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4a9b7d136f
zstd/lib/dictBuilder/fastcover.c
Carl Woffenden 4a9b7d136f Initial implementation (files added, macros fixed) 
Hashing functions still to fix.
2020-06-22 10:31:36 +02:00

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/*
* Copyright (c) 2018-2020, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/
/*-*************************************
* Dependencies
***************************************/
#include <stdio.h> /* fprintf */
#include <stdlib.h> /* malloc, free, qsort */
#include <string.h> /* memset */
#include <time.h> /* clock */
#include "../common/mem.h" /* read */
#include "../common/pool.h"
#include "../common/threading.h"
#include "cover.h"
#include "../common/zstd_internal.h" /* includes zstd.h */
#ifndef ZDICT_STATIC_LINKING_ONLY
#define ZDICT_STATIC_LINKING_ONLY
#endif
#include "zdict.h"
/*-*************************************
* Constants
***************************************/
#define FASTCOVER_MAX_SAMPLES_SIZE (sizeof(size_t) == 8 ? ((unsigned)-1) : ((unsigned)1 GB))
#define FASTCOVER_MAX_F 31
#define FASTCOVER_MAX_ACCEL 10
#define FASTCOVER_DEFAULT_SPLITPOINT 0.75
#define DEFAULT_F 20
#define DEFAULT_ACCEL 1
/*-*************************************
* Console display
***************************************/
#ifndef LOCALDISPLAYLEVEL
static int g_displayLevel = 2;
#endif
#undef DISPLAY
#define DISPLAY(...) \
{ \
fprintf(stderr, __VA_ARGS__); \
fflush(stderr); \
}
#undef LOCALDISPLAYLEVEL
#define LOCALDISPLAYLEVEL(displayLevel, l, ...) \
if (displayLevel >= l) { \
DISPLAY(__VA_ARGS__); \
} /* 0 : no display; 1: errors; 2: default; 3: details; 4: debug */
#undef DISPLAYLEVEL
#define DISPLAYLEVEL(l, ...) LOCALDISPLAYLEVEL(g_displayLevel, l, __VA_ARGS__)
#ifndef LOCALDISPLAYUPDATE
static const clock_t refreshRate = CLOCKS_PER_SEC * 15 / 100;
static clock_t g_time = 0;
#endif
#undef LOCALDISPLAYUPDATE
#define LOCALDISPLAYUPDATE(displayLevel, l, ...) \
if (displayLevel >= l) { \
if ((clock() - g_time > refreshRate) || (displayLevel >= 4)) { \
g_time = clock(); \
DISPLAY(__VA_ARGS__); \
} \
}
#undef DISPLAYUPDATE
#define DISPLAYUPDATE(l, ...) LOCALDISPLAYUPDATE(g_displayLevel, l, __VA_ARGS__)
/*-*************************************
* Hash Functions
***************************************/
static const U64 prime6bytes = 227718039650203ULL;
static size_t ZSTD_hash6(U64 u, U32 h) { return (size_t)(((u << (64-48)) * prime6bytes) >> (64-h)) ; }
static size_t ZSTD_hash6Ptr(const void* p, U32 h) { return ZSTD_hash6(MEM_readLE64(p), h); }
static const U64 prime8bytes = 0xCF1BBCDCB7A56463ULL;
static size_t ZSTD_hash8(U64 u, U32 h) { return (size_t)(((u) * prime8bytes) >> (64-h)) ; }
static size_t ZSTD_hash8Ptr(const void* p, U32 h) { return ZSTD_hash8(MEM_readLE64(p), h); }
/**
* Hash the d-byte value pointed to by p and mod 2^f
*/
static size_t FASTCOVER_hashPtrToIndex(const void* p, U32 h, unsigned d) {
if (d == 6) {
return ZSTD_hash6Ptr(p, h) & ((1 << h) - 1);
}
return ZSTD_hash8Ptr(p, h) & ((1 << h) - 1);
}
/*-*************************************
* Acceleration
***************************************/
typedef struct {
unsigned finalize; /* Percentage of training samples used for ZDICT_finalizeDictionary */
unsigned skip; /* Number of dmer skipped between each dmer counted in computeFrequency */
} FASTCOVER_accel_t;
static const FASTCOVER_accel_t FASTCOVER_defaultAccelParameters[FASTCOVER_MAX_ACCEL+1] = {
{ 100, 0 }, /* accel = 0, should not happen because accel = 0 defaults to accel = 1 */
{ 100, 0 }, /* accel = 1 */
{ 50, 1 }, /* accel = 2 */
{ 34, 2 }, /* accel = 3 */
{ 25, 3 }, /* accel = 4 */
{ 20, 4 }, /* accel = 5 */
{ 17, 5 }, /* accel = 6 */
{ 14, 6 }, /* accel = 7 */
{ 13, 7 }, /* accel = 8 */
{ 11, 8 }, /* accel = 9 */
{ 10, 9 }, /* accel = 10 */
};
/*-*************************************
* Context
***************************************/
typedef struct {
const BYTE *samples;
size_t *offsets;
const size_t *samplesSizes;
size_t nbSamples;
size_t nbTrainSamples;
size_t nbTestSamples;
size_t nbDmers;
U32 *freqs;
unsigned d;
unsigned f;
FASTCOVER_accel_t accelParams;
} FASTCOVER_ctx_t;
/*-*************************************
* Helper functions
***************************************/
/**
* Selects the best segment in an epoch.
* Segments of are scored according to the function:
*
* Let F(d) be the frequency of all dmers with hash value d.
* Let S_i be hash value of the dmer at position i of segment S which has length k.
*
* Score(S) = F(S_1) + F(S_2) + ... + F(S_{k-d+1})
*
* Once the dmer with hash value d is in the dictionary we set F(d) = 0.
*/
static COVER_segment_t FASTCOVER_selectSegment(const FASTCOVER_ctx_t *ctx,
U32 *freqs, U32 begin, U32 end,
ZDICT_cover_params_t parameters,
U16* segmentFreqs) {
/* Constants */
const U32 k = parameters.k;
const U32 d = parameters.d;
const U32 f = ctx->f;
const U32 dmersInK = k - d + 1;
/* Try each segment (activeSegment) and save the best (bestSegment) */
COVER_segment_t bestSegment = {0, 0, 0};
COVER_segment_t activeSegment;
/* Reset the activeDmers in the segment */
/* The activeSegment starts at the beginning of the epoch. */
activeSegment.begin = begin;
activeSegment.end = begin;
activeSegment.score = 0;
/* Slide the activeSegment through the whole epoch.
* Save the best segment in bestSegment.
*/
while (activeSegment.end < end) {
/* Get hash value of current dmer */
const size_t idx = FASTCOVER_hashPtrToIndex(ctx->samples + activeSegment.end, f, d);
/* Add frequency of this index to score if this is the first occurrence of index in active segment */
if (segmentFreqs[idx] == 0) {
activeSegment.score += freqs[idx];
}
/* Increment end of segment and segmentFreqs*/
activeSegment.end += 1;
segmentFreqs[idx] += 1;
/* If the window is now too large, drop the first position */
if (activeSegment.end - activeSegment.begin == dmersInK + 1) {
/* Get hash value of the dmer to be eliminated from active segment */
const size_t delIndex = FASTCOVER_hashPtrToIndex(ctx->samples + activeSegment.begin, f, d);
segmentFreqs[delIndex] -= 1;
/* Subtract frequency of this index from score if this is the last occurrence of this index in active segment */
if (segmentFreqs[delIndex] == 0) {
activeSegment.score -= freqs[delIndex];
}
/* Increment start of segment */
activeSegment.begin += 1;
}
/* If this segment is the best so far save it */
if (activeSegment.score > bestSegment.score) {
bestSegment = activeSegment;
}
}
/* Zero out rest of segmentFreqs array */
while (activeSegment.begin < end) {
const size_t delIndex = FASTCOVER_hashPtrToIndex(ctx->samples + activeSegment.begin, f, d);
segmentFreqs[delIndex] -= 1;
activeSegment.begin += 1;
}
{
/* Zero the frequency of hash value of each dmer covered by the chosen segment. */
U32 pos;
for (pos = bestSegment.begin; pos != bestSegment.end; ++pos) {
const size_t i = FASTCOVER_hashPtrToIndex(ctx->samples + pos, f, d);
freqs[i] = 0;
}
}
return bestSegment;
}
static int FASTCOVER_checkParameters(ZDICT_cover_params_t parameters,
size_t maxDictSize, unsigned f,
unsigned accel) {
/* k, d, and f are required parameters */
if (parameters.d == 0 || parameters.k == 0) {
return 0;
}
/* d has to be 6 or 8 */
if (parameters.d != 6 && parameters.d != 8) {
return 0;
}
/* k <= maxDictSize */
if (parameters.k > maxDictSize) {
return 0;
}
/* d <= k */
if (parameters.d > parameters.k) {
return 0;
}
/* 0 < f <= FASTCOVER_MAX_F*/
if (f > FASTCOVER_MAX_F || f == 0) {
return 0;
}
/* 0 < splitPoint <= 1 */
if (parameters.splitPoint <= 0 || parameters.splitPoint > 1) {
return 0;
}
/* 0 < accel <= 10 */
if (accel > 10 || accel == 0) {
return 0;
}
return 1;
}
/**
* Clean up a context initialized with `FASTCOVER_ctx_init()`.
*/
static void
FASTCOVER_ctx_destroy(FASTCOVER_ctx_t* ctx)
{
if (!ctx) return;
free(ctx->freqs);
ctx->freqs = NULL;
free(ctx->offsets);
ctx->offsets = NULL;
}
/**
* Calculate for frequency of hash value of each dmer in ctx->samples
*/
static void
FASTCOVER_computeFrequency(U32* freqs, const FASTCOVER_ctx_t* ctx)
{
const unsigned f = ctx->f;
const unsigned d = ctx->d;
const unsigned skip = ctx->accelParams.skip;
const unsigned readLength = MAX(d, 8);
size_t i;
assert(ctx->nbTrainSamples >= 5);
assert(ctx->nbTrainSamples <= ctx->nbSamples);
for (i = 0; i < ctx->nbTrainSamples; i++) {
size_t start = ctx->offsets[i]; /* start of current dmer */
size_t const currSampleEnd = ctx->offsets[i+1];
while (start + readLength <= currSampleEnd) {
const size_t dmerIndex = FASTCOVER_hashPtrToIndex(ctx->samples + start, f, d);
freqs[dmerIndex]++;
start = start + skip + 1;
}
}
}
/**
* Prepare a context for dictionary building.
* The context is only dependent on the parameter `d` and can used multiple
* times.
* Returns 0 on success or error code on error.
* The context must be destroyed with `FASTCOVER_ctx_destroy()`.
*/
static size_t
FASTCOVER_ctx_init(FASTCOVER_ctx_t* ctx,
const void* samplesBuffer,
const size_t* samplesSizes, unsigned nbSamples,
unsigned d, double splitPoint, unsigned f,
FASTCOVER_accel_t accelParams)
{
const BYTE* const samples = (const BYTE*)samplesBuffer;
const size_t totalSamplesSize = COVER_sum(samplesSizes, nbSamples);
/* Split samples into testing and training sets */
const unsigned nbTrainSamples = splitPoint < 1.0 ? (unsigned)((double)nbSamples * splitPoint) : nbSamples;
const unsigned nbTestSamples = splitPoint < 1.0 ? nbSamples - nbTrainSamples : nbSamples;
const size_t trainingSamplesSize = splitPoint < 1.0 ? COVER_sum(samplesSizes, nbTrainSamples) : totalSamplesSize;
const size_t testSamplesSize = splitPoint < 1.0 ? COVER_sum(samplesSizes + nbTrainSamples, nbTestSamples) : totalSamplesSize;
/* Checks */
if (totalSamplesSize < MAX(d, sizeof(U64)) ||
totalSamplesSize >= (size_t)FASTCOVER_MAX_SAMPLES_SIZE) {
DISPLAYLEVEL(1, "Total samples size is too large (%u MB), maximum size is %u MB\n",
(unsigned)(totalSamplesSize >> 20), (FASTCOVER_MAX_SAMPLES_SIZE >> 20));
return ERROR(srcSize_wrong);
}
/* Check if there are at least 5 training samples */
if (nbTrainSamples < 5) {
DISPLAYLEVEL(1, "Total number of training samples is %u and is invalid\n", nbTrainSamples);
return ERROR(srcSize_wrong);
}
/* Check if there's testing sample */
if (nbTestSamples < 1) {
DISPLAYLEVEL(1, "Total number of testing samples is %u and is invalid.\n", nbTestSamples);
return ERROR(srcSize_wrong);
}
/* Zero the context */
memset(ctx, 0, sizeof(*ctx));
DISPLAYLEVEL(2, "Training on %u samples of total size %u\n", nbTrainSamples,
(unsigned)trainingSamplesSize);
DISPLAYLEVEL(2, "Testing on %u samples of total size %u\n", nbTestSamples,
(unsigned)testSamplesSize);
ctx->samples = samples;
ctx->samplesSizes = samplesSizes;
ctx->nbSamples = nbSamples;
ctx->nbTrainSamples = nbTrainSamples;
ctx->nbTestSamples = nbTestSamples;
ctx->nbDmers = trainingSamplesSize - MAX(d, sizeof(U64)) + 1;
ctx->d = d;
ctx->f = f;
ctx->accelParams = accelParams;
/* The offsets of each file */
ctx->offsets = (size_t*)calloc((nbSamples + 1), sizeof(size_t));
if (ctx->offsets == NULL) {
DISPLAYLEVEL(1, "Failed to allocate scratch buffers \n");
FASTCOVER_ctx_destroy(ctx);
return ERROR(memory_allocation);
}
/* Fill offsets from the samplesSizes */
{ U32 i;
ctx->offsets[0] = 0;
assert(nbSamples >= 5);
for (i = 1; i <= nbSamples; ++i) {
ctx->offsets[i] = ctx->offsets[i - 1] + samplesSizes[i - 1];
}
}
/* Initialize frequency array of size 2^f */
ctx->freqs = (U32*)calloc(((U64)1 << f), sizeof(U32));
if (ctx->freqs == NULL) {
DISPLAYLEVEL(1, "Failed to allocate frequency table \n");
FASTCOVER_ctx_destroy(ctx);
return ERROR(memory_allocation);
}
DISPLAYLEVEL(2, "Computing frequencies\n");
FASTCOVER_computeFrequency(ctx->freqs, ctx);
return 0;
}
/**
* Given the prepared context build the dictionary.
*/
static size_t
FASTCOVER_buildDictionary(const FASTCOVER_ctx_t* ctx,
U32* freqs,
void* dictBuffer, size_t dictBufferCapacity,
ZDICT_cover_params_t parameters,
U16* segmentFreqs)
{
BYTE *const dict = (BYTE *)dictBuffer;
size_t tail = dictBufferCapacity;
/* Divide the data into epochs. We will select one segment from each epoch. */
const COVER_epoch_info_t epochs = COVER_computeEpochs(
(U32)dictBufferCapacity, (U32)ctx->nbDmers, parameters.k, 1);
const size_t maxZeroScoreRun = 10;
size_t zeroScoreRun = 0;
size_t epoch;
DISPLAYLEVEL(2, "Breaking content into %u epochs of size %u\n",
(U32)epochs.num, (U32)epochs.size);
/* Loop through the epochs until there are no more segments or the dictionary
* is full.
*/
for (epoch = 0; tail > 0; epoch = (epoch + 1) % epochs.num) {
const U32 epochBegin = (U32)(epoch * epochs.size);
const U32 epochEnd = epochBegin + epochs.size;
size_t segmentSize;
/* Select a segment */
COVER_segment_t segment = FASTCOVER_selectSegment(
ctx, freqs, epochBegin, epochEnd, parameters, segmentFreqs);
/* If the segment covers no dmers, then we are out of content.
* There may be new content in other epochs, for continue for some time.
*/
if (segment.score == 0) {
if (++zeroScoreRun >= maxZeroScoreRun) {
break;
}
continue;
}
zeroScoreRun = 0;
/* Trim the segment if necessary and if it is too small then we are done */
segmentSize = MIN(segment.end - segment.begin + parameters.d - 1, tail);
if (segmentSize < parameters.d) {
break;
}
/* We fill the dictionary from the back to allow the best segments to be
* referenced with the smallest offsets.
*/
tail -= segmentSize;
memcpy(dict + tail, ctx->samples + segment.begin, segmentSize);
DISPLAYUPDATE(
2, "\r%u%% ",
(unsigned)(((dictBufferCapacity - tail) * 100) / dictBufferCapacity));
}
DISPLAYLEVEL(2, "\r%79s\r", "");
return tail;
}
/**
* Parameters for FASTCOVER_tryParameters().
*/
typedef struct FASTCOVER_tryParameters_data_s {
const FASTCOVER_ctx_t* ctx;
COVER_best_t* best;
size_t dictBufferCapacity;
ZDICT_cover_params_t parameters;
} FASTCOVER_tryParameters_data_t;
/**
* Tries a set of parameters and updates the COVER_best_t with the results.
* This function is thread safe if zstd is compiled with multithreaded support.
* It takes its parameters as an *OWNING* opaque pointer to support threading.
*/
static void FASTCOVER_tryParameters(void *opaque)
{
/* Save parameters as local variables */
FASTCOVER_tryParameters_data_t *const data = (FASTCOVER_tryParameters_data_t *)opaque;
const FASTCOVER_ctx_t *const ctx = data->ctx;
const ZDICT_cover_params_t parameters = data->parameters;
size_t dictBufferCapacity = data->dictBufferCapacity;
size_t totalCompressedSize = ERROR(GENERIC);
/* Initialize array to keep track of frequency of dmer within activeSegment */
U16* segmentFreqs = (U16 *)calloc(((U64)1 << ctx->f), sizeof(U16));
/* Allocate space for hash table, dict, and freqs */
BYTE *const dict = (BYTE * const)malloc(dictBufferCapacity);
COVER_dictSelection_t selection = COVER_dictSelectionError(ERROR(GENERIC));
U32 *freqs = (U32*) malloc(((U64)1 << ctx->f) * sizeof(U32));
if (!segmentFreqs || !dict || !freqs) {
DISPLAYLEVEL(1, "Failed to allocate buffers: out of memory\n");
goto _cleanup;
}
/* Copy the frequencies because we need to modify them */
memcpy(freqs, ctx->freqs, ((U64)1 << ctx->f) * sizeof(U32));
/* Build the dictionary */
{ const size_t tail = FASTCOVER_buildDictionary(ctx, freqs, dict, dictBufferCapacity,
parameters, segmentFreqs);
const unsigned nbFinalizeSamples = (unsigned)(ctx->nbTrainSamples * ctx->accelParams.finalize / 100);
selection = COVER_selectDict(dict + tail, dictBufferCapacity - tail,
ctx->samples, ctx->samplesSizes, nbFinalizeSamples, ctx->nbTrainSamples, ctx->nbSamples, parameters, ctx->offsets,
totalCompressedSize);
if (COVER_dictSelectionIsError(selection)) {
DISPLAYLEVEL(1, "Failed to select dictionary\n");
goto _cleanup;
}
}
_cleanup:
free(dict);
COVER_best_finish(data->best, parameters, selection);
free(data);
free(segmentFreqs);
COVER_dictSelectionFree(selection);
free(freqs);
}
static void
FASTCOVER_convertToCoverParams(ZDICT_fastCover_params_t fastCoverParams,
ZDICT_cover_params_t* coverParams)
{
coverParams->k = fastCoverParams.k;
coverParams->d = fastCoverParams.d;
coverParams->steps = fastCoverParams.steps;
coverParams->nbThreads = fastCoverParams.nbThreads;
coverParams->splitPoint = fastCoverParams.splitPoint;
coverParams->zParams = fastCoverParams.zParams;
coverParams->shrinkDict = fastCoverParams.shrinkDict;
}
static void
FASTCOVER_convertToFastCoverParams(ZDICT_cover_params_t coverParams,
ZDICT_fastCover_params_t* fastCoverParams,
unsigned f, unsigned accel)
{
fastCoverParams->k = coverParams.k;
fastCoverParams->d = coverParams.d;
fastCoverParams->steps = coverParams.steps;
fastCoverParams->nbThreads = coverParams.nbThreads;
fastCoverParams->splitPoint = coverParams.splitPoint;
fastCoverParams->f = f;
fastCoverParams->accel = accel;
fastCoverParams->zParams = coverParams.zParams;
fastCoverParams->shrinkDict = coverParams.shrinkDict;
}
ZDICTLIB_API size_t
ZDICT_trainFromBuffer_fastCover(void* dictBuffer, size_t dictBufferCapacity,
const void* samplesBuffer,
const size_t* samplesSizes, unsigned nbSamples,
ZDICT_fastCover_params_t parameters)
{
BYTE* const dict = (BYTE*)dictBuffer;
FASTCOVER_ctx_t ctx;
ZDICT_cover_params_t coverParams;
FASTCOVER_accel_t accelParams;
/* Initialize global data */
g_displayLevel = parameters.zParams.notificationLevel;
/* Assign splitPoint and f if not provided */
parameters.splitPoint = 1.0;
parameters.f = parameters.f == 0 ? DEFAULT_F : parameters.f;
parameters.accel = parameters.accel == 0 ? DEFAULT_ACCEL : parameters.accel;
/* Convert to cover parameter */
memset(&coverParams, 0 , sizeof(coverParams));
FASTCOVER_convertToCoverParams(parameters, &coverParams);
/* Checks */
if (!FASTCOVER_checkParameters(coverParams, dictBufferCapacity, parameters.f,
parameters.accel)) {
DISPLAYLEVEL(1, "FASTCOVER parameters incorrect\n");
return ERROR(parameter_outOfBound);
}
if (nbSamples == 0) {
DISPLAYLEVEL(1, "FASTCOVER must have at least one input file\n");
return ERROR(srcSize_wrong);
}
if (dictBufferCapacity < ZDICT_DICTSIZE_MIN) {
DISPLAYLEVEL(1, "dictBufferCapacity must be at least %u\n",
ZDICT_DICTSIZE_MIN);
return ERROR(dstSize_tooSmall);
}
/* Assign corresponding FASTCOVER_accel_t to accelParams*/
accelParams = FASTCOVER_defaultAccelParameters[parameters.accel];
/* Initialize context */
{
size_t const initVal = FASTCOVER_ctx_init(&ctx, samplesBuffer, samplesSizes, nbSamples,
coverParams.d, parameters.splitPoint, parameters.f,
accelParams);
if (ZSTD_isError(initVal)) {
DISPLAYLEVEL(1, "Failed to initialize context\n");
return initVal;
}
}
COVER_warnOnSmallCorpus(dictBufferCapacity, ctx.nbDmers, g_displayLevel);
/* Build the dictionary */
DISPLAYLEVEL(2, "Building dictionary\n");
{
/* Initialize array to keep track of frequency of dmer within activeSegment */
U16* segmentFreqs = (U16 *)calloc(((U64)1 << parameters.f), sizeof(U16));
const size_t tail = FASTCOVER_buildDictionary(&ctx, ctx.freqs, dictBuffer,
dictBufferCapacity, coverParams, segmentFreqs);
const unsigned nbFinalizeSamples = (unsigned)(ctx.nbTrainSamples * ctx.accelParams.finalize / 100);
const size_t dictionarySize = ZDICT_finalizeDictionary(
dict, dictBufferCapacity, dict + tail, dictBufferCapacity - tail,
samplesBuffer, samplesSizes, nbFinalizeSamples, coverParams.zParams);
if (!ZSTD_isError(dictionarySize)) {
DISPLAYLEVEL(2, "Constructed dictionary of size %u\n",
(unsigned)dictionarySize);
}
FASTCOVER_ctx_destroy(&ctx);
free(segmentFreqs);
return dictionarySize;
}
}
ZDICTLIB_API size_t
ZDICT_optimizeTrainFromBuffer_fastCover(
void* dictBuffer, size_t dictBufferCapacity,
const void* samplesBuffer,
const size_t* samplesSizes, unsigned nbSamples,
ZDICT_fastCover_params_t* parameters)
{
ZDICT_cover_params_t coverParams;
FASTCOVER_accel_t accelParams;
/* constants */
const unsigned nbThreads = parameters->nbThreads;
const double splitPoint =
parameters->splitPoint <= 0.0 ? FASTCOVER_DEFAULT_SPLITPOINT : parameters->splitPoint;
const unsigned kMinD = parameters->d == 0 ? 6 : parameters->d;
const unsigned kMaxD = parameters->d == 0 ? 8 : parameters->d;
const unsigned kMinK = parameters->k == 0 ? 50 : parameters->k;
const unsigned kMaxK = parameters->k == 0 ? 2000 : parameters->k;
const unsigned kSteps = parameters->steps == 0 ? 40 : parameters->steps;
const unsigned kStepSize = MAX((kMaxK - kMinK) / kSteps, 1);
const unsigned kIterations =
(1 + (kMaxD - kMinD) / 2) * (1 + (kMaxK - kMinK) / kStepSize);
const unsigned f = parameters->f == 0 ? DEFAULT_F : parameters->f;
const unsigned accel = parameters->accel == 0 ? DEFAULT_ACCEL : parameters->accel;
const unsigned shrinkDict = 0;
/* Local variables */
const int displayLevel = parameters->zParams.notificationLevel;
unsigned iteration = 1;
unsigned d;
unsigned k;
COVER_best_t best;
POOL_ctx *pool = NULL;
int warned = 0;
/* Checks */
if (splitPoint <= 0 || splitPoint > 1) {
LOCALDISPLAYLEVEL(displayLevel, 1, "Incorrect splitPoint\n");
return ERROR(parameter_outOfBound);
}
if (accel == 0 || accel > FASTCOVER_MAX_ACCEL) {
LOCALDISPLAYLEVEL(displayLevel, 1, "Incorrect accel\n");
return ERROR(parameter_outOfBound);
}
if (kMinK < kMaxD || kMaxK < kMinK) {
LOCALDISPLAYLEVEL(displayLevel, 1, "Incorrect k\n");
return ERROR(parameter_outOfBound);
}
if (nbSamples == 0) {
LOCALDISPLAYLEVEL(displayLevel, 1, "FASTCOVER must have at least one input file\n");
return ERROR(srcSize_wrong);
}
if (dictBufferCapacity < ZDICT_DICTSIZE_MIN) {
LOCALDISPLAYLEVEL(displayLevel, 1, "dictBufferCapacity must be at least %u\n",
ZDICT_DICTSIZE_MIN);
return ERROR(dstSize_tooSmall);
}
if (nbThreads > 1) {
pool = POOL_create(nbThreads, 1);
if (!pool) {
return ERROR(memory_allocation);
}
}
/* Initialization */
COVER_best_init(&best);
memset(&coverParams, 0 , sizeof(coverParams));
FASTCOVER_convertToCoverParams(*parameters, &coverParams);
accelParams = FASTCOVER_defaultAccelParameters[accel];
/* Turn down global display level to clean up display at level 2 and below */
g_displayLevel = displayLevel == 0 ? 0 : displayLevel - 1;
/* Loop through d first because each new value needs a new context */
LOCALDISPLAYLEVEL(displayLevel, 2, "Trying %u different sets of parameters\n",
kIterations);
for (d = kMinD; d <= kMaxD; d += 2) {
/* Initialize the context for this value of d */
FASTCOVER_ctx_t ctx;
LOCALDISPLAYLEVEL(displayLevel, 3, "d=%u\n", d);
{
size_t const initVal = FASTCOVER_ctx_init(&ctx, samplesBuffer, samplesSizes, nbSamples, d, splitPoint, f, accelParams);
if (ZSTD_isError(initVal)) {
LOCALDISPLAYLEVEL(displayLevel, 1, "Failed to initialize context\n");
COVER_best_destroy(&best);
POOL_free(pool);
return initVal;
}
}
if (!warned) {
COVER_warnOnSmallCorpus(dictBufferCapacity, ctx.nbDmers, displayLevel);
warned = 1;
}
/* Loop through k reusing the same context */
for (k = kMinK; k <= kMaxK; k += kStepSize) {
/* Prepare the arguments */
FASTCOVER_tryParameters_data_t *data = (FASTCOVER_tryParameters_data_t *)malloc(
sizeof(FASTCOVER_tryParameters_data_t));
LOCALDISPLAYLEVEL(displayLevel, 3, "k=%u\n", k);
if (!data) {
LOCALDISPLAYLEVEL(displayLevel, 1, "Failed to allocate parameters\n");
COVER_best_destroy(&best);
FASTCOVER_ctx_destroy(&ctx);
POOL_free(pool);
return ERROR(memory_allocation);
}
data->ctx = &ctx;
data->best = &best;
data->dictBufferCapacity = dictBufferCapacity;
data->parameters = coverParams;
data->parameters.k = k;
data->parameters.d = d;
data->parameters.splitPoint = splitPoint;
data->parameters.steps = kSteps;
data->parameters.shrinkDict = shrinkDict;
data->parameters.zParams.notificationLevel = g_displayLevel;
/* Check the parameters */
if (!FASTCOVER_checkParameters(data->parameters, dictBufferCapacity,
data->ctx->f, accel)) {
DISPLAYLEVEL(1, "FASTCOVER parameters incorrect\n");
free(data);
continue;
}
/* Call the function and pass ownership of data to it */
COVER_best_start(&best);
if (pool) {
POOL_add(pool, &FASTCOVER_tryParameters, data);
} else {
FASTCOVER_tryParameters(data);
}
/* Print status */
LOCALDISPLAYUPDATE(displayLevel, 2, "\r%u%% ",
(unsigned)((iteration * 100) / kIterations));
++iteration;
}
COVER_best_wait(&best);
FASTCOVER_ctx_destroy(&ctx);
}
LOCALDISPLAYLEVEL(displayLevel, 2, "\r%79s\r", "");
/* Fill the output buffer and parameters with output of the best parameters */
{
const size_t dictSize = best.dictSize;
if (ZSTD_isError(best.compressedSize)) {
const size_t compressedSize = best.compressedSize;
COVER_best_destroy(&best);
POOL_free(pool);
return compressedSize;
}
FASTCOVER_convertToFastCoverParams(best.parameters, parameters, f, accel);
memcpy(dictBuffer, best.dict, dictSize);
COVER_best_destroy(&best);
POOL_free(pool);
return dictSize;
}
}
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