| 1 | /* |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 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 ZDICT_STATIC_LINKING_ONLY |
| 12 | # define ZDICT_STATIC_LINKING_ONLY |
| 13 | #endif |
| 14 | |
| 15 | #include <stdio.h> /* fprintf */ |
| 16 | #include <stdlib.h> /* malloc, free, qsort */ |
| 17 | #include <string.h> /* memset */ |
| 18 | #include <time.h> /* clock */ |
| 19 | #include "../common/mem.h" /* read */ |
| 20 | #include "../common/pool.h" |
| 21 | #include "../common/threading.h" |
| 22 | #include "../common/zstd_internal.h" /* includes zstd.h */ |
| 23 | #include "../zdict.h" |
| 24 | |
| 25 | /** |
| 26 | * COVER_best_t is used for two purposes: |
| 27 | * 1. Synchronizing threads. |
| 28 | * 2. Saving the best parameters and dictionary. |
| 29 | * |
| 30 | * All of the methods except COVER_best_init() are thread safe if zstd is |
| 31 | * compiled with multithreaded support. |
| 32 | */ |
| 33 | typedef struct COVER_best_s { |
| 34 | ZSTD_pthread_mutex_t mutex; |
| 35 | ZSTD_pthread_cond_t cond; |
| 36 | size_t liveJobs; |
| 37 | void *dict; |
| 38 | size_t dictSize; |
| 39 | ZDICT_cover_params_t parameters; |
| 40 | size_t compressedSize; |
| 41 | } COVER_best_t; |
| 42 | |
| 43 | /** |
| 44 | * A segment is a range in the source as well as the score of the segment. |
| 45 | */ |
| 46 | typedef struct { |
| 47 | U32 begin; |
| 48 | U32 end; |
| 49 | U32 score; |
| 50 | } COVER_segment_t; |
| 51 | |
| 52 | /** |
| 53 | *Number of epochs and size of each epoch. |
| 54 | */ |
| 55 | typedef struct { |
| 56 | U32 num; |
| 57 | U32 size; |
| 58 | } COVER_epoch_info_t; |
| 59 | |
| 60 | /** |
| 61 | * Struct used for the dictionary selection function. |
| 62 | */ |
| 63 | typedef struct COVER_dictSelection { |
| 64 | BYTE* dictContent; |
| 65 | size_t dictSize; |
| 66 | size_t totalCompressedSize; |
| 67 | } COVER_dictSelection_t; |
| 68 | |
| 69 | /** |
| 70 | * Computes the number of epochs and the size of each epoch. |
| 71 | * We will make sure that each epoch gets at least 10 * k bytes. |
| 72 | * |
| 73 | * The COVER algorithms divide the data up into epochs of equal size and |
| 74 | * select one segment from each epoch. |
| 75 | * |
| 76 | * @param maxDictSize The maximum allowed dictionary size. |
| 77 | * @param nbDmers The number of dmers we are training on. |
| 78 | * @param k The parameter k (segment size). |
| 79 | * @param passes The target number of passes over the dmer corpus. |
| 80 | * More passes means a better dictionary. |
| 81 | */ |
| 82 | COVER_epoch_info_t COVER_computeEpochs(U32 maxDictSize, U32 nbDmers, |
| 83 | U32 k, U32 passes); |
| 84 | |
| 85 | /** |
| 86 | * Warns the user when their corpus is too small. |
| 87 | */ |
| 88 | void COVER_warnOnSmallCorpus(size_t maxDictSize, size_t nbDmers, int displayLevel); |
| 89 | |
| 90 | /** |
| 91 | * Checks total compressed size of a dictionary |
| 92 | */ |
| 93 | size_t COVER_checkTotalCompressedSize(const ZDICT_cover_params_t parameters, |
| 94 | const size_t *samplesSizes, const BYTE *samples, |
| 95 | size_t *offsets, |
| 96 | size_t nbTrainSamples, size_t nbSamples, |
| 97 | BYTE *const dict, size_t dictBufferCapacity); |
| 98 | |
| 99 | /** |
| 100 | * Returns the sum of the sample sizes. |
| 101 | */ |
| 102 | size_t COVER_sum(const size_t *samplesSizes, unsigned nbSamples) ; |
| 103 | |
| 104 | /** |
| 105 | * Initialize the `COVER_best_t`. |
| 106 | */ |
| 107 | void COVER_best_init(COVER_best_t *best); |
| 108 | |
| 109 | /** |
| 110 | * Wait until liveJobs == 0. |
| 111 | */ |
| 112 | void COVER_best_wait(COVER_best_t *best); |
| 113 | |
| 114 | /** |
| 115 | * Call COVER_best_wait() and then destroy the COVER_best_t. |
| 116 | */ |
| 117 | void COVER_best_destroy(COVER_best_t *best); |
| 118 | |
| 119 | /** |
| 120 | * Called when a thread is about to be launched. |
| 121 | * Increments liveJobs. |
| 122 | */ |
| 123 | void COVER_best_start(COVER_best_t *best); |
| 124 | |
| 125 | /** |
| 126 | * Called when a thread finishes executing, both on error or success. |
| 127 | * Decrements liveJobs and signals any waiting threads if liveJobs == 0. |
| 128 | * If this dictionary is the best so far save it and its parameters. |
| 129 | */ |
| 130 | void COVER_best_finish(COVER_best_t *best, ZDICT_cover_params_t parameters, |
| 131 | COVER_dictSelection_t selection); |
| 132 | /** |
| 133 | * Error function for COVER_selectDict function. Checks if the return |
| 134 | * value is an error. |
| 135 | */ |
| 136 | unsigned COVER_dictSelectionIsError(COVER_dictSelection_t selection); |
| 137 | |
| 138 | /** |
| 139 | * Error function for COVER_selectDict function. Returns a struct where |
| 140 | * return.totalCompressedSize is a ZSTD error. |
| 141 | */ |
| 142 | COVER_dictSelection_t COVER_dictSelectionError(size_t error); |
| 143 | |
| 144 | /** |
| 145 | * Always call after selectDict is called to free up used memory from |
| 146 | * newly created dictionary. |
| 147 | */ |
| 148 | void COVER_dictSelectionFree(COVER_dictSelection_t selection); |
| 149 | |
| 150 | /** |
| 151 | * Called to finalize the dictionary and select one based on whether or not |
| 152 | * the shrink-dict flag was enabled. If enabled the dictionary used is the |
| 153 | * smallest dictionary within a specified regression of the compressed size |
| 154 | * from the largest dictionary. |
| 155 | */ |
| 156 | COVER_dictSelection_t COVER_selectDict(BYTE* customDictContent, size_t dictBufferCapacity, |
| 157 | size_t dictContentSize, const BYTE* samplesBuffer, const size_t* samplesSizes, unsigned nbFinalizeSamples, |
| 158 | size_t nbCheckSamples, size_t nbSamples, ZDICT_cover_params_t params, size_t* offsets, size_t totalCompressedSize); |