1/*
2 * LZ4 - Fast LZ compression algorithm
3 * Header File
4 * Copyright (C) 2011-2020, 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)
36extern "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 >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 It gives full buffer control to user.
55 Compression can be done in:
56 - a single step (described as Simple Functions)
57 - a single step, reusing a context (described in Advanced Functions)
58 - unbounded multiple steps (described as Streaming compression)
59
60 lz4.h generates and decodes LZ4-compressed blocks (doc/lz4_Block_format.md).
61 Decompressing such a compressed block requires additional metadata.
62 Exact metadata depends on exact decompression function.
63 For the typical case of LZ4_decompress_safe(),
64 metadata includes block's compressed size, and maximum bound of decompressed size.
65 Each application is free to encode and pass such metadata in whichever way it wants.
66
67 lz4.h only handle blocks, it can not generate Frames.
68
69 Blocks are different from Frames (doc/lz4_Frame_format.md).
70 Frames bundle both blocks and metadata in a specified manner.
71 Embedding metadata is required for compressed data to be self-contained and portable.
72 Frame format is delivered through a companion API, declared in lz4frame.h.
73 The `lz4` CLI can only manage frames.
74*/
75
76/*^***************************************************************
77* Export parameters
78*****************************************************************/
79/*
80* LZ4_DLL_EXPORT :
81* Enable exporting of functions when building a Windows DLL
82* LZ4LIB_VISIBILITY :
83* Control library symbols visibility.
84*/
85#ifndef LZ4LIB_VISIBILITY
86# if defined(__GNUC__) && (__GNUC__ >= 4)
87# define LZ4LIB_VISIBILITY __attribute__ ((visibility ("default")))
88# else
89# define LZ4LIB_VISIBILITY
90# endif
91#endif
92#if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1)
93# define LZ4LIB_API __declspec(dllexport) LZ4LIB_VISIBILITY
94#elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1)
95# 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.*/
96#else
97# define LZ4LIB_API LZ4LIB_VISIBILITY
98#endif
99
100/*! LZ4_FREESTANDING :
101 * When this macro is set to 1, it enables "freestanding mode" that is
102 * suitable for typical freestanding environment which doesn't support
103 * standard C library.
104 *
105 * - LZ4_FREESTANDING is a compile-time switch.
106 * - It requires the following macros to be defined:
107 * LZ4_memcpy, LZ4_memmove, LZ4_memset.
108 * - It only enables LZ4/HC functions which don't use heap.
109 * All LZ4F_* functions are not supported.
110 * - See tests/freestanding.c to check its basic setup.
111 */
112#if defined(LZ4_FREESTANDING) && (LZ4_FREESTANDING == 1)
113# define LZ4_HEAPMODE 0
114# define LZ4HC_HEAPMODE 0
115# define LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION 1
116# if !defined(LZ4_memcpy)
117# error "LZ4_FREESTANDING requires macro 'LZ4_memcpy'."
118# endif
119# if !defined(LZ4_memset)
120# error "LZ4_FREESTANDING requires macro 'LZ4_memset'."
121# endif
122# if !defined(LZ4_memmove)
123# error "LZ4_FREESTANDING requires macro 'LZ4_memmove'."
124# endif
125#elif ! defined(LZ4_FREESTANDING)
126# define LZ4_FREESTANDING 0
127#endif
128
129
130/*------ Version ------*/
131#define LZ4_VERSION_MAJOR 1 /* for breaking interface changes */
132#define LZ4_VERSION_MINOR 9 /* for new (non-breaking) interface capabilities */
133#define LZ4_VERSION_RELEASE 4 /* for tweaks, bug-fixes, or development */
134
135#define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR *100*100 + LZ4_VERSION_MINOR *100 + LZ4_VERSION_RELEASE)
136
137#define LZ4_LIB_VERSION LZ4_VERSION_MAJOR.LZ4_VERSION_MINOR.LZ4_VERSION_RELEASE
138#define LZ4_QUOTE(str) #str
139#define LZ4_EXPAND_AND_QUOTE(str) LZ4_QUOTE(str)
140#define LZ4_VERSION_STRING LZ4_EXPAND_AND_QUOTE(LZ4_LIB_VERSION) /* requires v1.7.3+ */
141
142LZ4LIB_API int LZ4_versionNumber (void); /**< library version number; useful to check dll version; requires v1.3.0+ */
143LZ4LIB_API const char* LZ4_versionString (void); /**< library version string; useful to check dll version; requires v1.7.5+ */
144
145
146/*-************************************
147* Tuning parameter
148**************************************/
149#define LZ4_MEMORY_USAGE_MIN 10
150#define LZ4_MEMORY_USAGE_DEFAULT 14
151#define LZ4_MEMORY_USAGE_MAX 20
152
153/*!
154 * LZ4_MEMORY_USAGE :
155 * Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; )
156 * Increasing memory usage improves compression ratio, at the cost of speed.
157 * Reduced memory usage may improve speed at the cost of ratio, thanks to better cache locality.
158 * Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache
159 */
160#ifndef LZ4_MEMORY_USAGE
161# define LZ4_MEMORY_USAGE LZ4_MEMORY_USAGE_DEFAULT
162#endif
163
164#if (LZ4_MEMORY_USAGE < LZ4_MEMORY_USAGE_MIN)
165# error "LZ4_MEMORY_USAGE is too small !"
166#endif
167
168#if (LZ4_MEMORY_USAGE > LZ4_MEMORY_USAGE_MAX)
169# error "LZ4_MEMORY_USAGE is too large !"
170#endif
171
172/*-************************************
173* Simple Functions
174**************************************/
175/*! LZ4_compress_default() :
176 * Compresses 'srcSize' bytes from buffer 'src'
177 * into already allocated 'dst' buffer of size 'dstCapacity'.
178 * Compression is guaranteed to succeed if 'dstCapacity' >= LZ4_compressBound(srcSize).
179 * It also runs faster, so it's a recommended setting.
180 * If the function cannot compress 'src' into a more limited 'dst' budget,
181 * compression stops *immediately*, and the function result is zero.
182 * In which case, 'dst' content is undefined (invalid).
183 * srcSize : max supported value is LZ4_MAX_INPUT_SIZE.
184 * dstCapacity : size of buffer 'dst' (which must be already allocated)
185 * @return : the number of bytes written into buffer 'dst' (necessarily <= dstCapacity)
186 * or 0 if compression fails
187 * Note : This function is protected against buffer overflow scenarios (never writes outside 'dst' buffer, nor read outside 'source' buffer).
188 */
189LZ4LIB_API int LZ4_compress_default(const char* src, char* dst, int srcSize, int dstCapacity);
190
191/*! LZ4_decompress_safe() :
192 * compressedSize : is the exact complete size of the compressed block.
193 * dstCapacity : is the size of destination buffer (which must be already allocated), presumed an upper bound of decompressed size.
194 * @return : the number of bytes decompressed into destination buffer (necessarily <= dstCapacity)
195 * If destination buffer is not large enough, decoding will stop and output an error code (negative value).
196 * If the source stream is detected malformed, the function will stop decoding and return a negative result.
197 * Note 1 : This function is protected against malicious data packets :
198 * it will never writes outside 'dst' buffer, nor read outside 'source' buffer,
199 * even if the compressed block is maliciously modified to order the decoder to do these actions.
200 * In such case, the decoder stops immediately, and considers the compressed block malformed.
201 * Note 2 : compressedSize and dstCapacity must be provided to the function, the compressed block does not contain them.
202 * The implementation is free to send / store / derive this information in whichever way is most beneficial.
203 * If there is a need for a different format which bundles together both compressed data and its metadata, consider looking at lz4frame.h instead.
204 */
205LZ4LIB_API int LZ4_decompress_safe (const char* src, char* dst, int compressedSize, int dstCapacity);
206
207
208/*-************************************
209* Advanced Functions
210**************************************/
211#define LZ4_MAX_INPUT_SIZE 0x7E000000 /* 2 113 929 216 bytes */
212#define LZ4_COMPRESSBOUND(isize) ((unsigned)(isize) > (unsigned)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize)/255) + 16)
213
214/*! LZ4_compressBound() :
215 Provides the maximum size that LZ4 compression may output in a "worst case" scenario (input data not compressible)
216 This function is primarily useful for memory allocation purposes (destination buffer size).
217 Macro LZ4_COMPRESSBOUND() is also provided for compilation-time evaluation (stack memory allocation for example).
218 Note that LZ4_compress_default() compresses faster when dstCapacity is >= LZ4_compressBound(srcSize)
219 inputSize : max supported value is LZ4_MAX_INPUT_SIZE
220 return : maximum output size in a "worst case" scenario
221 or 0, if input size is incorrect (too large or negative)
222*/
223LZ4LIB_API int LZ4_compressBound(int inputSize);
224
225/*! LZ4_compress_fast() :
226 Same as LZ4_compress_default(), but allows selection of "acceleration" factor.
227 The larger the acceleration value, the faster the algorithm, but also the lesser the compression.
228 It's a trade-off. It can be fine tuned, with each successive value providing roughly +~3% to speed.
229 An acceleration value of "1" is the same as regular LZ4_compress_default()
230 Values <= 0 will be replaced by LZ4_ACCELERATION_DEFAULT (currently == 1, see lz4.c).
231 Values > LZ4_ACCELERATION_MAX will be replaced by LZ4_ACCELERATION_MAX (currently == 65537, see lz4.c).
232*/
233LZ4LIB_API int LZ4_compress_fast (const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
234
235
236/*! LZ4_compress_fast_extState() :
237 * Same as LZ4_compress_fast(), using an externally allocated memory space for its state.
238 * Use LZ4_sizeofState() to know how much memory must be allocated,
239 * and allocate it on 8-bytes boundaries (using `malloc()` typically).
240 * Then, provide this buffer as `void* state` to compression function.
241 */
242LZ4LIB_API int LZ4_sizeofState(void);
243LZ4LIB_API int LZ4_compress_fast_extState (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
244
245
246/*! LZ4_compress_destSize() :
247 * Reverse the logic : compresses as much data as possible from 'src' buffer
248 * into already allocated buffer 'dst', of size >= 'targetDestSize'.
249 * This function either compresses the entire 'src' content into 'dst' if it's large enough,
250 * or fill 'dst' buffer completely with as much data as possible from 'src'.
251 * note: acceleration parameter is fixed to "default".
252 *
253 * *srcSizePtr : will be modified to indicate how many bytes where read from 'src' to fill 'dst'.
254 * New value is necessarily <= input value.
255 * @return : Nb bytes written into 'dst' (necessarily <= targetDestSize)
256 * or 0 if compression fails.
257 *
258 * Note : from v1.8.2 to v1.9.1, this function had a bug (fixed un v1.9.2+):
259 * the produced compressed content could, in specific circumstances,
260 * require to be decompressed into a destination buffer larger
261 * by at least 1 byte than the content to decompress.
262 * If an application uses `LZ4_compress_destSize()`,
263 * it's highly recommended to update liblz4 to v1.9.2 or better.
264 * If this can't be done or ensured,
265 * the receiving decompression function should provide
266 * a dstCapacity which is > decompressedSize, by at least 1 byte.
267 * See https://github.com/lz4/lz4/issues/859 for details
268 */
269LZ4LIB_API int LZ4_compress_destSize (const char* src, char* dst, int* srcSizePtr, int targetDstSize);
270
271
272/*! LZ4_decompress_safe_partial() :
273 * Decompress an LZ4 compressed block, of size 'srcSize' at position 'src',
274 * into destination buffer 'dst' of size 'dstCapacity'.
275 * Up to 'targetOutputSize' bytes will be decoded.
276 * The function stops decoding on reaching this objective.
277 * This can be useful to boost performance
278 * whenever only the beginning of a block is required.
279 *
280 * @return : the number of bytes decoded in `dst` (necessarily <= targetOutputSize)
281 * If source stream is detected malformed, function returns a negative result.
282 *
283 * Note 1 : @return can be < targetOutputSize, if compressed block contains less data.
284 *
285 * Note 2 : targetOutputSize must be <= dstCapacity
286 *
287 * Note 3 : this function effectively stops decoding on reaching targetOutputSize,
288 * so dstCapacity is kind of redundant.
289 * This is because in older versions of this function,
290 * decoding operation would still write complete sequences.
291 * Therefore, there was no guarantee that it would stop writing at exactly targetOutputSize,
292 * it could write more bytes, though only up to dstCapacity.
293 * Some "margin" used to be required for this operation to work properly.
294 * Thankfully, this is no longer necessary.
295 * The function nonetheless keeps the same signature, in an effort to preserve API compatibility.
296 *
297 * Note 4 : If srcSize is the exact size of the block,
298 * then targetOutputSize can be any value,
299 * including larger than the block's decompressed size.
300 * The function will, at most, generate block's decompressed size.
301 *
302 * Note 5 : If srcSize is _larger_ than block's compressed size,
303 * then targetOutputSize **MUST** be <= block's decompressed size.
304 * Otherwise, *silent corruption will occur*.
305 */
306LZ4LIB_API int LZ4_decompress_safe_partial (const char* src, char* dst, int srcSize, int targetOutputSize, int dstCapacity);
307
308
309/*-*********************************************
310* Streaming Compression Functions
311***********************************************/
312typedef union LZ4_stream_u LZ4_stream_t; /* incomplete type (defined later) */
313
314/**
315 Note about RC_INVOKED
316
317 - RC_INVOKED is predefined symbol of rc.exe (the resource compiler which is part of MSVC/Visual Studio).
318 https://docs.microsoft.com/en-us/windows/win32/menurc/predefined-macros
319
320 - Since rc.exe is a legacy compiler, it truncates long symbol (> 30 chars)
321 and reports warning "RC4011: identifier truncated".
322
323 - To eliminate the warning, we surround long preprocessor symbol with
324 "#if !defined(RC_INVOKED) ... #endif" block that means
325 "skip this block when rc.exe is trying to read it".
326*/
327#if !defined(RC_INVOKED) /* https://docs.microsoft.com/en-us/windows/win32/menurc/predefined-macros */
328#if !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
329LZ4LIB_API LZ4_stream_t* LZ4_createStream(void);
330LZ4LIB_API int LZ4_freeStream (LZ4_stream_t* streamPtr);
331#endif /* !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION) */
332#endif
333
334/*! LZ4_resetStream_fast() : v1.9.0+
335 * Use this to prepare an LZ4_stream_t for a new chain of dependent blocks
336 * (e.g., LZ4_compress_fast_continue()).
337 *
338 * An LZ4_stream_t must be initialized once before usage.
339 * This is automatically done when created by LZ4_createStream().
340 * However, should the LZ4_stream_t be simply declared on stack (for example),
341 * it's necessary to initialize it first, using LZ4_initStream().
342 *
343 * After init, start any new stream with LZ4_resetStream_fast().
344 * A same LZ4_stream_t can be re-used multiple times consecutively
345 * and compress multiple streams,
346 * provided that it starts each new stream with LZ4_resetStream_fast().
347 *
348 * LZ4_resetStream_fast() is much faster than LZ4_initStream(),
349 * but is not compatible with memory regions containing garbage data.
350 *
351 * Note: it's only useful to call LZ4_resetStream_fast()
352 * in the context of streaming compression.
353 * The *extState* functions perform their own resets.
354 * Invoking LZ4_resetStream_fast() before is redundant, and even counterproductive.
355 */
356LZ4LIB_API void LZ4_resetStream_fast (LZ4_stream_t* streamPtr);
357
358/*! LZ4_loadDict() :
359 * Use this function to reference a static dictionary into LZ4_stream_t.
360 * The dictionary must remain available during compression.
361 * LZ4_loadDict() triggers a reset, so any previous data will be forgotten.
362 * The same dictionary will have to be loaded on decompression side for successful decoding.
363 * Dictionary are useful for better compression of small data (KB range).
364 * While LZ4 accept any input as dictionary,
365 * results are generally better when using Zstandard's Dictionary Builder.
366 * Loading a size of 0 is allowed, and is the same as reset.
367 * @return : loaded dictionary size, in bytes (necessarily <= 64 KB)
368 */
369LZ4LIB_API int LZ4_loadDict (LZ4_stream_t* streamPtr, const char* dictionary, int dictSize);
370
371/*! LZ4_compress_fast_continue() :
372 * Compress 'src' content using data from previously compressed blocks, for better compression ratio.
373 * 'dst' buffer must be already allocated.
374 * If dstCapacity >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster.
375 *
376 * @return : size of compressed block
377 * or 0 if there is an error (typically, cannot fit into 'dst').
378 *
379 * Note 1 : Each invocation to LZ4_compress_fast_continue() generates a new block.
380 * Each block has precise boundaries.
381 * Each block must be decompressed separately, calling LZ4_decompress_*() with relevant metadata.
382 * It's not possible to append blocks together and expect a single invocation of LZ4_decompress_*() to decompress them together.
383 *
384 * Note 2 : The previous 64KB of source data is __assumed__ to remain present, unmodified, at same address in memory !
385 *
386 * Note 3 : When input is structured as a double-buffer, each buffer can have any size, including < 64 KB.
387 * Make sure that buffers are separated, by at least one byte.
388 * This construction ensures that each block only depends on previous block.
389 *
390 * Note 4 : If input buffer is a ring-buffer, it can have any size, including < 64 KB.
391 *
392 * Note 5 : After an error, the stream status is undefined (invalid), it can only be reset or freed.
393 */
394LZ4LIB_API int LZ4_compress_fast_continue (LZ4_stream_t* streamPtr, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
395
396/*! LZ4_saveDict() :
397 * If last 64KB data cannot be guaranteed to remain available at its current memory location,
398 * save it into a safer place (char* safeBuffer).
399 * This is schematically equivalent to a memcpy() followed by LZ4_loadDict(),
400 * but is much faster, because LZ4_saveDict() doesn't need to rebuild tables.
401 * @return : saved dictionary size in bytes (necessarily <= maxDictSize), or 0 if error.
402 */
403LZ4LIB_API int LZ4_saveDict (LZ4_stream_t* streamPtr, char* safeBuffer, int maxDictSize);
404
405
406/*-**********************************************
407* Streaming Decompression Functions
408* Bufferless synchronous API
409************************************************/
410typedef union LZ4_streamDecode_u LZ4_streamDecode_t; /* tracking context */
411
412/*! LZ4_createStreamDecode() and LZ4_freeStreamDecode() :
413 * creation / destruction of streaming decompression tracking context.
414 * A tracking context can be re-used multiple times.
415 */
416#if !defined(RC_INVOKED) /* https://docs.microsoft.com/en-us/windows/win32/menurc/predefined-macros */
417#if !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
418LZ4LIB_API LZ4_streamDecode_t* LZ4_createStreamDecode(void);
419LZ4LIB_API int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream);
420#endif /* !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION) */
421#endif
422
423/*! LZ4_setStreamDecode() :
424 * An LZ4_streamDecode_t context can be allocated once and re-used multiple times.
425 * Use this function to start decompression of a new stream of blocks.
426 * A dictionary can optionally be set. Use NULL or size 0 for a reset order.
427 * Dictionary is presumed stable : it must remain accessible and unmodified during next decompression.
428 * @return : 1 if OK, 0 if error
429 */
430LZ4LIB_API int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize);
431
432/*! LZ4_decoderRingBufferSize() : v1.8.2+
433 * Note : in a ring buffer scenario (optional),
434 * blocks are presumed decompressed next to each other
435 * up to the moment there is not enough remaining space for next block (remainingSize < maxBlockSize),
436 * at which stage it resumes from beginning of ring buffer.
437 * When setting such a ring buffer for streaming decompression,
438 * provides the minimum size of this ring buffer
439 * to be compatible with any source respecting maxBlockSize condition.
440 * @return : minimum ring buffer size,
441 * or 0 if there is an error (invalid maxBlockSize).
442 */
443LZ4LIB_API int LZ4_decoderRingBufferSize(int maxBlockSize);
444#define LZ4_DECODER_RING_BUFFER_SIZE(maxBlockSize) (65536 + 14 + (maxBlockSize)) /* for static allocation; maxBlockSize presumed valid */
445
446/*! LZ4_decompress_*_continue() :
447 * These decoding functions allow decompression of consecutive blocks in "streaming" mode.
448 * A block is an unsplittable entity, it must be presented entirely to a decompression function.
449 * Decompression functions only accepts one block at a time.
450 * The last 64KB of previously decoded data *must* remain available and unmodified at the memory position where they were decoded.
451 * If less than 64KB of data has been decoded, all the data must be present.
452 *
453 * Special : if decompression side sets a ring buffer, it must respect one of the following conditions :
454 * - Decompression buffer size is _at least_ LZ4_decoderRingBufferSize(maxBlockSize).
455 * maxBlockSize is the maximum size of any single block. It can have any value > 16 bytes.
456 * In which case, encoding and decoding buffers do not need to be synchronized.
457 * Actually, data can be produced by any source compliant with LZ4 format specification, and respecting maxBlockSize.
458 * - Synchronized mode :
459 * Decompression buffer size is _exactly_ the same as compression buffer size,
460 * and follows exactly same update rule (block boundaries at same positions),
461 * and decoding function is provided with exact decompressed size of each block (exception for last block of the stream),
462 * _then_ decoding & encoding ring buffer can have any size, including small ones ( < 64 KB).
463 * - Decompression buffer is larger than encoding buffer, by a minimum of maxBlockSize more bytes.
464 * In which case, encoding and decoding buffers do not need to be synchronized,
465 * and encoding ring buffer can have any size, including small ones ( < 64 KB).
466 *
467 * Whenever these conditions are not possible,
468 * save the last 64KB of decoded data into a safe buffer where it can't be modified during decompression,
469 * then indicate where this data is saved using LZ4_setStreamDecode(), before decompressing next block.
470*/
471LZ4LIB_API int
472LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode,
473 const char* src, char* dst,
474 int srcSize, int dstCapacity);
475
476
477/*! LZ4_decompress_*_usingDict() :
478 * These decoding functions work the same as
479 * a combination of LZ4_setStreamDecode() followed by LZ4_decompress_*_continue()
480 * They are stand-alone, and don't need an LZ4_streamDecode_t structure.
481 * Dictionary is presumed stable : it must remain accessible and unmodified during decompression.
482 * Performance tip : Decompression speed can be substantially increased
483 * when dst == dictStart + dictSize.
484 */
485LZ4LIB_API int
486LZ4_decompress_safe_usingDict(const char* src, char* dst,
487 int srcSize, int dstCapacity,
488 const char* dictStart, int dictSize);
489
490LZ4LIB_API int
491LZ4_decompress_safe_partial_usingDict(const char* src, char* dst,
492 int compressedSize,
493 int targetOutputSize, int maxOutputSize,
494 const char* dictStart, int dictSize);
495
496#endif /* LZ4_H_2983827168210 */
497
498
499/*^*************************************
500 * !!!!!! STATIC LINKING ONLY !!!!!!
501 ***************************************/
502
503/*-****************************************************************************
504 * Experimental section
505 *
506 * Symbols declared in this section must be considered unstable. Their
507 * signatures or semantics may change, or they may be removed altogether in the
508 * future. They are therefore only safe to depend on when the caller is
509 * statically linked against the library.
510 *
511 * To protect against unsafe usage, not only are the declarations guarded,
512 * the definitions are hidden by default
513 * when building LZ4 as a shared/dynamic library.
514 *
515 * In order to access these declarations,
516 * define LZ4_STATIC_LINKING_ONLY in your application
517 * before including LZ4's headers.
518 *
519 * In order to make their implementations accessible dynamically, you must
520 * define LZ4_PUBLISH_STATIC_FUNCTIONS when building the LZ4 library.
521 ******************************************************************************/
522
523#ifdef LZ4_STATIC_LINKING_ONLY
524
525#ifndef LZ4_STATIC_3504398509
526#define LZ4_STATIC_3504398509
527
528#ifdef LZ4_PUBLISH_STATIC_FUNCTIONS
529#define LZ4LIB_STATIC_API LZ4LIB_API
530#else
531#define LZ4LIB_STATIC_API
532#endif
533
534
535/*! LZ4_compress_fast_extState_fastReset() :
536 * A variant of LZ4_compress_fast_extState().
537 *
538 * Using this variant avoids an expensive initialization step.
539 * It is only safe to call if the state buffer is known to be correctly initialized already
540 * (see above comment on LZ4_resetStream_fast() for a definition of "correctly initialized").
541 * From a high level, the difference is that
542 * this function initializes the provided state with a call to something like LZ4_resetStream_fast()
543 * while LZ4_compress_fast_extState() starts with a call to LZ4_resetStream().
544 */
545LZ4LIB_STATIC_API int LZ4_compress_fast_extState_fastReset (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
546
547/*! LZ4_attach_dictionary() :
548 * This is an experimental API that allows
549 * efficient use of a static dictionary many times.
550 *
551 * Rather than re-loading the dictionary buffer into a working context before
552 * each compression, or copying a pre-loaded dictionary's LZ4_stream_t into a
553 * working LZ4_stream_t, this function introduces a no-copy setup mechanism,
554 * in which the working stream references the dictionary stream in-place.
555 *
556 * Several assumptions are made about the state of the dictionary stream.
557 * Currently, only streams which have been prepared by LZ4_loadDict() should
558 * be expected to work.
559 *
560 * Alternatively, the provided dictionaryStream may be NULL,
561 * in which case any existing dictionary stream is unset.
562 *
563 * If a dictionary is provided, it replaces any pre-existing stream history.
564 * The dictionary contents are the only history that can be referenced and
565 * logically immediately precede the data compressed in the first subsequent
566 * compression call.
567 *
568 * The dictionary will only remain attached to the working stream through the
569 * first compression call, at the end of which it is cleared. The dictionary
570 * stream (and source buffer) must remain in-place / accessible / unchanged
571 * through the completion of the first compression call on the stream.
572 */
573LZ4LIB_STATIC_API void
574LZ4_attach_dictionary(LZ4_stream_t* workingStream,
575 const LZ4_stream_t* dictionaryStream);
576
577
578/*! In-place compression and decompression
579 *
580 * It's possible to have input and output sharing the same buffer,
581 * for highly constrained memory environments.
582 * In both cases, it requires input to lay at the end of the buffer,
583 * and decompression to start at beginning of the buffer.
584 * Buffer size must feature some margin, hence be larger than final size.
585 *
586 * |<------------------------buffer--------------------------------->|
587 * |<-----------compressed data--------->|
588 * |<-----------decompressed size------------------>|
589 * |<----margin---->|
590 *
591 * This technique is more useful for decompression,
592 * since decompressed size is typically larger,
593 * and margin is short.
594 *
595 * In-place decompression will work inside any buffer
596 * which size is >= LZ4_DECOMPRESS_INPLACE_BUFFER_SIZE(decompressedSize).
597 * This presumes that decompressedSize > compressedSize.
598 * Otherwise, it means compression actually expanded data,
599 * and it would be more efficient to store such data with a flag indicating it's not compressed.
600 * This can happen when data is not compressible (already compressed, or encrypted).
601 *
602 * For in-place compression, margin is larger, as it must be able to cope with both
603 * history preservation, requiring input data to remain unmodified up to LZ4_DISTANCE_MAX,
604 * and data expansion, which can happen when input is not compressible.
605 * As a consequence, buffer size requirements are much higher,
606 * and memory savings offered by in-place compression are more limited.
607 *
608 * There are ways to limit this cost for compression :
609 * - Reduce history size, by modifying LZ4_DISTANCE_MAX.
610 * Note that it is a compile-time constant, so all compressions will apply this limit.
611 * Lower values will reduce compression ratio, except when input_size < LZ4_DISTANCE_MAX,
612 * so it's a reasonable trick when inputs are known to be small.
613 * - Require the compressor to deliver a "maximum compressed size".
614 * This is the `dstCapacity` parameter in `LZ4_compress*()`.
615 * When this size is < LZ4_COMPRESSBOUND(inputSize), then compression can fail,
616 * in which case, the return code will be 0 (zero).
617 * The caller must be ready for these cases to happen,
618 * and typically design a backup scheme to send data uncompressed.
619 * The combination of both techniques can significantly reduce
620 * the amount of margin required for in-place compression.
621 *
622 * In-place compression can work in any buffer
623 * which size is >= (maxCompressedSize)
624 * with maxCompressedSize == LZ4_COMPRESSBOUND(srcSize) for guaranteed compression success.
625 * LZ4_COMPRESS_INPLACE_BUFFER_SIZE() depends on both maxCompressedSize and LZ4_DISTANCE_MAX,
626 * so it's possible to reduce memory requirements by playing with them.
627 */
628
629#define LZ4_DECOMPRESS_INPLACE_MARGIN(compressedSize) (((compressedSize) >> 8) + 32)
630#define LZ4_DECOMPRESS_INPLACE_BUFFER_SIZE(decompressedSize) ((decompressedSize) + LZ4_DECOMPRESS_INPLACE_MARGIN(decompressedSize)) /**< note: presumes that compressedSize < decompressedSize. note2: margin is overestimated a bit, since it could use compressedSize instead */
631
632#ifndef LZ4_DISTANCE_MAX /* history window size; can be user-defined at compile time */
633# define LZ4_DISTANCE_MAX 65535 /* set to maximum value by default */
634#endif
635
636#define LZ4_COMPRESS_INPLACE_MARGIN (LZ4_DISTANCE_MAX + 32) /* LZ4_DISTANCE_MAX can be safely replaced by srcSize when it's smaller */
637#define LZ4_COMPRESS_INPLACE_BUFFER_SIZE(maxCompressedSize) ((maxCompressedSize) + LZ4_COMPRESS_INPLACE_MARGIN) /**< maxCompressedSize is generally LZ4_COMPRESSBOUND(inputSize), but can be set to any lower value, with the risk that compression can fail (return code 0(zero)) */
638
639#endif /* LZ4_STATIC_3504398509 */
640#endif /* LZ4_STATIC_LINKING_ONLY */
641
642
643
644#ifndef LZ4_H_98237428734687
645#define LZ4_H_98237428734687
646
647/*-************************************************************
648 * Private Definitions
649 **************************************************************
650 * Do not use these definitions directly.
651 * They are only exposed to allow static allocation of `LZ4_stream_t` and `LZ4_streamDecode_t`.
652 * Accessing members will expose user code to API and/or ABI break in future versions of the library.
653 **************************************************************/
654#define LZ4_HASHLOG (LZ4_MEMORY_USAGE-2)
655#define LZ4_HASHTABLESIZE (1 << LZ4_MEMORY_USAGE)
656#define LZ4_HASH_SIZE_U32 (1 << LZ4_HASHLOG) /* required as macro for static allocation */
657
658#if defined(__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
659# include <stdint.h>
660 typedef int8_t LZ4_i8;
661 typedef uint8_t LZ4_byte;
662 typedef uint16_t LZ4_u16;
663 typedef uint32_t LZ4_u32;
664#else
665 typedef signed char LZ4_i8;
666 typedef unsigned char LZ4_byte;
667 typedef unsigned short LZ4_u16;
668 typedef unsigned int LZ4_u32;
669#endif
670
671/*! LZ4_stream_t :
672 * Never ever use below internal definitions directly !
673 * These definitions are not API/ABI safe, and may change in future versions.
674 * If you need static allocation, declare or allocate an LZ4_stream_t object.
675**/
676
677typedef struct LZ4_stream_t_internal LZ4_stream_t_internal;
678struct LZ4_stream_t_internal {
679 LZ4_u32 hashTable[LZ4_HASH_SIZE_U32];
680 const LZ4_byte* dictionary;
681 const LZ4_stream_t_internal* dictCtx;
682 LZ4_u32 currentOffset;
683 LZ4_u32 tableType;
684 LZ4_u32 dictSize;
685 /* Implicit padding to ensure structure is aligned */
686};
687
688#define LZ4_STREAM_MINSIZE ((1UL << LZ4_MEMORY_USAGE) + 32) /* static size, for inter-version compatibility */
689union LZ4_stream_u {
690 char minStateSize[LZ4_STREAM_MINSIZE];
691 LZ4_stream_t_internal internal_donotuse;
692}; /* previously typedef'd to LZ4_stream_t */
693
694
695/*! LZ4_initStream() : v1.9.0+
696 * An LZ4_stream_t structure must be initialized at least once.
697 * This is automatically done when invoking LZ4_createStream(),
698 * but it's not when the structure is simply declared on stack (for example).
699 *
700 * Use LZ4_initStream() to properly initialize a newly declared LZ4_stream_t.
701 * It can also initialize any arbitrary buffer of sufficient size,
702 * and will @return a pointer of proper type upon initialization.
703 *
704 * Note : initialization fails if size and alignment conditions are not respected.
705 * In which case, the function will @return NULL.
706 * Note2: An LZ4_stream_t structure guarantees correct alignment and size.
707 * Note3: Before v1.9.0, use LZ4_resetStream() instead
708**/
709LZ4LIB_API LZ4_stream_t* LZ4_initStream (void* buffer, size_t size);
710
711
712/*! LZ4_streamDecode_t :
713 * Never ever use below internal definitions directly !
714 * These definitions are not API/ABI safe, and may change in future versions.
715 * If you need static allocation, declare or allocate an LZ4_streamDecode_t object.
716**/
717typedef struct {
718 const LZ4_byte* externalDict;
719 const LZ4_byte* prefixEnd;
720 size_t extDictSize;
721 size_t prefixSize;
722} LZ4_streamDecode_t_internal;
723
724#define LZ4_STREAMDECODE_MINSIZE 32
725union LZ4_streamDecode_u {
726 char minStateSize[LZ4_STREAMDECODE_MINSIZE];
727 LZ4_streamDecode_t_internal internal_donotuse;
728} ; /* previously typedef'd to LZ4_streamDecode_t */
729
730
731
732/*-************************************
733* Obsolete Functions
734**************************************/
735
736/*! Deprecation warnings
737 *
738 * Deprecated functions make the compiler generate a warning when invoked.
739 * This is meant to invite users to update their source code.
740 * Should deprecation warnings be a problem, it is generally possible to disable them,
741 * typically with -Wno-deprecated-declarations for gcc
742 * or _CRT_SECURE_NO_WARNINGS in Visual.
743 *
744 * Another method is to define LZ4_DISABLE_DEPRECATE_WARNINGS
745 * before including the header file.
746 */
747#ifdef LZ4_DISABLE_DEPRECATE_WARNINGS
748# define LZ4_DEPRECATED(message) /* disable deprecation warnings */
749#else
750# if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */
751# define LZ4_DEPRECATED(message) [[deprecated(message)]]
752# elif defined(_MSC_VER)
753# define LZ4_DEPRECATED(message) __declspec(deprecated(message))
754# elif defined(__clang__) || (defined(__GNUC__) && (__GNUC__ * 10 + __GNUC_MINOR__ >= 45))
755# define LZ4_DEPRECATED(message) __attribute__((deprecated(message)))
756# elif defined(__GNUC__) && (__GNUC__ * 10 + __GNUC_MINOR__ >= 31)
757# define LZ4_DEPRECATED(message) __attribute__((deprecated))
758# else
759# pragma message("WARNING: LZ4_DEPRECATED needs custom implementation for this compiler")
760# define LZ4_DEPRECATED(message) /* disabled */
761# endif
762#endif /* LZ4_DISABLE_DEPRECATE_WARNINGS */
763
764/*! Obsolete compression functions (since v1.7.3) */
765LZ4_DEPRECATED("use LZ4_compress_default() instead") LZ4LIB_API int LZ4_compress (const char* src, char* dest, int srcSize);
766LZ4_DEPRECATED("use LZ4_compress_default() instead") LZ4LIB_API int LZ4_compress_limitedOutput (const char* src, char* dest, int srcSize, int maxOutputSize);
767LZ4_DEPRECATED("use LZ4_compress_fast_extState() instead") LZ4LIB_API int LZ4_compress_withState (void* state, const char* source, char* dest, int inputSize);
768LZ4_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);
769LZ4_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);
770LZ4_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);
771
772/*! Obsolete decompression functions (since v1.8.0) */
773LZ4_DEPRECATED("use LZ4_decompress_fast() instead") LZ4LIB_API int LZ4_uncompress (const char* source, char* dest, int outputSize);
774LZ4_DEPRECATED("use LZ4_decompress_safe() instead") LZ4LIB_API int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize);
775
776/* Obsolete streaming functions (since v1.7.0)
777 * degraded functionality; do not use!
778 *
779 * In order to perform streaming compression, these functions depended on data
780 * that is no longer tracked in the state. They have been preserved as well as
781 * possible: using them will still produce a correct output. However, they don't
782 * actually retain any history between compression calls. The compression ratio
783 * achieved will therefore be no better than compressing each chunk
784 * independently.
785 */
786LZ4_DEPRECATED("Use LZ4_createStream() instead") LZ4LIB_API void* LZ4_create (char* inputBuffer);
787LZ4_DEPRECATED("Use LZ4_createStream() instead") LZ4LIB_API int LZ4_sizeofStreamState(void);
788LZ4_DEPRECATED("Use LZ4_resetStream() instead") LZ4LIB_API int LZ4_resetStreamState(void* state, char* inputBuffer);
789LZ4_DEPRECATED("Use LZ4_saveDict() instead") LZ4LIB_API char* LZ4_slideInputBuffer (void* state);
790
791/*! Obsolete streaming decoding functions (since v1.7.0) */
792LZ4_DEPRECATED("use LZ4_decompress_safe_usingDict() instead") LZ4LIB_API int LZ4_decompress_safe_withPrefix64k (const char* src, char* dst, int compressedSize, int maxDstSize);
793LZ4_DEPRECATED("use LZ4_decompress_fast_usingDict() instead") LZ4LIB_API int LZ4_decompress_fast_withPrefix64k (const char* src, char* dst, int originalSize);
794
795/*! Obsolete LZ4_decompress_fast variants (since v1.9.0) :
796 * These functions used to be faster than LZ4_decompress_safe(),
797 * but this is no longer the case. They are now slower.
798 * This is because LZ4_decompress_fast() doesn't know the input size,
799 * and therefore must progress more cautiously into the input buffer to not read beyond the end of block.
800 * On top of that `LZ4_decompress_fast()` is not protected vs malformed or malicious inputs, making it a security liability.
801 * As a consequence, LZ4_decompress_fast() is strongly discouraged, and deprecated.
802 *
803 * The last remaining LZ4_decompress_fast() specificity is that
804 * it can decompress a block without knowing its compressed size.
805 * Such functionality can be achieved in a more secure manner
806 * by employing LZ4_decompress_safe_partial().
807 *
808 * Parameters:
809 * originalSize : is the uncompressed size to regenerate.
810 * `dst` must be already allocated, its size must be >= 'originalSize' bytes.
811 * @return : number of bytes read from source buffer (== compressed size).
812 * The function expects to finish at block's end exactly.
813 * If the source stream is detected malformed, the function stops decoding and returns a negative result.
814 * note : LZ4_decompress_fast*() requires originalSize. Thanks to this information, it never writes past the output buffer.
815 * However, since it doesn't know its 'src' size, it may read an unknown amount of input, past input buffer bounds.
816 * Also, since match offsets are not validated, match reads from 'src' may underflow too.
817 * These issues never happen if input (compressed) data is correct.
818 * But they may happen if input data is invalid (error or intentional tampering).
819 * As a consequence, use these functions in trusted environments with trusted data **only**.
820 */
821LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe() instead")
822LZ4LIB_API int LZ4_decompress_fast (const char* src, char* dst, int originalSize);
823LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe_continue() instead")
824LZ4LIB_API int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* src, char* dst, int originalSize);
825LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe_usingDict() instead")
826LZ4LIB_API int LZ4_decompress_fast_usingDict (const char* src, char* dst, int originalSize, const char* dictStart, int dictSize);
827
828/*! LZ4_resetStream() :
829 * An LZ4_stream_t structure must be initialized at least once.
830 * This is done with LZ4_initStream(), or LZ4_resetStream().
831 * Consider switching to LZ4_initStream(),
832 * invoking LZ4_resetStream() will trigger deprecation warnings in the future.
833 */
834LZ4LIB_API void LZ4_resetStream (LZ4_stream_t* streamPtr);
835
836
837#endif /* LZ4_H_98237428734687 */
838
839
840#if defined (__cplusplus)
841}
842#endif
843