1/*
2 LZ4 auto-framing library
3 Header File
4 Copyright (C) 2011-2017, 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 constant such as LZ4_VERSION_NUMBER.
43 * */
44
45#ifndef LZ4F_H_09782039843
46#define LZ4F_H_09782039843
47
48#if defined (__cplusplus)
49extern "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 (doc/lz4_Frame_format.md).
60 lz4frame.h provides frame compression functions that take care
61 of encoding standard metadata alongside LZ4-compressed blocks.
62*/
63
64/*-***************************************************************
65 * Compiler specifics
66 *****************************************************************/
67/* LZ4_DLL_EXPORT :
68 * Enable exporting of functions when building a Windows DLL
69 * LZ4FLIB_API :
70 * Control library symbols visibility.
71 */
72#if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1)
73# define LZ4FLIB_API __declspec(dllexport)
74#elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1)
75# define LZ4FLIB_API __declspec(dllimport)
76#elif defined(__GNUC__) && (__GNUC__ >= 4)
77# define LZ4FLIB_API __attribute__ ((__visibility__ ("default")))
78#else
79# define LZ4FLIB_API
80#endif
81
82#ifdef LZ4F_DISABLE_DEPRECATE_WARNINGS
83# define LZ4F_DEPRECATE(x) x
84#else
85# if defined(_MSC_VER)
86# define LZ4F_DEPRECATE(x) x /* __declspec(deprecated) x - only works with C++ */
87# elif defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 6))
88# define LZ4F_DEPRECATE(x) x __attribute__((deprecated))
89# else
90# define LZ4F_DEPRECATE(x) x /* no deprecation warning for this compiler */
91# endif
92#endif
93
94
95/*-************************************
96 * Error management
97 **************************************/
98typedef size_t LZ4F_errorCode_t;
99
100LZ4FLIB_API unsigned LZ4F_isError(LZ4F_errorCode_t code); /**< tells when a function result is an error code */
101LZ4FLIB_API const char* LZ4F_getErrorName(LZ4F_errorCode_t code); /**< return error code string; for debugging */
102
103
104/*-************************************
105 * Frame compression types
106 **************************************/
107/* #define LZ4F_ENABLE_OBSOLETE_ENUMS // uncomment to enable obsolete enums */
108#ifdef LZ4F_ENABLE_OBSOLETE_ENUMS
109# define LZ4F_OBSOLETE_ENUM(x) , LZ4F_DEPRECATE(x) = LZ4F_##x
110#else
111# define LZ4F_OBSOLETE_ENUM(x)
112#endif
113
114/* The larger the block size, the (slightly) better the compression ratio,
115 * though there are diminishing returns.
116 * Larger blocks also increase memory usage on both compression and decompression sides. */
117typedef enum {
118 LZ4F_default=0,
119 LZ4F_max64KB=4,
120 LZ4F_max256KB=5,
121 LZ4F_max1MB=6,
122 LZ4F_max4MB=7
123 LZ4F_OBSOLETE_ENUM(max64KB)
124 LZ4F_OBSOLETE_ENUM(max256KB)
125 LZ4F_OBSOLETE_ENUM(max1MB)
126 LZ4F_OBSOLETE_ENUM(max4MB)
127} LZ4F_blockSizeID_t;
128
129/* Linked blocks sharply reduce inefficiencies when using small blocks,
130 * they compress better.
131 * However, some LZ4 decoders are only compatible with independent blocks */
132typedef enum {
133 LZ4F_blockLinked=0,
134 LZ4F_blockIndependent
135 LZ4F_OBSOLETE_ENUM(blockLinked)
136 LZ4F_OBSOLETE_ENUM(blockIndependent)
137} LZ4F_blockMode_t;
138
139typedef enum {
140 LZ4F_noContentChecksum=0,
141 LZ4F_contentChecksumEnabled
142 LZ4F_OBSOLETE_ENUM(noContentChecksum)
143 LZ4F_OBSOLETE_ENUM(contentChecksumEnabled)
144} LZ4F_contentChecksum_t;
145
146typedef enum {
147 LZ4F_noBlockChecksum=0,
148 LZ4F_blockChecksumEnabled
149} LZ4F_blockChecksum_t;
150
151typedef enum {
152 LZ4F_frame=0,
153 LZ4F_skippableFrame
154 LZ4F_OBSOLETE_ENUM(skippableFrame)
155} LZ4F_frameType_t;
156
157#ifdef LZ4F_ENABLE_OBSOLETE_ENUMS
158typedef LZ4F_blockSizeID_t blockSizeID_t;
159typedef LZ4F_blockMode_t blockMode_t;
160typedef LZ4F_frameType_t frameType_t;
161typedef LZ4F_contentChecksum_t contentChecksum_t;
162#endif
163
164/*! LZ4F_frameInfo_t :
165 * makes it possible to set or read frame parameters.
166 * Structure must be first init to 0, using memset() or LZ4F_INIT_FRAMEINFO,
167 * setting all parameters to default.
168 * It's then possible to update selectively some parameters */
169typedef struct {
170 LZ4F_blockSizeID_t blockSizeID; /* max64KB, max256KB, max1MB, max4MB; 0 == default */
171 LZ4F_blockMode_t blockMode; /* LZ4F_blockLinked, LZ4F_blockIndependent; 0 == default */
172 LZ4F_contentChecksum_t contentChecksumFlag; /* 1: frame terminated with 32-bit checksum of decompressed data; 0: disabled (default) */
173 LZ4F_frameType_t frameType; /* read-only field : LZ4F_frame or LZ4F_skippableFrame */
174 unsigned long long contentSize; /* Size of uncompressed content ; 0 == unknown */
175 unsigned dictID; /* Dictionary ID, sent by compressor to help decoder select correct dictionary; 0 == no dictID provided */
176 LZ4F_blockChecksum_t blockChecksumFlag; /* 1: each block followed by a checksum of block's compressed data; 0: disabled (default) */
177} LZ4F_frameInfo_t;
178
179#define LZ4F_INIT_FRAMEINFO { LZ4F_default, LZ4F_blockLinked, LZ4F_noContentChecksum, LZ4F_frame, 0ULL, 0U, LZ4F_noBlockChecksum } /* v1.8.3+ */
180
181/*! LZ4F_preferences_t :
182 * makes it possible to supply advanced compression instructions to streaming interface.
183 * Structure must be first init to 0, using memset() or LZ4F_INIT_PREFERENCES,
184 * setting all parameters to default.
185 * All reserved fields must be set to zero. */
186typedef struct {
187 LZ4F_frameInfo_t frameInfo;
188 int compressionLevel; /* 0: default (fast mode); values > LZ4HC_CLEVEL_MAX count as LZ4HC_CLEVEL_MAX; values < 0 trigger "fast acceleration" */
189 unsigned autoFlush; /* 1: always flush; reduces usage of internal buffers */
190 unsigned favorDecSpeed; /* 1: parser favors decompression speed vs compression ratio. Only works for high compression modes (>= LZ4HC_CLEVEL_OPT_MIN) */ /* v1.8.2+ */
191 unsigned reserved[3]; /* must be zero for forward compatibility */
192} LZ4F_preferences_t;
193
194#define LZ4F_INIT_PREFERENCES { LZ4F_INIT_FRAMEINFO, 0, 0u, 0u, { 0u, 0u, 0u } } /* v1.8.3+ */
195
196
197/*-*********************************
198* Simple compression function
199***********************************/
200
201LZ4FLIB_API int LZ4F_compressionLevel_max(void); /* v1.8.0+ */
202
203/*! LZ4F_compressFrameBound() :
204 * Returns the maximum possible compressed size with LZ4F_compressFrame() given srcSize and preferences.
205 * `preferencesPtr` is optional. It can be replaced by NULL, in which case, the function will assume default preferences.
206 * Note : this result is only usable with LZ4F_compressFrame().
207 * It may also be used with LZ4F_compressUpdate() _if no flush() operation_ is performed.
208 */
209LZ4FLIB_API size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr);
210
211/*! LZ4F_compressFrame() :
212 * Compress an entire srcBuffer into a valid LZ4 frame.
213 * dstCapacity MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr).
214 * The LZ4F_preferences_t structure is optional : you can provide NULL as argument. All preferences will be set to default.
215 * @return : number of bytes written into dstBuffer.
216 * or an error code if it fails (can be tested using LZ4F_isError())
217 */
218LZ4FLIB_API size_t LZ4F_compressFrame(void* dstBuffer, size_t dstCapacity,
219 const void* srcBuffer, size_t srcSize,
220 const LZ4F_preferences_t* preferencesPtr);
221
222
223/*-***********************************
224* Advanced compression functions
225*************************************/
226typedef struct LZ4F_cctx_s LZ4F_cctx; /* incomplete type */
227typedef LZ4F_cctx* LZ4F_compressionContext_t; /* for compatibility with previous API version */
228
229typedef struct {
230 unsigned stableSrc; /* 1 == src content will remain present on future calls to LZ4F_compress(); skip copying src content within tmp buffer */
231 unsigned reserved[3];
232} LZ4F_compressOptions_t;
233
234/*--- Resource Management ---*/
235
236#define LZ4F_VERSION 100 /* This number can be used to check for an incompatible API breaking change */
237LZ4FLIB_API unsigned LZ4F_getVersion(void);
238
239/*! LZ4F_createCompressionContext() :
240 * The first thing to do is to create a compressionContext object, which will be used in all compression operations.
241 * This is achieved using LZ4F_createCompressionContext(), which takes as argument a version.
242 * The version provided MUST be LZ4F_VERSION. It is intended to track potential version mismatch, notably when using DLL.
243 * The function will provide a pointer to a fully allocated LZ4F_cctx object.
244 * If @return != zero, there was an error during context creation.
245 * Object can release its memory using LZ4F_freeCompressionContext();
246 */
247LZ4FLIB_API LZ4F_errorCode_t LZ4F_createCompressionContext(LZ4F_cctx** cctxPtr, unsigned version);
248LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_cctx* cctx);
249
250
251/*---- Compression ----*/
252
253#define LZ4F_HEADER_SIZE_MIN 7 /* LZ4 Frame header size can vary, depending on selected paramaters */
254#define LZ4F_HEADER_SIZE_MAX 19
255
256/* Size in bytes of a block header in little-endian format. Highest bit indicates if block data is uncompressed */
257#define LZ4F_BLOCK_HEADER_SIZE 4
258
259/* Size in bytes of a block checksum footer in little-endian format. */
260#define LZ4F_BLOCK_CHECKSUM_SIZE 4
261
262/* Size in bytes of the content checksum. */
263#define LZ4F_CONTENT_CHECKSUM_SIZE 4
264
265/*! LZ4F_compressBegin() :
266 * will write the frame header into dstBuffer.
267 * dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes.
268 * `prefsPtr` is optional : you can provide NULL as argument, all preferences will then be set to default.
269 * @return : number of bytes written into dstBuffer for the header
270 * or an error code (which can be tested using LZ4F_isError())
271 */
272LZ4FLIB_API size_t LZ4F_compressBegin(LZ4F_cctx* cctx,
273 void* dstBuffer, size_t dstCapacity,
274 const LZ4F_preferences_t* prefsPtr);
275
276/*! LZ4F_compressBound() :
277 * Provides minimum dstCapacity required to guarantee success of
278 * LZ4F_compressUpdate(), given a srcSize and preferences, for a worst case scenario.
279 * When srcSize==0, LZ4F_compressBound() provides an upper bound for LZ4F_flush() and LZ4F_compressEnd() instead.
280 * Note that the result is only valid for a single invocation of LZ4F_compressUpdate().
281 * When invoking LZ4F_compressUpdate() multiple times,
282 * if the output buffer is gradually filled up instead of emptied and re-used from its start,
283 * one must check if there is enough remaining capacity before each invocation, using LZ4F_compressBound().
284 * @return is always the same for a srcSize and prefsPtr.
285 * prefsPtr is optional : when NULL is provided, preferences will be set to cover worst case scenario.
286 * tech details :
287 * @return includes the possibility that internal buffer might already be filled by up to (blockSize-1) bytes.
288 * It also includes frame footer (ending + checksum), since it might be generated by LZ4F_compressEnd().
289 * @return doesn't include frame header, as it was already generated by LZ4F_compressBegin().
290 */
291LZ4FLIB_API size_t LZ4F_compressBound(size_t srcSize, const LZ4F_preferences_t* prefsPtr);
292
293/*! LZ4F_compressUpdate() :
294 * LZ4F_compressUpdate() can be called repetitively to compress as much data as necessary.
295 * Important rule: dstCapacity MUST be large enough to ensure operation success even in worst case situations.
296 * This value is provided by LZ4F_compressBound().
297 * If this condition is not respected, LZ4F_compress() will fail (result is an errorCode).
298 * LZ4F_compressUpdate() doesn't guarantee error recovery.
299 * When an error occurs, compression context must be freed or resized.
300 * `cOptPtr` is optional : NULL can be provided, in which case all options are set to default.
301 * @return : number of bytes written into `dstBuffer` (it can be zero, meaning input data was just buffered).
302 * or an error code if it fails (which can be tested using LZ4F_isError())
303 */
304LZ4FLIB_API size_t LZ4F_compressUpdate(LZ4F_cctx* cctx,
305 void* dstBuffer, size_t dstCapacity,
306 const void* srcBuffer, size_t srcSize,
307 const LZ4F_compressOptions_t* cOptPtr);
308
309/*! LZ4F_flush() :
310 * When data must be generated and sent immediately, without waiting for a block to be completely filled,
311 * it's possible to call LZ4_flush(). It will immediately compress any data buffered within cctx.
312 * `dstCapacity` must be large enough to ensure the operation will be successful.
313 * `cOptPtr` is optional : it's possible to provide NULL, all options will be set to default.
314 * @return : nb of bytes written into dstBuffer (can be zero, when there is no data stored within cctx)
315 * or an error code if it fails (which can be tested using LZ4F_isError())
316 * Note : LZ4F_flush() is guaranteed to be successful when dstCapacity >= LZ4F_compressBound(0, prefsPtr).
317 */
318LZ4FLIB_API size_t LZ4F_flush(LZ4F_cctx* cctx,
319 void* dstBuffer, size_t dstCapacity,
320 const LZ4F_compressOptions_t* cOptPtr);
321
322/*! LZ4F_compressEnd() :
323 * To properly finish an LZ4 frame, invoke LZ4F_compressEnd().
324 * It will flush whatever data remained within `cctx` (like LZ4_flush())
325 * and properly finalize the frame, with an endMark and a checksum.
326 * `cOptPtr` is optional : NULL can be provided, in which case all options will be set to default.
327 * @return : nb of bytes written into dstBuffer, necessarily >= 4 (endMark),
328 * or an error code if it fails (which can be tested using LZ4F_isError())
329 * Note : LZ4F_compressEnd() is guaranteed to be successful when dstCapacity >= LZ4F_compressBound(0, prefsPtr).
330 * A successful call to LZ4F_compressEnd() makes `cctx` available again for another compression task.
331 */
332LZ4FLIB_API size_t LZ4F_compressEnd(LZ4F_cctx* cctx,
333 void* dstBuffer, size_t dstCapacity,
334 const LZ4F_compressOptions_t* cOptPtr);
335
336
337/*-*********************************
338* Decompression functions
339***********************************/
340typedef struct LZ4F_dctx_s LZ4F_dctx; /* incomplete type */
341typedef LZ4F_dctx* LZ4F_decompressionContext_t; /* compatibility with previous API versions */
342
343typedef struct {
344 unsigned stableDst; /* pledges that last 64KB decompressed data will remain available unmodified. This optimization skips storage operations in tmp buffers. */
345 unsigned reserved[3]; /* must be set to zero for forward compatibility */
346} LZ4F_decompressOptions_t;
347
348
349/* Resource management */
350
351/*! LZ4F_createDecompressionContext() :
352 * Create an LZ4F_dctx object, to track all decompression operations.
353 * The version provided MUST be LZ4F_VERSION.
354 * The function provides a pointer to an allocated and initialized LZ4F_dctx object.
355 * The result is an errorCode, which can be tested using LZ4F_isError().
356 * dctx memory can be released using LZ4F_freeDecompressionContext();
357 * Result of LZ4F_freeDecompressionContext() indicates current state of decompressionContext when being released.
358 * That is, it should be == 0 if decompression has been completed fully and correctly.
359 */
360LZ4FLIB_API LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_dctx** dctxPtr, unsigned version);
361LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* dctx);
362
363
364/*-***********************************
365* Streaming decompression functions
366*************************************/
367
368#define LZ4F_MIN_SIZE_TO_KNOW_HEADER_LENGTH 5
369
370/*! LZ4F_headerSize() : v1.9.0+
371 * Provide the header size of a frame starting at `src`.
372 * `srcSize` must be >= LZ4F_MIN_SIZE_TO_KNOW_HEADER_LENGTH,
373 * which is enough to decode the header length.
374 * @return : size of frame header
375 * or an error code, which can be tested using LZ4F_isError()
376 * note : Frame header size is variable, but is guaranteed to be
377 * >= LZ4F_HEADER_SIZE_MIN bytes, and <= LZ4F_HEADER_SIZE_MAX bytes.
378 */
379size_t LZ4F_headerSize(const void* src, size_t srcSize);
380
381/*! LZ4F_getFrameInfo() :
382 * This function extracts frame parameters (max blockSize, dictID, etc.).
383 * Its usage is optional: user can call LZ4F_decompress() directly.
384 *
385 * Extracted information will fill an existing LZ4F_frameInfo_t structure.
386 * This can be useful for allocation and dictionary identification purposes.
387 *
388 * LZ4F_getFrameInfo() can work in the following situations :
389 *
390 * 1) At the beginning of a new frame, before any invocation of LZ4F_decompress().
391 * It will decode header from `srcBuffer`,
392 * consuming the header and starting the decoding process.
393 *
394 * Input size must be large enough to contain the full frame header.
395 * Frame header size can be known beforehand by LZ4F_headerSize().
396 * Frame header size is variable, but is guaranteed to be >= LZ4F_HEADER_SIZE_MIN bytes,
397 * and not more than <= LZ4F_HEADER_SIZE_MAX bytes.
398 * Hence, blindly providing LZ4F_HEADER_SIZE_MAX bytes or more will always work.
399 * It's allowed to provide more input data than the header size,
400 * LZ4F_getFrameInfo() will only consume the header.
401 *
402 * If input size is not large enough,
403 * aka if it's smaller than header size,
404 * function will fail and return an error code.
405 *
406 * 2) After decoding has been started,
407 * it's possible to invoke LZ4F_getFrameInfo() anytime
408 * to extract already decoded frame parameters stored within dctx.
409 *
410 * Note that, if decoding has barely started,
411 * and not yet read enough information to decode the header,
412 * LZ4F_getFrameInfo() will fail.
413 *
414 * The number of bytes consumed from srcBuffer will be updated in *srcSizePtr (necessarily <= original value).
415 * LZ4F_getFrameInfo() only consumes bytes when decoding has not yet started,
416 * and when decoding the header has been successful.
417 * Decompression must then resume from (srcBuffer + *srcSizePtr).
418 *
419 * @return : a hint about how many srcSize bytes LZ4F_decompress() expects for next call,
420 * or an error code which can be tested using LZ4F_isError().
421 * note 1 : in case of error, dctx is not modified. Decoding operation can resume from beginning safely.
422 * note 2 : frame parameters are *copied into* an already allocated LZ4F_frameInfo_t structure.
423 */
424LZ4FLIB_API size_t LZ4F_getFrameInfo(LZ4F_dctx* dctx,
425 LZ4F_frameInfo_t* frameInfoPtr,
426 const void* srcBuffer, size_t* srcSizePtr);
427
428/*! LZ4F_decompress() :
429 * Call this function repetitively to regenerate compressed data from `srcBuffer`.
430 * The function will read up to *srcSizePtr bytes from srcBuffer,
431 * and decompress data into dstBuffer, of capacity *dstSizePtr.
432 *
433 * The nb of bytes consumed from srcBuffer will be written into *srcSizePtr (necessarily <= original value).
434 * The nb of bytes decompressed into dstBuffer will be written into *dstSizePtr (necessarily <= original value).
435 *
436 * The function does not necessarily read all input bytes, so always check value in *srcSizePtr.
437 * Unconsumed source data must be presented again in subsequent invocations.
438 *
439 * `dstBuffer` can freely change between each consecutive function invocation.
440 * `dstBuffer` content will be overwritten.
441 *
442 * @return : an hint of how many `srcSize` bytes LZ4F_decompress() expects for next call.
443 * Schematically, it's the size of the current (or remaining) compressed block + header of next block.
444 * Respecting the hint provides some small speed benefit, because it skips intermediate buffers.
445 * This is just a hint though, it's always possible to provide any srcSize.
446 *
447 * When a frame is fully decoded, @return will be 0 (no more data expected).
448 * When provided with more bytes than necessary to decode a frame,
449 * LZ4F_decompress() will stop reading exactly at end of current frame, and @return 0.
450 *
451 * If decompression failed, @return is an error code, which can be tested using LZ4F_isError().
452 * After a decompression error, the `dctx` context is not resumable.
453 * Use LZ4F_resetDecompressionContext() to return to clean state.
454 *
455 * After a frame is fully decoded, dctx can be used again to decompress another frame.
456 */
457LZ4FLIB_API size_t LZ4F_decompress(LZ4F_dctx* dctx,
458 void* dstBuffer, size_t* dstSizePtr,
459 const void* srcBuffer, size_t* srcSizePtr,
460 const LZ4F_decompressOptions_t* dOptPtr);
461
462
463/*! LZ4F_resetDecompressionContext() : added in v1.8.0
464 * In case of an error, the context is left in "undefined" state.
465 * In which case, it's necessary to reset it, before re-using it.
466 * This method can also be used to abruptly stop any unfinished decompression,
467 * and start a new one using same context resources. */
468LZ4FLIB_API void LZ4F_resetDecompressionContext(LZ4F_dctx* dctx); /* always successful */
469
470
471
472#if defined (__cplusplus)
473}
474#endif
475
476#endif /* LZ4F_H_09782039843 */
477
478#if defined(LZ4F_STATIC_LINKING_ONLY) && !defined(LZ4F_H_STATIC_09782039843)
479#define LZ4F_H_STATIC_09782039843
480
481#if defined (__cplusplus)
482extern "C" {
483#endif
484
485/* These declarations are not stable and may change in the future.
486 * They are therefore only safe to depend on
487 * when the caller is statically linked against the library.
488 * To access their declarations, define LZ4F_STATIC_LINKING_ONLY.
489 *
490 * By default, these symbols aren't published into shared/dynamic libraries.
491 * You can override this behavior and force them to be published
492 * by defining LZ4F_PUBLISH_STATIC_FUNCTIONS.
493 * Use at your own risk.
494 */
495#ifdef LZ4F_PUBLISH_STATIC_FUNCTIONS
496#define LZ4FLIB_STATIC_API LZ4FLIB_API
497#else
498#define LZ4FLIB_STATIC_API
499#endif
500
501
502/* --- Error List --- */
503#define LZ4F_LIST_ERRORS(ITEM) \
504 ITEM(OK_NoError) \
505 ITEM(ERROR_GENERIC) \
506 ITEM(ERROR_maxBlockSize_invalid) \
507 ITEM(ERROR_blockMode_invalid) \
508 ITEM(ERROR_contentChecksumFlag_invalid) \
509 ITEM(ERROR_compressionLevel_invalid) \
510 ITEM(ERROR_headerVersion_wrong) \
511 ITEM(ERROR_blockChecksum_invalid) \
512 ITEM(ERROR_reservedFlag_set) \
513 ITEM(ERROR_allocation_failed) \
514 ITEM(ERROR_srcSize_tooLarge) \
515 ITEM(ERROR_dstMaxSize_tooSmall) \
516 ITEM(ERROR_frameHeader_incomplete) \
517 ITEM(ERROR_frameType_unknown) \
518 ITEM(ERROR_frameSize_wrong) \
519 ITEM(ERROR_srcPtr_wrong) \
520 ITEM(ERROR_decompressionFailed) \
521 ITEM(ERROR_headerChecksum_invalid) \
522 ITEM(ERROR_contentChecksum_invalid) \
523 ITEM(ERROR_frameDecoding_alreadyStarted) \
524 ITEM(ERROR_maxCode)
525
526#define LZ4F_GENERATE_ENUM(ENUM) LZ4F_##ENUM,
527
528/* enum list is exposed, to handle specific errors */
529typedef enum { LZ4F_LIST_ERRORS(LZ4F_GENERATE_ENUM)
530 _LZ4F_dummy_error_enum_for_c89_never_used } LZ4F_errorCodes;
531
532LZ4FLIB_STATIC_API LZ4F_errorCodes LZ4F_getErrorCode(size_t functionResult);
533
534LZ4FLIB_STATIC_API size_t LZ4F_getBlockSize(unsigned);
535
536/**********************************
537 * Bulk processing dictionary API
538 *********************************/
539
540/* A Dictionary is useful for the compression of small messages (KB range).
541 * It dramatically improves compression efficiency.
542 *
543 * LZ4 can ingest any input as dictionary, though only the last 64 KB are useful.
544 * Best results are generally achieved by using Zstandard's Dictionary Builder
545 * to generate a high-quality dictionary from a set of samples.
546 *
547 * Loading a dictionary has a cost, since it involves construction of tables.
548 * The Bulk processing dictionary API makes it possible to share this cost
549 * over an arbitrary number of compression jobs, even concurrently,
550 * markedly improving compression latency for these cases.
551 *
552 * The same dictionary will have to be used on the decompression side
553 * for decoding to be successful.
554 * To help identify the correct dictionary at decoding stage,
555 * the frame header allows optional embedding of a dictID field.
556 */
557typedef struct LZ4F_CDict_s LZ4F_CDict;
558
559/*! LZ4_createCDict() :
560 * When compressing multiple messages / blocks using the same dictionary, it's recommended to load it just once.
561 * LZ4_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
562 * LZ4_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only.
563 * `dictBuffer` can be released after LZ4_CDict creation, since its content is copied within CDict */
564LZ4FLIB_STATIC_API LZ4F_CDict* LZ4F_createCDict(const void* dictBuffer, size_t dictSize);
565LZ4FLIB_STATIC_API void LZ4F_freeCDict(LZ4F_CDict* CDict);
566
567
568/*! LZ4_compressFrame_usingCDict() :
569 * Compress an entire srcBuffer into a valid LZ4 frame using a digested Dictionary.
570 * cctx must point to a context created by LZ4F_createCompressionContext().
571 * If cdict==NULL, compress without a dictionary.
572 * dstBuffer MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr).
573 * If this condition is not respected, function will fail (@return an errorCode).
574 * The LZ4F_preferences_t structure is optional : you may provide NULL as argument,
575 * but it's not recommended, as it's the only way to provide dictID in the frame header.
576 * @return : number of bytes written into dstBuffer.
577 * or an error code if it fails (can be tested using LZ4F_isError()) */
578LZ4FLIB_STATIC_API size_t LZ4F_compressFrame_usingCDict(
579 LZ4F_cctx* cctx,
580 void* dst, size_t dstCapacity,
581 const void* src, size_t srcSize,
582 const LZ4F_CDict* cdict,
583 const LZ4F_preferences_t* preferencesPtr);
584
585
586/*! LZ4F_compressBegin_usingCDict() :
587 * Inits streaming dictionary compression, and writes the frame header into dstBuffer.
588 * dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes.
589 * `prefsPtr` is optional : you may provide NULL as argument,
590 * however, it's the only way to provide dictID in the frame header.
591 * @return : number of bytes written into dstBuffer for the header,
592 * or an error code (which can be tested using LZ4F_isError()) */
593LZ4FLIB_STATIC_API size_t LZ4F_compressBegin_usingCDict(
594 LZ4F_cctx* cctx,
595 void* dstBuffer, size_t dstCapacity,
596 const LZ4F_CDict* cdict,
597 const LZ4F_preferences_t* prefsPtr);
598
599
600/*! LZ4F_decompress_usingDict() :
601 * Same as LZ4F_decompress(), using a predefined dictionary.
602 * Dictionary is used "in place", without any preprocessing.
603 * It must remain accessible throughout the entire frame decoding. */
604LZ4FLIB_STATIC_API size_t LZ4F_decompress_usingDict(
605 LZ4F_dctx* dctxPtr,
606 void* dstBuffer, size_t* dstSizePtr,
607 const void* srcBuffer, size_t* srcSizePtr,
608 const void* dict, size_t dictSize,
609 const LZ4F_decompressOptions_t* decompressOptionsPtr);
610
611#if defined (__cplusplus)
612}
613#endif
614
615#endif /* defined(LZ4F_STATIC_LINKING_ONLY) && !defined(LZ4F_H_STATIC_09782039843) */
616