lz4 (1.9.4)
1 /*
2 LZ4F - LZ4-Frame library
3 Header File
4 Copyright (C) 2011-2020, Yann Collet.
5 BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
6
7 Redistribution and use in source and binary forms, with or without
8 modification, are permitted provided that the following conditions are
9 met:
10
11 * Redistributions of source code must retain the above copyright
12 notice, this list of conditions and the following disclaimer.
13 * Redistributions in binary form must reproduce the above
14 copyright notice, this list of conditions and the following disclaimer
15 in the documentation and/or other materials provided with the
16 distribution.
17
18 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30 You can contact the author at :
31 - LZ4 source repository : https://github.com/lz4/lz4
32 - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
33 */
34
35 /* LZ4F is a stand-alone API able to create and decode LZ4 frames
36 * conformant with specification v1.6.1 in doc/lz4_Frame_format.md .
37 * Generated frames are compatible with `lz4` CLI.
38 *
39 * LZ4F also offers streaming capabilities.
40 *
41 * lz4.h is not required when using lz4frame.h,
42 * except to extract common constants such as LZ4_VERSION_NUMBER.
43 * */
44
45 #ifndef LZ4F_H_09782039843
46 #define LZ4F_H_09782039843
47
48 #if defined (__cplusplus)
49 extern "C" {
50 #endif
51
52 /* --- Dependency --- */
53 #include <stddef.h> /* size_t */
54
55
56 /**
57 * Introduction
58 *
59 * lz4frame.h implements LZ4 frame specification: see doc/lz4_Frame_format.md .
60 * LZ4 Frames are compatible with `lz4` CLI,
61 * and designed to be interoperable with any system.
62 **/
63
64 /*-***************************************************************
65 * Compiler specifics
66 *****************************************************************/
67 /* LZ4_DLL_EXPORT :
68 * Enable exporting of functions when building a Windows DLL
69 * LZ4FLIB_VISIBILITY :
70 * Control library symbols visibility.
71 */
72 #ifndef LZ4FLIB_VISIBILITY
73 # if defined(__GNUC__) && (__GNUC__ >= 4)
74 # define LZ4FLIB_VISIBILITY __attribute__ ((visibility ("default")))
75 # else
76 # define LZ4FLIB_VISIBILITY
77 # endif
78 #endif
79 #if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1)
80 # define LZ4FLIB_API __declspec(dllexport) LZ4FLIB_VISIBILITY
81 #elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1)
82 # define LZ4FLIB_API __declspec(dllimport) LZ4FLIB_VISIBILITY
83 #else
84 # define LZ4FLIB_API LZ4FLIB_VISIBILITY
85 #endif
86
87 #ifdef LZ4F_DISABLE_DEPRECATE_WARNINGS
88 # define LZ4F_DEPRECATE(x) x
89 #else
90 # if defined(_MSC_VER)
91 # define LZ4F_DEPRECATE(x) x /* __declspec(deprecated) x - only works with C++ */
92 # elif defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 6))
93 # define LZ4F_DEPRECATE(x) x __attribute__((deprecated))
94 # else
95 # define LZ4F_DEPRECATE(x) x /* no deprecation warning for this compiler */
96 # endif
97 #endif
98
99
100 /*-************************************
101 * Error management
102 **************************************/
103 typedef size_t LZ4F_errorCode_t;
104
105 LZ4FLIB_API unsigned LZ4F_isError(LZ4F_errorCode_t code); /**< tells when a function result is an error code */
106 LZ4FLIB_API const char* LZ4F_getErrorName(LZ4F_errorCode_t code); /**< return error code string; for debugging */
107
108
109 /*-************************************
110 * Frame compression types
111 ************************************* */
112 /* #define LZ4F_ENABLE_OBSOLETE_ENUMS // uncomment to enable obsolete enums */
113 #ifdef LZ4F_ENABLE_OBSOLETE_ENUMS
114 # define LZ4F_OBSOLETE_ENUM(x) , LZ4F_DEPRECATE(x) = LZ4F_##x
115 #else
116 # define LZ4F_OBSOLETE_ENUM(x)
117 #endif
118
119 /* The larger the block size, the (slightly) better the compression ratio,
120 * though there are diminishing returns.
121 * Larger blocks also increase memory usage on both compression and decompression sides.
122 */
123 typedef enum {
124 LZ4F_default=0,
125 LZ4F_max64KB=4,
126 LZ4F_max256KB=5,
127 LZ4F_max1MB=6,
128 LZ4F_max4MB=7
129 LZ4F_OBSOLETE_ENUM(max64KB)
130 LZ4F_OBSOLETE_ENUM(max256KB)
131 LZ4F_OBSOLETE_ENUM(max1MB)
132 LZ4F_OBSOLETE_ENUM(max4MB)
133 } LZ4F_blockSizeID_t;
134
135 /* Linked blocks sharply reduce inefficiencies when using small blocks,
136 * they compress better.
137 * However, some LZ4 decoders are only compatible with independent blocks */
138 typedef enum {
139 LZ4F_blockLinked=0,
140 LZ4F_blockIndependent
141 LZ4F_OBSOLETE_ENUM(blockLinked)
142 LZ4F_OBSOLETE_ENUM(blockIndependent)
143 } LZ4F_blockMode_t;
144
145 typedef enum {
146 LZ4F_noContentChecksum=0,
147 LZ4F_contentChecksumEnabled
148 LZ4F_OBSOLETE_ENUM(noContentChecksum)
149 LZ4F_OBSOLETE_ENUM(contentChecksumEnabled)
150 } LZ4F_contentChecksum_t;
151
152 typedef enum {
153 LZ4F_noBlockChecksum=0,
154 LZ4F_blockChecksumEnabled
155 } LZ4F_blockChecksum_t;
156
157 typedef enum {
158 LZ4F_frame=0,
159 LZ4F_skippableFrame
160 LZ4F_OBSOLETE_ENUM(skippableFrame)
161 } LZ4F_frameType_t;
162
163 #ifdef LZ4F_ENABLE_OBSOLETE_ENUMS
164 typedef LZ4F_blockSizeID_t blockSizeID_t;
165 typedef LZ4F_blockMode_t blockMode_t;
166 typedef LZ4F_frameType_t frameType_t;
167 typedef LZ4F_contentChecksum_t contentChecksum_t;
168 #endif
169
170 /*! LZ4F_frameInfo_t :
171 * makes it possible to set or read frame parameters.
172 * Structure must be first init to 0, using memset() or LZ4F_INIT_FRAMEINFO,
173 * setting all parameters to default.
174 * It's then possible to update selectively some parameters */
175 typedef struct {
176 LZ4F_blockSizeID_t blockSizeID; /* max64KB, max256KB, max1MB, max4MB; 0 == default */
177 LZ4F_blockMode_t blockMode; /* LZ4F_blockLinked, LZ4F_blockIndependent; 0 == default */
178 LZ4F_contentChecksum_t contentChecksumFlag; /* 1: frame terminated with 32-bit checksum of decompressed data; 0: disabled (default) */
179 LZ4F_frameType_t frameType; /* read-only field : LZ4F_frame or LZ4F_skippableFrame */
180 unsigned long long contentSize; /* Size of uncompressed content ; 0 == unknown */
181 unsigned dictID; /* Dictionary ID, sent by compressor to help decoder select correct dictionary; 0 == no dictID provided */
182 LZ4F_blockChecksum_t blockChecksumFlag; /* 1: each block followed by a checksum of block's compressed data; 0: disabled (default) */
183 } LZ4F_frameInfo_t;
184
185 #define LZ4F_INIT_FRAMEINFO { LZ4F_default, LZ4F_blockLinked, LZ4F_noContentChecksum, LZ4F_frame, 0ULL, 0U, LZ4F_noBlockChecksum } /* v1.8.3+ */
186
187 /*! LZ4F_preferences_t :
188 * makes it possible to supply advanced compression instructions to streaming interface.
189 * Structure must be first init to 0, using memset() or LZ4F_INIT_PREFERENCES,
190 * setting all parameters to default.
191 * All reserved fields must be set to zero. */
192 typedef struct {
193 LZ4F_frameInfo_t frameInfo;
194 int compressionLevel; /* 0: default (fast mode); values > LZ4HC_CLEVEL_MAX count as LZ4HC_CLEVEL_MAX; values < 0 trigger "fast acceleration" */
195 unsigned autoFlush; /* 1: always flush; reduces usage of internal buffers */
196 unsigned favorDecSpeed; /* 1: parser favors decompression speed vs compression ratio. Only works for high compression modes (>= LZ4HC_CLEVEL_OPT_MIN) */ /* v1.8.2+ */
197 unsigned reserved[3]; /* must be zero for forward compatibility */
198 } LZ4F_preferences_t;
199
200 #define LZ4F_INIT_PREFERENCES { LZ4F_INIT_FRAMEINFO, 0, 0u, 0u, { 0u, 0u, 0u } } /* v1.8.3+ */
201
202
203 /*-*********************************
204 * Simple compression function
205 ***********************************/
206
207 LZ4FLIB_API int LZ4F_compressionLevel_max(void); /* v1.8.0+ */
208
209 /*! LZ4F_compressFrameBound() :
210 * Returns the maximum possible compressed size with LZ4F_compressFrame() given srcSize and preferences.
211 * `preferencesPtr` is optional. It can be replaced by NULL, in which case, the function will assume default preferences.
212 * Note : this result is only usable with LZ4F_compressFrame().
213 * It may also be relevant to LZ4F_compressUpdate() _only if_ no flush() operation is ever performed.
214 */
215 LZ4FLIB_API size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr);
216
217 /*! LZ4F_compressFrame() :
218 * Compress an entire srcBuffer into a valid LZ4 frame.
219 * dstCapacity MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr).
220 * The LZ4F_preferences_t structure is optional : you can provide NULL as argument. All preferences will be set to default.
221 * @return : number of bytes written into dstBuffer.
222 * or an error code if it fails (can be tested using LZ4F_isError())
223 */
224 LZ4FLIB_API size_t LZ4F_compressFrame(void* dstBuffer, size_t dstCapacity,
225 const void* srcBuffer, size_t srcSize,
226 const LZ4F_preferences_t* preferencesPtr);
227
228
229 /*-***********************************
230 * Advanced compression functions
231 *************************************/
232 typedef struct LZ4F_cctx_s LZ4F_cctx; /* incomplete type */
233 typedef LZ4F_cctx* LZ4F_compressionContext_t; /* for compatibility with older APIs, prefer using LZ4F_cctx */
234
235 typedef struct {
236 unsigned stableSrc; /* 1 == src content will remain present on future calls to LZ4F_compress(); skip copying src content within tmp buffer */
237 unsigned reserved[3];
238 } LZ4F_compressOptions_t;
239
240 /*--- Resource Management ---*/
241
242 #define LZ4F_VERSION 100 /* This number can be used to check for an incompatible API breaking change */
243 LZ4FLIB_API unsigned LZ4F_getVersion(void);
244
245 /*! LZ4F_createCompressionContext() :
246 * The first thing to do is to create a compressionContext object,
247 * which will keep track of operation state during streaming compression.
248 * This is achieved using LZ4F_createCompressionContext(), which takes as argument a version,
249 * and a pointer to LZ4F_cctx*, to write the resulting pointer into.
250 * @version provided MUST be LZ4F_VERSION. It is intended to track potential version mismatch, notably when using DLL.
251 * The function provides a pointer to a fully allocated LZ4F_cctx object.
252 * @cctxPtr MUST be != NULL.
253 * If @return != zero, context creation failed.
254 * A created compression context can be employed multiple times for consecutive streaming operations.
255 * Once all streaming compression jobs are completed,
256 * the state object can be released using LZ4F_freeCompressionContext().
257 * Note1 : LZ4F_freeCompressionContext() is always successful. Its return value can be ignored.
258 * Note2 : LZ4F_freeCompressionContext() works fine with NULL input pointers (do nothing).
259 **/
260 LZ4FLIB_API LZ4F_errorCode_t LZ4F_createCompressionContext(LZ4F_cctx** cctxPtr, unsigned version);
261 LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_cctx* cctx);
262
263
264 /*---- Compression ----*/
265
266 #define LZ4F_HEADER_SIZE_MIN 7 /* LZ4 Frame header size can vary, depending on selected parameters */
267 #define LZ4F_HEADER_SIZE_MAX 19
268
269 /* Size in bytes of a block header in little-endian format. Highest bit indicates if block data is uncompressed */
270 #define LZ4F_BLOCK_HEADER_SIZE 4
271
272 /* Size in bytes of a block checksum footer in little-endian format. */
273 #define LZ4F_BLOCK_CHECKSUM_SIZE 4
274
275 /* Size in bytes of the content checksum. */
276 #define LZ4F_CONTENT_CHECKSUM_SIZE 4
277
278 /*! LZ4F_compressBegin() :
279 * will write the frame header into dstBuffer.
280 * dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes.
281 * `prefsPtr` is optional : you can provide NULL as argument, all preferences will then be set to default.
282 * @return : number of bytes written into dstBuffer for the header
283 * or an error code (which can be tested using LZ4F_isError())
284 */
285 LZ4FLIB_API size_t LZ4F_compressBegin(LZ4F_cctx* cctx,
286 void* dstBuffer, size_t dstCapacity,
287 const LZ4F_preferences_t* prefsPtr);
288
289 /*! LZ4F_compressBound() :
290 * Provides minimum dstCapacity required to guarantee success of
291 * LZ4F_compressUpdate(), given a srcSize and preferences, for a worst case scenario.
292 * When srcSize==0, LZ4F_compressBound() provides an upper bound for LZ4F_flush() and LZ4F_compressEnd() instead.
293 * Note that the result is only valid for a single invocation of LZ4F_compressUpdate().
294 * When invoking LZ4F_compressUpdate() multiple times,
295 * if the output buffer is gradually filled up instead of emptied and re-used from its start,
296 * one must check if there is enough remaining capacity before each invocation, using LZ4F_compressBound().
297 * @return is always the same for a srcSize and prefsPtr.
298 * prefsPtr is optional : when NULL is provided, preferences will be set to cover worst case scenario.
299 * tech details :
300 * @return if automatic flushing is not enabled, includes the possibility that internal buffer might already be filled by up to (blockSize-1) bytes.
301 * It also includes frame footer (ending + checksum), since it might be generated by LZ4F_compressEnd().
302 * @return doesn't include frame header, as it was already generated by LZ4F_compressBegin().
303 */
304 LZ4FLIB_API size_t LZ4F_compressBound(size_t srcSize, const LZ4F_preferences_t* prefsPtr);
305
306 /*! LZ4F_compressUpdate() :
307 * LZ4F_compressUpdate() can be called repetitively to compress as much data as necessary.
308 * Important rule: dstCapacity MUST be large enough to ensure operation success even in worst case situations.
309 * This value is provided by LZ4F_compressBound().
310 * If this condition is not respected, LZ4F_compress() will fail (result is an errorCode).
311 * After an error, the state is left in a UB state, and must be re-initialized or freed.
312 * If previously an uncompressed block was written, buffered data is flushed
313 * before appending compressed data is continued.
314 * `cOptPtr` is optional : NULL can be provided, in which case all options are set to default.
315 * @return : number of bytes written into `dstBuffer` (it can be zero, meaning input data was just buffered).
316 * or an error code if it fails (which can be tested using LZ4F_isError())
317 */
318 LZ4FLIB_API size_t LZ4F_compressUpdate(LZ4F_cctx* cctx,
319 void* dstBuffer, size_t dstCapacity,
320 const void* srcBuffer, size_t srcSize,
321 const LZ4F_compressOptions_t* cOptPtr);
322
323 /*! LZ4F_flush() :
324 * When data must be generated and sent immediately, without waiting for a block to be completely filled,
325 * it's possible to call LZ4_flush(). It will immediately compress any data buffered within cctx.
326 * `dstCapacity` must be large enough to ensure the operation will be successful.
327 * `cOptPtr` is optional : it's possible to provide NULL, all options will be set to default.
328 * @return : nb of bytes written into dstBuffer (can be zero, when there is no data stored within cctx)
329 * or an error code if it fails (which can be tested using LZ4F_isError())
330 * Note : LZ4F_flush() is guaranteed to be successful when dstCapacity >= LZ4F_compressBound(0, prefsPtr).
331 */
332 LZ4FLIB_API size_t LZ4F_flush(LZ4F_cctx* cctx,
333 void* dstBuffer, size_t dstCapacity,
334 const LZ4F_compressOptions_t* cOptPtr);
335
336 /*! LZ4F_compressEnd() :
337 * To properly finish an LZ4 frame, invoke LZ4F_compressEnd().
338 * It will flush whatever data remained within `cctx` (like LZ4_flush())
339 * and properly finalize the frame, with an endMark and a checksum.
340 * `cOptPtr` is optional : NULL can be provided, in which case all options will be set to default.
341 * @return : nb of bytes written into dstBuffer, necessarily >= 4 (endMark),
342 * or an error code if it fails (which can be tested using LZ4F_isError())
343 * Note : LZ4F_compressEnd() is guaranteed to be successful when dstCapacity >= LZ4F_compressBound(0, prefsPtr).
344 * A successful call to LZ4F_compressEnd() makes `cctx` available again for another compression task.
345 */
346 LZ4FLIB_API size_t LZ4F_compressEnd(LZ4F_cctx* cctx,
347 void* dstBuffer, size_t dstCapacity,
348 const LZ4F_compressOptions_t* cOptPtr);
349
350
351 /*-*********************************
352 * Decompression functions
353 ***********************************/
354 typedef struct LZ4F_dctx_s LZ4F_dctx; /* incomplete type */
355 typedef LZ4F_dctx* LZ4F_decompressionContext_t; /* compatibility with previous API versions */
356
357 typedef struct {
358 unsigned stableDst; /* pledges that last 64KB decompressed data will remain available unmodified between invocations.
359 * This optimization skips storage operations in tmp buffers. */
360 unsigned skipChecksums; /* disable checksum calculation and verification, even when one is present in frame, to save CPU time.
361 * Setting this option to 1 once disables all checksums for the rest of the frame. */
362 unsigned reserved1; /* must be set to zero for forward compatibility */
363 unsigned reserved0; /* idem */
364 } LZ4F_decompressOptions_t;
365
366
367 /* Resource management */
368
369 /*! LZ4F_createDecompressionContext() :
370 * Create an LZ4F_dctx object, to track all decompression operations.
371 * @version provided MUST be LZ4F_VERSION.
372 * @dctxPtr MUST be valid.
373 * The function fills @dctxPtr with the value of a pointer to an allocated and initialized LZ4F_dctx object.
374 * The @return is an errorCode, which can be tested using LZ4F_isError().
375 * dctx memory can be released using LZ4F_freeDecompressionContext();
376 * Result of LZ4F_freeDecompressionContext() indicates current state of decompressionContext when being released.
377 * That is, it should be == 0 if decompression has been completed fully and correctly.
378 */
379 LZ4FLIB_API LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_dctx** dctxPtr, unsigned version);
380 LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* dctx);
381
382
383 /*-***********************************
384 * Streaming decompression functions
385 *************************************/
386
387 #define LZ4F_MAGICNUMBER 0x184D2204U
388 #define LZ4F_MAGIC_SKIPPABLE_START 0x184D2A50U
389 #define LZ4F_MIN_SIZE_TO_KNOW_HEADER_LENGTH 5
390
391 /*! LZ4F_headerSize() : v1.9.0+
392 * Provide the header size of a frame starting at `src`.
393 * `srcSize` must be >= LZ4F_MIN_SIZE_TO_KNOW_HEADER_LENGTH,
394 * which is enough to decode the header length.
395 * @return : size of frame header
396 * or an error code, which can be tested using LZ4F_isError()
397 * note : Frame header size is variable, but is guaranteed to be
398 * >= LZ4F_HEADER_SIZE_MIN bytes, and <= LZ4F_HEADER_SIZE_MAX bytes.
399 */
400 LZ4FLIB_API size_t LZ4F_headerSize(const void* src, size_t srcSize);
401
402 /*! LZ4F_getFrameInfo() :
403 * This function extracts frame parameters (max blockSize, dictID, etc.).
404 * Its usage is optional: user can also invoke LZ4F_decompress() directly.
405 *
406 * Extracted information will fill an existing LZ4F_frameInfo_t structure.
407 * This can be useful for allocation and dictionary identification purposes.
408 *
409 * LZ4F_getFrameInfo() can work in the following situations :
410 *
411 * 1) At the beginning of a new frame, before any invocation of LZ4F_decompress().
412 * It will decode header from `srcBuffer`,
413 * consuming the header and starting the decoding process.
414 *
415 * Input size must be large enough to contain the full frame header.
416 * Frame header size can be known beforehand by LZ4F_headerSize().
417 * Frame header size is variable, but is guaranteed to be >= LZ4F_HEADER_SIZE_MIN bytes,
418 * and not more than <= LZ4F_HEADER_SIZE_MAX bytes.
419 * Hence, blindly providing LZ4F_HEADER_SIZE_MAX bytes or more will always work.
420 * It's allowed to provide more input data than the header size,
421 * LZ4F_getFrameInfo() will only consume the header.
422 *
423 * If input size is not large enough,
424 * aka if it's smaller than header size,
425 * function will fail and return an error code.
426 *
427 * 2) After decoding has been started,
428 * it's possible to invoke LZ4F_getFrameInfo() anytime
429 * to extract already decoded frame parameters stored within dctx.
430 *
431 * Note that, if decoding has barely started,
432 * and not yet read enough information to decode the header,
433 * LZ4F_getFrameInfo() will fail.
434 *
435 * The number of bytes consumed from srcBuffer will be updated in *srcSizePtr (necessarily <= original value).
436 * LZ4F_getFrameInfo() only consumes bytes when decoding has not yet started,
437 * and when decoding the header has been successful.
438 * Decompression must then resume from (srcBuffer + *srcSizePtr).
439 *
440 * @return : a hint about how many srcSize bytes LZ4F_decompress() expects for next call,
441 * or an error code which can be tested using LZ4F_isError().
442 * note 1 : in case of error, dctx is not modified. Decoding operation can resume from beginning safely.
443 * note 2 : frame parameters are *copied into* an already allocated LZ4F_frameInfo_t structure.
444 */
445 LZ4FLIB_API size_t
446 LZ4F_getFrameInfo(LZ4F_dctx* dctx,
447 LZ4F_frameInfo_t* frameInfoPtr,
448 const void* srcBuffer, size_t* srcSizePtr);
449
450 /*! LZ4F_decompress() :
451 * Call this function repetitively to regenerate data compressed in `srcBuffer`.
452 *
453 * The function requires a valid dctx state.
454 * It will read up to *srcSizePtr bytes from srcBuffer,
455 * and decompress data into dstBuffer, of capacity *dstSizePtr.
456 *
457 * The nb of bytes consumed from srcBuffer will be written into *srcSizePtr (necessarily <= original value).
458 * The nb of bytes decompressed into dstBuffer will be written into *dstSizePtr (necessarily <= original value).
459 *
460 * The function does not necessarily read all input bytes, so always check value in *srcSizePtr.
461 * Unconsumed source data must be presented again in subsequent invocations.
462 *
463 * `dstBuffer` can freely change between each consecutive function invocation.
464 * `dstBuffer` content will be overwritten.
465 *
466 * @return : an hint of how many `srcSize` bytes LZ4F_decompress() expects for next call.
467 * Schematically, it's the size of the current (or remaining) compressed block + header of next block.
468 * Respecting the hint provides some small speed benefit, because it skips intermediate buffers.
469 * This is just a hint though, it's always possible to provide any srcSize.
470 *
471 * When a frame is fully decoded, @return will be 0 (no more data expected).
472 * When provided with more bytes than necessary to decode a frame,
473 * LZ4F_decompress() will stop reading exactly at end of current frame, and @return 0.
474 *
475 * If decompression failed, @return is an error code, which can be tested using LZ4F_isError().
476 * After a decompression error, the `dctx` context is not resumable.
477 * Use LZ4F_resetDecompressionContext() to return to clean state.
478 *
479 * After a frame is fully decoded, dctx can be used again to decompress another frame.
480 */
481 LZ4FLIB_API size_t
482 LZ4F_decompress(LZ4F_dctx* dctx,
483 void* dstBuffer, size_t* dstSizePtr,
484 const void* srcBuffer, size_t* srcSizePtr,
485 const LZ4F_decompressOptions_t* dOptPtr);
486
487
488 /*! LZ4F_resetDecompressionContext() : added in v1.8.0
489 * In case of an error, the context is left in "undefined" state.
490 * In which case, it's necessary to reset it, before re-using it.
491 * This method can also be used to abruptly stop any unfinished decompression,
492 * and start a new one using same context resources. */
493 LZ4FLIB_API void LZ4F_resetDecompressionContext(LZ4F_dctx* dctx); /* always successful */
494
495
496
497 #if defined (__cplusplus)
498 }
499 #endif
500
501 #endif /* LZ4F_H_09782039843 */
502
503 #if defined(LZ4F_STATIC_LINKING_ONLY) && !defined(LZ4F_H_STATIC_09782039843)
504 #define LZ4F_H_STATIC_09782039843
505
506 #if defined (__cplusplus)
507 extern "C" {
508 #endif
509
510 /* These declarations are not stable and may change in the future.
511 * They are therefore only safe to depend on
512 * when the caller is statically linked against the library.
513 * To access their declarations, define LZ4F_STATIC_LINKING_ONLY.
514 *
515 * By default, these symbols aren't published into shared/dynamic libraries.
516 * You can override this behavior and force them to be published
517 * by defining LZ4F_PUBLISH_STATIC_FUNCTIONS.
518 * Use at your own risk.
519 */
520 #ifdef LZ4F_PUBLISH_STATIC_FUNCTIONS
521 # define LZ4FLIB_STATIC_API LZ4FLIB_API
522 #else
523 # define LZ4FLIB_STATIC_API
524 #endif
525
526
527 /* --- Error List --- */
528 #define LZ4F_LIST_ERRORS(ITEM) \
529 ITEM(OK_NoError) \
530 ITEM(ERROR_GENERIC) \
531 ITEM(ERROR_maxBlockSize_invalid) \
532 ITEM(ERROR_blockMode_invalid) \
533 ITEM(ERROR_contentChecksumFlag_invalid) \
534 ITEM(ERROR_compressionLevel_invalid) \
535 ITEM(ERROR_headerVersion_wrong) \
536 ITEM(ERROR_blockChecksum_invalid) \
537 ITEM(ERROR_reservedFlag_set) \
538 ITEM(ERROR_allocation_failed) \
539 ITEM(ERROR_srcSize_tooLarge) \
540 ITEM(ERROR_dstMaxSize_tooSmall) \
541 ITEM(ERROR_frameHeader_incomplete) \
542 ITEM(ERROR_frameType_unknown) \
543 ITEM(ERROR_frameSize_wrong) \
544 ITEM(ERROR_srcPtr_wrong) \
545 ITEM(ERROR_decompressionFailed) \
546 ITEM(ERROR_headerChecksum_invalid) \
547 ITEM(ERROR_contentChecksum_invalid) \
548 ITEM(ERROR_frameDecoding_alreadyStarted) \
549 ITEM(ERROR_compressionState_uninitialized) \
550 ITEM(ERROR_parameter_null) \
551 ITEM(ERROR_maxCode)
552
553 #define LZ4F_GENERATE_ENUM(ENUM) LZ4F_##ENUM,
554
555 /* enum list is exposed, to handle specific errors */
556 typedef enum { LZ4F_LIST_ERRORS(LZ4F_GENERATE_ENUM)
557 _LZ4F_dummy_error_enum_for_c89_never_used } LZ4F_errorCodes;
558
559 LZ4FLIB_STATIC_API LZ4F_errorCodes LZ4F_getErrorCode(size_t functionResult);
560
561
562 /*! LZ4F_getBlockSize() :
563 * Return, in scalar format (size_t),
564 * the maximum block size associated with blockSizeID.
565 **/
566 LZ4FLIB_STATIC_API size_t LZ4F_getBlockSize(LZ4F_blockSizeID_t blockSizeID);
567
568 /*! LZ4F_uncompressedUpdate() :
569 * LZ4F_uncompressedUpdate() can be called repetitively to add as much data uncompressed data as necessary.
570 * Important rule: dstCapacity MUST be large enough to store the entire source buffer as
571 * no compression is done for this operation
572 * If this condition is not respected, LZ4F_uncompressedUpdate() will fail (result is an errorCode).
573 * After an error, the state is left in a UB state, and must be re-initialized or freed.
574 * If previously a compressed block was written, buffered data is flushed
575 * before appending uncompressed data is continued.
576 * This is only supported when LZ4F_blockIndependent is used
577 * `cOptPtr` is optional : NULL can be provided, in which case all options are set to default.
578 * @return : number of bytes written into `dstBuffer` (it can be zero, meaning input data was just buffered).
579 * or an error code if it fails (which can be tested using LZ4F_isError())
580 */
581 LZ4FLIB_STATIC_API size_t
582 LZ4F_uncompressedUpdate(LZ4F_cctx* cctx,
583 void* dstBuffer, size_t dstCapacity,
584 const void* srcBuffer, size_t srcSize,
585 const LZ4F_compressOptions_t* cOptPtr);
586
587 /**********************************
588 * Bulk processing dictionary API
589 *********************************/
590
591 /* A Dictionary is useful for the compression of small messages (KB range).
592 * It dramatically improves compression efficiency.
593 *
594 * LZ4 can ingest any input as dictionary, though only the last 64 KB are useful.
595 * Best results are generally achieved by using Zstandard's Dictionary Builder
596 * to generate a high-quality dictionary from a set of samples.
597 *
598 * Loading a dictionary has a cost, since it involves construction of tables.
599 * The Bulk processing dictionary API makes it possible to share this cost
600 * over an arbitrary number of compression jobs, even concurrently,
601 * markedly improving compression latency for these cases.
602 *
603 * The same dictionary will have to be used on the decompression side
604 * for decoding to be successful.
605 * To help identify the correct dictionary at decoding stage,
606 * the frame header allows optional embedding of a dictID field.
607 */
608 typedef struct LZ4F_CDict_s LZ4F_CDict;
609
610 /*! LZ4_createCDict() :
611 * When compressing multiple messages / blocks using the same dictionary, it's recommended to load it just once.
612 * LZ4_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
613 * LZ4_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only.
614 * `dictBuffer` can be released after LZ4_CDict creation, since its content is copied within CDict */
615 LZ4FLIB_STATIC_API LZ4F_CDict* LZ4F_createCDict(const void* dictBuffer, size_t dictSize);
616 LZ4FLIB_STATIC_API void LZ4F_freeCDict(LZ4F_CDict* CDict);
617
618
619 /*! LZ4_compressFrame_usingCDict() :
620 * Compress an entire srcBuffer into a valid LZ4 frame using a digested Dictionary.
621 * cctx must point to a context created by LZ4F_createCompressionContext().
622 * If cdict==NULL, compress without a dictionary.
623 * dstBuffer MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr).
624 * If this condition is not respected, function will fail (@return an errorCode).
625 * The LZ4F_preferences_t structure is optional : you may provide NULL as argument,
626 * but it's not recommended, as it's the only way to provide dictID in the frame header.
627 * @return : number of bytes written into dstBuffer.
628 * or an error code if it fails (can be tested using LZ4F_isError()) */
629 LZ4FLIB_STATIC_API size_t
630 LZ4F_compressFrame_usingCDict(LZ4F_cctx* cctx,
631 void* dst, size_t dstCapacity,
632 const void* src, size_t srcSize,
633 const LZ4F_CDict* cdict,
634 const LZ4F_preferences_t* preferencesPtr);
635
636
637 /*! LZ4F_compressBegin_usingCDict() :
638 * Inits streaming dictionary compression, and writes the frame header into dstBuffer.
639 * dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes.
640 * `prefsPtr` is optional : you may provide NULL as argument,
641 * however, it's the only way to provide dictID in the frame header.
642 * @return : number of bytes written into dstBuffer for the header,
643 * or an error code (which can be tested using LZ4F_isError()) */
644 LZ4FLIB_STATIC_API size_t
645 LZ4F_compressBegin_usingCDict(LZ4F_cctx* cctx,
646 void* dstBuffer, size_t dstCapacity,
647 const LZ4F_CDict* cdict,
648 const LZ4F_preferences_t* prefsPtr);
649
650
651 /*! LZ4F_decompress_usingDict() :
652 * Same as LZ4F_decompress(), using a predefined dictionary.
653 * Dictionary is used "in place", without any preprocessing.
654 ** It must remain accessible throughout the entire frame decoding. */
655 LZ4FLIB_STATIC_API size_t
656 LZ4F_decompress_usingDict(LZ4F_dctx* dctxPtr,
657 void* dstBuffer, size_t* dstSizePtr,
658 const void* srcBuffer, size_t* srcSizePtr,
659 const void* dict, size_t dictSize,
660 const LZ4F_decompressOptions_t* decompressOptionsPtr);
661
662
663 /*! Custom memory allocation :
664 * These prototypes make it possible to pass custom allocation/free functions.
665 * LZ4F_customMem is provided at state creation time, using LZ4F_create*_advanced() listed below.
666 * All allocation/free operations will be completed using these custom variants instead of regular <stdlib.h> ones.
667 */
668 typedef void* (*LZ4F_AllocFunction) (void* opaqueState, size_t size);
669 typedef void* (*LZ4F_CallocFunction) (void* opaqueState, size_t size);
670 typedef void (*LZ4F_FreeFunction) (void* opaqueState, void* address);
671 typedef struct {
672 LZ4F_AllocFunction customAlloc;
673 LZ4F_CallocFunction customCalloc; /* optional; when not defined, uses customAlloc + memset */
674 LZ4F_FreeFunction customFree;
675 void* opaqueState;
676 } LZ4F_CustomMem;
677 static
678 #ifdef __GNUC__
679 __attribute__((__unused__))
680 #endif
681 LZ4F_CustomMem const LZ4F_defaultCMem = { NULL, NULL, NULL, NULL }; /**< this constant defers to stdlib's functions */
682
683 LZ4FLIB_STATIC_API LZ4F_cctx* LZ4F_createCompressionContext_advanced(LZ4F_CustomMem customMem, unsigned version);
684 LZ4FLIB_STATIC_API LZ4F_dctx* LZ4F_createDecompressionContext_advanced(LZ4F_CustomMem customMem, unsigned version);
685 LZ4FLIB_STATIC_API LZ4F_CDict* LZ4F_createCDict_advanced(LZ4F_CustomMem customMem, const void* dictBuffer, size_t dictSize);
686
687
688 #if defined (__cplusplus)
689 }
690 #endif
691
692 #endif /* defined(LZ4F_STATIC_LINKING_ONLY) && !defined(LZ4F_H_STATIC_09782039843) */
Browse
Usage
Versions