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[zdict] Make COVER the default algorithm

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This commit is contained in:
Nick Terrell
2017-06-26 21:09:22 -07:00
parent ef269c1b68
commit 5b7fd7c422
8 changed files with 182 additions and 196 deletions
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lib/dictBuilder/cover.c
+23 -37
View File
@@ -398,7 +398,8 @@ typedef struct {
*/
static COVER_segment_t COVER_selectSegment(const COVER_ctx_t *ctx, U32 *freqs,
COVER_map_t *activeDmers, U32 begin,
U32 end, COVER_params_t parameters) {
U32 end,
ZDICT_cover_params_t parameters) {
/* Constants */
const U32 k = parameters.k;
const U32 d = parameters.d;
@@ -478,7 +479,7 @@ static COVER_segment_t COVER_selectSegment(const COVER_ctx_t *ctx, U32 *freqs,
* Check the validity of the parameters.
* Returns non-zero if the parameters are valid and 0 otherwise.
*/
static int COVER_checkParameters(COVER_params_t parameters) {
static int COVER_checkParameters(ZDICT_cover_params_t parameters) {
/* k and d are required parameters */
if (parameters.d == 0 || parameters.k == 0) {
return 0;
@@ -600,7 +601,7 @@ static int COVER_ctx_init(COVER_ctx_t *ctx, const void *samplesBuffer,
static size_t COVER_buildDictionary(const COVER_ctx_t *ctx, U32 *freqs,
COVER_map_t *activeDmers, void *dictBuffer,
size_t dictBufferCapacity,
COVER_params_t parameters) {
ZDICT_cover_params_t parameters) {
BYTE *const dict = (BYTE *)dictBuffer;
size_t tail = dictBufferCapacity;
/* Divide the data up into epochs of equal size.
@@ -639,22 +640,10 @@ static size_t COVER_buildDictionary(const COVER_ctx_t *ctx, U32 *freqs,
return tail;
}
/**
* Translate from COVER_params_t to ZDICT_params_t required for finalizing the
* dictionary.
*/
static ZDICT_params_t COVER_translateParams(COVER_params_t parameters) {
ZDICT_params_t zdictParams;
memset(&zdictParams, 0, sizeof(zdictParams));
zdictParams.notificationLevel = 1;
zdictParams.dictID = parameters.dictID;
zdictParams.compressionLevel = parameters.compressionLevel;
return zdictParams;
}
ZDICTLIB_API size_t COVER_trainFromBuffer(
ZDICTLIB_API size_t ZDICT_trainFromBuffer_cover(
void *dictBuffer, size_t dictBufferCapacity, const void *samplesBuffer,
const size_t *samplesSizes, unsigned nbSamples, COVER_params_t parameters) {
const size_t *samplesSizes, unsigned nbSamples,
ZDICT_cover_params_t parameters) {
BYTE *const dict = (BYTE *)dictBuffer;
COVER_ctx_t ctx;
COVER_map_t activeDmers;
@@ -673,7 +662,7 @@ ZDICTLIB_API size_t COVER_trainFromBuffer(
return ERROR(dstSize_tooSmall);
}
/* Initialize global data */
g_displayLevel = parameters.notificationLevel;
g_displayLevel = parameters.zParams.notificationLevel;
/* Initialize context and activeDmers */
if (!COVER_ctx_init(&ctx, samplesBuffer, samplesSizes, nbSamples,
parameters.d)) {
@@ -690,10 +679,9 @@ ZDICTLIB_API size_t COVER_trainFromBuffer(
const size_t tail =
COVER_buildDictionary(&ctx, ctx.freqs, &activeDmers, dictBuffer,
dictBufferCapacity, parameters);
ZDICT_params_t zdictParams = COVER_translateParams(parameters);
const size_t dictionarySize = ZDICT_finalizeDictionary(
dict, dictBufferCapacity, dict + tail, dictBufferCapacity - tail,
samplesBuffer, samplesSizes, nbSamples, zdictParams);
samplesBuffer, samplesSizes, nbSamples, parameters.zParams);
if (!ZSTD_isError(dictionarySize)) {
DISPLAYLEVEL(2, "Constructed dictionary of size %u\n",
(U32)dictionarySize);
@@ -718,7 +706,7 @@ typedef struct COVER_best_s {
size_t liveJobs;
void *dict;
size_t dictSize;
COVER_params_t parameters;
ZDICT_cover_params_t parameters;
size_t compressedSize;
} COVER_best_t;
@@ -786,7 +774,7 @@ static void COVER_best_start(COVER_best_t *best) {
* If this dictionary is the best so far save it and its parameters.
*/
static void COVER_best_finish(COVER_best_t *best, size_t compressedSize,
COVER_params_t parameters, void *dict,
ZDICT_cover_params_t parameters, void *dict,
size_t dictSize) {
if (!best) {
return;
@@ -830,7 +818,7 @@ typedef struct COVER_tryParameters_data_s {
const COVER_ctx_t *ctx;
COVER_best_t *best;
size_t dictBufferCapacity;
COVER_params_t parameters;
ZDICT_cover_params_t parameters;
} COVER_tryParameters_data_t;
/**
@@ -842,7 +830,7 @@ static void COVER_tryParameters(void *opaque) {
/* Save parameters as local variables */
COVER_tryParameters_data_t *const data = (COVER_tryParameters_data_t *)opaque;
const COVER_ctx_t *const ctx = data->ctx;
const COVER_params_t parameters = data->parameters;
const ZDICT_cover_params_t parameters = data->parameters;
size_t dictBufferCapacity = data->dictBufferCapacity;
size_t totalCompressedSize = ERROR(GENERIC);
/* Allocate space for hash table, dict, and freqs */
@@ -863,10 +851,10 @@ static void COVER_tryParameters(void *opaque) {
{
const size_t tail = COVER_buildDictionary(ctx, freqs, &activeDmers, dict,
dictBufferCapacity, parameters);
const ZDICT_params_t zdictParams = COVER_translateParams(parameters);
dictBufferCapacity = ZDICT_finalizeDictionary(
dict, dictBufferCapacity, dict + tail, dictBufferCapacity - tail,
ctx->samples, ctx->samplesSizes, (unsigned)ctx->nbSamples, zdictParams);
ctx->samples, ctx->samplesSizes, (unsigned)ctx->nbSamples,
parameters.zParams);
if (ZDICT_isError(dictBufferCapacity)) {
DISPLAYLEVEL(1, "Failed to finalize dictionary\n");
goto _cleanup;
@@ -892,8 +880,8 @@ static void COVER_tryParameters(void *opaque) {
}
/* Create the cctx and cdict */
cctx = ZSTD_createCCtx();
cdict =
ZSTD_createCDict(dict, dictBufferCapacity, parameters.compressionLevel);
cdict = ZSTD_createCDict(dict, dictBufferCapacity,
parameters.zParams.compressionLevel);
if (!dst || !cctx || !cdict) {
goto _compressCleanup;
}
@@ -930,12 +918,10 @@ _cleanup:
}
}
ZDICTLIB_API size_t COVER_optimizeTrainFromBuffer(void *dictBuffer,
size_t dictBufferCapacity,
const void *samplesBuffer,
const size_t *samplesSizes,
unsigned nbSamples,
COVER_params_t *parameters) {
ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_cover(
void *dictBuffer, size_t dictBufferCapacity, const void *samplesBuffer,
const size_t *samplesSizes, unsigned nbSamples,
ZDICT_cover_params_t *parameters) {
/* constants */
const unsigned nbThreads = parameters->nbThreads;
const unsigned kMinD = parameters->d == 0 ? 6 : parameters->d;
@@ -947,7 +933,7 @@ ZDICTLIB_API size_t COVER_optimizeTrainFromBuffer(void *dictBuffer,
const unsigned kIterations =
(1 + (kMaxD - kMinD) / 2) * (1 + (kMaxK - kMinK) / kStepSize);
/* Local variables */
const int displayLevel = parameters->notificationLevel;
const int displayLevel = parameters->zParams.notificationLevel;
unsigned iteration = 1;
unsigned d;
unsigned k;
@@ -976,7 +962,7 @@ ZDICTLIB_API size_t COVER_optimizeTrainFromBuffer(void *dictBuffer,
/* Initialization */
COVER_best_init(&best);
/* Turn down global display level to clean up display at level 2 and below */
g_displayLevel = parameters->notificationLevel - 1;
g_displayLevel = parameters->zParams.notificationLevel - 1;
/* Loop through d first because each new value needs a new context */
LOCALDISPLAYLEVEL(displayLevel, 2, "Trying %u different sets of parameters\n",
kIterations);
lib/dictBuilder/zdict.c
+23 -33
View File
@@ -487,7 +487,7 @@ static U32 ZDICT_dictSize(const dictItem* dictList)
}
static size_t ZDICT_trainBuffer(dictItem* dictList, U32 dictListSize,
static size_t ZDICT_trainBuffer_legacy(dictItem* dictList, U32 dictListSize,
const void* const buffer, size_t bufferSize, /* buffer must end with noisy guard band */
const size_t* fileSizes, unsigned nbFiles,
U32 minRatio, U32 notificationLevel)
@@ -634,17 +634,6 @@ static void ZDICT_countEStats(EStats_ress_t esr, ZSTD_parameters params,
} } }
}
/*
static size_t ZDICT_maxSampleSize(const size_t* fileSizes, unsigned nbFiles)
{
unsigned u;
size_t max=0;
for (u=0; u<nbFiles; u++)
if (max < fileSizes[u]) max = fileSizes[u];
return max;
}
*/
static size_t ZDICT_totalSampleSize(const size_t* fileSizes, unsigned nbFiles)
{
size_t total=0;
@@ -930,14 +919,14 @@ size_t ZDICT_addEntropyTablesFromBuffer_advanced(void* dictBuffer, size_t dictCo
}
/*! ZDICT_trainFromBuffer_unsafe() :
/*! ZDICT_trainFromBuffer_unsafe_legacy() :
* Warning : `samplesBuffer` must be followed by noisy guard band.
* @return : size of dictionary, or an error code which can be tested with ZDICT_isError()
*/
size_t ZDICT_trainFromBuffer_unsafe(
size_t ZDICT_trainFromBuffer_unsafe_legacy(
void* dictBuffer, size_t maxDictSize,
const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
ZDICT_params_t params)
ZDICT_legacy_params_t params)
{
U32 const dictListSize = MAX(MAX(DICTLISTSIZE_DEFAULT, nbSamples), (U32)(maxDictSize/16));
dictItem* const dictList = (dictItem*)malloc(dictListSize * sizeof(*dictList));
@@ -946,7 +935,7 @@ size_t ZDICT_trainFromBuffer_unsafe(
size_t const targetDictSize = maxDictSize;
size_t const samplesBuffSize = ZDICT_totalSampleSize(samplesSizes, nbSamples);
size_t dictSize = 0;
U32 const notificationLevel = params.notificationLevel;
U32 const notificationLevel = params.zParams.notificationLevel;
/* checks */
if (!dictList) return ERROR(memory_allocation);
@@ -957,13 +946,13 @@ size_t ZDICT_trainFromBuffer_unsafe(
ZDICT_initDictItem(dictList);
/* build dictionary */
ZDICT_trainBuffer(dictList, dictListSize,
samplesBuffer, samplesBuffSize,
samplesSizes, nbSamples,
minRep, notificationLevel);
ZDICT_trainBuffer_legacy(dictList, dictListSize,
samplesBuffer, samplesBuffSize,
samplesSizes, nbSamples,
minRep, notificationLevel);
/* display best matches */
if (params.notificationLevel>= 3) {
if (params.zParams.notificationLevel>= 3) {
U32 const nb = MIN(25, dictList[0].pos);
U32 const dictContentSize = ZDICT_dictSize(dictList);
U32 u;
@@ -1026,7 +1015,7 @@ size_t ZDICT_trainFromBuffer_unsafe(
dictSize = ZDICT_addEntropyTablesFromBuffer_advanced(dictBuffer, dictContentSize, maxDictSize,
samplesBuffer, samplesSizes, nbSamples,
params);
params.zParams);
}
/* clean up */
@@ -1037,9 +1026,9 @@ size_t ZDICT_trainFromBuffer_unsafe(
/* issue : samplesBuffer need to be followed by a noisy guard band.
* work around : duplicate the buffer, and add the noise */
size_t ZDICT_trainFromBuffer_advanced(void* dictBuffer, size_t dictBufferCapacity,
const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
ZDICT_params_t params)
size_t ZDICT_trainFromBuffer_legacy(void* dictBuffer, size_t dictBufferCapacity,
const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
ZDICT_legacy_params_t params)
{
size_t result;
void* newBuff;
@@ -1052,10 +1041,9 @@ size_t ZDICT_trainFromBuffer_advanced(void* dictBuffer, size_t dictBufferCapacit
memcpy(newBuff, samplesBuffer, sBuffSize);
ZDICT_fillNoise((char*)newBuff + sBuffSize, NOISELENGTH); /* guard band, for end of buffer condition */
result = ZDICT_trainFromBuffer_unsafe(
dictBuffer, dictBufferCapacity,
newBuff, samplesSizes, nbSamples,
params);
result =
ZDICT_trainFromBuffer_unsafe_legacy(dictBuffer, dictBufferCapacity, newBuff,
samplesSizes, nbSamples, params);
free(newBuff);
return result;
}
@@ -1064,11 +1052,13 @@ size_t ZDICT_trainFromBuffer_advanced(void* dictBuffer, size_t dictBufferCapacit
size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples)
{
ZDICT_params_t params;
ZDICT_cover_params_t params;
memset(&params, 0, sizeof(params));
return ZDICT_trainFromBuffer_advanced(dictBuffer, dictBufferCapacity,
samplesBuffer, samplesSizes, nbSamples,
params);
params.d = 8;
params.steps = 4;
return ZDICT_optimizeTrainFromBuffer_cover(dictBuffer, dictBufferCapacity,
samplesBuffer, samplesSizes,
nbSamples, &params);
}
size_t ZDICT_addEntropyTablesFromBuffer(void* dictBuffer, size_t dictContentSize, size_t dictBufferCapacity,
lib/dictBuilder/zdict.h
+93 -86
View File
@@ -36,18 +36,20 @@ extern "C" {
#endif
/*! ZDICT_trainFromBuffer() :
Train a dictionary from an array of samples.
Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
The resulting dictionary will be saved into `dictBuffer`.
@return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
or an error code, which can be tested with ZDICT_isError().
Tips : In general, a reasonable dictionary has a size of ~ 100 KB.
It's obviously possible to target smaller or larger ones, just by specifying different `dictBufferCapacity`.
In general, it's recommended to provide a few thousands samples, but this can vary a lot.
It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
*/
/*! ZDICT_trainFromBuffer():
* Train a dictionary from an array of samples.
* Uses ZDICT_optimizeTrainFromBuffer_cover() single-threaded, with d=8 and steps=4.
* Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
* supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
* The resulting dictionary will be saved into `dictBuffer`.
* @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
* or an error code, which can be tested with ZDICT_isError().
* Note: ZDICT_trainFromBuffer() requires about 9 bytes of memory for each input byte.
* Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
* It's obviously possible to target smaller or larger ones, just by specifying different `dictBufferCapacity`.
* In general, it's recommended to provide a few thousands samples, but this can vary a lot.
* It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
*/
ZDICTLIB_API size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples);
@@ -69,94 +71,78 @@ ZDICTLIB_API const char* ZDICT_getErrorName(size_t errorCode);
* ==================================================================================== */
typedef struct {
unsigned selectivityLevel; /* 0 means default; larger => select more => larger dictionary */
int compressionLevel; /* 0 means default; target a specific zstd compression level */
unsigned notificationLevel; /* Write to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */
unsigned dictID; /* 0 means auto mode (32-bits random value); other : force dictID value */
unsigned reserved[2]; /* reserved space for future parameters */
} ZDICT_params_t;
/*! ZDICT_trainFromBuffer_advanced() :
Same as ZDICT_trainFromBuffer() with control over more parameters.
`parameters` is optional and can be provided with values set to 0 to mean "default".
@return : size of dictionary stored into `dictBuffer` (<= `dictBufferSize`),
or an error code, which can be tested by ZDICT_isError().
note : ZDICT_trainFromBuffer_advanced() will send notifications into stderr if instructed to, using notificationLevel>0.
*/
ZDICTLIB_API size_t ZDICT_trainFromBuffer_advanced(void* dictBuffer, size_t dictBufferCapacity,
const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
ZDICT_params_t parameters);
/*! COVER_params_t :
For all values 0 means default.
k and d are the only required parameters.
*/
/*! ZDICT_cover_params_t:
* For all values 0 means default.
* k and d are the only required parameters.
*/
typedef struct {
unsigned k; /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */
unsigned d; /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */
unsigned steps; /* Number of steps : Only used for optimization : 0 means default (32) : Higher means more parameters checked */
unsigned nbThreads; /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */
unsigned notificationLevel; /* Write to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */
unsigned dictID; /* 0 means auto mode (32-bits random value); other : force dictID value */
int compressionLevel; /* 0 means default; target a specific zstd compression level */
} COVER_params_t;
ZDICT_params_t zParams;
} ZDICT_cover_params_t;
/*! COVER_trainFromBuffer() :
Train a dictionary from an array of samples using the COVER algorithm.
Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
The resulting dictionary will be saved into `dictBuffer`.
@return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
or an error code, which can be tested with ZDICT_isError().
Note : COVER_trainFromBuffer() requires about 9 bytes of memory for each input byte.
Tips : In general, a reasonable dictionary has a size of ~ 100 KB.
It's obviously possible to target smaller or larger ones, just by specifying different `dictBufferCapacity`.
In general, it's recommended to provide a few thousands samples, but this can vary a lot.
It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
*/
ZDICTLIB_API size_t COVER_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
COVER_params_t parameters);
/*! ZDICT_trainFromBuffer_cover():
* Train a dictionary from an array of samples using the COVER algorithm.
* Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
* supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
* The resulting dictionary will be saved into `dictBuffer`.
* @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
* or an error code, which can be tested with ZDICT_isError().
* Note: ZDICT_trainFromBuffer_cover() requires about 9 bytes of memory for each input byte.
* Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
* It's obviously possible to target smaller or larger ones, just by specifying different `dictBufferCapacity`.
* In general, it's recommended to provide a few thousands samples, but this can vary a lot.
* It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
*/
ZDICTLIB_API size_t ZDICT_trainFromBuffer_cover(
void *dictBuffer, size_t dictBufferCapacity, const void *samplesBuffer,
const size_t *samplesSizes, unsigned nbSamples,
ZDICT_cover_params_t parameters);
/*! COVER_optimizeTrainFromBuffer() :
The same requirements as above hold for all the parameters except `parameters`.
This function tries many parameter combinations and picks the best parameters.
`*parameters` is filled with the best parameters found, and the dictionary
constructed with those parameters is stored in `dictBuffer`.
/*! ZDICT_optimizeTrainFromBuffer_cover():
* The same requirements as above hold for all the parameters except `parameters`.
* This function tries many parameter combinations and picks the best parameters.
* `*parameters` is filled with the best parameters found, and the dictionary
* constructed with those parameters is stored in `dictBuffer`.
*
* All of the parameters d, k, steps are optional.
* If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8, 10, 12, 14, 16}.
* if steps is zero it defaults to its default value.
* If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [16, 2048].
*
* @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
* or an error code, which can be tested with ZDICT_isError().
* On success `*parameters` contains the parameters selected.
* Note: ZDICT_optimizeTrainFromBuffer_cover() requires about 8 bytes of memory for each input byte and additionally another 5 bytes of memory for each byte of memory for each thread.
*/
ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_cover(
void *dictBuffer, size_t dictBufferCapacity, const void *samplesBuffer,
const size_t *samplesSizes, unsigned nbSamples,
ZDICT_cover_params_t *parameters);
All of the parameters d, k, steps are optional.
If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8, 10, 12, 14, 16}.
if steps is zero it defaults to its default value.
If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [16, 2048].
@return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
or an error code, which can be tested with ZDICT_isError().
On success `*parameters` contains the parameters selected.
Note : COVER_optimizeTrainFromBuffer() requires about 8 bytes of memory for each input byte and additionally another 5 bytes of memory for each byte of memory for each thread.
*/
ZDICTLIB_API size_t COVER_optimizeTrainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
const void* samplesBuffer, const size_t *samplesSizes, unsigned nbSamples,
COVER_params_t *parameters);
/*! ZDICT_finalizeDictionary() :
Given a custom content as a basis for dictionary, and a set of samples,
finalize dictionary by adding headers and statistics.
Samples must be stored concatenated in a flat buffer `samplesBuffer`,
supplied with an array of sizes `samplesSizes`, providing the size of each sample in order.
dictContentSize must be >= ZDICT_CONTENTSIZE_MIN bytes.
maxDictSize must be >= dictContentSize, and must be >= ZDICT_DICTSIZE_MIN bytes.
@return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`),
or an error code, which can be tested by ZDICT_isError().
note : ZDICT_finalizeDictionary() will push notifications into stderr if instructed to, using notificationLevel>0.
note 2 : dictBuffer and dictContent can overlap
*/
/*! ZDICT_finalizeDictionary():
* Given a custom content as a basis for dictionary, and a set of samples,
* finalize dictionary by adding headers and statistics.
*
* Samples must be stored concatenated in a flat buffer `samplesBuffer`,
* supplied with an array of sizes `samplesSizes`, providing the size of each sample in order.
*
* dictContentSize must be >= ZDICT_CONTENTSIZE_MIN bytes.
* maxDictSize must be >= dictContentSize, and must be >= ZDICT_DICTSIZE_MIN bytes.
*
* @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`),
* or an error code, which can be tested by ZDICT_isError().
* Note: ZDICT_finalizeDictionary() will push notifications into stderr if instructed to, using notificationLevel>0.
* Note 2: dictBuffer and dictContent can overlap
*/
#define ZDICT_CONTENTSIZE_MIN 128
#define ZDICT_DICTSIZE_MIN 256
ZDICTLIB_API size_t ZDICT_finalizeDictionary(void* dictBuffer, size_t dictBufferCapacity,
@@ -164,7 +150,28 @@ ZDICTLIB_API size_t ZDICT_finalizeDictionary(void* dictBuffer, size_t dictBuffer
const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
ZDICT_params_t parameters);
typedef struct {
unsigned selectivityLevel; /* 0 means default; larger => select more => larger dictionary */
ZDICT_params_t zParams;
} ZDICT_legacy_params_t;
/*! ZDICT_trainFromBuffer_legacy():
* Train a dictionary from an array of samples.
* Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
* supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
* The resulting dictionary will be saved into `dictBuffer`.
* `parameters` is optional and can be provided with values set to 0 to mean "default".
* @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
* or an error code, which can be tested with ZDICT_isError().
* Tips: In general, a reasonable dictionary has a size of ~ 100 KB.
* It's obviously possible to target smaller or larger ones, just by specifying different `dictBufferCapacity`.
* In general, it's recommended to provide a few thousands samples, but this can vary a lot.
* It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
* Note: ZDICT_trainFromBuffer_legacy() will send notifications into stderr if instructed to, using notificationLevel>0.
*/
ZDICTLIB_API size_t ZDICT_trainFromBuffer_legacy(
void *dictBuffer, size_t dictBufferCapacity, const void *samplesBuffer,
const size_t *samplesSizes, unsigned nbSamples, ZDICT_legacy_params_t parameters);
/* Deprecation warnings */
/* It is generally possible to disable deprecation warnings from compiler,