ceph/src/zstd/lib/dictBuilder/cover.h

   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 */
   6 #include "pool.h"
   7 #include "threading.h"
   8 #include "zstd_internal.h" /* includes zstd.h */
   9 #ifndef ZDICT_STATIC_LINKING_ONLY
  10 #define ZDICT_STATIC_LINKING_ONLY
  11 #endif
  12 #include "zdict.h"
  13
  14 /**
  15  * COVER_best_t is used for two purposes:
  16  * 1. Synchronizing threads.
  17  * 2. Saving the best parameters and dictionary.
  18  *
  19  * All of the methods except COVER_best_init() are thread safe if zstd is
  20  * compiled with multithreaded support.
  21  */
  22 typedef struct COVER_best_s {
  23   ZSTD_pthread_mutex_t mutex;
  24   ZSTD_pthread_cond_t cond;
  25   size_t liveJobs;
  26   void *dict;
  27   size_t dictSize;
  28   ZDICT_cover_params_t parameters;
  29   size_t compressedSize;
  30 } COVER_best_t;
  31
  32 /**
  33  * A segment is a range in the source as well as the score of the segment.
  34  */
  35 typedef struct {
  36   U32 begin;
  37   U32 end;
  38   U32 score;
  39 } COVER_segment_t;
  40
  41 /**
  42  *Number of epochs and size of each epoch.
  43  */
  44 typedef struct {
  45   U32 num;
  46   U32 size;
  47 } COVER_epoch_info_t;
  48
  49 /**
  50  * Computes the number of epochs and the size of each epoch.
  51  * We will make sure that each epoch gets at least 10 * k bytes.
  52  *
  53  * The COVER algorithms divide the data up into epochs of equal size and
  54  * select one segment from each epoch.
  55  *
  56  * @param maxDictSize The maximum allowed dictionary size.
  57  * @param nbDmers     The number of dmers we are training on.
  58  * @param k           The parameter k (segment size).
  59  * @param passes      The target number of passes over the dmer corpus.
  60  *                    More passes means a better dictionary.
  61  */
  62 COVER_epoch_info_t COVER_computeEpochs(U32 maxDictSize, U32 nbDmers,
  63                                        U32 k, U32 passes);
  64
  65 /**
  66  * Warns the user when their corpus is too small.
  67  */
  68 void COVER_warnOnSmallCorpus(size_t maxDictSize, size_t nbDmers, int displayLevel);
  69
  70 /**
  71  *  Checks total compressed size of a dictionary
  72  */
  73 size_t COVER_checkTotalCompressedSize(const ZDICT_cover_params_t parameters,
  74                                       const size_t *samplesSizes, const BYTE *samples,
  75                                       size_t *offsets,
  76                                       size_t nbTrainSamples, size_t nbSamples,
  77                                       BYTE *const dict, size_t dictBufferCapacity);
  78
  79 /**
  80  * Returns the sum of the sample sizes.
  81  */
  82 size_t COVER_sum(const size_t *samplesSizes, unsigned nbSamples) ;
  83
  84 /**
  85  * Initialize the `COVER_best_t`.
  86  */
  87 void COVER_best_init(COVER_best_t *best);
  88
  89 /**
  90  * Wait until liveJobs == 0.
  91  */
  92 void COVER_best_wait(COVER_best_t *best);
  93
  94 /**
  95  * Call COVER_best_wait() and then destroy the COVER_best_t.
  96  */
  97 void COVER_best_destroy(COVER_best_t *best);
  98
  99 /**
 100  * Called when a thread is about to be launched.
 101  * Increments liveJobs.
 102  */
 103 void COVER_best_start(COVER_best_t *best);
 104
 105 /**
 106  * Called when a thread finishes executing, both on error or success.
 107  * Decrements liveJobs and signals any waiting threads if liveJobs == 0.
 108  * If this dictionary is the best so far save it and its parameters.
 109  */
 110 void COVER_best_finish(COVER_best_t *best, size_t compressedSize,
 111                        ZDICT_cover_params_t parameters, void *dict,
 112                        size_t dictSize);