return (cParams->strategy >= ZSTD_btopt && cParams->windowLog >= 27) ? ZSTD_ps_enable : ZSTD_ps_disable;
}
+/* Returns 1 if compression parameters are such that CDict hashtable and chaintable indices are tagged.
+ * If so, the tags need to be removed in ZSTD_resetCCtx_byCopyingCDict. */
+static int ZSTD_CDictIndicesAreTagged(const ZSTD_compressionParameters* const cParams) {
+ return cParams->strategy == ZSTD_fast || cParams->strategy == ZSTD_dfast;
+}
+
static ZSTD_CCtx_params ZSTD_makeCCtxParamsFromCParams(
ZSTD_compressionParameters cParams)
{
if (cPar.windowLog < ZSTD_WINDOWLOG_ABSOLUTEMIN)
cPar.windowLog = ZSTD_WINDOWLOG_ABSOLUTEMIN; /* minimum wlog required for valid frame header */
+ if (mode == ZSTD_cpm_createCDict && ZSTD_CDictIndicesAreTagged(&cPar)) {
+ U32 const maxShortCacheHashLog = 32 - ZSTD_SHORT_CACHE_TAG_BITS;
+ if (cPar.hashLog > maxShortCacheHashLog) {
+ cPar.hashLog = maxShortCacheHashLog;
+ }
+ }
+
return cPar;
}
return 0;
}
+static void ZSTD_copyCDictTableIntoCCtx(U32* dst, U32 const* src, size_t tableSize,
+ ZSTD_compressionParameters const* cParams) {
+ if (ZSTD_CDictIndicesAreTagged(cParams)){
+ /* Remove tags from the CDict table if they are present.
+ * See docs on "short cache" in zstd_compress_internal.h for context. */
+ size_t i;
+ for (i = 0; i < tableSize; i++) {
+ U32 const taggedIndex = src[i];
+ U32 const index = taggedIndex >> ZSTD_SHORT_CACHE_TAG_BITS;
+ dst[i] = index;
+ }
+ } else {
+ ZSTD_memcpy(dst, src, tableSize * sizeof(U32));
+ }
+}
+
static size_t ZSTD_resetCCtx_byCopyingCDict(ZSTD_CCtx* cctx,
const ZSTD_CDict* cdict,
ZSTD_CCtx_params params,
: 0;
size_t const hSize = (size_t)1 << cdict_cParams->hashLog;
- ZSTD_memcpy(cctx->blockState.matchState.hashTable,
- cdict->matchState.hashTable,
- hSize * sizeof(U32));
+ ZSTD_copyCDictTableIntoCCtx(cctx->blockState.matchState.hashTable,
+ cdict->matchState.hashTable,
+ hSize, cdict_cParams);
+
/* Do not copy cdict's chainTable if cctx has parameters such that it would not use chainTable */
if (ZSTD_allocateChainTable(cctx->appliedParams.cParams.strategy, cctx->appliedParams.useRowMatchFinder, 0 /* forDDSDict */)) {
- ZSTD_memcpy(cctx->blockState.matchState.chainTable,
- cdict->matchState.chainTable,
- chainSize * sizeof(U32));
+ ZSTD_copyCDictTableIntoCCtx(cctx->blockState.matchState.chainTable,
+ cdict->matchState.chainTable,
+ chainSize, cdict_cParams);
}
/* copy tag table */
if (ZSTD_rowMatchFinderUsed(cdict_cParams->strategy, cdict->useRowMatchFinder)) {
ZSTD_cwksp* ws,
ZSTD_CCtx_params const* params,
const void* src, size_t srcSize,
- ZSTD_dictTableLoadMethod_e dtlm)
+ ZSTD_dictTableLoadMethod_e dtlm,
+ ZSTD_tableFillPurpose_e tfp)
{
const BYTE* ip = (const BYTE*) src;
const BYTE* const iend = ip + srcSize;
/* Assert that the ms params match the params we're being given */
ZSTD_assertEqualCParams(params->cParams, ms->cParams);
- if (srcSize > ZSTD_CHUNKSIZE_MAX) {
+ { /* Ensure large dictionaries can't cause index overflow */
+
/* Allow the dictionary to set indices up to exactly ZSTD_CURRENT_MAX.
* Dictionaries right at the edge will immediately trigger overflow
* correction, but I don't want to insert extra constraints here.
*/
- U32 const maxDictSize = ZSTD_CURRENT_MAX - ZSTD_WINDOW_START_INDEX;
- /* We must have cleared our windows when our source is this large. */
- assert(ZSTD_window_isEmpty(ms->window));
- if (loadLdmDict)
- assert(ZSTD_window_isEmpty(ls->window));
+ U32 maxDictSize = ZSTD_CURRENT_MAX - ZSTD_WINDOW_START_INDEX;
+
+ int const CDictTaggedIndices = ZSTD_CDictIndicesAreTagged(¶ms->cParams);
+ if (CDictTaggedIndices && tfp == ZSTD_tfp_forCDict) {
+ /* Some dictionary matchfinders in zstd use "short cache",
+ * which treats the lower ZSTD_SHORT_CACHE_TAG_BITS of each
+ * CDict hashtable entry as a tag rather than as part of an index.
+ * When short cache is used, we need to truncate the dictionary
+ * so that its indices don't overlap with the tag. */
+ U32 const shortCacheMaxDictSize = (1u << (32 - ZSTD_SHORT_CACHE_TAG_BITS)) - ZSTD_WINDOW_START_INDEX;
+ maxDictSize = MIN(maxDictSize, shortCacheMaxDictSize);
+ assert(!loadLdmDict);
+ }
+
/* If the dictionary is too large, only load the suffix of the dictionary. */
if (srcSize > maxDictSize) {
ip = iend - maxDictSize;
src = ip;
srcSize = maxDictSize;
- }
+ } }
+
+ if (srcSize > ZSTD_CHUNKSIZE_MAX) {
+ /* We must have cleared our windows when our source is this large. */
+ assert(ZSTD_window_isEmpty(ms->window));
+ if (loadLdmDict) assert(ZSTD_window_isEmpty(ls->window));
}
DEBUGLOG(4, "ZSTD_loadDictionaryContent(): useRowMatchFinder=%d", (int)params->useRowMatchFinder);
switch(params->cParams.strategy)
{
case ZSTD_fast:
- ZSTD_fillHashTable(ms, iend, dtlm);
+ ZSTD_fillHashTable(ms, iend, dtlm, tfp);
break;
case ZSTD_dfast:
- ZSTD_fillDoubleHashTable(ms, iend, dtlm);
+ ZSTD_fillDoubleHashTable(ms, iend, dtlm, tfp);
break;
case ZSTD_greedy:
ZSTD_CCtx_params const* params,
const void* dict, size_t dictSize,
ZSTD_dictTableLoadMethod_e dtlm,
+ ZSTD_tableFillPurpose_e tfp,
void* workspace)
{
const BYTE* dictPtr = (const BYTE*)dict;
{
size_t const dictContentSize = (size_t)(dictEnd - dictPtr);
FORWARD_IF_ERROR(ZSTD_loadDictionaryContent(
- ms, NULL, ws, params, dictPtr, dictContentSize, dtlm), "");
+ ms, NULL, ws, params, dictPtr, dictContentSize, dtlm, tfp), "");
}
return dictID;
}
const void* dict, size_t dictSize,
ZSTD_dictContentType_e dictContentType,
ZSTD_dictTableLoadMethod_e dtlm,
+ ZSTD_tableFillPurpose_e tfp,
void* workspace)
{
DEBUGLOG(4, "ZSTD_compress_insertDictionary (dictSize=%u)", (U32)dictSize);
/* dict restricted modes */
if (dictContentType == ZSTD_dct_rawContent)
- return ZSTD_loadDictionaryContent(ms, ls, ws, params, dict, dictSize, dtlm);
+ return ZSTD_loadDictionaryContent(ms, ls, ws, params, dict, dictSize, dtlm, tfp);
if (MEM_readLE32(dict) != ZSTD_MAGIC_DICTIONARY) {
if (dictContentType == ZSTD_dct_auto) {
DEBUGLOG(4, "raw content dictionary detected");
return ZSTD_loadDictionaryContent(
- ms, ls, ws, params, dict, dictSize, dtlm);
+ ms, ls, ws, params, dict, dictSize, dtlm, tfp);
}
RETURN_ERROR_IF(dictContentType == ZSTD_dct_fullDict, dictionary_wrong, "");
assert(0); /* impossible */
/* dict as full zstd dictionary */
return ZSTD_loadZstdDictionary(
- bs, ms, ws, params, dict, dictSize, dtlm, workspace);
+ bs, ms, ws, params, dict, dictSize, dtlm, tfp, workspace);
}
#define ZSTD_USE_CDICT_PARAMS_SRCSIZE_CUTOFF (128 KB)
cctx->blockState.prevCBlock, &cctx->blockState.matchState,
&cctx->ldmState, &cctx->workspace, &cctx->appliedParams, cdict->dictContent,
cdict->dictContentSize, cdict->dictContentType, dtlm,
- cctx->entropyWorkspace)
+ ZSTD_tfp_forCCtx, cctx->entropyWorkspace)
: ZSTD_compress_insertDictionary(
cctx->blockState.prevCBlock, &cctx->blockState.matchState,
&cctx->ldmState, &cctx->workspace, &cctx->appliedParams, dict, dictSize,
- dictContentType, dtlm, cctx->entropyWorkspace);
+ dictContentType, dtlm, ZSTD_tfp_forCCtx, cctx->entropyWorkspace);
FORWARD_IF_ERROR(dictID, "ZSTD_compress_insertDictionary failed");
assert(dictID <= UINT_MAX);
cctx->dictID = (U32)dictID;
{ size_t const dictID = ZSTD_compress_insertDictionary(
&cdict->cBlockState, &cdict->matchState, NULL, &cdict->workspace,
¶ms, cdict->dictContent, cdict->dictContentSize,
- dictContentType, ZSTD_dtlm_full, cdict->entropyWorkspace);
+ dictContentType, ZSTD_dtlm_full, ZSTD_tfp_forCDict, cdict->entropyWorkspace);
FORWARD_IF_ERROR(dictID, "ZSTD_compress_insertDictionary failed");
assert(dictID <= (size_t)(U32)-1);
cdict->dictID = (U32)dictID;
};
typedef enum { ZSTD_dtlm_fast, ZSTD_dtlm_full } ZSTD_dictTableLoadMethod_e;
+typedef enum { ZSTD_tfp_forCCtx, ZSTD_tfp_forCDict } ZSTD_tableFillPurpose_e;
typedef enum {
ZSTD_noDict = 0,
* Hashes
***************************************/
static const U32 prime3bytes = 506832829U;
-static U32 ZSTD_hash3(U32 u, U32 h) { return ((u << (32-24)) * prime3bytes) >> (32-h) ; }
+static U32 ZSTD_hash3(U32 u, U32 h) { assert(h <= 32); return ((u << (32-24)) * prime3bytes) >> (32-h) ; }
MEM_STATIC size_t ZSTD_hash3Ptr(const void* ptr, U32 h) { return ZSTD_hash3(MEM_readLE32(ptr), h); } /* only in zstd_opt.h */
static const U32 prime4bytes = 2654435761U;
-static U32 ZSTD_hash4(U32 u, U32 h) { return (u * prime4bytes) >> (32-h) ; }
+static U32 ZSTD_hash4(U32 u, U32 h) { assert(h <= 32); return (u * prime4bytes) >> (32-h) ; }
static size_t ZSTD_hash4Ptr(const void* ptr, U32 h) { return ZSTD_hash4(MEM_read32(ptr), h); }
static const U64 prime5bytes = 889523592379ULL;
-static size_t ZSTD_hash5(U64 u, U32 h) { return (size_t)(((u << (64-40)) * prime5bytes) >> (64-h)) ; }
+static size_t ZSTD_hash5(U64 u, U32 h) { assert(h <= 64); return (size_t)(((u << (64-40)) * prime5bytes) >> (64-h)) ; }
static size_t ZSTD_hash5Ptr(const void* p, U32 h) { return ZSTD_hash5(MEM_readLE64(p), h); }
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_hash6(U64 u, U32 h) { assert(h <= 64); 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 prime7bytes = 58295818150454627ULL;
-static size_t ZSTD_hash7(U64 u, U32 h) { return (size_t)(((u << (64-56)) * prime7bytes) >> (64-h)) ; }
+static size_t ZSTD_hash7(U64 u, U32 h) { assert(h <= 64); return (size_t)(((u << (64-56)) * prime7bytes) >> (64-h)) ; }
static size_t ZSTD_hash7Ptr(const void* p, U32 h) { return ZSTD_hash7(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_hash8(U64 u, U32 h) { assert(h <= 64); return (size_t)(((u) * prime8bytes) >> (64-h)) ; }
static size_t ZSTD_hash8Ptr(const void* p, U32 h) { return ZSTD_hash8(MEM_readLE64(p), h); }
MEM_STATIC FORCE_INLINE_ATTR
size_t ZSTD_hashPtr(const void* p, U32 hBits, U32 mls)
{
+ /* Although some of these hashes do support hBits up to 64, some do not.
+ * To be on the safe side, always avoid hBits > 32. */
+ assert(hBits <= 32);
+
switch(mls)
{
default:
#endif
+/* Short Cache */
+
+/* Normally, zstd matchfinders follow this flow:
+ * 1. Compute hash at ip
+ * 2. Load index from hashTable[hash]
+ * 3. Check if *ip == *(base + index)
+ * In dictionary compression, loading *(base + index) is often an L2 or even L3 miss.
+ *
+ * Short cache is an optimization which allows us to avoid step 3 most of the time
+ * when the data doesn't actually match. With short cache, the flow becomes:
+ * 1. Compute (hash, currentTag) at ip. currentTag is an 8-bit independent hash at ip.
+ * 2. Load (index, matchTag) from hashTable[hash]. See ZSTD_writeTaggedIndex to understand how this works.
+ * 3. Only if currentTag == matchTag, check *ip == *(base + index). Otherwise, continue.
+ *
+ * Currently, short cache is only implemented in CDict hashtables. Thus, its use is limited to
+ * dictMatchState matchfinders.
+ */
+#define ZSTD_SHORT_CACHE_TAG_BITS 8
+#define ZSTD_SHORT_CACHE_TAG_MASK ((1u << ZSTD_SHORT_CACHE_TAG_BITS) - 1)
+
+/* Helper function for ZSTD_fillHashTable and ZSTD_fillDoubleHashTable.
+ * Unpacks hashAndTag into (hash, tag), then packs (index, tag) into hashTable[hash]. */
+MEM_STATIC void ZSTD_writeTaggedIndex(U32* const hashTable, size_t hashAndTag, U32 index) {
+ size_t const hash = hashAndTag >> ZSTD_SHORT_CACHE_TAG_BITS;
+ U32 const tag = (U32)(hashAndTag & ZSTD_SHORT_CACHE_TAG_MASK);
+ assert(index >> (32 - ZSTD_SHORT_CACHE_TAG_BITS) == 0);
+ hashTable[hash] = (index << ZSTD_SHORT_CACHE_TAG_BITS) | tag;
+}
+
+/* Helper function for short cache matchfinders.
+ * Unpacks tag1 and tag2 from lower bits of packedTag1 and packedTag2, then checks if the tags match. */
+MEM_STATIC int ZSTD_comparePackedTags(size_t packedTag1, size_t packedTag2) {
+ U32 const tag1 = packedTag1 & ZSTD_SHORT_CACHE_TAG_MASK;
+ U32 const tag2 = packedTag2 & ZSTD_SHORT_CACHE_TAG_MASK;
+ return tag1 == tag2;
+}
#if defined (__cplusplus)
}
#include "zstd_compress_internal.h"
#include "zstd_double_fast.h"
+static void ZSTD_fillDoubleHashTableForCDict(ZSTD_matchState_t* ms,
+ void const* end, ZSTD_dictTableLoadMethod_e dtlm)
+{
+ const ZSTD_compressionParameters* const cParams = &ms->cParams;
+ U32* const hashLarge = ms->hashTable;
+ U32 const hBitsL = cParams->hashLog + ZSTD_SHORT_CACHE_TAG_BITS;
+ U32 const mls = cParams->minMatch;
+ U32* const hashSmall = ms->chainTable;
+ U32 const hBitsS = cParams->chainLog + ZSTD_SHORT_CACHE_TAG_BITS;
+ const BYTE* const base = ms->window.base;
+ const BYTE* ip = base + ms->nextToUpdate;
+ const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
+ const U32 fastHashFillStep = 3;
-void ZSTD_fillDoubleHashTable(ZSTD_matchState_t* ms,
+ /* Always insert every fastHashFillStep position into the hash tables.
+ * Insert the other positions into the large hash table if their entry
+ * is empty.
+ */
+ for (; ip + fastHashFillStep - 1 <= iend; ip += fastHashFillStep) {
+ U32 const curr = (U32)(ip - base);
+ U32 i;
+ for (i = 0; i < fastHashFillStep; ++i) {
+ size_t const smHashAndTag = ZSTD_hashPtr(ip + i, hBitsS, mls);
+ size_t const lgHashAndTag = ZSTD_hashPtr(ip + i, hBitsL, 8);
+ if (i == 0) {
+ ZSTD_writeTaggedIndex(hashSmall, smHashAndTag, curr + i);
+ }
+ if (i == 0 || hashLarge[lgHashAndTag >> ZSTD_SHORT_CACHE_TAG_BITS] == 0) {
+ ZSTD_writeTaggedIndex(hashLarge, lgHashAndTag, curr + i);
+ }
+ /* Only load extra positions for ZSTD_dtlm_full */
+ if (dtlm == ZSTD_dtlm_fast)
+ break;
+ } }
+}
+
+static void ZSTD_fillDoubleHashTableForCCtx(ZSTD_matchState_t* ms,
void const* end, ZSTD_dictTableLoadMethod_e dtlm)
{
const ZSTD_compressionParameters* const cParams = &ms->cParams;
/* Only load extra positions for ZSTD_dtlm_full */
if (dtlm == ZSTD_dtlm_fast)
break;
- } }
+ } }
+}
+
+void ZSTD_fillDoubleHashTable(ZSTD_matchState_t* ms,
+ const void* const end,
+ ZSTD_dictTableLoadMethod_e dtlm,
+ ZSTD_tableFillPurpose_e tfp)
+{
+ if (tfp == ZSTD_tfp_forCDict) {
+ ZSTD_fillDoubleHashTableForCDict(ms, end, dtlm);
+ } else {
+ ZSTD_fillDoubleHashTableForCCtx(ms, end, dtlm);
+ }
}
const BYTE* const dictStart = dictBase + dictStartIndex;
const BYTE* const dictEnd = dms->window.nextSrc;
const U32 dictIndexDelta = prefixLowestIndex - (U32)(dictEnd - dictBase);
- const U32 dictHBitsL = dictCParams->hashLog;
- const U32 dictHBitsS = dictCParams->chainLog;
+ const U32 dictHBitsL = dictCParams->hashLog + ZSTD_SHORT_CACHE_TAG_BITS;
+ const U32 dictHBitsS = dictCParams->chainLog + ZSTD_SHORT_CACHE_TAG_BITS;
const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictStart));
DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_dictMatchState_generic");
U32 offset;
size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8);
size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
- size_t const dictHL = ZSTD_hashPtr(ip, dictHBitsL, 8);
- size_t const dictHS = ZSTD_hashPtr(ip, dictHBitsS, mls);
+ size_t const dictHashAndTagL = ZSTD_hashPtr(ip, dictHBitsL, 8);
+ size_t const dictHashAndTagS = ZSTD_hashPtr(ip, dictHBitsS, mls);
+ U32 const dictMatchIndexAndTagL = dictHashLong[dictHashAndTagL >> ZSTD_SHORT_CACHE_TAG_BITS];
+ U32 const dictMatchIndexAndTagS = dictHashSmall[dictHashAndTagS >> ZSTD_SHORT_CACHE_TAG_BITS];
+ int const dictTagsMatchL = ZSTD_comparePackedTags(dictMatchIndexAndTagL, dictHashAndTagL);
+ int const dictTagsMatchS = ZSTD_comparePackedTags(dictMatchIndexAndTagS, dictHashAndTagS);
U32 const curr = (U32)(ip-base);
U32 const matchIndexL = hashLong[h2];
U32 matchIndexS = hashSmall[h];
while (((ip>anchor) & (matchLong>prefixLowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
goto _match_found;
}
- } else {
+ } else if (dictTagsMatchL) {
/* check dictMatchState long match */
- U32 const dictMatchIndexL = dictHashLong[dictHL];
+ U32 const dictMatchIndexL = dictMatchIndexAndTagL >> ZSTD_SHORT_CACHE_TAG_BITS;
const BYTE* dictMatchL = dictBase + dictMatchIndexL;
assert(dictMatchL < dictEnd);
if (MEM_read32(match) == MEM_read32(ip)) {
goto _search_next_long;
}
- } else {
+ } else if (dictTagsMatchS) {
/* check dictMatchState short match */
- U32 const dictMatchIndexS = dictHashSmall[dictHS];
+ U32 const dictMatchIndexS = dictMatchIndexAndTagS >> ZSTD_SHORT_CACHE_TAG_BITS;
match = dictBase + dictMatchIndexS;
matchIndexS = dictMatchIndexS + dictIndexDelta;
continue;
_search_next_long:
-
{ size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
- size_t const dictHLNext = ZSTD_hashPtr(ip+1, dictHBitsL, 8);
+ size_t const dictHashAndTagL3 = ZSTD_hashPtr(ip+1, dictHBitsL, 8);
U32 const matchIndexL3 = hashLong[hl3];
+ U32 const dictMatchIndexAndTagL3 = dictHashLong[dictHashAndTagL3 >> ZSTD_SHORT_CACHE_TAG_BITS];
+ int const dictTagsMatchL3 = ZSTD_comparePackedTags(dictMatchIndexAndTagL3, dictHashAndTagL3);
const BYTE* matchL3 = base + matchIndexL3;
hashLong[hl3] = curr + 1;
while (((ip>anchor) & (matchL3>prefixLowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */
goto _match_found;
}
- } else {
+ } else if (dictTagsMatchL3) {
/* check dict long +1 match */
- U32 const dictMatchIndexL3 = dictHashLong[dictHLNext];
+ U32 const dictMatchIndexL3 = dictMatchIndexAndTagL3 >> ZSTD_SHORT_CACHE_TAG_BITS;
const BYTE* dictMatchL3 = dictBase + dictMatchIndexL3;
assert(dictMatchL3 < dictEnd);
if (dictMatchL3 > dictStart && MEM_read64(dictMatchL3) == MEM_read64(ip+1)) {
#include "zstd_compress_internal.h" /* ZSTD_CCtx, size_t */
void ZSTD_fillDoubleHashTable(ZSTD_matchState_t* ms,
- void const* end, ZSTD_dictTableLoadMethod_e dtlm);
+ void const* end, ZSTD_dictTableLoadMethod_e dtlm,
+ ZSTD_tableFillPurpose_e tfp);
size_t ZSTD_compressBlock_doubleFast(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
void const* src, size_t srcSize);
#include "zstd_compress_internal.h" /* ZSTD_hashPtr, ZSTD_count, ZSTD_storeSeq */
#include "zstd_fast.h"
+static void ZSTD_fillHashTableForCDict(ZSTD_matchState_t* ms,
+ const void* const end,
+ ZSTD_dictTableLoadMethod_e dtlm)
+{
+ const ZSTD_compressionParameters* const cParams = &ms->cParams;
+ U32* const hashTable = ms->hashTable;
+ U32 const hBits = cParams->hashLog + ZSTD_SHORT_CACHE_TAG_BITS;
+ U32 const mls = cParams->minMatch;
+ const BYTE* const base = ms->window.base;
+ const BYTE* ip = base + ms->nextToUpdate;
+ const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
+ const U32 fastHashFillStep = 3;
-void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
+ /* Currently, we always use ZSTD_dtlm_full for filling CDict tables.
+ * Feel free to remove this assert if there's a good reason! */
+ assert(dtlm == ZSTD_dtlm_full);
+
+ /* Always insert every fastHashFillStep position into the hash table.
+ * Insert the other positions if their hash entry is empty.
+ */
+ for ( ; ip + fastHashFillStep < iend + 2; ip += fastHashFillStep) {
+ U32 const curr = (U32)(ip - base);
+ { size_t const hashAndTag = ZSTD_hashPtr(ip, hBits, mls);
+ ZSTD_writeTaggedIndex(hashTable, hashAndTag, curr); }
+
+ if (dtlm == ZSTD_dtlm_fast) continue;
+ /* Only load extra positions for ZSTD_dtlm_full */
+ { U32 p;
+ for (p = 1; p < fastHashFillStep; ++p) {
+ size_t const hashAndTag = ZSTD_hashPtr(ip + p, hBits, mls);
+ if (hashTable[hashAndTag >> ZSTD_SHORT_CACHE_TAG_BITS] == 0) { /* not yet filled */
+ ZSTD_writeTaggedIndex(hashTable, hashAndTag, curr + p);
+ } } } }
+}
+
+static void ZSTD_fillHashTableForCCtx(ZSTD_matchState_t* ms,
const void* const end,
ZSTD_dictTableLoadMethod_e dtlm)
{
const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
const U32 fastHashFillStep = 3;
+ /* Currently, we always use ZSTD_dtlm_fast for filling CCtx tables.
+ * Feel free to remove this assert if there's a good reason! */
+ assert(dtlm == ZSTD_dtlm_fast);
+
/* Always insert every fastHashFillStep position into the hash table.
* Insert the other positions if their hash entry is empty.
*/
} } } }
}
+void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
+ const void* const end,
+ ZSTD_dictTableLoadMethod_e dtlm,
+ ZSTD_tableFillPurpose_e tfp)
+{
+ if (tfp == ZSTD_tfp_forCDict) {
+ ZSTD_fillHashTableForCDict(ms, end, dtlm);
+ } else {
+ ZSTD_fillHashTableForCCtx(ms, end, dtlm);
+ }
+}
+
/**
* If you squint hard enough (and ignore repcodes), the search operation at any
const BYTE* const dictEnd = dms->window.nextSrc;
const U32 dictIndexDelta = prefixStartIndex - (U32)(dictEnd - dictBase);
const U32 dictAndPrefixLength = (U32)(istart - prefixStart + dictEnd - dictStart);
- const U32 dictHLog = dictCParams->hashLog;
+ const U32 dictHBits = dictCParams->hashLog + ZSTD_SHORT_CACHE_TAG_BITS;
/* if a dictionary is still attached, it necessarily means that
* it is within window size. So we just check it. */
while (ip1 <= ilimit) { /* repcode check at (ip0 + 1) is safe because ip0 < ip1 */
size_t mLength;
size_t hash0 = ZSTD_hashPtr(ip0, hlog, mls);
- const size_t dictHash0 = ZSTD_hashPtr(ip0, dictHLog, mls);
- U32 dictMatchIndex = dictHashTable[dictHash0];
+
+ size_t const dictHashAndTag0 = ZSTD_hashPtr(ip0, dictHBits, mls);
+ U32 dictMatchIndexAndTag = dictHashTable[dictHashAndTag0 >> ZSTD_SHORT_CACHE_TAG_BITS];
+ int dictTagsMatch = ZSTD_comparePackedTags(dictMatchIndexAndTag, dictHashAndTag0);
+
U32 matchIndex = hashTable[hash0];
U32 curr = (U32)(ip0 - base);
size_t step = stepSize;
dictBase + (repIndex - dictIndexDelta) :
base + repIndex;
const size_t hash1 = ZSTD_hashPtr(ip1, hlog, mls);
- const size_t dictHash1 = ZSTD_hashPtr(ip1, dictHLog, mls);
+ size_t const dictHashAndTag1 = ZSTD_hashPtr(ip1, dictHBits, mls);
hashTable[hash0] = curr; /* update hash table */
if (((U32) ((prefixStartIndex - 1) - repIndex) >=
ip0++;
ZSTD_storeSeq(seqStore, (size_t) (ip0 - anchor), anchor, iend, REPCODE1_TO_OFFBASE, mLength);
break;
- } else if (matchIndex <= prefixStartIndex) {
- /* We only look for a dict match if the normal matchIndex is invalid */
+ }
+
+ if (dictTagsMatch) {
+ /* Found a possible dict match */
+ const U32 dictMatchIndex = dictMatchIndexAndTag >> ZSTD_SHORT_CACHE_TAG_BITS;
const BYTE* dictMatch = dictBase + dictMatchIndex;
if (dictMatchIndex > dictStartIndex &&
MEM_read32(dictMatch) == MEM_read32(ip0)) {
- /* found a dict match */
- U32 const offset = (U32) (curr - dictMatchIndex - dictIndexDelta);
- mLength = ZSTD_count_2segments(ip0 + 4, dictMatch + 4, iend, dictEnd, prefixStart) + 4;
- while (((ip0 > anchor) & (dictMatch > dictStart))
- && (ip0[-1] == dictMatch[-1])) {
- ip0--;
- dictMatch--;
- mLength++;
- } /* catch up */
- offset_2 = offset_1;
- offset_1 = offset;
- ZSTD_storeSeq(seqStore, (size_t) (ip0 - anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength);
- break;
+ /* To replicate extDict parse behavior, we only use dict matches when the normal matchIndex is invalid */
+ if (matchIndex <= prefixStartIndex) {
+ U32 const offset = (U32) (curr - dictMatchIndex - dictIndexDelta);
+ mLength = ZSTD_count_2segments(ip0 + 4, dictMatch + 4, iend, dictEnd, prefixStart) + 4;
+ while (((ip0 > anchor) & (dictMatch > dictStart))
+ && (ip0[-1] == dictMatch[-1])) {
+ ip0--;
+ dictMatch--;
+ mLength++;
+ } /* catch up */
+ offset_2 = offset_1;
+ offset_1 = offset;
+ ZSTD_storeSeq(seqStore, (size_t) (ip0 - anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength);
+ break;
+ }
}
- } else if (MEM_read32(match) == MEM_read32(ip0)) {
+ }
+
+ if (matchIndex > prefixStartIndex && MEM_read32(match) == MEM_read32(ip0)) {
/* found a regular match */
U32 const offset = (U32) (ip0 - match);
mLength = ZSTD_count(ip0 + 4, match + 4, iend) + 4;
}
/* Prepare for next iteration */
- dictMatchIndex = dictHashTable[dictHash1];
+ dictMatchIndexAndTag = dictHashTable[dictHashAndTag1 >> ZSTD_SHORT_CACHE_TAG_BITS];
+ dictTagsMatch = ZSTD_comparePackedTags(dictMatchIndexAndTag, dictHashAndTag1);
matchIndex = hashTable[hash1];
if (ip1 >= nextStep) {
#include "zstd_compress_internal.h"
void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
- void const* end, ZSTD_dictTableLoadMethod_e dtlm);
+ void const* end, ZSTD_dictTableLoadMethod_e dtlm,
+ ZSTD_tableFillPurpose_e tfp);
size_t ZSTD_compressBlock_fast(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
void const* src, size_t srcSize);
switch(ms->cParams.strategy)
{
case ZSTD_fast:
- ZSTD_fillHashTable(ms, iend, ZSTD_dtlm_fast);
+ ZSTD_fillHashTable(ms, iend, ZSTD_dtlm_fast, ZSTD_tfp_forCCtx);
break;
case ZSTD_dfast:
- ZSTD_fillDoubleHashTable(ms, iend, ZSTD_dtlm_fast);
+ ZSTD_fillDoubleHashTable(ms, iend, ZSTD_dtlm_fast, ZSTD_tfp_forCCtx);
break;
case ZSTD_greedy:
projects / thirdparty / zstd.git / commitdiff
