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zdict.c
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zdict.c
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#ifndef USE_EXTERNAL_ZSTD
/*
* Copyright (c) Yann Collet, 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.
*/
/*-**************************************
* Tuning parameters
****************************************/
#define MINRATIO 4 /* minimum nb of apparition to be selected in dictionary */
#define ZDICT_MAX_SAMPLES_SIZE (2000U << 20)
#define ZDICT_MIN_SAMPLES_SIZE (ZDICT_CONTENTSIZE_MIN * MINRATIO)
/*-**************************************
* Compiler Options
****************************************/
/* Unix Large Files support (>4GB) */
#define _FILE_OFFSET_BITS 64
#if (defined(__sun__) && (!defined(__LP64__))) /* Sun Solaris 32-bits requires specific definitions */
# ifndef _LARGEFILE_SOURCE
# define _LARGEFILE_SOURCE
# endif
#elif ! defined(__LP64__) /* No point defining Large file for 64 bit */
# ifndef _LARGEFILE64_SOURCE
# define _LARGEFILE64_SOURCE
# endif
#endif
/*-*************************************
* Dependencies
***************************************/
#include <stdlib.h> /* malloc, free */
#include <string.h> /* memset */
#include <stdio.h> /* fprintf, fopen, ftello64 */
#include <time.h> /* clock */
#ifndef ZDICT_STATIC_LINKING_ONLY
# define ZDICT_STATIC_LINKING_ONLY
#endif
#define HUF_STATIC_LINKING_ONLY
#include "mem.h" /* read */
#include "fse.h" /* FSE_normalizeCount, FSE_writeNCount */
#include "huf.h" /* HUF_buildCTable, HUF_writeCTable */
#include "zstd_internal.h" /* includes zstd.h */
#include "xxhash.h" /* XXH64 */
#include "zstd_compress_internal.h" /* ZSTD_loadCEntropy() */
#include "zdict.h"
#include "divsufsort.h"
/*-*************************************
* Constants
***************************************/
#define KB *(1 <<10)
#define MB *(1 <<20)
#define GB *(1U<<30)
#define DICTLISTSIZE_DEFAULT 10000
#define NOISELENGTH 32
static const U32 g_selectivity_default = 9;
/*-*************************************
* Console display
***************************************/
#undef DISPLAY
#define DISPLAY(...) { fprintf(stderr, __VA_ARGS__); fflush( stderr ); }
#undef DISPLAYLEVEL
#define DISPLAYLEVEL(l, ...) if (notificationLevel>=l) { DISPLAY(__VA_ARGS__); } /* 0 : no display; 1: errors; 2: default; 3: details; 4: debug */
static clock_t ZDICT_clockSpan(clock_t nPrevious) { return clock() - nPrevious; }
static void ZDICT_printHex(const void* ptr, size_t length)
{
const BYTE* const b = (const BYTE*)ptr;
size_t u;
for (u=0; u<length; u++) {
BYTE c = b[u];
if (c<32 || c>126) c = '.'; /* non-printable char */
DISPLAY("%c", c);
}
}
/*-********************************************************
* Helper functions
**********************************************************/
unsigned ZDICT_isError(size_t errorCode) { return ERR_isError(errorCode); }
const char* ZDICT_getErrorName(size_t errorCode) { return ERR_getErrorName(errorCode); }
unsigned ZDICT_getDictID(const void* dictBuffer, size_t dictSize)
{
if (dictSize < 8) return 0;
if (MEM_readLE32(dictBuffer) != ZSTD_MAGIC_DICTIONARY) return 0;
return MEM_readLE32((const char*)dictBuffer + 4);
}
size_t ZDICT_getDictHeaderSize(const void* dictBuffer, size_t dictSize)
{
size_t headerSize;
if (dictSize <= 8 || MEM_readLE32(dictBuffer) != ZSTD_MAGIC_DICTIONARY) return ERROR(dictionary_corrupted);
{ ZSTD_compressedBlockState_t* bs = (ZSTD_compressedBlockState_t*)malloc(sizeof(ZSTD_compressedBlockState_t));
U32* wksp = (U32*)malloc(HUF_WORKSPACE_SIZE);
if (!bs || !wksp) {
headerSize = ERROR(memory_allocation);
} else {
ZSTD_reset_compressedBlockState(bs);
headerSize = ZSTD_loadCEntropy(bs, wksp, dictBuffer, dictSize);
}
free(bs);
free(wksp);
}
return headerSize;
}
/*-********************************************************
* Dictionary training functions
**********************************************************/
static unsigned ZDICT_NbCommonBytes (size_t val)
{
if (MEM_isLittleEndian()) {
if (MEM_64bits()) {
# if defined(_MSC_VER) && defined(_WIN64)
if (val != 0) {
unsigned long r;
_BitScanForward64(&r, (U64)val);
return (unsigned)(r >> 3);
} else {
/* Should not reach this code path */
__assume(0);
}
# elif defined(__GNUC__) && (__GNUC__ >= 3)
return (unsigned)(__builtin_ctzll((U64)val) >> 3);
# else
static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
return DeBruijnBytePos[((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];
# endif
} else { /* 32 bits */
# if defined(_MSC_VER)
if (val != 0) {
unsigned long r;
_BitScanForward(&r, (U32)val);
return (unsigned)(r >> 3);
} else {
/* Should not reach this code path */
__assume(0);
}
# elif defined(__GNUC__) && (__GNUC__ >= 3)
return (unsigned)(__builtin_ctz((U32)val) >> 3);
# else
static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
# endif
}
} else { /* Big Endian CPU */
if (MEM_64bits()) {
# if defined(_MSC_VER) && defined(_WIN64)
if (val != 0) {
unsigned long r;
_BitScanReverse64(&r, val);
return (unsigned)(r >> 3);
} else {
/* Should not reach this code path */
__assume(0);
}
# elif defined(__GNUC__) && (__GNUC__ >= 3)
return (unsigned)(__builtin_clzll(val) >> 3);
# else
unsigned r;
const unsigned n32 = sizeof(size_t)*4; /* calculate this way due to compiler complaining in 32-bits mode */
if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; }
if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
r += (!val);
return r;
# endif
} else { /* 32 bits */
# if defined(_MSC_VER)
if (val != 0) {
unsigned long r;
_BitScanReverse(&r, (unsigned long)val);
return (unsigned)(r >> 3);
} else {
/* Should not reach this code path */
__assume(0);
}
# elif defined(__GNUC__) && (__GNUC__ >= 3)
return (unsigned)(__builtin_clz((U32)val) >> 3);
# else
unsigned r;
if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
r += (!val);
return r;
# endif
} }
}
/*! ZDICT_count() :
Count the nb of common bytes between 2 pointers.
Note : this function presumes end of buffer followed by noisy guard band.
*/
static size_t ZDICT_count(const void* pIn, const void* pMatch)
{
const char* const pStart = (const char*)pIn;
for (;;) {
size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);
if (!diff) {
pIn = (const char*)pIn+sizeof(size_t);
pMatch = (const char*)pMatch+sizeof(size_t);
continue;
}
pIn = (const char*)pIn+ZDICT_NbCommonBytes(diff);
return (size_t)((const char*)pIn - pStart);
}
}
typedef struct {
U32 pos;
U32 length;
U32 savings;
} dictItem;
static void ZDICT_initDictItem(dictItem* d)
{
d->pos = 1;
d->length = 0;
d->savings = (U32)(-1);
}
#define LLIMIT 64 /* heuristic determined experimentally */
#define MINMATCHLENGTH 7 /* heuristic determined experimentally */
static dictItem ZDICT_analyzePos(
BYTE* doneMarks,
const int* suffix, U32 start,
const void* buffer, U32 minRatio, U32 notificationLevel)
{
U32 lengthList[LLIMIT] = {0};
U32 cumulLength[LLIMIT] = {0};
U32 savings[LLIMIT] = {0};
const BYTE* b = (const BYTE*)buffer;
size_t maxLength = LLIMIT;
size_t pos = (size_t)suffix[start];
U32 end = start;
dictItem solution;
/* init */
memset(&solution, 0, sizeof(solution));
doneMarks[pos] = 1;
/* trivial repetition cases */
if ( (MEM_read16(b+pos+0) == MEM_read16(b+pos+2))
||(MEM_read16(b+pos+1) == MEM_read16(b+pos+3))
||(MEM_read16(b+pos+2) == MEM_read16(b+pos+4)) ) {
/* skip and mark segment */
U16 const pattern16 = MEM_read16(b+pos+4);
U32 u, patternEnd = 6;
while (MEM_read16(b+pos+patternEnd) == pattern16) patternEnd+=2 ;
if (b[pos+patternEnd] == b[pos+patternEnd-1]) patternEnd++;
for (u=1; u<patternEnd; u++)
doneMarks[pos+u] = 1;
return solution;
}
/* look forward */
{ size_t length;
do {
end++;
length = ZDICT_count(b + pos, b + suffix[end]);
} while (length >= MINMATCHLENGTH);
}
/* look backward */
{ size_t length;
do {
length = ZDICT_count(b + pos, b + *(suffix+start-1));
if (length >=MINMATCHLENGTH) start--;
} while(length >= MINMATCHLENGTH);
}
/* exit if not found a minimum nb of repetitions */
if (end-start < minRatio) {
U32 idx;
for(idx=start; idx<end; idx++)
doneMarks[suffix[idx]] = 1;
return solution;
}
{ int i;
U32 mml;
U32 refinedStart = start;
U32 refinedEnd = end;
DISPLAYLEVEL(4, "\n");
DISPLAYLEVEL(4, "found %3u matches of length >= %i at pos %7u ", (unsigned)(end-start), MINMATCHLENGTH, (unsigned)pos);
DISPLAYLEVEL(4, "\n");
for (mml = MINMATCHLENGTH ; ; mml++) {
BYTE currentChar = 0;
U32 currentCount = 0;
U32 currentID = refinedStart;
U32 id;
U32 selectedCount = 0;
U32 selectedID = currentID;
for (id =refinedStart; id < refinedEnd; id++) {
if (b[suffix[id] + mml] != currentChar) {
if (currentCount > selectedCount) {
selectedCount = currentCount;
selectedID = currentID;
}
currentID = id;
currentChar = b[ suffix[id] + mml];
currentCount = 0;
}
currentCount ++;
}
if (currentCount > selectedCount) { /* for last */
selectedCount = currentCount;
selectedID = currentID;
}
if (selectedCount < minRatio)
break;
refinedStart = selectedID;
refinedEnd = refinedStart + selectedCount;
}
/* evaluate gain based on new dict */
start = refinedStart;
pos = suffix[refinedStart];
end = start;
memset(lengthList, 0, sizeof(lengthList));
/* look forward */
{ size_t length;
do {
end++;
length = ZDICT_count(b + pos, b + suffix[end]);
if (length >= LLIMIT) length = LLIMIT-1;
lengthList[length]++;
} while (length >=MINMATCHLENGTH);
}
/* look backward */
{ size_t length = MINMATCHLENGTH;
while ((length >= MINMATCHLENGTH) & (start > 0)) {
length = ZDICT_count(b + pos, b + suffix[start - 1]);
if (length >= LLIMIT) length = LLIMIT - 1;
lengthList[length]++;
if (length >= MINMATCHLENGTH) start--;
}
}
/* largest useful length */
memset(cumulLength, 0, sizeof(cumulLength));
cumulLength[maxLength-1] = lengthList[maxLength-1];
for (i=(int)(maxLength-2); i>=0; i--)
cumulLength[i] = cumulLength[i+1] + lengthList[i];
for (i=LLIMIT-1; i>=MINMATCHLENGTH; i--) if (cumulLength[i]>=minRatio) break;
maxLength = i;
/* reduce maxLength in case of final into repetitive data */
{ U32 l = (U32)maxLength;
BYTE const c = b[pos + maxLength-1];
while (b[pos+l-2]==c) l--;
maxLength = l;
}
if (maxLength < MINMATCHLENGTH) return solution; /* skip : no long-enough solution */
/* calculate savings */
savings[5] = 0;
for (i=MINMATCHLENGTH; i<=(int)maxLength; i++)
savings[i] = savings[i-1] + (lengthList[i] * (i-3));
DISPLAYLEVEL(4, "Selected dict at position %u, of length %u : saves %u (ratio: %.2f) \n",
(unsigned)pos, (unsigned)maxLength, (unsigned)savings[maxLength], (double)savings[maxLength] / (double)maxLength);
solution.pos = (U32)pos;
solution.length = (U32)maxLength;
solution.savings = savings[maxLength];
/* mark positions done */
{ U32 id;
for (id=start; id<end; id++) {
U32 p, pEnd, length;
U32 const testedPos = (U32)suffix[id];
if (testedPos == pos)
length = solution.length;
else {
length = (U32)ZDICT_count(b+pos, b+testedPos);
if (length > solution.length) length = solution.length;
}
pEnd = (U32)(testedPos + length);
for (p=testedPos; p<pEnd; p++)
doneMarks[p] = 1;
} } }
return solution;
}
static int isIncluded(const void* in, const void* container, size_t length)
{
const char* const ip = (const char*) in;
const char* const into = (const char*) container;
size_t u;
for (u=0; u<length; u++) { /* works because end of buffer is a noisy guard band */
if (ip[u] != into[u]) break;
}
return u==length;
}
/*! ZDICT_tryMerge() :
check if dictItem can be merged, do it if possible
@return : id of destination elt, 0 if not merged
*/
static U32 ZDICT_tryMerge(dictItem* table, dictItem elt, U32 eltNbToSkip, const void* buffer)
{
const U32 tableSize = table->pos;
const U32 eltEnd = elt.pos + elt.length;
const char* const buf = (const char*) buffer;
/* tail overlap */
U32 u; for (u=1; u<tableSize; u++) {
if (u==eltNbToSkip) continue;
if ((table[u].pos > elt.pos) && (table[u].pos <= eltEnd)) { /* overlap, existing > new */
/* append */
U32 const addedLength = table[u].pos - elt.pos;
table[u].length += addedLength;
table[u].pos = elt.pos;
table[u].savings += elt.savings * addedLength / elt.length; /* rough approx */
table[u].savings += elt.length / 8; /* rough approx bonus */
elt = table[u];
/* sort : improve rank */
while ((u>1) && (table[u-1].savings < elt.savings))
table[u] = table[u-1], u--;
table[u] = elt;
return u;
} }
/* front overlap */
for (u=1; u<tableSize; u++) {
if (u==eltNbToSkip) continue;
if ((table[u].pos + table[u].length >= elt.pos) && (table[u].pos < elt.pos)) { /* overlap, existing < new */
/* append */
int const addedLength = (int)eltEnd - (int)(table[u].pos + table[u].length);
table[u].savings += elt.length / 8; /* rough approx bonus */
if (addedLength > 0) { /* otherwise, elt fully included into existing */
table[u].length += addedLength;
table[u].savings += elt.savings * addedLength / elt.length; /* rough approx */
}
/* sort : improve rank */
elt = table[u];
while ((u>1) && (table[u-1].savings < elt.savings))
table[u] = table[u-1], u--;
table[u] = elt;
return u;
}
if (MEM_read64(buf + table[u].pos) == MEM_read64(buf + elt.pos + 1)) {
if (isIncluded(buf + table[u].pos, buf + elt.pos + 1, table[u].length)) {
size_t const addedLength = MAX( (int)elt.length - (int)table[u].length , 1 );
table[u].pos = elt.pos;
table[u].savings += (U32)(elt.savings * addedLength / elt.length);
table[u].length = MIN(elt.length, table[u].length + 1);
return u;
}
}
}
return 0;
}
static void ZDICT_removeDictItem(dictItem* table, U32 id)
{
/* convention : table[0].pos stores nb of elts */
U32 const max = table[0].pos;
U32 u;
if (!id) return; /* protection, should never happen */
for (u=id; u<max-1; u++)
table[u] = table[u+1];
table->pos--;
}
static void ZDICT_insertDictItem(dictItem* table, U32 maxSize, dictItem elt, const void* buffer)
{
/* merge if possible */
U32 mergeId = ZDICT_tryMerge(table, elt, 0, buffer);
if (mergeId) {
U32 newMerge = 1;
while (newMerge) {
newMerge = ZDICT_tryMerge(table, table[mergeId], mergeId, buffer);
if (newMerge) ZDICT_removeDictItem(table, mergeId);
mergeId = newMerge;
}
return;
}
/* insert */
{ U32 current;
U32 nextElt = table->pos;
if (nextElt >= maxSize) nextElt = maxSize-1;
current = nextElt-1;
while (table[current].savings < elt.savings) {
table[current+1] = table[current];
current--;
}
table[current+1] = elt;
table->pos = nextElt+1;
}
}
static U32 ZDICT_dictSize(const dictItem* dictList)
{
U32 u, dictSize = 0;
for (u=1; u<dictList[0].pos; u++)
dictSize += dictList[u].length;
return dictSize;
}
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,
unsigned minRatio, U32 notificationLevel)
{
int* const suffix0 = (int*)malloc((bufferSize+2)*sizeof(*suffix0));
int* const suffix = suffix0+1;
U32* reverseSuffix = (U32*)malloc((bufferSize)*sizeof(*reverseSuffix));
BYTE* doneMarks = (BYTE*)malloc((bufferSize+16)*sizeof(*doneMarks)); /* +16 for overflow security */
U32* filePos = (U32*)malloc(nbFiles * sizeof(*filePos));
size_t result = 0;
clock_t displayClock = 0;
clock_t const refreshRate = CLOCKS_PER_SEC * 3 / 10;
# undef DISPLAYUPDATE
# define DISPLAYUPDATE(l, ...) if (notificationLevel>=l) { \
if (ZDICT_clockSpan(displayClock) > refreshRate) \
{ displayClock = clock(); DISPLAY(__VA_ARGS__); \
if (notificationLevel>=4) fflush(stderr); } }
/* init */
DISPLAYLEVEL(2, "\r%70s\r", ""); /* clean display line */
if (!suffix0 || !reverseSuffix || !doneMarks || !filePos) {
result = ERROR(memory_allocation);
goto _cleanup;
}
if (minRatio < MINRATIO) minRatio = MINRATIO;
memset(doneMarks, 0, bufferSize+16);
/* limit sample set size (divsufsort limitation)*/
if (bufferSize > ZDICT_MAX_SAMPLES_SIZE) DISPLAYLEVEL(3, "sample set too large : reduced to %u MB ...\n", (unsigned)(ZDICT_MAX_SAMPLES_SIZE>>20));
while (bufferSize > ZDICT_MAX_SAMPLES_SIZE) bufferSize -= fileSizes[--nbFiles];
/* sort */
DISPLAYLEVEL(2, "sorting %u files of total size %u MB ...\n", nbFiles, (unsigned)(bufferSize>>20));
{ int const divSuftSortResult = divsufsort((const unsigned char*)buffer, suffix, (int)bufferSize, 0);
if (divSuftSortResult != 0) { result = ERROR(GENERIC); goto _cleanup; }
}
suffix[bufferSize] = (int)bufferSize; /* leads into noise */
suffix0[0] = (int)bufferSize; /* leads into noise */
/* build reverse suffix sort */
{ size_t pos;
for (pos=0; pos < bufferSize; pos++)
reverseSuffix[suffix[pos]] = (U32)pos;
/* note filePos tracks borders between samples.
It's not used at this stage, but planned to become useful in a later update */
filePos[0] = 0;
for (pos=1; pos<nbFiles; pos++)
filePos[pos] = (U32)(filePos[pos-1] + fileSizes[pos-1]);
}
DISPLAYLEVEL(2, "finding patterns ... \n");
DISPLAYLEVEL(3, "minimum ratio : %u \n", minRatio);
{ U32 cursor; for (cursor=0; cursor < bufferSize; ) {
dictItem solution;
if (doneMarks[cursor]) { cursor++; continue; }
solution = ZDICT_analyzePos(doneMarks, suffix, reverseSuffix[cursor], buffer, minRatio, notificationLevel);
if (solution.length==0) { cursor++; continue; }
ZDICT_insertDictItem(dictList, dictListSize, solution, buffer);
cursor += solution.length;
DISPLAYUPDATE(2, "\r%4.2f %% \r", (double)cursor / bufferSize * 100);
} }
_cleanup:
free(suffix0);
free(reverseSuffix);
free(doneMarks);
free(filePos);
return result;
}
static void ZDICT_fillNoise(void* buffer, size_t length)
{
unsigned const prime1 = 2654435761U;
unsigned const prime2 = 2246822519U;
unsigned acc = prime1;
size_t p=0;
for (p=0; p<length; p++) {
acc *= prime2;
((unsigned char*)buffer)[p] = (unsigned char)(acc >> 21);
}
}
typedef struct
{
ZSTD_CDict* dict; /* dictionary */
ZSTD_CCtx* zc; /* working context */
void* workPlace; /* must be ZSTD_BLOCKSIZE_MAX allocated */
} EStats_ress_t;
#define MAXREPOFFSET 1024
static void ZDICT_countEStats(EStats_ress_t esr, const ZSTD_parameters* params,
unsigned* countLit, unsigned* offsetcodeCount, unsigned* matchlengthCount, unsigned* litlengthCount, U32* repOffsets,
const void* src, size_t srcSize,
U32 notificationLevel)
{
size_t const blockSizeMax = MIN (ZSTD_BLOCKSIZE_MAX, 1 << params->cParams.windowLog);
size_t cSize;
if (srcSize > blockSizeMax) srcSize = blockSizeMax; /* protection vs large samples */
{ size_t const errorCode = ZSTD_compressBegin_usingCDict(esr.zc, esr.dict);
if (ZSTD_isError(errorCode)) { DISPLAYLEVEL(1, "warning : ZSTD_compressBegin_usingCDict failed \n"); return; }
}
cSize = ZSTD_compressBlock(esr.zc, esr.workPlace, ZSTD_BLOCKSIZE_MAX, src, srcSize);
if (ZSTD_isError(cSize)) { DISPLAYLEVEL(3, "warning : could not compress sample size %u \n", (unsigned)srcSize); return; }
if (cSize) { /* if == 0; block is not compressible */
const seqStore_t* const seqStorePtr = ZSTD_getSeqStore(esr.zc);
/* literals stats */
{ const BYTE* bytePtr;
for(bytePtr = seqStorePtr->litStart; bytePtr < seqStorePtr->lit; bytePtr++)
countLit[*bytePtr]++;
}
/* seqStats */
{ U32 const nbSeq = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
ZSTD_seqToCodes(seqStorePtr);
{ const BYTE* codePtr = seqStorePtr->ofCode;
U32 u;
for (u=0; u<nbSeq; u++) offsetcodeCount[codePtr[u]]++;
}
{ const BYTE* codePtr = seqStorePtr->mlCode;
U32 u;
for (u=0; u<nbSeq; u++) matchlengthCount[codePtr[u]]++;
}
{ const BYTE* codePtr = seqStorePtr->llCode;
U32 u;
for (u=0; u<nbSeq; u++) litlengthCount[codePtr[u]]++;
}
if (nbSeq >= 2) { /* rep offsets */
const seqDef* const seq = seqStorePtr->sequencesStart;
U32 offset1 = seq[0].offBase - ZSTD_REP_NUM;
U32 offset2 = seq[1].offBase - ZSTD_REP_NUM;
if (offset1 >= MAXREPOFFSET) offset1 = 0;
if (offset2 >= MAXREPOFFSET) offset2 = 0;
repOffsets[offset1] += 3;
repOffsets[offset2] += 1;
} } }
}
static size_t ZDICT_totalSampleSize(const size_t* fileSizes, unsigned nbFiles)
{
size_t total=0;
unsigned u;
for (u=0; u<nbFiles; u++) total += fileSizes[u];
return total;
}
typedef struct { U32 offset; U32 count; } offsetCount_t;
static void ZDICT_insertSortCount(offsetCount_t table[ZSTD_REP_NUM+1], U32 val, U32 count)
{
U32 u;
table[ZSTD_REP_NUM].offset = val;
table[ZSTD_REP_NUM].count = count;
for (u=ZSTD_REP_NUM; u>0; u--) {
offsetCount_t tmp;
if (table[u-1].count >= table[u].count) break;
tmp = table[u-1];
table[u-1] = table[u];
table[u] = tmp;
}
}
/* ZDICT_flatLit() :
* rewrite `countLit` to contain a mostly flat but still compressible distribution of literals.
* necessary to avoid generating a non-compressible distribution that HUF_writeCTable() cannot encode.
*/
static void ZDICT_flatLit(unsigned* countLit)
{
int u;
for (u=1; u<256; u++) countLit[u] = 2;
countLit[0] = 4;
countLit[253] = 1;
countLit[254] = 1;
}
#define OFFCODE_MAX 30 /* only applicable to first block */
static size_t ZDICT_analyzeEntropy(void* dstBuffer, size_t maxDstSize,
int compressionLevel,
const void* srcBuffer, const size_t* fileSizes, unsigned nbFiles,
const void* dictBuffer, size_t dictBufferSize,
unsigned notificationLevel)
{
unsigned countLit[256];
HUF_CREATE_STATIC_CTABLE(hufTable, 255);
unsigned offcodeCount[OFFCODE_MAX+1];
short offcodeNCount[OFFCODE_MAX+1];
U32 offcodeMax = ZSTD_highbit32((U32)(dictBufferSize + 128 KB));
unsigned matchLengthCount[MaxML+1];
short matchLengthNCount[MaxML+1];
unsigned litLengthCount[MaxLL+1];
short litLengthNCount[MaxLL+1];
U32 repOffset[MAXREPOFFSET];
offsetCount_t bestRepOffset[ZSTD_REP_NUM+1];
EStats_ress_t esr = { NULL, NULL, NULL };
ZSTD_parameters params;
U32 u, huffLog = 11, Offlog = OffFSELog, mlLog = MLFSELog, llLog = LLFSELog, total;
size_t pos = 0, errorCode;
size_t eSize = 0;
size_t const totalSrcSize = ZDICT_totalSampleSize(fileSizes, nbFiles);
size_t const averageSampleSize = totalSrcSize / (nbFiles + !nbFiles);
BYTE* dstPtr = (BYTE*)dstBuffer;
/* init */
DEBUGLOG(4, "ZDICT_analyzeEntropy");
if (offcodeMax>OFFCODE_MAX) { eSize = ERROR(dictionaryCreation_failed); goto _cleanup; } /* too large dictionary */
for (u=0; u<256; u++) countLit[u] = 1; /* any character must be described */
for (u=0; u<=offcodeMax; u++) offcodeCount[u] = 1;
for (u=0; u<=MaxML; u++) matchLengthCount[u] = 1;
for (u=0; u<=MaxLL; u++) litLengthCount[u] = 1;
memset(repOffset, 0, sizeof(repOffset));
repOffset[1] = repOffset[4] = repOffset[8] = 1;
memset(bestRepOffset, 0, sizeof(bestRepOffset));
if (compressionLevel==0) compressionLevel = ZSTD_CLEVEL_DEFAULT;
params = ZSTD_getParams(compressionLevel, averageSampleSize, dictBufferSize);
esr.dict = ZSTD_createCDict_advanced(dictBuffer, dictBufferSize, ZSTD_dlm_byRef, ZSTD_dct_rawContent, params.cParams, ZSTD_defaultCMem);
esr.zc = ZSTD_createCCtx();
esr.workPlace = malloc(ZSTD_BLOCKSIZE_MAX);
if (!esr.dict || !esr.zc || !esr.workPlace) {
eSize = ERROR(memory_allocation);
DISPLAYLEVEL(1, "Not enough memory \n");
goto _cleanup;
}
/* collect stats on all samples */
for (u=0; u<nbFiles; u++) {
ZDICT_countEStats(esr, ¶ms,
countLit, offcodeCount, matchLengthCount, litLengthCount, repOffset,
(const char*)srcBuffer + pos, fileSizes[u],
notificationLevel);
pos += fileSizes[u];
}
if (notificationLevel >= 4) {
/* writeStats */
DISPLAYLEVEL(4, "Offset Code Frequencies : \n");
for (u=0; u<=offcodeMax; u++) {
DISPLAYLEVEL(4, "%2u :%7u \n", u, offcodeCount[u]);
} }
/* analyze, build stats, starting with literals */
{ size_t maxNbBits = HUF_buildCTable (hufTable, countLit, 255, huffLog);
if (HUF_isError(maxNbBits)) {
eSize = maxNbBits;
DISPLAYLEVEL(1, " HUF_buildCTable error \n");
goto _cleanup;
}
if (maxNbBits==8) { /* not compressible : will fail on HUF_writeCTable() */
DISPLAYLEVEL(2, "warning : pathological dataset : literals are not compressible : samples are noisy or too regular \n");
ZDICT_flatLit(countLit); /* replace distribution by a fake "mostly flat but still compressible" distribution, that HUF_writeCTable() can encode */
maxNbBits = HUF_buildCTable (hufTable, countLit, 255, huffLog);
assert(maxNbBits==9);
}
huffLog = (U32)maxNbBits;
}
/* looking for most common first offsets */
{ U32 offset;
for (offset=1; offset<MAXREPOFFSET; offset++)
ZDICT_insertSortCount(bestRepOffset, offset, repOffset[offset]);
}
/* note : the result of this phase should be used to better appreciate the impact on statistics */
total=0; for (u=0; u<=offcodeMax; u++) total+=offcodeCount[u];
errorCode = FSE_normalizeCount(offcodeNCount, Offlog, offcodeCount, total, offcodeMax, /* useLowProbCount */ 1);
if (FSE_isError(errorCode)) {
eSize = errorCode;
DISPLAYLEVEL(1, "FSE_normalizeCount error with offcodeCount \n");
goto _cleanup;
}
Offlog = (U32)errorCode;
total=0; for (u=0; u<=MaxML; u++) total+=matchLengthCount[u];
errorCode = FSE_normalizeCount(matchLengthNCount, mlLog, matchLengthCount, total, MaxML, /* useLowProbCount */ 1);
if (FSE_isError(errorCode)) {
eSize = errorCode;
DISPLAYLEVEL(1, "FSE_normalizeCount error with matchLengthCount \n");
goto _cleanup;
}
mlLog = (U32)errorCode;
total=0; for (u=0; u<=MaxLL; u++) total+=litLengthCount[u];
errorCode = FSE_normalizeCount(litLengthNCount, llLog, litLengthCount, total, MaxLL, /* useLowProbCount */ 1);
if (FSE_isError(errorCode)) {
eSize = errorCode;
DISPLAYLEVEL(1, "FSE_normalizeCount error with litLengthCount \n");
goto _cleanup;
}
llLog = (U32)errorCode;
/* write result to buffer */
{ size_t const hhSize = HUF_writeCTable(dstPtr, maxDstSize, hufTable, 255, huffLog);
if (HUF_isError(hhSize)) {
eSize = hhSize;
DISPLAYLEVEL(1, "HUF_writeCTable error \n");
goto _cleanup;
}
dstPtr += hhSize;
maxDstSize -= hhSize;
eSize += hhSize;
}
{ size_t const ohSize = FSE_writeNCount(dstPtr, maxDstSize, offcodeNCount, OFFCODE_MAX, Offlog);
if (FSE_isError(ohSize)) {
eSize = ohSize;
DISPLAYLEVEL(1, "FSE_writeNCount error with offcodeNCount \n");
goto _cleanup;
}
dstPtr += ohSize;
maxDstSize -= ohSize;
eSize += ohSize;
}
{ size_t const mhSize = FSE_writeNCount(dstPtr, maxDstSize, matchLengthNCount, MaxML, mlLog);
if (FSE_isError(mhSize)) {
eSize = mhSize;
DISPLAYLEVEL(1, "FSE_writeNCount error with matchLengthNCount \n");
goto _cleanup;
}
dstPtr += mhSize;
maxDstSize -= mhSize;
eSize += mhSize;
}
{ size_t const lhSize = FSE_writeNCount(dstPtr, maxDstSize, litLengthNCount, MaxLL, llLog);
if (FSE_isError(lhSize)) {
eSize = lhSize;
DISPLAYLEVEL(1, "FSE_writeNCount error with litlengthNCount \n");
goto _cleanup;
}
dstPtr += lhSize;
maxDstSize -= lhSize;
eSize += lhSize;
}
if (maxDstSize<12) {
eSize = ERROR(dstSize_tooSmall);
DISPLAYLEVEL(1, "not enough space to write RepOffsets \n");
goto _cleanup;
}
# if 0
MEM_writeLE32(dstPtr+0, bestRepOffset[0].offset);
MEM_writeLE32(dstPtr+4, bestRepOffset[1].offset);
MEM_writeLE32(dstPtr+8, bestRepOffset[2].offset);
#else
/* at this stage, we don't use the result of "most common first offset",
* as the impact of statistics is not properly evaluated */
MEM_writeLE32(dstPtr+0, repStartValue[0]);
MEM_writeLE32(dstPtr+4, repStartValue[1]);
MEM_writeLE32(dstPtr+8, repStartValue[2]);
#endif
eSize += 12;
_cleanup:
ZSTD_freeCDict(esr.dict);
ZSTD_freeCCtx(esr.zc);
free(esr.workPlace);
return eSize;
}
/**
* @returns the maximum repcode value
*/
static U32 ZDICT_maxRep(U32 const reps[ZSTD_REP_NUM])
{
U32 maxRep = reps[0];
int r;
for (r = 1; r < ZSTD_REP_NUM; ++r)
maxRep = MAX(maxRep, reps[r]);
return maxRep;
}
size_t ZDICT_finalizeDictionary(void* dictBuffer, size_t dictBufferCapacity,
const void* customDictContent, size_t dictContentSize,
const void* samplesBuffer, const size_t* samplesSizes,
unsigned nbSamples, ZDICT_params_t params)
{
size_t hSize;
#define HBUFFSIZE 256 /* should prove large enough for all entropy headers */
BYTE header[HBUFFSIZE];
int const compressionLevel = (params.compressionLevel == 0) ? ZSTD_CLEVEL_DEFAULT : params.compressionLevel;
U32 const notificationLevel = params.notificationLevel;
/* The final dictionary content must be at least as large as the largest repcode */
size_t const minContentSize = (size_t)ZDICT_maxRep(repStartValue);
size_t paddingSize;
/* check conditions */
DEBUGLOG(4, "ZDICT_finalizeDictionary");
if (dictBufferCapacity < dictContentSize) return ERROR(dstSize_tooSmall);
if (dictBufferCapacity < ZDICT_DICTSIZE_MIN) return ERROR(dstSize_tooSmall);
/* dictionary header */
MEM_writeLE32(header, ZSTD_MAGIC_DICTIONARY);
{ U64 const randomID = XXH64(customDictContent, dictContentSize, 0);
U32 const compliantID = (randomID % ((1U<<31)-32768)) + 32768;
U32 const dictID = params.dictID ? params.dictID : compliantID;
MEM_writeLE32(header+4, dictID);
}
hSize = 8;
/* entropy tables */
DISPLAYLEVEL(2, "\r%70s\r", ""); /* clean display line */
DISPLAYLEVEL(2, "statistics ... \n");
{ size_t const eSize = ZDICT_analyzeEntropy(header+hSize, HBUFFSIZE-hSize,
compressionLevel,
samplesBuffer, samplesSizes, nbSamples,
customDictContent, dictContentSize,
notificationLevel);
if (ZDICT_isError(eSize)) return eSize;
hSize += eSize;
}
/* Shrink the content size if it doesn't fit in the buffer */
if (hSize + dictContentSize > dictBufferCapacity) {
dictContentSize = dictBufferCapacity - hSize;
}
/* Pad the dictionary content with zeros if it is too small */
if (dictContentSize < minContentSize) {
RETURN_ERROR_IF(hSize + minContentSize > dictBufferCapacity, dstSize_tooSmall,
"dictBufferCapacity too small to fit max repcode");
paddingSize = minContentSize - dictContentSize;
} else {
paddingSize = 0;
}
{
size_t const dictSize = hSize + paddingSize + dictContentSize;
/* The dictionary consists of the header, optional padding, and the content.
* The padding comes before the content because the "best" position in the
* dictionary is the last byte.
*/
BYTE* const outDictHeader = (BYTE*)dictBuffer;
BYTE* const outDictPadding = outDictHeader + hSize;
BYTE* const outDictContent = outDictPadding + paddingSize;
assert(dictSize <= dictBufferCapacity);
assert(outDictContent + dictContentSize == (BYTE*)dictBuffer + dictSize);
/* First copy the customDictContent into its final location.
* `customDictContent` and `dictBuffer` may overlap, so we must