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Added : ability to manually select the dictionary ID of a newly created dictionary

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This commit is contained in:
Yann Collet 2016-05-30 21:18:52 +02:00
parent 815580a538
commit 290aaa7521
6 changed files with 81 additions and 57 deletions
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14
lib/dictBuilder/zdict.c
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@ -819,10 +819,10 @@ size_t ZDICT_trainFromBuffer_unsafe(
ZDICT_params_t params)
{
U32 const dictListSize = MAX( MAX(DICTLISTSIZE, nbSamples), (U32)(maxDictSize/16));
dictItem* dictList = (dictItem*)malloc(dictListSize * sizeof(*dictList));
dictItem* const dictList = (dictItem*)malloc(dictListSize * sizeof(*dictList));
unsigned selectivity = params.selectivityLevel;
unsigned compressionLevel = params.compressionLevel;
size_t targetDictSize = maxDictSize;
size_t const targetDictSize = maxDictSize;
size_t sBuffSize;
size_t dictSize = 0;
@ -865,17 +865,16 @@ size_t ZDICT_trainFromBuffer_unsafe(
/* create dictionary */
{ U32 dictContentSize = ZDICT_dictSize(dictList);
size_t hSize;
BYTE* ptr;
U32 u;
/* build dict content */
ptr = (BYTE*)dictBuffer + maxDictSize;
{ U32 u;
BYTE* ptr = (BYTE*)dictBuffer + maxDictSize;
for (u=1; u<dictList->pos; u++) {
U32 l = dictList[u].length;
ptr -= l;
if (ptr<(BYTE*)dictBuffer) return ERROR(GENERIC); /* should not happen */
memcpy(ptr, (const char*)samplesBuffer+dictList[u].pos, l);
}
} }
/* fast mode dict content */
if (selectivity==1) { /* note could also be used to complete a dictionary, but not necessarily better */
@ -888,7 +887,8 @@ size_t ZDICT_trainFromBuffer_unsafe(
/* dictionary header */
MEM_writeLE32(dictBuffer, ZSTD_DICT_MAGIC);
{ U64 const randomID = XXH64((char*)dictBuffer + maxDictSize - dictContentSize, dictContentSize, 0);
MEM_writeLE32((char*)dictBuffer+4, (U32)(randomID>>11));
U32 const dictID = params.dictID ? params.dictID : (U32)(randomID>>11);
MEM_writeLE32((char*)dictBuffer+4, dictID);
}
hSize = 8;

5
lib/dictBuilder/zdict_static.h
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@ -54,7 +54,8 @@ typedef struct {
unsigned selectivityLevel; /* 0 means default; larger => bigger selection => larger dictionary */
unsigned 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 reserved[3]; /* space for future parameters */
unsigned dictID; /* 0 means auto mode (32-bits random value); other : force dictID value */
unsigned reserved[2]; /* space for future parameters */
} ZDICT_params_t;
@ -65,7 +66,7 @@ typedef struct {
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 DiB_isError().
or an error code, which can be tested by ZDICT_isError().
note : ZDICT_trainFromBuffer_advanced() will send notifications into stderr if instructed to, using ZDICT_setNotificationLevel()
*/
size_t ZDICT_trainFromBuffer_advanced(void* dictBuffer, size_t dictBufferCapacity,

56
programs/dibio.c
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@ -101,27 +101,30 @@ const char* DiB_getErrorName(size_t errorCode) { return ERR_getErrorName(errorCo
/* ********************************************************
* File related operations
**********************************************************/
static void DiB_loadFiles(void* buffer, size_t bufferSize,
/** DiB_loadFiles() :
* @return : nb of files effectively loaded into `buffer` */
static unsigned DiB_loadFiles(void* buffer, size_t bufferSize,
size_t* fileSizes,
const char** fileNamesTable, unsigned nbFiles)
{
char* buff = (char*)buffer;
char* const buff = (char*)buffer;
size_t pos = 0;
unsigned n;
for (n=0; n<nbFiles; n++) {
size_t readSize;
unsigned long long fileSize = UTIL_getFileSize(fileNamesTable[n]);
FILE* f = fopen(fileNamesTable[n], "rb");
unsigned long long const fs64 = UTIL_getFileSize(fileNamesTable[n]);
size_t const fileSize = (size_t)(fs64 > bufferSize-pos ? 0 : fs64);
FILE* const f = fopen(fileNamesTable[n], "rb");
if (f==NULL) EXM_THROW(10, "impossible to open file %s", fileNamesTable[n]);
DISPLAYUPDATE(2, "Loading %s... \r", fileNamesTable[n]);
if (fileSize > bufferSize-pos) fileSize = 0; /* stop there, not enough memory to load all files */
readSize = fread(buff+pos, 1, (size_t)fileSize, f);
if (readSize != (size_t)fileSize) EXM_THROW(11, "could not read %s", fileNamesTable[n]);
pos += readSize;
fileSizes[n] = (size_t)fileSize;
{ size_t const readSize = fread(buff+pos, 1, fileSize, f);
if (readSize != fileSize) EXM_THROW(11, "could not read %s", fileNamesTable[n]);
pos += readSize; }
fileSizes[n] = fileSize;
fclose(f);
if (fileSize == 0) break; /* stop there, not enough memory to load all files */
}
return n;
}
@ -130,7 +133,7 @@ static void DiB_loadFiles(void* buffer, size_t bufferSize,
**********************************************************/
static size_t DiB_findMaxMem(unsigned long long requiredMem)
{
size_t step = 8 MB;
size_t const step = 8 MB;
void* testmem = NULL;
requiredMem = (((requiredMem >> 23) + 1) << 23);
@ -162,7 +165,7 @@ static void DiB_fillNoise(void* buffer, size_t length)
static void DiB_saveDict(const char* dictFileName,
const void* buff, size_t buffSize)
{
FILE* f = fopen(dictFileName, "wb");
FILE* const f = fopen(dictFileName, "wb");
if (f==NULL) EXM_THROW(3, "cannot open %s ", dictFileName);
{ size_t const n = fwrite(buff, 1, buffSize, f);
@ -185,35 +188,32 @@ size_t ZDICT_trainFromBuffer_unsafe(void* dictBuffer, size_t dictBufferCapacity,
ZDICT_params_t parameters);
#define MIN(a,b) ((a)<(b)?(a):(b))
int DiB_trainFromFiles(const char* dictFileName, unsigned maxDictSize,
const char** fileNamesTable, unsigned nbFiles,
ZDICT_params_t params)
{
void* srcBuffer;
size_t benchedSize;
size_t* fileSizes = (size_t*)malloc(nbFiles * sizeof(size_t));
unsigned long long totalSizeToLoad = UTIL_getTotalFileSize(fileNamesTable, nbFiles);
void* dictBuffer = malloc(maxDictSize);
size_t dictSize;
void* const dictBuffer = malloc(maxDictSize);
size_t* const fileSizes = (size_t*)malloc(nbFiles * sizeof(size_t));
unsigned long long const totalSizeToLoad = UTIL_getTotalFileSize(fileNamesTable, nbFiles);
size_t const maxMem = DiB_findMaxMem(totalSizeToLoad * MEMMULT) / MEMMULT;
size_t const benchedSize = MIN (maxMem, (size_t)totalSizeToLoad);
void* const srcBuffer = malloc(benchedSize+NOISELENGTH);
int result = 0;
/* Checks */
if ((!fileSizes) || (!srcBuffer) || (!dictBuffer)) EXM_THROW(12, "not enough memory for DiB_trainFiles"); /* should not happen */
/* init */
g_displayLevel = params.notificationLevel;
benchedSize = DiB_findMaxMem(totalSizeToLoad * MEMMULT) / MEMMULT;
if ((unsigned long long)benchedSize > totalSizeToLoad) benchedSize = (size_t)totalSizeToLoad;
if (benchedSize < totalSizeToLoad)
DISPLAYLEVEL(1, "Not enough memory; training on %u MB only...\n", (unsigned)(benchedSize >> 20));
/* Memory allocation & restrictions */
srcBuffer = malloc(benchedSize+NOISELENGTH); /* + noise */
if ((!fileSizes) || (!srcBuffer) || (!dictBuffer)) EXM_THROW(12, "not enough memory for DiB_trainFiles"); /* should not happen */
/* Load input buffer */
DiB_loadFiles(srcBuffer, benchedSize, fileSizes, fileNamesTable, nbFiles);
nbFiles = DiB_loadFiles(srcBuffer, benchedSize, fileSizes, fileNamesTable, nbFiles);
DiB_fillNoise((char*)srcBuffer + benchedSize, NOISELENGTH); /* guard band, for end of buffer condition */
/* call buffer version */
dictSize = ZDICT_trainFromBuffer_unsafe(dictBuffer, maxDictSize,
{ size_t const dictSize = ZDICT_trainFromBuffer_unsafe(dictBuffer, maxDictSize,
srcBuffer, fileSizes, nbFiles,
params);
if (ZDICT_isError(dictSize)) {
@ -221,10 +221,10 @@ int DiB_trainFromFiles(const char* dictFileName, unsigned maxDictSize,
result = 1;
goto _cleanup;
}
/* save dict */
DISPLAYLEVEL(2, "Save dictionary of size %u into file %s \n", (U32)dictSize, dictFileName);
DiB_saveDict(dictFileName, dictBuffer, dictSize);
}
/* clean up */
_cleanup:

2
programs/tests/playTests.sh
View File

@ -129,6 +129,8 @@ $ZSTD -d tmp -D tmpDict -of result
diff zstdcli.c result
$ZSTD --train *.c *.h -o tmpDictC
$ZSTD -d tmp -D tmpDictC -of result && die "wrong dictionary not detected!"
$ZSTD --train *.c --dictID 1 -o tmpDict1
cmp tmpDict tmpDict1 && die "dictionaries should have different ID !"
$ECHO "\n**** multiple files tests **** "

8
programs/zstd.1
View File

@ -92,6 +92,14 @@ Typical gains range from ~10% (at 64KB) to x5 better (at <1KB).
.B \--maxdict #
limit dictionary to specified size (default : 112640)
.TP
.B \--dictID #
A dictionary ID is a locally unique ID that a decoder can use to verify it is using the right dictionary.
By default, zstd will create a 4-bytes random number ID.
It's possible to give a precise number instead.
Short numbers have an advantage : an ID < 256 will only need 1 byte in the compressed frame header,
and an ID < 65536 will only need 2 bytes. This compares favorably to 4 bytes default.
However, it's up to the dictionary manager to not assign twice the same ID to 2 different dictionaries.
.TP
.B \-s#
dictionary selectivity level (default: 9)
the smaller the value, the denser the dictionary, improving its efficiency but reducing its possible maximum size.

15
programs/zstdcli.c
View File

@ -143,6 +143,7 @@ static int usage_advanced(const char* programName)
DISPLAY( " -o file: `file` is dictionary name (default: %s) \n", g_defaultDictName);
DISPLAY( "--maxdict:limit dictionary to specified size (default : %u) \n", g_defaultMaxDictSize);
DISPLAY( " -s# : dictionary selectivity level (default: %u)\n", g_defaultSelectivityLevel);
DISPLAY( "--dictID: force dictionary ID to specified value (default: random)\n");
#endif
#ifndef ZSTD_NOBENCH
DISPLAY( "\n");
@ -185,7 +186,8 @@ int main(int argCount, const char** argv)
operationResult=0,
dictBuild=0,
nextArgumentIsOutFileName=0,
nextArgumentIsMaxDict=0;
nextArgumentIsMaxDict=0,
nextArgumentIsDictID=0;
unsigned cLevel = 1;
unsigned cLevelLast = 1;
unsigned recursive = 0;
@ -196,6 +198,7 @@ int main(int argCount, const char** argv)
const char* dictFileName = NULL;
char* dynNameSpace = NULL;
unsigned maxDictSize = g_defaultMaxDictSize;
unsigned dictID = 0;
unsigned dictCLevel = g_defaultDictCLevel;
unsigned dictSelect = g_defaultSelectivityLevel;
#ifdef UTIL_HAS_CREATEFILELIST
@ -236,6 +239,7 @@ int main(int argCount, const char** argv)
if (!strcmp(argument, "--test")) { decode=1; outFileName=nulmark; FIO_overwriteMode(); continue; }
if (!strcmp(argument, "--train")) { dictBuild=1; outFileName=g_defaultDictName; continue; }
if (!strcmp(argument, "--maxdict")) { nextArgumentIsMaxDict=1; continue; }
if (!strcmp(argument, "--dictID")) { nextArgumentIsDictID=1; continue; }
if (!strcmp(argument, "--keep")) { continue; } /* does nothing, since preserving input is default; for gzip/xz compatibility */
if (!strcmp(argument, "--ultra")) { FIO_setMaxWLog(0); continue; }
if (!strcmp(argument, "--sparse")) { FIO_setSparseWrite(2); continue; }
@ -393,6 +397,14 @@ int main(int argCount, const char** argv)
continue;
}
if (nextArgumentIsDictID) {
nextArgumentIsDictID = 0;
dictID = 0;
while ((*argument>='0') && (*argument<='9'))
dictID = dictID * 10 + (*argument - '0'), argument++;
continue;
}
/* add filename to list */
filenameTable[filenameIdx++] = argument;
}
@ -429,6 +441,7 @@ int main(int argCount, const char** argv)
dictParams.compressionLevel = dictCLevel;
dictParams.selectivityLevel = dictSelect;
dictParams.notificationLevel = displayLevel;
dictParams.dictID = dictID;
DiB_trainFromFiles(outFileName, maxDictSize, filenameTable, filenameIdx, dictParams);
#endif
goto _end;