xref: /freebsd/sys/contrib/zstd/lib/zdict.h (revision 5ff13fbc199bdf5f0572845351c68ee5ca828e71)
1 /*
2  * Copyright (c) Yann Collet, Facebook, Inc.
3  * All rights reserved.
4  *
5  * This source code is licensed under both the BSD-style license (found in the
6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7  * in the COPYING file in the root directory of this source tree).
8  * You may select, at your option, one of the above-listed licenses.
9  */
10 
11 #ifndef DICTBUILDER_H_001
12 #define DICTBUILDER_H_001
13 
14 #if defined (__cplusplus)
15 extern "C" {
16 #endif
17 
18 
19 /*======  Dependencies  ======*/
20 #include <stddef.h>  /* size_t */
21 
22 
23 /* =====   ZDICTLIB_API : control library symbols visibility   ===== */
24 #ifndef ZDICTLIB_VISIBILITY
25 #  if defined(__GNUC__) && (__GNUC__ >= 4)
26 #    define ZDICTLIB_VISIBILITY __attribute__ ((visibility ("default")))
27 #  else
28 #    define ZDICTLIB_VISIBILITY
29 #  endif
30 #endif
31 #if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
32 #  define ZDICTLIB_API __declspec(dllexport) ZDICTLIB_VISIBILITY
33 #elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1)
34 #  define ZDICTLIB_API __declspec(dllimport) ZDICTLIB_VISIBILITY /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/
35 #else
36 #  define ZDICTLIB_API ZDICTLIB_VISIBILITY
37 #endif
38 
39 /*******************************************************************************
40  * Zstd dictionary builder
41  *
42  * FAQ
43  * ===
44  * Why should I use a dictionary?
45  * ------------------------------
46  *
47  * Zstd can use dictionaries to improve compression ratio of small data.
48  * Traditionally small files don't compress well because there is very little
49  * repetition in a single sample, since it is small. But, if you are compressing
50  * many similar files, like a bunch of JSON records that share the same
51  * structure, you can train a dictionary on ahead of time on some samples of
52  * these files. Then, zstd can use the dictionary to find repetitions that are
53  * present across samples. This can vastly improve compression ratio.
54  *
55  * When is a dictionary useful?
56  * ----------------------------
57  *
58  * Dictionaries are useful when compressing many small files that are similar.
59  * The larger a file is, the less benefit a dictionary will have. Generally,
60  * we don't expect dictionary compression to be effective past 100KB. And the
61  * smaller a file is, the more we would expect the dictionary to help.
62  *
63  * How do I use a dictionary?
64  * --------------------------
65  *
66  * Simply pass the dictionary to the zstd compressor with
67  * `ZSTD_CCtx_loadDictionary()`. The same dictionary must then be passed to
68  * the decompressor, using `ZSTD_DCtx_loadDictionary()`. There are other
69  * more advanced functions that allow selecting some options, see zstd.h for
70  * complete documentation.
71  *
72  * What is a zstd dictionary?
73  * --------------------------
74  *
75  * A zstd dictionary has two pieces: Its header, and its content. The header
76  * contains a magic number, the dictionary ID, and entropy tables. These
77  * entropy tables allow zstd to save on header costs in the compressed file,
78  * which really matters for small data. The content is just bytes, which are
79  * repeated content that is common across many samples.
80  *
81  * What is a raw content dictionary?
82  * ---------------------------------
83  *
84  * A raw content dictionary is just bytes. It doesn't have a zstd dictionary
85  * header, a dictionary ID, or entropy tables. Any buffer is a valid raw
86  * content dictionary.
87  *
88  * How do I train a dictionary?
89  * ----------------------------
90  *
91  * Gather samples from your use case. These samples should be similar to each
92  * other. If you have several use cases, you could try to train one dictionary
93  * per use case.
94  *
95  * Pass those samples to `ZDICT_trainFromBuffer()` and that will train your
96  * dictionary. There are a few advanced versions of this function, but this
97  * is a great starting point. If you want to further tune your dictionary
98  * you could try `ZDICT_optimizeTrainFromBuffer_cover()`. If that is too slow
99  * you can try `ZDICT_optimizeTrainFromBuffer_fastCover()`.
100  *
101  * If the dictionary training function fails, that is likely because you
102  * either passed too few samples, or a dictionary would not be effective
103  * for your data. Look at the messages that the dictionary trainer printed,
104  * if it doesn't say too few samples, then a dictionary would not be effective.
105  *
106  * How large should my dictionary be?
107  * ----------------------------------
108  *
109  * A reasonable dictionary size, the `dictBufferCapacity`, is about 100KB.
110  * The zstd CLI defaults to a 110KB dictionary. You likely don't need a
111  * dictionary larger than that. But, most use cases can get away with a
112  * smaller dictionary. The advanced dictionary builders can automatically
113  * shrink the dictionary for you, and select a the smallest size that
114  * doesn't hurt compression ratio too much. See the `shrinkDict` parameter.
115  * A smaller dictionary can save memory, and potentially speed up
116  * compression.
117  *
118  * How many samples should I provide to the dictionary builder?
119  * ------------------------------------------------------------
120  *
121  * We generally recommend passing ~100x the size of the dictionary
122  * in samples. A few thousand should suffice. Having too few samples
123  * can hurt the dictionaries effectiveness. Having more samples will
124  * only improve the dictionaries effectiveness. But having too many
125  * samples can slow down the dictionary builder.
126  *
127  * How do I determine if a dictionary will be effective?
128  * -----------------------------------------------------
129  *
130  * Simply train a dictionary and try it out. You can use zstd's built in
131  * benchmarking tool to test the dictionary effectiveness.
132  *
133  *   # Benchmark levels 1-3 without a dictionary
134  *   zstd -b1e3 -r /path/to/my/files
135  *   # Benchmark levels 1-3 with a dictionary
136  *   zstd -b1e3 -r /path/to/my/files -D /path/to/my/dictionary
137  *
138  * When should I retrain a dictionary?
139  * -----------------------------------
140  *
141  * You should retrain a dictionary when its effectiveness drops. Dictionary
142  * effectiveness drops as the data you are compressing changes. Generally, we do
143  * expect dictionaries to "decay" over time, as your data changes, but the rate
144  * at which they decay depends on your use case. Internally, we regularly
145  * retrain dictionaries, and if the new dictionary performs significantly
146  * better than the old dictionary, we will ship the new dictionary.
147  *
148  * I have a raw content dictionary, how do I turn it into a zstd dictionary?
149  * -------------------------------------------------------------------------
150  *
151  * If you have a raw content dictionary, e.g. by manually constructing it, or
152  * using a third-party dictionary builder, you can turn it into a zstd
153  * dictionary by using `ZDICT_finalizeDictionary()`. You'll also have to
154  * provide some samples of the data. It will add the zstd header to the
155  * raw content, which contains a dictionary ID and entropy tables, which
156  * will improve compression ratio, and allow zstd to write the dictionary ID
157  * into the frame, if you so choose.
158  *
159  * Do I have to use zstd's dictionary builder?
160  * -------------------------------------------
161  *
162  * No! You can construct dictionary content however you please, it is just
163  * bytes. It will always be valid as a raw content dictionary. If you want
164  * a zstd dictionary, which can improve compression ratio, use
165  * `ZDICT_finalizeDictionary()`.
166  *
167  * What is the attack surface of a zstd dictionary?
168  * ------------------------------------------------
169  *
170  * Zstd is heavily fuzz tested, including loading fuzzed dictionaries, so
171  * zstd should never crash, or access out-of-bounds memory no matter what
172  * the dictionary is. However, if an attacker can control the dictionary
173  * during decompression, they can cause zstd to generate arbitrary bytes,
174  * just like if they controlled the compressed data.
175  *
176  ******************************************************************************/
177 
178 
179 /*! ZDICT_trainFromBuffer():
180  *  Train a dictionary from an array of samples.
181  *  Redirect towards ZDICT_optimizeTrainFromBuffer_fastCover() single-threaded, with d=8, steps=4,
182  *  f=20, and accel=1.
183  *  Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
184  *  supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
185  *  The resulting dictionary will be saved into `dictBuffer`.
186  * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
187  *          or an error code, which can be tested with ZDICT_isError().
188  *  Note:  Dictionary training will fail if there are not enough samples to construct a
189  *         dictionary, or if most of the samples are too small (< 8 bytes being the lower limit).
190  *         If dictionary training fails, you should use zstd without a dictionary, as the dictionary
191  *         would've been ineffective anyways. If you believe your samples would benefit from a dictionary
192  *         please open an issue with details, and we can look into it.
193  *  Note: ZDICT_trainFromBuffer()'s memory usage is about 6 MB.
194  *  Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
195  *        It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`.
196  *        In general, it's recommended to provide a few thousands samples, though this can vary a lot.
197  *        It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
198  */
199 ZDICTLIB_API size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
200                                     const void* samplesBuffer,
201                                     const size_t* samplesSizes, unsigned nbSamples);
202 
203 typedef struct {
204     int      compressionLevel;   /*< optimize for a specific zstd compression level; 0 means default */
205     unsigned notificationLevel;  /*< Write log to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */
206     unsigned dictID;             /*< force dictID value; 0 means auto mode (32-bits random value)
207                                   *   NOTE: The zstd format reserves some dictionary IDs for future use.
208                                   *         You may use them in private settings, but be warned that they
209                                   *         may be used by zstd in a public dictionary registry in the future.
210                                   *         These dictionary IDs are:
211                                   *           - low range  : <= 32767
212                                   *           - high range : >= (2^31)
213                                   */
214 } ZDICT_params_t;
215 
216 /*! ZDICT_finalizeDictionary():
217  * Given a custom content as a basis for dictionary, and a set of samples,
218  * finalize dictionary by adding headers and statistics according to the zstd
219  * dictionary format.
220  *
221  * Samples must be stored concatenated in a flat buffer `samplesBuffer`,
222  * supplied with an array of sizes `samplesSizes`, providing the size of each
223  * sample in order. The samples are used to construct the statistics, so they
224  * should be representative of what you will compress with this dictionary.
225  *
226  * The compression level can be set in `parameters`. You should pass the
227  * compression level you expect to use in production. The statistics for each
228  * compression level differ, so tuning the dictionary for the compression level
229  * can help quite a bit.
230  *
231  * You can set an explicit dictionary ID in `parameters`, or allow us to pick
232  * a random dictionary ID for you, but we can't guarantee no collisions.
233  *
234  * The dstDictBuffer and the dictContent may overlap, and the content will be
235  * appended to the end of the header. If the header + the content doesn't fit in
236  * maxDictSize the beginning of the content is truncated to make room, since it
237  * is presumed that the most profitable content is at the end of the dictionary,
238  * since that is the cheapest to reference.
239  *
240  * `maxDictSize` must be >= max(dictContentSize, ZSTD_DICTSIZE_MIN).
241  *
242  * @return: size of dictionary stored into `dstDictBuffer` (<= `maxDictSize`),
243  *          or an error code, which can be tested by ZDICT_isError().
244  * Note: ZDICT_finalizeDictionary() will push notifications into stderr if
245  *       instructed to, using notificationLevel>0.
246  * NOTE: This function currently may fail in several edge cases including:
247  *         * Not enough samples
248  *         * Samples are uncompressible
249  *         * Samples are all exactly the same
250  */
251 ZDICTLIB_API size_t ZDICT_finalizeDictionary(void* dstDictBuffer, size_t maxDictSize,
252                                 const void* dictContent, size_t dictContentSize,
253                                 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
254                                 ZDICT_params_t parameters);
255 
256 
257 /*======   Helper functions   ======*/
258 ZDICTLIB_API unsigned ZDICT_getDictID(const void* dictBuffer, size_t dictSize);  /**< extracts dictID; @return zero if error (not a valid dictionary) */
259 ZDICTLIB_API size_t ZDICT_getDictHeaderSize(const void* dictBuffer, size_t dictSize);  /* returns dict header size; returns a ZSTD error code on failure */
260 ZDICTLIB_API unsigned ZDICT_isError(size_t errorCode);
261 ZDICTLIB_API const char* ZDICT_getErrorName(size_t errorCode);
262 
263 
264 
265 #ifdef ZDICT_STATIC_LINKING_ONLY
266 
267 /* ====================================================================================
268  * The definitions in this section are considered experimental.
269  * They should never be used with a dynamic library, as they may change in the future.
270  * They are provided for advanced usages.
271  * Use them only in association with static linking.
272  * ==================================================================================== */
273 
274 #define ZDICT_DICTSIZE_MIN    256
275 /* Deprecated: Remove in v1.6.0 */
276 #define ZDICT_CONTENTSIZE_MIN 128
277 
278 /*! ZDICT_cover_params_t:
279  *  k and d are the only required parameters.
280  *  For others, value 0 means default.
281  */
282 typedef struct {
283     unsigned k;                  /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */
284     unsigned d;                  /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */
285     unsigned steps;              /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */
286     unsigned nbThreads;          /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */
287     double splitPoint;           /* Percentage of samples used for training: Only used for optimization : the first nbSamples * splitPoint samples will be used to training, the last nbSamples * (1 - splitPoint) samples will be used for testing, 0 means default (1.0), 1.0 when all samples are used for both training and testing */
288     unsigned shrinkDict;         /* Train dictionaries to shrink in size starting from the minimum size and selects the smallest dictionary that is shrinkDictMaxRegression% worse than the largest dictionary. 0 means no shrinking and 1 means shrinking  */
289     unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */
290     ZDICT_params_t zParams;
291 } ZDICT_cover_params_t;
292 
293 typedef struct {
294     unsigned k;                  /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */
295     unsigned d;                  /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */
296     unsigned f;                  /* log of size of frequency array : constraint: 0 < f <= 31 : 1 means default(20)*/
297     unsigned steps;              /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */
298     unsigned nbThreads;          /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */
299     double splitPoint;           /* Percentage of samples used for training: Only used for optimization : the first nbSamples * splitPoint samples will be used to training, the last nbSamples * (1 - splitPoint) samples will be used for testing, 0 means default (0.75), 1.0 when all samples are used for both training and testing */
300     unsigned accel;              /* Acceleration level: constraint: 0 < accel <= 10, higher means faster and less accurate, 0 means default(1) */
301     unsigned shrinkDict;         /* Train dictionaries to shrink in size starting from the minimum size and selects the smallest dictionary that is shrinkDictMaxRegression% worse than the largest dictionary. 0 means no shrinking and 1 means shrinking  */
302     unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */
303 
304     ZDICT_params_t zParams;
305 } ZDICT_fastCover_params_t;
306 
307 /*! ZDICT_trainFromBuffer_cover():
308  *  Train a dictionary from an array of samples using the COVER algorithm.
309  *  Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
310  *  supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
311  *  The resulting dictionary will be saved into `dictBuffer`.
312  * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
313  *          or an error code, which can be tested with ZDICT_isError().
314  *          See ZDICT_trainFromBuffer() for details on failure modes.
315  *  Note: ZDICT_trainFromBuffer_cover() requires about 9 bytes of memory for each input byte.
316  *  Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
317  *        It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`.
318  *        In general, it's recommended to provide a few thousands samples, though this can vary a lot.
319  *        It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
320  */
321 ZDICTLIB_API size_t ZDICT_trainFromBuffer_cover(
322           void *dictBuffer, size_t dictBufferCapacity,
323     const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples,
324           ZDICT_cover_params_t parameters);
325 
326 /*! ZDICT_optimizeTrainFromBuffer_cover():
327  * The same requirements as above hold for all the parameters except `parameters`.
328  * This function tries many parameter combinations and picks the best parameters.
329  * `*parameters` is filled with the best parameters found,
330  * dictionary constructed with those parameters is stored in `dictBuffer`.
331  *
332  * All of the parameters d, k, steps are optional.
333  * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}.
334  * if steps is zero it defaults to its default value.
335  * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000].
336  *
337  * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
338  *          or an error code, which can be tested with ZDICT_isError().
339  *          On success `*parameters` contains the parameters selected.
340  *          See ZDICT_trainFromBuffer() for details on failure modes.
341  * Note: ZDICT_optimizeTrainFromBuffer_cover() requires about 8 bytes of memory for each input byte and additionally another 5 bytes of memory for each byte of memory for each thread.
342  */
343 ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_cover(
344           void* dictBuffer, size_t dictBufferCapacity,
345     const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
346           ZDICT_cover_params_t* parameters);
347 
348 /*! ZDICT_trainFromBuffer_fastCover():
349  *  Train a dictionary from an array of samples using a modified version of COVER algorithm.
350  *  Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
351  *  supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
352  *  d and k are required.
353  *  All other parameters are optional, will use default values if not provided
354  *  The resulting dictionary will be saved into `dictBuffer`.
355  * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
356  *          or an error code, which can be tested with ZDICT_isError().
357  *          See ZDICT_trainFromBuffer() for details on failure modes.
358  *  Note: ZDICT_trainFromBuffer_fastCover() requires 6 * 2^f bytes of memory.
359  *  Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
360  *        It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`.
361  *        In general, it's recommended to provide a few thousands samples, though this can vary a lot.
362  *        It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
363  */
364 ZDICTLIB_API size_t ZDICT_trainFromBuffer_fastCover(void *dictBuffer,
365                     size_t dictBufferCapacity, const void *samplesBuffer,
366                     const size_t *samplesSizes, unsigned nbSamples,
367                     ZDICT_fastCover_params_t parameters);
368 
369 /*! ZDICT_optimizeTrainFromBuffer_fastCover():
370  * The same requirements as above hold for all the parameters except `parameters`.
371  * This function tries many parameter combinations (specifically, k and d combinations)
372  * and picks the best parameters. `*parameters` is filled with the best parameters found,
373  * dictionary constructed with those parameters is stored in `dictBuffer`.
374  * All of the parameters d, k, steps, f, and accel are optional.
375  * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}.
376  * if steps is zero it defaults to its default value.
377  * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000].
378  * If f is zero, default value of 20 is used.
379  * If accel is zero, default value of 1 is used.
380  *
381  * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
382  *          or an error code, which can be tested with ZDICT_isError().
383  *          On success `*parameters` contains the parameters selected.
384  *          See ZDICT_trainFromBuffer() for details on failure modes.
385  * Note: ZDICT_optimizeTrainFromBuffer_fastCover() requires about 6 * 2^f bytes of memory for each thread.
386  */
387 ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_fastCover(void* dictBuffer,
388                     size_t dictBufferCapacity, const void* samplesBuffer,
389                     const size_t* samplesSizes, unsigned nbSamples,
390                     ZDICT_fastCover_params_t* parameters);
391 
392 typedef struct {
393     unsigned selectivityLevel;   /* 0 means default; larger => select more => larger dictionary */
394     ZDICT_params_t zParams;
395 } ZDICT_legacy_params_t;
396 
397 /*! ZDICT_trainFromBuffer_legacy():
398  *  Train a dictionary from an array of samples.
399  *  Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
400  *  supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
401  *  The resulting dictionary will be saved into `dictBuffer`.
402  * `parameters` is optional and can be provided with values set to 0 to mean "default".
403  * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
404  *          or an error code, which can be tested with ZDICT_isError().
405  *          See ZDICT_trainFromBuffer() for details on failure modes.
406  *  Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
407  *        It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`.
408  *        In general, it's recommended to provide a few thousands samples, though this can vary a lot.
409  *        It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
410  *  Note: ZDICT_trainFromBuffer_legacy() will send notifications into stderr if instructed to, using notificationLevel>0.
411  */
412 ZDICTLIB_API size_t ZDICT_trainFromBuffer_legacy(
413     void* dictBuffer, size_t dictBufferCapacity,
414     const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
415     ZDICT_legacy_params_t parameters);
416 
417 
418 /* Deprecation warnings */
419 /* It is generally possible to disable deprecation warnings from compiler,
420    for example with -Wno-deprecated-declarations for gcc
421    or _CRT_SECURE_NO_WARNINGS in Visual.
422    Otherwise, it's also possible to manually define ZDICT_DISABLE_DEPRECATE_WARNINGS */
423 #ifdef ZDICT_DISABLE_DEPRECATE_WARNINGS
424 #  define ZDICT_DEPRECATED(message) ZDICTLIB_API   /* disable deprecation warnings */
425 #else
426 #  define ZDICT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
427 #  if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */
428 #    define ZDICT_DEPRECATED(message) [[deprecated(message)]] ZDICTLIB_API
429 #  elif defined(__clang__) || (ZDICT_GCC_VERSION >= 405)
430 #    define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated(message)))
431 #  elif (ZDICT_GCC_VERSION >= 301)
432 #    define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated))
433 #  elif defined(_MSC_VER)
434 #    define ZDICT_DEPRECATED(message) ZDICTLIB_API __declspec(deprecated(message))
435 #  else
436 #    pragma message("WARNING: You need to implement ZDICT_DEPRECATED for this compiler")
437 #    define ZDICT_DEPRECATED(message) ZDICTLIB_API
438 #  endif
439 #endif /* ZDICT_DISABLE_DEPRECATE_WARNINGS */
440 
441 ZDICT_DEPRECATED("use ZDICT_finalizeDictionary() instead")
442 size_t ZDICT_addEntropyTablesFromBuffer(void* dictBuffer, size_t dictContentSize, size_t dictBufferCapacity,
443                                   const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples);
444 
445 
446 #endif   /* ZDICT_STATIC_LINKING_ONLY */
447 
448 #if defined (__cplusplus)
449 }
450 #endif
451 
452 #endif   /* DICTBUILDER_H_001 */
453