1 #include <stdio.h> /* fprintf */
2 #include <stdlib.h> /* malloc, free, qsort */
3 #include <string.h> /* memset */
4 #include <time.h> /* clock */
5 #include "mem.h" /* read */
8 #include "zstd_internal.h" /* includes zstd.h */
9 #ifndef ZDICT_STATIC_LINKING_ONLY
10 #define ZDICT_STATIC_LINKING_ONLY
15 * COVER_best_t is used for two purposes:
16 * 1. Synchronizing threads.
17 * 2. Saving the best parameters and dictionary.
19 * All of the methods except COVER_best_init() are thread safe if zstd is
20 * compiled with multithreaded support.
22 typedef struct COVER_best_s {
23 ZSTD_pthread_mutex_t mutex;
24 ZSTD_pthread_cond_t cond;
28 ZDICT_cover_params_t parameters;
29 size_t compressedSize;
33 * A segment is a range in the source as well as the score of the segment.
42 *Number of epochs and size of each epoch.
50 * Struct used for the dictionary selection function.
52 typedef struct COVER_dictSelection {
55 size_t totalCompressedSize;
56 } COVER_dictSelection_t;
59 * Computes the number of epochs and the size of each epoch.
60 * We will make sure that each epoch gets at least 10 * k bytes.
62 * The COVER algorithms divide the data up into epochs of equal size and
63 * select one segment from each epoch.
65 * @param maxDictSize The maximum allowed dictionary size.
66 * @param nbDmers The number of dmers we are training on.
67 * @param k The parameter k (segment size).
68 * @param passes The target number of passes over the dmer corpus.
69 * More passes means a better dictionary.
71 COVER_epoch_info_t COVER_computeEpochs(U32 maxDictSize, U32 nbDmers,
75 * Warns the user when their corpus is too small.
77 void COVER_warnOnSmallCorpus(size_t maxDictSize, size_t nbDmers, int displayLevel);
80 * Checks total compressed size of a dictionary
82 size_t COVER_checkTotalCompressedSize(const ZDICT_cover_params_t parameters,
83 const size_t *samplesSizes, const BYTE *samples,
85 size_t nbTrainSamples, size_t nbSamples,
86 BYTE *const dict, size_t dictBufferCapacity);
89 * Returns the sum of the sample sizes.
91 size_t COVER_sum(const size_t *samplesSizes, unsigned nbSamples) ;
94 * Initialize the `COVER_best_t`.
96 void COVER_best_init(COVER_best_t *best);
99 * Wait until liveJobs == 0.
101 void COVER_best_wait(COVER_best_t *best);
104 * Call COVER_best_wait() and then destroy the COVER_best_t.
106 void COVER_best_destroy(COVER_best_t *best);
109 * Called when a thread is about to be launched.
110 * Increments liveJobs.
112 void COVER_best_start(COVER_best_t *best);
115 * Called when a thread finishes executing, both on error or success.
116 * Decrements liveJobs and signals any waiting threads if liveJobs == 0.
117 * If this dictionary is the best so far save it and its parameters.
119 void COVER_best_finish(COVER_best_t *best, ZDICT_cover_params_t parameters,
120 COVER_dictSelection_t selection);
122 * Error function for COVER_selectDict function. Checks if the return
125 unsigned COVER_dictSelectionIsError(COVER_dictSelection_t selection);
128 * Error function for COVER_selectDict function. Returns a struct where
129 * return.totalCompressedSize is a ZSTD error.
131 COVER_dictSelection_t COVER_dictSelectionError(size_t error);
134 * Always call after selectDict is called to free up used memory from
135 * newly created dictionary.
137 void COVER_dictSelectionFree(COVER_dictSelection_t selection);
140 * Called to finalize the dictionary and select one based on whether or not
141 * the shrink-dict flag was enabled. If enabled the dictionary used is the
142 * smallest dictionary within a specified regression of the compressed size
143 * from the largest dictionary.
145 COVER_dictSelection_t COVER_selectDict(BYTE* customDictContent,
146 size_t dictContentSize, const BYTE* samplesBuffer, const size_t* samplesSizes, unsigned nbFinalizeSamples,
147 size_t nbCheckSamples, size_t nbSamples, ZDICT_cover_params_t params, size_t* offsets, size_t totalCompressedSize);