lz4.h revision 6b1600f41e039639b24f7780db8f1c26b28b1b6b
1/* 2 LZ4 - Fast LZ compression algorithm 3 Header File 4 Copyright (C) 2011-2016, 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/Cyan4973/lz4 34*/ 35#pragma once 36 37#if defined (__cplusplus) 38extern "C" { 39#endif 40 41/* 42 * lz4.h provides block compression functions. It gives full buffer control to user. 43 * For inter-operable compressed data, respecting LZ4 frame specification, 44 * and can let the library handle its own memory, use lz4frame.h instead. 45*/ 46 47/*-************************************ 48* Version 49**************************************/ 50#define LZ4_VERSION_MAJOR 1 /* for breaking interface changes */ 51#define LZ4_VERSION_MINOR 7 /* for new (non-breaking) interface capabilities */ 52#define LZ4_VERSION_RELEASE 2 /* for tweaks, bug-fixes, or development */ 53 54#define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR *100*100 + LZ4_VERSION_MINOR *100 + LZ4_VERSION_RELEASE) 55int LZ4_versionNumber (void); 56 57#define LZ4_STR(str) #str 58#define LZ4_XSTR(str) LZ4_STR(str) 59#define LZ4_VERSION_STRING LZ4_XSTR(LZ4_VERSION_MAJOR) "." \ 60 LZ4_XSTR(LZ4_VERSION_MINOR) "." LZ4_XSTR(LZ4_VERSION_RELEASE) 61const char* LZ4_versionString (void); 62 63/*-************************************ 64* Tuning parameter 65**************************************/ 66/* 67 * LZ4_MEMORY_USAGE : 68 * Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.) 69 * Increasing memory usage improves compression ratio 70 * Reduced memory usage can improve speed, due to cache effect 71 * Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache 72 */ 73#define LZ4_MEMORY_USAGE 14 74 75 76/*-************************************ 77* Simple Functions 78**************************************/ 79 80int LZ4_compress_default(const char* source, char* dest, int sourceSize, int maxDestSize); 81int LZ4_decompress_safe (const char* source, char* dest, int compressedSize, int maxDecompressedSize); 82 83/* 84LZ4_compress_default() : 85 Compresses 'sourceSize' bytes from buffer 'source' 86 into already allocated 'dest' buffer of size 'maxDestSize'. 87 Compression is guaranteed to succeed if 'maxDestSize' >= LZ4_compressBound(sourceSize). 88 It also runs faster, so it's a recommended setting. 89 If the function cannot compress 'source' into a more limited 'dest' budget, 90 compression stops *immediately*, and the function result is zero. 91 As a consequence, 'dest' content is not valid. 92 This function never writes outside 'dest' buffer, nor read outside 'source' buffer. 93 sourceSize : Max supported value is LZ4_MAX_INPUT_VALUE 94 maxDestSize : full or partial size of buffer 'dest' (which must be already allocated) 95 return : the number of bytes written into buffer 'dest' (necessarily <= maxOutputSize) 96 or 0 if compression fails 97 98LZ4_decompress_safe() : 99 compressedSize : is the precise full size of the compressed block. 100 maxDecompressedSize : is the size of destination buffer, which must be already allocated. 101 return : the number of bytes decompressed into destination buffer (necessarily <= maxDecompressedSize) 102 If destination buffer is not large enough, decoding will stop and output an error code (<0). 103 If the source stream is detected malformed, the function will stop decoding and return a negative result. 104 This function is protected against buffer overflow exploits, including malicious data packets. 105 It never writes outside output buffer, nor reads outside input buffer. 106*/ 107 108 109/*-************************************ 110* Advanced Functions 111**************************************/ 112#define LZ4_MAX_INPUT_SIZE 0x7E000000 /* 2 113 929 216 bytes */ 113#define LZ4_COMPRESSBOUND(isize) ((unsigned)(isize) > (unsigned)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize)/255) + 16) 114 115/*! 116LZ4_compressBound() : 117 Provides the maximum size that LZ4 compression may output in a "worst case" scenario (input data not compressible) 118 This function is primarily useful for memory allocation purposes (destination buffer size). 119 Macro LZ4_COMPRESSBOUND() is also provided for compilation-time evaluation (stack memory allocation for example). 120 Note that LZ4_compress_default() compress faster when dest buffer size is >= LZ4_compressBound(srcSize) 121 inputSize : max supported value is LZ4_MAX_INPUT_SIZE 122 return : maximum output size in a "worst case" scenario 123 or 0, if input size is too large ( > LZ4_MAX_INPUT_SIZE) 124*/ 125int LZ4_compressBound(int inputSize); 126 127/*! 128LZ4_compress_fast() : 129 Same as LZ4_compress_default(), but allows to select an "acceleration" factor. 130 The larger the acceleration value, the faster the algorithm, but also the lesser the compression. 131 It's a trade-off. It can be fine tuned, with each successive value providing roughly +~3% to speed. 132 An acceleration value of "1" is the same as regular LZ4_compress_default() 133 Values <= 0 will be replaced by ACCELERATION_DEFAULT (see lz4.c), which is 1. 134*/ 135int LZ4_compress_fast (const char* source, char* dest, int sourceSize, int maxDestSize, int acceleration); 136 137 138/*! 139LZ4_compress_fast_extState() : 140 Same compression function, just using an externally allocated memory space to store compression state. 141 Use LZ4_sizeofState() to know how much memory must be allocated, 142 and allocate it on 8-bytes boundaries (using malloc() typically). 143 Then, provide it as 'void* state' to compression function. 144*/ 145int LZ4_sizeofState(void); 146int LZ4_compress_fast_extState (void* state, const char* source, char* dest, int inputSize, int maxDestSize, int acceleration); 147 148 149/*! 150LZ4_compress_destSize() : 151 Reverse the logic, by compressing as much data as possible from 'source' buffer 152 into already allocated buffer 'dest' of size 'targetDestSize'. 153 This function either compresses the entire 'source' content into 'dest' if it's large enough, 154 or fill 'dest' buffer completely with as much data as possible from 'source'. 155 *sourceSizePtr : will be modified to indicate how many bytes where read from 'source' to fill 'dest'. 156 New value is necessarily <= old value. 157 return : Nb bytes written into 'dest' (necessarily <= targetDestSize) 158 or 0 if compression fails 159*/ 160int LZ4_compress_destSize (const char* source, char* dest, int* sourceSizePtr, int targetDestSize); 161 162 163/*! 164LZ4_decompress_fast() : 165 originalSize : is the original and therefore uncompressed size 166 return : the number of bytes read from the source buffer (in other words, the compressed size) 167 If the source stream is detected malformed, the function will stop decoding and return a negative result. 168 Destination buffer must be already allocated. Its size must be a minimum of 'originalSize' bytes. 169 note : This function fully respect memory boundaries for properly formed compressed data. 170 It is a bit faster than LZ4_decompress_safe(). 171 However, it does not provide any protection against intentionally modified data stream (malicious input). 172 Use this function in trusted environment only (data to decode comes from a trusted source). 173*/ 174int LZ4_decompress_fast (const char* source, char* dest, int originalSize); 175 176/*! 177LZ4_decompress_safe_partial() : 178 This function decompress a compressed block of size 'compressedSize' at position 'source' 179 into destination buffer 'dest' of size 'maxDecompressedSize'. 180 The function tries to stop decompressing operation as soon as 'targetOutputSize' has been reached, 181 reducing decompression time. 182 return : the number of bytes decoded in the destination buffer (necessarily <= maxDecompressedSize) 183 Note : this number can be < 'targetOutputSize' should the compressed block to decode be smaller. 184 Always control how many bytes were decoded. 185 If the source stream is detected malformed, the function will stop decoding and return a negative result. 186 This function never writes outside of output buffer, and never reads outside of input buffer. It is therefore protected against malicious data packets 187*/ 188int LZ4_decompress_safe_partial (const char* source, char* dest, int compressedSize, int targetOutputSize, int maxDecompressedSize); 189 190 191/*-********************************************* 192* Streaming Compression Functions 193***********************************************/ 194#define LZ4_STREAMSIZE_U64 ((1 << (LZ4_MEMORY_USAGE-3)) + 4) 195#define LZ4_STREAMSIZE (LZ4_STREAMSIZE_U64 * sizeof(long long)) 196/* 197 * LZ4_stream_t : 198 * information structure to track an LZ4 stream. 199 * important : init this structure content before first use ! 200 * note : only allocated directly the structure if you are statically linking LZ4 201 * If you are using liblz4 as a DLL, please use below construction methods instead. 202 */ 203typedef struct { long long table[LZ4_STREAMSIZE_U64]; } LZ4_stream_t; 204 205/*! LZ4_resetStream() : 206 * Use this function to init an allocated `LZ4_stream_t` structure 207 */ 208void LZ4_resetStream (LZ4_stream_t* streamPtr); 209 210/*! LZ4_createStream() will allocate and initialize an `LZ4_stream_t` structure 211 * LZ4_freeStream() releases its memory. 212 * In the context of a DLL (liblz4), please use these methods rather than the static struct. 213 * They are more future proof, in case of a change of `LZ4_stream_t` size. 214 */ 215LZ4_stream_t* LZ4_createStream(void); 216int LZ4_freeStream (LZ4_stream_t* streamPtr); 217 218/*! LZ4_loadDict() : 219 * Use this function to load a static dictionary into LZ4_stream. 220 * Any previous data will be forgotten, only 'dictionary' will remain in memory. 221 * Loading a size of 0 is allowed. 222 * Return : dictionary size, in bytes (necessarily <= 64 KB) 223 */ 224int LZ4_loadDict (LZ4_stream_t* streamPtr, const char* dictionary, int dictSize); 225 226/*! LZ4_compress_fast_continue() : 227 * Compress buffer content 'src', using data from previously compressed blocks as dictionary to improve compression ratio. 228 * Important : Previous data blocks are assumed to still be present and unmodified ! 229 * 'dst' buffer must be already allocated. 230 * If maxDstSize >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster. 231 * If not, and if compressed data cannot fit into 'dst' buffer size, compression stops, and function returns a zero. 232 */ 233int LZ4_compress_fast_continue (LZ4_stream_t* streamPtr, const char* src, char* dst, int srcSize, int maxDstSize, int acceleration); 234 235/*! LZ4_saveDict() : 236 * If previously compressed data block is not guaranteed to remain available at its memory location 237 * save it into a safer place (char* safeBuffer) 238 * Note : you don't need to call LZ4_loadDict() afterwards, 239 * dictionary is immediately usable, you can therefore call LZ4_compress_fast_continue() 240 * Return : saved dictionary size in bytes (necessarily <= dictSize), or 0 if error 241 */ 242int LZ4_saveDict (LZ4_stream_t* streamPtr, char* safeBuffer, int dictSize); 243 244 245/*-********************************************** 246* Streaming Decompression Functions 247************************************************/ 248 249#define LZ4_STREAMDECODESIZE_U64 4 250#define LZ4_STREAMDECODESIZE (LZ4_STREAMDECODESIZE_U64 * sizeof(unsigned long long)) 251typedef struct { unsigned long long table[LZ4_STREAMDECODESIZE_U64]; } LZ4_streamDecode_t; 252/* 253 * LZ4_streamDecode_t 254 * information structure to track an LZ4 stream. 255 * init this structure content using LZ4_setStreamDecode or memset() before first use ! 256 * 257 * In the context of a DLL (liblz4) please prefer usage of construction methods below. 258 * They are more future proof, in case of a change of LZ4_streamDecode_t size in the future. 259 * LZ4_createStreamDecode will allocate and initialize an LZ4_streamDecode_t structure 260 * LZ4_freeStreamDecode releases its memory. 261 */ 262LZ4_streamDecode_t* LZ4_createStreamDecode(void); 263int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream); 264 265/* 266 * LZ4_setStreamDecode 267 * Use this function to instruct where to find the dictionary. 268 * Setting a size of 0 is allowed (same effect as reset). 269 * Return : 1 if OK, 0 if error 270 */ 271int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize); 272 273/* 274*_continue() : 275 These decoding functions allow decompression of multiple blocks in "streaming" mode. 276 Previously decoded blocks *must* remain available at the memory position where they were decoded (up to 64 KB) 277 In the case of a ring buffers, decoding buffer must be either : 278 - Exactly same size as encoding buffer, with same update rule (block boundaries at same positions) 279 In which case, the decoding & encoding ring buffer can have any size, including very small ones ( < 64 KB). 280 - Larger than encoding buffer, by a minimum of maxBlockSize more bytes. 281 maxBlockSize is implementation dependent. It's the maximum size you intend to compress into a single block. 282 In which case, encoding and decoding buffers do not need to be synchronized, 283 and encoding ring buffer can have any size, including small ones ( < 64 KB). 284 - _At least_ 64 KB + 8 bytes + maxBlockSize. 285 In which case, encoding and decoding buffers do not need to be synchronized, 286 and encoding ring buffer can have any size, including larger than decoding buffer. 287 Whenever these conditions are not possible, save the last 64KB of decoded data into a safe buffer, 288 and indicate where it is saved using LZ4_setStreamDecode() 289*/ 290int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxDecompressedSize); 291int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int originalSize); 292 293 294/* 295Advanced decoding functions : 296*_usingDict() : 297 These decoding functions work the same as 298 a combination of LZ4_setStreamDecode() followed by LZ4_decompress_x_continue() 299 They are stand-alone. They don't need nor update an LZ4_streamDecode_t structure. 300*/ 301int LZ4_decompress_safe_usingDict (const char* source, char* dest, int compressedSize, int maxDecompressedSize, const char* dictStart, int dictSize); 302int LZ4_decompress_fast_usingDict (const char* source, char* dest, int originalSize, const char* dictStart, int dictSize); 303 304 305/************************************** 306* Obsolete Functions 307**************************************/ 308/* Deprecate Warnings */ 309/* Should these warnings messages be a problem, 310 it is generally possible to disable them, 311 with -Wno-deprecated-declarations for gcc 312 or _CRT_SECURE_NO_WARNINGS in Visual for example. 313 Otherwise, you can also define LZ4_DISABLE_DEPRECATE_WARNINGS */ 314#define LZ4_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) 315#ifdef LZ4_DISABLE_DEPRECATE_WARNINGS 316# define LZ4_DEPRECATED() /* disable deprecation warnings */ 317#else 318# if (LZ4_GCC_VERSION >= 405) || defined(__clang__) 319# define LZ4_DEPRECATED(message) __attribute__((deprecated(message))) 320# elif (LZ4_GCC_VERSION >= 301) 321# define LZ4_DEPRECATED(message) __attribute__((deprecated)) 322# elif defined(_MSC_VER) 323# define LZ4_DEPRECATED(message) __declspec(deprecated(message)) 324# else 325# pragma message("WARNING: You need to implement LZ4_DEPRECATED for this compiler") 326# define LZ4_DEPRECATED(message) 327# endif 328#endif /* LZ4_DISABLE_DEPRECATE_WARNINGS */ 329 330/* Obsolete compression functions */ 331/* These functions will generate warnings in a future release */ 332int LZ4_compress (const char* source, char* dest, int sourceSize); 333int LZ4_compress_limitedOutput (const char* source, char* dest, int sourceSize, int maxOutputSize); 334int LZ4_compress_withState (void* state, const char* source, char* dest, int inputSize); 335int LZ4_compress_limitedOutput_withState (void* state, const char* source, char* dest, int inputSize, int maxOutputSize); 336int LZ4_compress_continue (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize); 337int LZ4_compress_limitedOutput_continue (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize, int maxOutputSize); 338 339/* Obsolete decompression functions */ 340/* These function names are completely deprecated and must no longer be used. 341 They are only provided in lz4.c for compatibility with older programs. 342 - LZ4_uncompress is the same as LZ4_decompress_fast 343 - LZ4_uncompress_unknownOutputSize is the same as LZ4_decompress_safe 344 These function prototypes are now disabled; uncomment them only if you really need them. 345 It is highly recommended to stop using these prototypes and migrate to maintained ones */ 346/* int LZ4_uncompress (const char* source, char* dest, int outputSize); */ 347/* int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize); */ 348 349/* Obsolete streaming functions; use new streaming interface whenever possible */ 350LZ4_DEPRECATED("use LZ4_createStream() instead") void* LZ4_create (char* inputBuffer); 351LZ4_DEPRECATED("use LZ4_createStream() instead") int LZ4_sizeofStreamState(void); 352LZ4_DEPRECATED("use LZ4_resetStream() instead") int LZ4_resetStreamState(void* state, char* inputBuffer); 353LZ4_DEPRECATED("use LZ4_saveDict() instead") char* LZ4_slideInputBuffer (void* state); 354 355/* Obsolete streaming decoding functions */ 356LZ4_DEPRECATED("use LZ4_decompress_safe_usingDict() instead") int LZ4_decompress_safe_withPrefix64k (const char* src, char* dst, int compressedSize, int maxDstSize); 357LZ4_DEPRECATED("use LZ4_decompress_fast_usingDict() instead") int LZ4_decompress_fast_withPrefix64k (const char* src, char* dst, int originalSize); 358 359 360#if defined (__cplusplus) 361} 362#endif 363