159 lines
4.9 KiB
C
159 lines
4.9 KiB
C
/*
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* Copyright (c) Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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*/
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#ifndef ZDICT_STATIC_LINKING_ONLY
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# define ZDICT_STATIC_LINKING_ONLY
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#endif
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#include <stdio.h> /* fprintf */
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#include <stdlib.h> /* malloc, free, qsort */
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#include <string.h> /* memset */
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#include <time.h> /* clock */
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#include "../common/mem.h" /* read */
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#include "../common/pool.h"
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#include "../common/threading.h"
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#include "../common/zstd_internal.h" /* includes zstd.h */
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#include "../zdict.h"
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/**
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* COVER_best_t is used for two purposes:
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* 1. Synchronizing threads.
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* 2. Saving the best parameters and dictionary.
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*
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* All of the methods except COVER_best_init() are thread safe if zstd is
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* compiled with multithreaded support.
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*/
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typedef struct COVER_best_s {
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ZSTD_pthread_mutex_t mutex;
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ZSTD_pthread_cond_t cond;
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size_t liveJobs;
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void *dict;
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size_t dictSize;
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ZDICT_cover_params_t parameters;
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size_t compressedSize;
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} COVER_best_t;
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/**
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* A segment is a range in the source as well as the score of the segment.
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*/
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typedef struct {
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U32 begin;
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U32 end;
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U32 score;
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} COVER_segment_t;
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/**
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*Number of epochs and size of each epoch.
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*/
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typedef struct {
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U32 num;
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U32 size;
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} COVER_epoch_info_t;
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/**
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* Struct used for the dictionary selection function.
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*/
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typedef struct COVER_dictSelection {
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BYTE* dictContent;
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size_t dictSize;
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size_t totalCompressedSize;
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} COVER_dictSelection_t;
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/**
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* Computes the number of epochs and the size of each epoch.
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* We will make sure that each epoch gets at least 10 * k bytes.
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*
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* The COVER algorithms divide the data up into epochs of equal size and
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* select one segment from each epoch.
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*
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* @param maxDictSize The maximum allowed dictionary size.
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* @param nbDmers The number of dmers we are training on.
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* @param k The parameter k (segment size).
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* @param passes The target number of passes over the dmer corpus.
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* More passes means a better dictionary.
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*/
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COVER_epoch_info_t COVER_computeEpochs(U32 maxDictSize, U32 nbDmers,
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U32 k, U32 passes);
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/**
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* Warns the user when their corpus is too small.
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*/
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void COVER_warnOnSmallCorpus(size_t maxDictSize, size_t nbDmers, int displayLevel);
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/**
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* Checks total compressed size of a dictionary
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*/
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size_t COVER_checkTotalCompressedSize(const ZDICT_cover_params_t parameters,
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const size_t *samplesSizes, const BYTE *samples,
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size_t *offsets,
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size_t nbTrainSamples, size_t nbSamples,
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BYTE *const dict, size_t dictBufferCapacity);
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/**
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* Returns the sum of the sample sizes.
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*/
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size_t COVER_sum(const size_t *samplesSizes, unsigned nbSamples) ;
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/**
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* Initialize the `COVER_best_t`.
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*/
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void COVER_best_init(COVER_best_t *best);
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/**
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* Wait until liveJobs == 0.
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*/
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void COVER_best_wait(COVER_best_t *best);
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/**
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* Call COVER_best_wait() and then destroy the COVER_best_t.
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*/
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void COVER_best_destroy(COVER_best_t *best);
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/**
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* Called when a thread is about to be launched.
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* Increments liveJobs.
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*/
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void COVER_best_start(COVER_best_t *best);
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/**
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* Called when a thread finishes executing, both on error or success.
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* Decrements liveJobs and signals any waiting threads if liveJobs == 0.
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* If this dictionary is the best so far save it and its parameters.
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*/
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void COVER_best_finish(COVER_best_t *best, ZDICT_cover_params_t parameters,
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COVER_dictSelection_t selection);
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/**
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* Error function for COVER_selectDict function. Checks if the return
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* value is an error.
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*/
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unsigned COVER_dictSelectionIsError(COVER_dictSelection_t selection);
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/**
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* Error function for COVER_selectDict function. Returns a struct where
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* return.totalCompressedSize is a ZSTD error.
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*/
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COVER_dictSelection_t COVER_dictSelectionError(size_t error);
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/**
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* Always call after selectDict is called to free up used memory from
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* newly created dictionary.
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*/
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void COVER_dictSelectionFree(COVER_dictSelection_t selection);
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/**
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* Called to finalize the dictionary and select one based on whether or not
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* the shrink-dict flag was enabled. If enabled the dictionary used is the
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* smallest dictionary within a specified regression of the compressed size
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* from the largest dictionary.
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*/
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COVER_dictSelection_t COVER_selectDict(BYTE* customDictContent, size_t dictBufferCapacity,
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size_t dictContentSize, const BYTE* samplesBuffer, const size_t* samplesSizes, unsigned nbFinalizeSamples,
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size_t nbCheckSamples, size_t nbSamples, ZDICT_cover_params_t params, size_t* offsets, size_t totalCompressedSize);
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