blob: 37978ecdfb818be65a11f34c90a66483da7af700 [file] [log] [blame]
Prince Pereirac1c21d62021-04-22 08:38:15 +00001/*
2 * Copyright (c) 2016-present, 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)
15extern "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/*! ZDICT_trainFromBuffer():
41 * Train a dictionary from an array of samples.
42 * Redirect towards ZDICT_optimizeTrainFromBuffer_fastCover() single-threaded, with d=8, steps=4,
43 * f=20, and accel=1.
44 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
45 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
46 * The resulting dictionary will be saved into `dictBuffer`.
47 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
48 * or an error code, which can be tested with ZDICT_isError().
49 * Note: Dictionary training will fail if there are not enough samples to construct a
50 * dictionary, or if most of the samples are too small (< 8 bytes being the lower limit).
51 * If dictionary training fails, you should use zstd without a dictionary, as the dictionary
52 * would've been ineffective anyways. If you believe your samples would benefit from a dictionary
53 * please open an issue with details, and we can look into it.
54 * Note: ZDICT_trainFromBuffer()'s memory usage is about 6 MB.
55 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
56 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`.
57 * In general, it's recommended to provide a few thousands samples, though this can vary a lot.
58 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
59 */
60ZDICTLIB_API size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
61 const void* samplesBuffer,
62 const size_t* samplesSizes, unsigned nbSamples);
63
64
65/*====== Helper functions ======*/
66ZDICTLIB_API unsigned ZDICT_getDictID(const void* dictBuffer, size_t dictSize); /**< extracts dictID; @return zero if error (not a valid dictionary) */
67ZDICTLIB_API unsigned ZDICT_isError(size_t errorCode);
68ZDICTLIB_API const char* ZDICT_getErrorName(size_t errorCode);
69
70
71
72#ifdef ZDICT_STATIC_LINKING_ONLY
73
74/* ====================================================================================
75 * The definitions in this section are considered experimental.
76 * They should never be used with a dynamic library, as they may change in the future.
77 * They are provided for advanced usages.
78 * Use them only in association with static linking.
79 * ==================================================================================== */
80
81typedef struct {
82 int compressionLevel; /* optimize for a specific zstd compression level; 0 means default */
83 unsigned notificationLevel; /* Write log to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */
84 unsigned dictID; /* force dictID value; 0 means auto mode (32-bits random value) */
85} ZDICT_params_t;
86
87/*! ZDICT_cover_params_t:
88 * k and d are the only required parameters.
89 * For others, value 0 means default.
90 */
91typedef struct {
92 unsigned k; /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */
93 unsigned d; /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */
94 unsigned steps; /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */
95 unsigned nbThreads; /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */
96 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 */
97 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 */
98 unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */
99 ZDICT_params_t zParams;
100} ZDICT_cover_params_t;
101
102typedef struct {
103 unsigned k; /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */
104 unsigned d; /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */
105 unsigned f; /* log of size of frequency array : constraint: 0 < f <= 31 : 1 means default(20)*/
106 unsigned steps; /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */
107 unsigned nbThreads; /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */
108 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 */
109 unsigned accel; /* Acceleration level: constraint: 0 < accel <= 10, higher means faster and less accurate, 0 means default(1) */
110 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 */
111 unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */
112
113 ZDICT_params_t zParams;
114} ZDICT_fastCover_params_t;
115
116/*! ZDICT_trainFromBuffer_cover():
117 * Train a dictionary from an array of samples using the COVER algorithm.
118 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
119 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
120 * The resulting dictionary will be saved into `dictBuffer`.
121 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
122 * or an error code, which can be tested with ZDICT_isError().
123 * See ZDICT_trainFromBuffer() for details on failure modes.
124 * Note: ZDICT_trainFromBuffer_cover() requires about 9 bytes of memory for each input byte.
125 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
126 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`.
127 * In general, it's recommended to provide a few thousands samples, though this can vary a lot.
128 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
129 */
130ZDICTLIB_API size_t ZDICT_trainFromBuffer_cover(
131 void *dictBuffer, size_t dictBufferCapacity,
132 const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples,
133 ZDICT_cover_params_t parameters);
134
135/*! ZDICT_optimizeTrainFromBuffer_cover():
136 * The same requirements as above hold for all the parameters except `parameters`.
137 * This function tries many parameter combinations and picks the best parameters.
138 * `*parameters` is filled with the best parameters found,
139 * dictionary constructed with those parameters is stored in `dictBuffer`.
140 *
141 * All of the parameters d, k, steps are optional.
142 * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}.
143 * if steps is zero it defaults to its default value.
144 * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000].
145 *
146 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
147 * or an error code, which can be tested with ZDICT_isError().
148 * On success `*parameters` contains the parameters selected.
149 * See ZDICT_trainFromBuffer() for details on failure modes.
150 * 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.
151 */
152ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_cover(
153 void* dictBuffer, size_t dictBufferCapacity,
154 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
155 ZDICT_cover_params_t* parameters);
156
157/*! ZDICT_trainFromBuffer_fastCover():
158 * Train a dictionary from an array of samples using a modified version of COVER algorithm.
159 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
160 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
161 * d and k are required.
162 * All other parameters are optional, will use default values if not provided
163 * The resulting dictionary will be saved into `dictBuffer`.
164 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
165 * or an error code, which can be tested with ZDICT_isError().
166 * See ZDICT_trainFromBuffer() for details on failure modes.
167 * Note: ZDICT_trainFromBuffer_fastCover() requires 6 * 2^f bytes of memory.
168 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
169 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`.
170 * In general, it's recommended to provide a few thousands samples, though this can vary a lot.
171 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
172 */
173ZDICTLIB_API size_t ZDICT_trainFromBuffer_fastCover(void *dictBuffer,
174 size_t dictBufferCapacity, const void *samplesBuffer,
175 const size_t *samplesSizes, unsigned nbSamples,
176 ZDICT_fastCover_params_t parameters);
177
178/*! ZDICT_optimizeTrainFromBuffer_fastCover():
179 * The same requirements as above hold for all the parameters except `parameters`.
180 * This function tries many parameter combinations (specifically, k and d combinations)
181 * and picks the best parameters. `*parameters` is filled with the best parameters found,
182 * dictionary constructed with those parameters is stored in `dictBuffer`.
183 * All of the parameters d, k, steps, f, and accel are optional.
184 * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}.
185 * if steps is zero it defaults to its default value.
186 * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000].
187 * If f is zero, default value of 20 is used.
188 * If accel is zero, default value of 1 is used.
189 *
190 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
191 * or an error code, which can be tested with ZDICT_isError().
192 * On success `*parameters` contains the parameters selected.
193 * See ZDICT_trainFromBuffer() for details on failure modes.
194 * Note: ZDICT_optimizeTrainFromBuffer_fastCover() requires about 6 * 2^f bytes of memory for each thread.
195 */
196ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_fastCover(void* dictBuffer,
197 size_t dictBufferCapacity, const void* samplesBuffer,
198 const size_t* samplesSizes, unsigned nbSamples,
199 ZDICT_fastCover_params_t* parameters);
200
201/*! ZDICT_finalizeDictionary():
202 * Given a custom content as a basis for dictionary, and a set of samples,
203 * finalize dictionary by adding headers and statistics.
204 *
205 * Samples must be stored concatenated in a flat buffer `samplesBuffer`,
206 * supplied with an array of sizes `samplesSizes`, providing the size of each sample in order.
207 *
208 * dictContentSize must be >= ZDICT_CONTENTSIZE_MIN bytes.
209 * maxDictSize must be >= dictContentSize, and must be >= ZDICT_DICTSIZE_MIN bytes.
210 *
211 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`),
212 * or an error code, which can be tested by ZDICT_isError().
213 * Note: ZDICT_finalizeDictionary() will push notifications into stderr if instructed to, using notificationLevel>0.
214 * Note 2: dictBuffer and dictContent can overlap
215 */
216#define ZDICT_CONTENTSIZE_MIN 128
217#define ZDICT_DICTSIZE_MIN 256
218ZDICTLIB_API size_t ZDICT_finalizeDictionary(void* dictBuffer, size_t dictBufferCapacity,
219 const void* dictContent, size_t dictContentSize,
220 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
221 ZDICT_params_t parameters);
222
223typedef struct {
224 unsigned selectivityLevel; /* 0 means default; larger => select more => larger dictionary */
225 ZDICT_params_t zParams;
226} ZDICT_legacy_params_t;
227
228/*! ZDICT_trainFromBuffer_legacy():
229 * Train a dictionary from an array of samples.
230 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
231 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
232 * The resulting dictionary will be saved into `dictBuffer`.
233 * `parameters` is optional and can be provided with values set to 0 to mean "default".
234 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
235 * or an error code, which can be tested with ZDICT_isError().
236 * See ZDICT_trainFromBuffer() for details on failure modes.
237 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
238 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`.
239 * In general, it's recommended to provide a few thousands samples, though this can vary a lot.
240 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
241 * Note: ZDICT_trainFromBuffer_legacy() will send notifications into stderr if instructed to, using notificationLevel>0.
242 */
243ZDICTLIB_API size_t ZDICT_trainFromBuffer_legacy(
244 void *dictBuffer, size_t dictBufferCapacity,
245 const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples,
246 ZDICT_legacy_params_t parameters);
247
248/* Deprecation warnings */
249/* It is generally possible to disable deprecation warnings from compiler,
250 for example with -Wno-deprecated-declarations for gcc
251 or _CRT_SECURE_NO_WARNINGS in Visual.
252 Otherwise, it's also possible to manually define ZDICT_DISABLE_DEPRECATE_WARNINGS */
253#ifdef ZDICT_DISABLE_DEPRECATE_WARNINGS
254# define ZDICT_DEPRECATED(message) ZDICTLIB_API /* disable deprecation warnings */
255#else
256# define ZDICT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
257# if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */
258# define ZDICT_DEPRECATED(message) [[deprecated(message)]] ZDICTLIB_API
259# elif (ZDICT_GCC_VERSION >= 405) || defined(__clang__)
260# define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated(message)))
261# elif (ZDICT_GCC_VERSION >= 301)
262# define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated))
263# elif defined(_MSC_VER)
264# define ZDICT_DEPRECATED(message) ZDICTLIB_API __declspec(deprecated(message))
265# else
266# pragma message("WARNING: You need to implement ZDICT_DEPRECATED for this compiler")
267# define ZDICT_DEPRECATED(message) ZDICTLIB_API
268# endif
269#endif /* ZDICT_DISABLE_DEPRECATE_WARNINGS */
270
271ZDICT_DEPRECATED("use ZDICT_finalizeDictionary() instead")
272size_t ZDICT_addEntropyTablesFromBuffer(void* dictBuffer, size_t dictContentSize, size_t dictBufferCapacity,
273 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples);
274
275
276#endif /* ZDICT_STATIC_LINKING_ONLY */
277
278#if defined (__cplusplus)
279}
280#endif
281
282#endif /* DICTBUILDER_H_001 */