ4FLIB_API LZ4F_CDict* LZ4F_createCDict(const void* dictBuffer, size_t dictSize); 584 LZ4FLIB_API void LZ4F_freeCDict(LZ4F_CDict* CDict); 585 586 /*! LZ4_compressFrame_usingCDict() : stable since v1.10 587 * Compress an entire srcBuffer into a valid LZ4 frame using a digested Dictionary. 588 * @cctx must point to a context created by LZ4F_createCompressionContext(). 589 * If @cdict==NULL, compress without a dictionary. 590 * @dstBuffer MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr). 591 * If this condition is not respected, function will fail (@return an errorCode). 592 * The LZ4F_preferences_t structure is optional : one may provide NULL as argument, 593 * but it's not recommended, as it's the only way to provide @dictID in the frame header. 594 * @return : number of bytes written into dstBuffer. 595 * or an error code if it fails (can be tested using LZ4F_isError()) 596 * Note: for larger inputs generating multiple independent blocks, 597 * this entry point uses the dictionary for each block. */ 598 LZ4FLIB_API size_t 599 LZ4F_compressFrame_usingCDict(LZ4F_cctx* cctx, 600 void* dst, size_t dstCapacity, 601 const void* src, size_t srcSize, 602 const LZ4F_CDict* cdict, 603 const LZ4F_preferences_t* preferencesPtr); 604 605 /*! LZ4F_compressBegin_usingCDict() : stable since v1.10 606 * Inits streaming dictionary compression, and writes the frame header into dstBuffer. 607 * @dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes. 608 * @prefsPtr is optional : one may provide NULL as argument, 609 * note however that it's the only way to insert a @dictID in the frame header. 610 * @cdict must outlive the compression session. 611 * @return : number of bytes written into dstBuffer for the header, 612 * or an error code, which can be tested using LZ4F_isError(). */ 613 LZ4FLIB_API size_t 614 LZ4F_compressBegin_usingCDict(LZ4F_cctx* cctx, 615 void* dstBuffer, size_t dstCapacity, 616 const LZ4F_CDict* cdict, 617 const LZ4F_preferences_t* prefsPtr); 618 619 620 #if defined (__cplusplus) 621 } 622 #endif 623 624 #endif /* LZ4F_H_09782039843 */ 625 626 #if defined(LZ4F_STATIC_LINKING_ONLY) && !defined(LZ4F_H_STATIC_09782039843) 627 #define LZ4F_H_STATIC_09782039843 628 629 /* Note : 630 * The below declarations are not stable and may change in the future. 631 * They are therefore only safe to depend on 632 * when the caller is statically linked against the library. 633 * To access their declarations, define LZ4F_STATIC_LINKING_ONLY. 634 * 635 * By default, these symbols aren't published into shared/dynamic libraries. 636 * You can override this behavior and force them to be published 637 * by defining LZ4F_PUBLISH_STATIC_FUNCTIONS. 638 * Use at your own risk. 639 */ 640 641 #if defined (__cplusplus) 642 extern "C" { 643 #endif 644 645 #ifdef LZ4F_PUBLISH_STATIC_FUNCTIONS 646 # define LZ4FLIB_STATIC_API LZ4FLIB_API 647 #else 648 # define LZ4FLIB_STATIC_API 649 #endif 650 651 652 /* --- Error List --- */ 653 #define LZ4F_LIST_ERRORS(ITEM) \ 654 ITEM(OK_NoError) \ 655 ITEM(ERROR_GENERIC) \ 656 ITEM(ERROR_maxBlockSize_invalid) \ 657 ITEM(ERROR_blockMode_invalid) \ 658 ITEM(ERROR_parameter_invalid) \ 659 ITEM(ERROR_compressionLevel_invalid) \ 660 ITEM(ERROR_headerVersion_wrong) \ 661 ITEM(ERROR_blockChecksum_invalid) \ 662 ITEM(ERROR_reservedFlag_set) \ 663 ITEM(ERROR_allocation_failed) \ 664 ITEM(ERROR_srcSize_tooLarge) \ 665 ITEM(ERROR_dstMaxSize_tooSmall) \ 666 ITEM(ERROR_frameHeader_incomplete) \ 667 ITEM(ERROR_frameType_unknown) \ 668 ITEM(ERROR_frameSize_wrong) \ 669 ITEM(ERROR_srcPtr_wrong) \ 670 ITEM(ERROR_decompressionFailed) \ 671 ITEM(ERROR_headerChecksum_invalid) \ 672 ITEM(ERROR_contentChecksum_invalid) \ 673 ITEM(ERROR_frameDecoding_alreadyStarted) \ 674 ITEM(ERROR_compressionState_uninitialized) \ 675 ITEM(ERROR_parameter_null) \ 676 ITEM(ERROR_io_write) \ 677 ITEM(ERROR_io_read) \ 678 ITEM(ERROR_maxCode) 679 680 #define LZ4F_GENERATE_ENUM(ENUM) LZ4F_##ENUM, 681 682 /* enum list is exposed, to handle specific errors */ 683 typedef enum { LZ4F_LIST_ERRORS(LZ4F_GENERATE_ENUM) 684 _LZ4F_dummy_error_enum_for_c89_never_used } LZ4F_errorCodes; 685 686 LZ4FLIB_STATIC_API LZ4F_errorCodes LZ4F_getErrorCode(size_t functionResult); 687 688 /********************************** 689 * Advanced compression operations 690 *********************************/ 691 692 /*! LZ4F_getBlockSize() : 693 * @return, in scalar format (size_t), 694 * the maximum block size associated with @blockSizeID, 695 * or an error code (can be tested using LZ4F_isError()) if @blockSizeID is invalid. 696 **/ 697 LZ4FLIB_STATIC_API size_t LZ4F_getBlockSize(LZ4F_blockSizeID_t blockSizeID); 698 699 /*! LZ4F_uncompressedUpdate() : 700 * LZ4F_uncompressedUpdate() can be called repetitively to add data stored as uncompressed blocks. 701 * Important rule: dstCapacity MUST be large enough to store the entire source buffer as 702 * no compression is done for this operation 703 * If this condition is not respected, LZ4F_uncompressedUpdate() will fail (result is an errorCode). 704 * After an error, the state is left in a UB state, and must be re-initialized or freed. 705 * If previously a compressed block was written, buffered data is flushed first, 706 * before appending uncompressed data is continued. 707 * This operation is only supported when LZ4F_blockIndependent is used. 708 * `cOptPtr` is optional : NULL can be provided, in which case all options are set to default. 709 * @return : number of bytes written into `dstBuffer` (it can be zero, meaning input data was just buffered). 710 * or an error code if it fails (which can be tested using LZ4F_isError()) 711 */ 712 LZ4FLIB_STATIC_API size_t 713 LZ4F_uncompressedUpdate(LZ4F_cctx* cctx, 714 void* dstBuffer, size_t dstCapacity, 715 const void* srcBuffer, size_t srcSize, 716 const LZ4F_compressOptions_t* cOptPtr); 717 718 /********************************** 719 * Custom memory allocation 720 *********************************/ 721 722 /*! Custom memory allocation : v1.9.4+ 723 * These prototypes make it possible to pass custom allocation/free functions. 724 * LZ4F_customMem is provided at state creation time, using LZ4F_create*_advanced() listed below. 725 * All allocation/free operations will be completed using these custom variants instead of regular <stdlib.h> ones. 726 */ 727 typedef void* (*LZ4F_AllocFunction) (void* opaqueState, size_t size); 728 typedef void* (*LZ4F_CallocFunction) (void* opaqueState, size_t size); 729 typedef void (*LZ4F_FreeFunction) (void* opaqueState, void* address); 730 typedef struct { 731 LZ4F_AllocFunction customAlloc; 732 LZ4F_CallocFunction customCalloc; /* optional; when not defined, uses customAlloc + memset */ 733 LZ4F_FreeFunction customFree; 734 void* opaqueState; 735 } LZ4F_CustomMem; 736 static 737 #ifdef __GNUC__ 738 __attribute__((__unused__)) 739 #endif 740 LZ4F_CustomMem const LZ4F_defaultCMem = { NULL, NULL, NULL, NULL }; /**< this constant defers to stdlib's functions */ 741 742 LZ4FLIB_STATIC_API LZ4F_cctx* LZ4F_createCompressionContext_advanced(LZ4F_CustomMem customMem, unsigned version); 743 LZ4FLIB_STATIC_API LZ4F_dctx* LZ4F_createDecompressionContext_advanced(LZ4F_CustomMem customMem, unsigned version); 744 LZ4FLIB_STATIC_API LZ4F_CDict* LZ4F_createCDict_advanced(LZ4F_CustomMem customMem, const void* dictBuffer, size_t dictSize); 745 746 747 #if defined (__cplusplus) 748 } 749 #endif 750 751 #endif /* defined(LZ4F_STATIC_LINKING_ONLY) && !defined(LZ4F_H_STATIC_09782039843) */ 752