<File
RelativePath="..\..\..\lib\compress\zstd_opt.c"
>
+ </File>
+ <File
+ RelativePath="..\..\..\lib\compress\zstd_ldm.c"
+ >
</File>
</Filter>
<Filter
<File
RelativePath="..\..\..\lib\compress\zstd_opt.h"
>
+ </File>
+ <File
+ RelativePath="..\..\..\lib\compress\zstd_ldm.h"
+ >
</File>
</Filter>
</Files>
<File
RelativePath="..\..\..\lib\compress\zstd_opt.c"
>
+ </File>
+ <File
+ RelativePath="..\..\..\lib\compress\zstd_ldm.c"
+ >
</File>
</Filter>
<Filter
<File
RelativePath="..\..\..\lib\compress\zstd_opt.h"
>
+ </File>
+ <File
+ RelativePath="..\..\..\lib\compress\zstd_ldm.h"
+ >
</File>
</Filter>
</Files>
<File
RelativePath="..\..\..\lib\compress\zstd_opt.c"
>
+ </File>
+ <File
+ RelativePath="..\..\..\lib\compress\zstd_ldm.c"
+ >
</File>
</Filter>
<Filter
<File
RelativePath="..\..\..\lib\compress\zstd_opt.h"
>
+ </File>
+ <File
+ RelativePath="..\..\..\lib\compress\zstd_ldm.h"
+ >
</File>
</Filter>
</Files>
<File
RelativePath="..\..\..\lib\compress\zstd_opt.c"
>
+ </File>
+ <File
+ RelativePath="..\..\..\lib\compress\zstd_ldm.c"
+ >
</File>
<File
RelativePath="..\..\..\lib\decompress\zstd_decompress.c"
<File
RelativePath="..\..\..\lib\compress\zstd_opt.h"
>
+ </File>
+ <File
+ RelativePath="..\..\..\lib\compress\zstd_ldm.h"
+ >
</File>
<File
RelativePath="..\..\..\lib\common\zstd_static.h"
<ClCompile Include="..\..\..\lib\compress\zstd_double_fast.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_lazy.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_opt.c" />
+ <ClCompile Include="..\..\..\lib\compress\zstd_ldm.c" />
<ClCompile Include="..\..\..\lib\decompress\huf_decompress.c" />
<ClCompile Include="..\..\..\lib\decompress\zstd_decompress.c" />
<ClCompile Include="..\..\..\programs\datagen.c" />
<ClInclude Include="..\..\..\lib\compress\zstd_double_fast.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_lazy.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_opt.h" />
+ <ClInclude Include="..\..\..\lib\compress\zstd_ldm.h" />
<ClInclude Include="..\..\..\lib\compress\zstdmt_compress.h" />
<ClInclude Include="..\..\..\lib\legacy\zstd_legacy.h" />
<ClInclude Include="..\..\..\programs\datagen.h" />
<ClCompile Include="..\..\..\lib\compress\zstd_double_fast.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_lazy.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_opt.c" />
+ <ClCompile Include="..\..\..\lib\compress\zstd_ldm.c" />
<ClCompile Include="..\..\..\lib\compress\zstdmt_compress.c" />
<ClCompile Include="..\..\..\lib\decompress\huf_decompress.c" />
<ClCompile Include="..\..\..\lib\decompress\zstd_decompress.c" />
<ClInclude Include="..\..\..\lib\compress\zstd_double_fast.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_lazy.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_opt.h" />
+ <ClInclude Include="..\..\..\lib\compress\zstd_ldm.h" />
<ClInclude Include="..\..\..\lib\compress\zstdmt_compress.h" />
<ClInclude Include="..\..\..\lib\dictBuilder\divsufsort.h" />
<ClInclude Include="..\..\..\lib\dictBuilder\zdict.h" />
<ClCompile Include="..\..\..\lib\compress\zstd_double_fast.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_lazy.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_opt.c" />
+ <ClCompile Include="..\..\..\lib\compress\zstd_ldm.c" />
<ClCompile Include="..\..\..\lib\compress\zstdmt_compress.c" />
<ClCompile Include="..\..\..\lib\decompress\huf_decompress.c" />
<ClCompile Include="..\..\..\lib\decompress\zstd_decompress.c" />
<ClInclude Include="..\..\..\lib\compress\zstd_double_fast.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_lazy.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_opt.h" />
+ <ClInclude Include="..\..\..\lib\compress\zstd_ldm.h" />
<ClInclude Include="..\..\..\lib\compress\zstdmt_compress.h" />
</ItemGroup>
<ItemGroup>
<ClCompile Include="..\..\..\lib\compress\zstd_double_fast.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_lazy.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_opt.c" />
+ <ClCompile Include="..\..\..\lib\compress\zstd_ldm.c" />
<ClCompile Include="..\..\..\lib\compress\zstdmt_compress.c" />
<ClCompile Include="..\..\..\lib\decompress\huf_decompress.c" />
<ClCompile Include="..\..\..\lib\decompress\zstd_decompress.c" />
<ClInclude Include="..\..\..\lib\compress\zstd_double_fast.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_lazy.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_opt.h" />
+ <ClInclude Include="..\..\..\lib\compress\zstd_ldm.h" />
<ClInclude Include="..\..\..\lib\compress\zstdmt_compress.h" />
</ItemGroup>
<PropertyGroup Label="Globals">
<ClCompile Include="..\..\..\lib\compress\zstd_double_fast.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_lazy.c" />
<ClCompile Include="..\..\..\lib\compress\zstd_opt.c" />
+ <ClCompile Include="..\..\..\lib\compress\zstd_ldm.c" />
<ClCompile Include="..\..\..\lib\decompress\huf_decompress.c" />
<ClCompile Include="..\..\..\lib\decompress\zstd_decompress.c" />
<ClCompile Include="..\..\..\lib\dictBuilder\cover.c" />
<ClInclude Include="..\..\..\lib\compress\zstd_double_fast.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_lazy.h" />
<ClInclude Include="..\..\..\lib\compress\zstd_opt.h" />
+ <ClInclude Include="..\..\..\lib\compress\zstd_ldm.h" />
<ClInclude Include="..\..\..\lib\legacy\zstd_legacy.h" />
<ClInclude Include="..\..\..\lib\legacy\zstd_v01.h" />
<ClInclude Include="..\..\..\lib\legacy\zstd_v02.h" />
${LIBRARY_DIR}/compress/zstd_double_fast.c
${LIBRARY_DIR}/compress/zstd_lazy.c
${LIBRARY_DIR}/compress/zstd_opt.c
+ ${LIBRARY_DIR}/compress/zstd_ldm.c
${LIBRARY_DIR}/decompress/huf_decompress.c
${LIBRARY_DIR}/decompress/zstd_decompress.c
${LIBRARY_DIR}/dictBuilder/cover.c
${LIBRARY_DIR}/compress/zstd_double_fast.h
${LIBRARY_DIR}/compress/zstd_lazy.h
${LIBRARY_DIR}/compress/zstd_opt.h
+ ${LIBRARY_DIR}/compress/zstd_ldm.h
${LIBRARY_DIR}/compress/zstdmt_compress.h
${LIBRARY_DIR}/dictBuilder/zdict.h
${LIBRARY_DIR}/deprecated/zbuff.h)
#include "zstd_double_fast.h"
#include "zstd_lazy.h"
#include "zstd_opt.h"
-
-
-#define LDM_BUCKET_SIZE_LOG 3
-#define LDM_MIN_MATCH_LENGTH 64
-#define LDM_WINDOW_LOG 27
-#define LDM_HASH_LOG 20
-#define LDM_HASH_CHAR_OFFSET 10
-#define LDM_HASHEVERYLOG_NOTSET 9999
+#include "zstd_ldm.h"
/*-*************************************
+ cctx->outBuffSize + cctx->inBuffSize
+ ZSTDMT_sizeof_CCtx(cctx->mtctx);
}
-#if 0
-static void ZSTD_debugPrintCCtxParams(ZSTD_CCtx_params* params)
-{
- DEBUGLOG(2, "======CCtxParams======");
- DEBUGLOG(2, "cParams: %u %u %u %u %u %u %u",
- params->cParams.windowLog,
- params->cParams.chainLog,
- params->cParams.hashLog,
- params->cParams.searchLog,
- params->cParams.searchLength,
- params->cParams.targetLength,
- params->cParams.strategy);
- DEBUGLOG(2, "fParams: %u %u %u",
- params->fParams.contentSizeFlag,
- params->fParams.checksumFlag,
- params->fParams.noDictIDFlag);
- DEBUGLOG(2, "cLevel, forceWindow: %u %u",
- params->compressionLevel,
- params->forceWindow);
- DEBUGLOG(2, "ldm: %u %u %u %u %u",
- params->ldmParams.enableLdm,
- params->ldmParams.hashLog,
- params->ldmParams.bucketSizeLog,
- params->ldmParams.minMatchLength,
- params->ldmParams.hashEveryLog);
-}
-#endif
size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs)
{
ZSTD_CCtx_params* params, ZSTDMT_parameter parameter, unsigned value);
size_t ZSTDMT_initializeCCtxParameters(ZSTD_CCtx_params* params, unsigned nbThreads);
-static size_t ZSTD_ldm_initializeParameters(ldmParams_t* params, U32 enableLdm)
-{
- ZSTD_STATIC_ASSERT(LDM_BUCKET_SIZE_LOG <= ZSTD_LDM_BUCKETSIZELOG_MAX);
- params->enableLdm = enableLdm>0;
- params->hashLog = LDM_HASH_LOG;
- params->bucketSizeLog = LDM_BUCKET_SIZE_LOG;
- params->minMatchLength = LDM_MIN_MATCH_LENGTH;
- params->hashEveryLog = LDM_HASHEVERYLOG_NOTSET;
- return 0;
-}
-
size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, unsigned value)
{
if (cctx->streamStage != zcss_init) return ERROR(stage_wrong);
case ZSTD_p_enableLongDistanceMatching :
if (value != 0) {
ZSTD_cLevelToCCtxParams(params);
- params->cParams.windowLog = LDM_WINDOW_LOG;
+ params->cParams.windowLog = ZSTD_LDM_WINDOW_LOG;
}
return ZSTD_ldm_initializeParameters(¶ms->ldmParams, value);
return ZSTD_adjustCParams_internal(cPar, srcSize, dictSize);
}
-/* Estimate the space needed for long distance matching tables. */
-static size_t ZSTD_ldm_getTableSize(U32 hashLog, U32 bucketSizeLog) {
- size_t const ldmHSize = ((size_t)1) << hashLog;
- size_t const ldmBucketSizeLog = MIN(bucketSizeLog, hashLog);
- size_t const ldmBucketSize =
- ((size_t)1) << (hashLog - ldmBucketSizeLog);
- return ldmBucketSize + (ldmHSize * (sizeof(ldmEntry_t)));
-}
-
size_t ZSTD_estimateCCtxSize_advanced_usingCCtxParams(const ZSTD_CCtx_params* params)
{
/* Estimate CCtx size is supported for single-threaded compression only. */
typedef enum { ZSTDcrp_continue, ZSTDcrp_noMemset } ZSTD_compResetPolicy_e;
typedef enum { ZSTDb_not_buffered, ZSTDb_buffered } ZSTD_buffered_policy_e;
-static U64 ZSTD_ldm_getHashPower(U32 minMatchLength);
-
/*! ZSTD_resetCCtx_internal() :
note : `params` are assumed fully validated at this stage */
static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
if (ZSTD_equivalentParams(params, zc->appliedParams)) {
DEBUGLOG(5, "ZSTD_equivalentParams()==1");
assert(!(params.ldmParams.enableLdm &&
- params.ldmParams.hashEveryLog == LDM_HASHEVERYLOG_NOTSET));
+ params.ldmParams.hashEveryLog == ZSTD_LDM_HASHEVERYLOG_NOTSET));
zc->entropy->hufCTable_repeatMode = HUF_repeat_none;
zc->entropy->offcode_repeatMode = FSE_repeat_none;
zc->entropy->matchlength_repeatMode = FSE_repeat_none;
if (params.ldmParams.enableLdm) {
/* Adjust long distance matching parameters */
- if (params.ldmParams.hashEveryLog == LDM_HASHEVERYLOG_NOTSET) {
- params.ldmParams.hashEveryLog =
- params.cParams.windowLog < params.ldmParams.hashLog ?
- 0 : params.cParams.windowLog - params.ldmParams.hashLog;
- }
- params.ldmParams.bucketSizeLog =
- MIN(params.ldmParams.bucketSizeLog, params.ldmParams.hashLog);
+ ZSTD_ldm_adjustParameters(¶ms.ldmParams, params.cParams.windowLog);
+ assert(params.ldmParams.hashLog >= params.ldmParams.bucketSizeLog);
zc->ldmState.hashPower =
ZSTD_ldm_getHashPower(params.ldmParams.minMatchLength);
}
size_t const ldmBucketSize =
((size_t)1) << (params.ldmParams.hashLog -
params.ldmParams.bucketSizeLog);
- assert(params.ldmParams.hashLog >= params.ldmParams.bucketSizeLog);
memset(ptr, 0, ldmBucketSize);
zc->ldmState.bucketOffsets = (BYTE*)ptr;
ptr = zc->ldmState.bucketOffsets + ldmBucketSize;
}
/* ZSTD_selectBlockCompressor() :
+ * Not static, but internal use only (used by long distance matcher)
* assumption : strat is a valid strategy */
typedef size_t (*ZSTD_blockCompressor) (ZSTD_CCtx* ctx, const void* src, size_t srcSize);
-static ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int extDict)
+ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int extDict)
{
static const ZSTD_blockCompressor blockCompressor[2][(unsigned)ZSTD_btultra+1] = {
{ ZSTD_compressBlock_fast /* default for 0 */,
return blockCompressor[extDict!=0][(U32)strat];
}
-/*-*************************************
-* Long distance matching
-***************************************/
-
-/** ZSTD_ldm_getSmallHash() :
- * numBits should be <= 32
- * If numBits==0, returns 0.
- * @return : the most significant numBits of value. */
-static U32 ZSTD_ldm_getSmallHash(U64 value, U32 numBits)
-{
- assert(numBits <= 32);
- return numBits == 0 ? 0 : (U32)(value >> (64 - numBits));
-}
-
-/** ZSTD_ldm_getChecksum() :
- * numBitsToDiscard should be <= 32
- * @return : the next most significant 32 bits after numBitsToDiscard */
-static U32 ZSTD_ldm_getChecksum(U64 hash, U32 numBitsToDiscard)
-{
- assert(numBitsToDiscard <= 32);
- return (hash >> (64 - 32 - numBitsToDiscard)) & 0xFFFFFFFF;
-}
-
-/** ZSTD_ldm_getTag() ;
- * Given the hash, returns the most significant numTagBits bits
- * after (32 + hbits) bits.
- *
- * If there are not enough bits remaining, return the last
- * numTagBits bits. */
-static U32 ZSTD_ldm_getTag(U64 hash, U32 hbits, U32 numTagBits)
-{
- assert(numTagBits <= 32 && hbits <= 32);
- if (32 - hbits < numTagBits) {
- return hash & ((1 << numTagBits) - 1);
- } else {
- return (hash >> (32 - hbits - numTagBits)) & ((1 << numTagBits) - 1);
- }
-}
-
-/** ZSTD_ldm_getBucket() :
- * Returns a pointer to the start of the bucket associated with hash. */
-static ldmEntry_t* ZSTD_ldm_getBucket(
- ldmState_t* ldmState, size_t hash, ldmParams_t const ldmParams)
-{
- return ldmState->hashTable + (hash << ldmParams.bucketSizeLog);
-}
-
-/** ZSTD_ldm_insertEntry() :
- * Insert the entry with corresponding hash into the hash table */
-static void ZSTD_ldm_insertEntry(ldmState_t* ldmState,
- size_t const hash, const ldmEntry_t entry,
- ldmParams_t const ldmParams)
-{
- BYTE* const bucketOffsets = ldmState->bucketOffsets;
- *(ZSTD_ldm_getBucket(ldmState, hash, ldmParams) + bucketOffsets[hash]) = entry;
- bucketOffsets[hash]++;
- bucketOffsets[hash] &= (1 << ldmParams.bucketSizeLog) - 1;
-}
-
-/** ZSTD_ldm_makeEntryAndInsertByTag() :
- *
- * Gets the small hash, checksum, and tag from the rollingHash.
- *
- * If the tag matches (1 << ldmParams.hashEveryLog)-1, then
- * creates an ldmEntry from the offset, and inserts it into the hash table.
- *
- * hBits is the length of the small hash, which is the most significant hBits
- * of rollingHash. The checksum is the next 32 most significant bits, followed
- * by ldmParams.hashEveryLog bits that make up the tag. */
-static void ZSTD_ldm_makeEntryAndInsertByTag(ldmState_t* ldmState,
- U64 const rollingHash,
- U32 const hBits,
- U32 const offset,
- ldmParams_t const ldmParams)
-{
- U32 const tag = ZSTD_ldm_getTag(rollingHash, hBits, ldmParams.hashEveryLog);
- U32 const tagMask = (1 << ldmParams.hashEveryLog) - 1;
- if (tag == tagMask) {
- U32 const hash = ZSTD_ldm_getSmallHash(rollingHash, hBits);
- U32 const checksum = ZSTD_ldm_getChecksum(rollingHash, hBits);
- ldmEntry_t entry;
- entry.offset = offset;
- entry.checksum = checksum;
- ZSTD_ldm_insertEntry(ldmState, hash, entry, ldmParams);
- }
-}
-
-/** ZSTD_ldm_getRollingHash() :
- * Get a 64-bit hash using the first len bytes from buf.
- *
- * Giving bytes s = s_1, s_2, ... s_k, the hash is defined to be
- * H(s) = s_1*(a^(k-1)) + s_2*(a^(k-2)) + ... + s_k*(a^0)
- *
- * where the constant a is defined to be prime8bytes.
- *
- * The implementation adds an offset to each byte, so
- * H(s) = (s_1 + HASH_CHAR_OFFSET)*(a^(k-1)) + ... */
-static U64 ZSTD_ldm_getRollingHash(const BYTE* buf, U32 len)
-{
- U64 ret = 0;
- U32 i;
- for (i = 0; i < len; i++) {
- ret *= prime8bytes;
- ret += buf[i] + LDM_HASH_CHAR_OFFSET;
- }
- return ret;
-}
-
-/** ZSTD_ldm_ipow() :
- * Return base^exp. */
-static U64 ZSTD_ldm_ipow(U64 base, U64 exp)
-{
- U64 ret = 1;
- while (exp) {
- if (exp & 1) { ret *= base; }
- exp >>= 1;
- base *= base;
- }
- return ret;
-}
-
-static U64 ZSTD_ldm_getHashPower(U32 minMatchLength) {
- assert(minMatchLength >= ZSTD_LDM_MINMATCH_MIN);
- return ZSTD_ldm_ipow(prime8bytes, minMatchLength - 1);
-}
-
-/** ZSTD_ldm_updateHash() :
- * Updates hash by removing toRemove and adding toAdd. */
-static U64 ZSTD_ldm_updateHash(U64 hash, BYTE toRemove, BYTE toAdd, U64 hashPower)
-{
- hash -= ((toRemove + LDM_HASH_CHAR_OFFSET) * hashPower);
- hash *= prime8bytes;
- hash += toAdd + LDM_HASH_CHAR_OFFSET;
- return hash;
-}
-
-/** ZSTD_ldm_countBackwardsMatch() :
- * Returns the number of bytes that match backwards before pIn and pMatch.
- *
- * We count only bytes where pMatch >= pBase and pIn >= pAnchor. */
-static size_t ZSTD_ldm_countBackwardsMatch(
- const BYTE* pIn, const BYTE* pAnchor,
- const BYTE* pMatch, const BYTE* pBase)
-{
- size_t matchLength = 0;
- while (pIn > pAnchor && pMatch > pBase && pIn[-1] == pMatch[-1]) {
- pIn--;
- pMatch--;
- matchLength++;
- }
- return matchLength;
-}
-
-/** ZSTD_ldm_fillFastTables() :
- *
- * Fills the relevant tables for the ZSTD_fast and ZSTD_dfast strategies.
- * This is similar to ZSTD_loadDictionaryContent.
- *
- * The tables for the other strategies are filled within their
- * block compressors. */
-static size_t ZSTD_ldm_fillFastTables(ZSTD_CCtx* zc, const void* end)
-{
- const BYTE* const iend = (const BYTE*)end;
- const U32 mls = zc->appliedParams.cParams.searchLength;
-
- switch(zc->appliedParams.cParams.strategy)
- {
- case ZSTD_fast:
- ZSTD_fillHashTable(zc, iend, mls);
- zc->nextToUpdate = (U32)(iend - zc->base);
- break;
-
- case ZSTD_dfast:
- ZSTD_fillDoubleHashTable(zc, iend, mls);
- zc->nextToUpdate = (U32)(iend - zc->base);
- break;
-
- case ZSTD_greedy:
- case ZSTD_lazy:
- case ZSTD_lazy2:
- case ZSTD_btlazy2:
- case ZSTD_btopt:
- case ZSTD_btultra:
- break;
- default:
- assert(0); /* not possible : not a valid strategy id */
- }
-
- return 0;
-}
-
-/** ZSTD_ldm_fillLdmHashTable() :
- *
- * Fills hashTable from (lastHashed + 1) to iend (non-inclusive).
- * lastHash is the rolling hash that corresponds to lastHashed.
- *
- * Returns the rolling hash corresponding to position iend-1. */
-static U64 ZSTD_ldm_fillLdmHashTable(ldmState_t* state,
- U64 lastHash, const BYTE* lastHashed,
- const BYTE* iend, const BYTE* base,
- U32 hBits, ldmParams_t const ldmParams)
-{
- U64 rollingHash = lastHash;
- const BYTE* cur = lastHashed + 1;
-
- while (cur < iend) {
- rollingHash = ZSTD_ldm_updateHash(rollingHash, cur[-1],
- cur[ldmParams.minMatchLength-1],
- state->hashPower);
- ZSTD_ldm_makeEntryAndInsertByTag(state,
- rollingHash, hBits,
- (U32)(cur - base), ldmParams);
- ++cur;
- }
- return rollingHash;
-}
-
-
-/** ZSTD_ldm_limitTableUpdate() :
- *
- * Sets cctx->nextToUpdate to a position corresponding closer to anchor
- * if it is far way
- * (after a long match, only update tables a limited amount). */
-static void ZSTD_ldm_limitTableUpdate(ZSTD_CCtx* cctx, const BYTE* anchor)
-{
- U32 const current = (U32)(anchor - cctx->base);
- if (current > cctx->nextToUpdate + 1024) {
- cctx->nextToUpdate =
- current - MIN(512, current - cctx->nextToUpdate - 1024);
- }
-}
-
-/** ZSTD_compressBlock_ldm_generic() :
- *
- * This is a block compressor intended for long distance matching.
- *
- * The function searches for matches of length at least
- * ldmParams.minMatchLength using a hash table in cctx->ldmState.
- * Matches can be at a distance of up to cParams.windowLog.
- *
- * Upon finding a match, the unmatched literals are compressed using a
- * ZSTD_blockCompressor (depending on the strategy in the compression
- * parameters), which stores the matched sequences. The "long distance"
- * match is then stored with the remaining literals from the
- * ZSTD_blockCompressor. */
-FORCE_INLINE_TEMPLATE
-size_t ZSTD_compressBlock_ldm_generic(ZSTD_CCtx* cctx,
- const void* src, size_t srcSize)
-{
- ldmState_t* const ldmState = &(cctx->ldmState);
- const ldmParams_t ldmParams = cctx->appliedParams.ldmParams;
- const U64 hashPower = ldmState->hashPower;
- const U32 hBits = ldmParams.hashLog - ldmParams.bucketSizeLog;
- const U32 ldmBucketSize = (1 << ldmParams.bucketSizeLog);
- const U32 ldmTagMask = (1 << ldmParams.hashEveryLog) - 1;
- seqStore_t* const seqStorePtr = &(cctx->seqStore);
- const BYTE* const base = cctx->base;
- const BYTE* const istart = (const BYTE*)src;
- const BYTE* ip = istart;
- const BYTE* anchor = istart;
- const U32 lowestIndex = cctx->dictLimit;
- const BYTE* const lowest = base + lowestIndex;
- const BYTE* const iend = istart + srcSize;
- const BYTE* const ilimit = iend - ldmParams.minMatchLength;
-
- const ZSTD_blockCompressor blockCompressor =
- ZSTD_selectBlockCompressor(cctx->appliedParams.cParams.strategy, 0);
- U32* const repToConfirm = seqStorePtr->repToConfirm;
- U32 savedRep[ZSTD_REP_NUM];
- U64 rollingHash = 0;
- const BYTE* lastHashed = NULL;
- size_t i, lastLiterals;
-
- /* Save seqStorePtr->rep and copy repToConfirm */
- for (i = 0; i < ZSTD_REP_NUM; i++)
- savedRep[i] = repToConfirm[i] = seqStorePtr->rep[i];
-
- /* Main Search Loop */
- while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
- size_t mLength;
- U32 const current = (U32)(ip - base);
- size_t forwardMatchLength = 0, backwardMatchLength = 0;
- ldmEntry_t* bestEntry = NULL;
- if (ip != istart) {
- rollingHash = ZSTD_ldm_updateHash(rollingHash, lastHashed[0],
- lastHashed[ldmParams.minMatchLength],
- hashPower);
- } else {
- rollingHash = ZSTD_ldm_getRollingHash(ip, ldmParams.minMatchLength);
- }
- lastHashed = ip;
-
- /* Do not insert and do not look for a match */
- if (ZSTD_ldm_getTag(rollingHash, hBits, ldmParams.hashEveryLog) !=
- ldmTagMask) {
- ip++;
- continue;
- }
-
- /* Get the best entry and compute the match lengths */
- {
- ldmEntry_t* const bucket =
- ZSTD_ldm_getBucket(ldmState,
- ZSTD_ldm_getSmallHash(rollingHash, hBits),
- ldmParams);
- ldmEntry_t* cur;
- size_t bestMatchLength = 0;
- U32 const checksum = ZSTD_ldm_getChecksum(rollingHash, hBits);
-
- for (cur = bucket; cur < bucket + ldmBucketSize; ++cur) {
- const BYTE* const pMatch = cur->offset + base;
- size_t curForwardMatchLength, curBackwardMatchLength,
- curTotalMatchLength;
- if (cur->checksum != checksum || cur->offset <= lowestIndex) {
- continue;
- }
-
- curForwardMatchLength = ZSTD_count(ip, pMatch, iend);
- if (curForwardMatchLength < ldmParams.minMatchLength) {
- continue;
- }
- curBackwardMatchLength = ZSTD_ldm_countBackwardsMatch(
- ip, anchor, pMatch, lowest);
- curTotalMatchLength = curForwardMatchLength +
- curBackwardMatchLength;
-
- if (curTotalMatchLength > bestMatchLength) {
- bestMatchLength = curTotalMatchLength;
- forwardMatchLength = curForwardMatchLength;
- backwardMatchLength = curBackwardMatchLength;
- bestEntry = cur;
- }
- }
- }
-
- /* No match found -- continue searching */
- if (bestEntry == NULL) {
- ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash,
- hBits, current,
- ldmParams);
- ip++;
- continue;
- }
-
- /* Match found */
- mLength = forwardMatchLength + backwardMatchLength;
- ip -= backwardMatchLength;
-
- /* Call the block compressor on the remaining literals */
- {
- U32 const matchIndex = bestEntry->offset;
- const BYTE* const match = base + matchIndex - backwardMatchLength;
- U32 const offset = (U32)(ip - match);
-
- /* Overwrite rep codes */
- for (i = 0; i < ZSTD_REP_NUM; i++)
- seqStorePtr->rep[i] = repToConfirm[i];
-
- /* Fill tables for block compressor */
- ZSTD_ldm_limitTableUpdate(cctx, anchor);
- ZSTD_ldm_fillFastTables(cctx, anchor);
-
- /* Call block compressor and get remaining literals */
- lastLiterals = blockCompressor(cctx, anchor, ip - anchor);
- cctx->nextToUpdate = (U32)(ip - base);
-
- /* Update repToConfirm with the new offset */
- for (i = ZSTD_REP_NUM - 1; i > 0; i--)
- repToConfirm[i] = repToConfirm[i-1];
- repToConfirm[0] = offset;
-
- /* Store the sequence with the leftover literals */
- ZSTD_storeSeq(seqStorePtr, lastLiterals, ip - lastLiterals,
- offset + ZSTD_REP_MOVE, mLength - MINMATCH);
- }
-
- /* Insert the current entry into the hash table */
- ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash, hBits,
- (U32)(lastHashed - base),
- ldmParams);
-
- assert(ip + backwardMatchLength == lastHashed);
-
- /* Fill the hash table from lastHashed+1 to ip+mLength*/
- /* Heuristic: don't need to fill the entire table at end of block */
- if (ip + mLength < ilimit) {
- rollingHash = ZSTD_ldm_fillLdmHashTable(
- ldmState, rollingHash, lastHashed,
- ip + mLength, base, hBits, ldmParams);
- lastHashed = ip + mLength - 1;
- }
- ip += mLength;
- anchor = ip;
- /* Check immediate repcode */
- while ( (ip < ilimit)
- && ( (repToConfirm[1] > 0) && (repToConfirm[1] <= (U32)(ip-lowest))
- && (MEM_read32(ip) == MEM_read32(ip - repToConfirm[1])) )) {
-
- size_t const rLength = ZSTD_count(ip+4, ip+4-repToConfirm[1],
- iend) + 4;
- /* Swap repToConfirm[1] <=> repToConfirm[0] */
- {
- U32 const tmpOff = repToConfirm[1];
- repToConfirm[1] = repToConfirm[0];
- repToConfirm[0] = tmpOff;
- }
-
- ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength-MINMATCH);
-
- /* Fill the hash table from lastHashed+1 to ip+rLength*/
- if (ip + rLength < ilimit) {
- rollingHash = ZSTD_ldm_fillLdmHashTable(
- ldmState, rollingHash, lastHashed,
- ip + rLength, base, hBits, ldmParams);
- lastHashed = ip + rLength - 1;
- }
- ip += rLength;
- anchor = ip;
- }
- }
-
- /* Overwrite rep */
- for (i = 0; i < ZSTD_REP_NUM; i++)
- seqStorePtr->rep[i] = repToConfirm[i];
-
- ZSTD_ldm_limitTableUpdate(cctx, anchor);
- ZSTD_ldm_fillFastTables(cctx, anchor);
-
- lastLiterals = blockCompressor(cctx, anchor, iend - anchor);
- cctx->nextToUpdate = (U32)(iend - base);
-
- /* Restore seqStorePtr->rep */
- for (i = 0; i < ZSTD_REP_NUM; i++)
- seqStorePtr->rep[i] = savedRep[i];
-
- /* Return the last literals size */
- return lastLiterals;
-}
-
-static size_t ZSTD_compressBlock_ldm(ZSTD_CCtx* ctx,
- const void* src, size_t srcSize)
-{
- return ZSTD_compressBlock_ldm_generic(ctx, src, srcSize);
-}
-
-static size_t ZSTD_compressBlock_ldm_extDict_generic(
- ZSTD_CCtx* ctx,
- const void* src, size_t srcSize)
-{
- ldmState_t* const ldmState = &(ctx->ldmState);
- const ldmParams_t ldmParams = ctx->appliedParams.ldmParams;
- const U64 hashPower = ldmState->hashPower;
- const U32 hBits = ldmParams.hashLog - ldmParams.bucketSizeLog;
- const U32 ldmBucketSize = (1 << ldmParams.bucketSizeLog);
- const U32 ldmTagMask = (1 << ldmParams.hashEveryLog) - 1;
- seqStore_t* const seqStorePtr = &(ctx->seqStore);
- const BYTE* const base = ctx->base;
- const BYTE* const dictBase = ctx->dictBase;
- const BYTE* const istart = (const BYTE*)src;
- const BYTE* ip = istart;
- const BYTE* anchor = istart;
- const U32 lowestIndex = ctx->lowLimit;
- const BYTE* const dictStart = dictBase + lowestIndex;
- const U32 dictLimit = ctx->dictLimit;
- const BYTE* const lowPrefixPtr = base + dictLimit;
- const BYTE* const dictEnd = dictBase + dictLimit;
- const BYTE* const iend = istart + srcSize;
- const BYTE* const ilimit = iend - ldmParams.minMatchLength;
-
- const ZSTD_blockCompressor blockCompressor =
- ZSTD_selectBlockCompressor(ctx->appliedParams.cParams.strategy, 1);
- U32* const repToConfirm = seqStorePtr->repToConfirm;
- U32 savedRep[ZSTD_REP_NUM];
- U64 rollingHash = 0;
- const BYTE* lastHashed = NULL;
- size_t i, lastLiterals;
-
- /* Save seqStorePtr->rep and copy repToConfirm */
- for (i = 0; i < ZSTD_REP_NUM; i++) {
- savedRep[i] = repToConfirm[i] = seqStorePtr->rep[i];
- }
-
- /* Search Loop */
- while (ip < ilimit) { /* < instead of <=, because (ip+1) */
- size_t mLength;
- const U32 current = (U32)(ip-base);
- size_t forwardMatchLength = 0, backwardMatchLength = 0;
- ldmEntry_t* bestEntry = NULL;
- if (ip != istart) {
- rollingHash = ZSTD_ldm_updateHash(rollingHash, lastHashed[0],
- lastHashed[ldmParams.minMatchLength],
- hashPower);
- } else {
- rollingHash = ZSTD_ldm_getRollingHash(ip, ldmParams.minMatchLength);
- }
- lastHashed = ip;
-
- if (ZSTD_ldm_getTag(rollingHash, hBits, ldmParams.hashEveryLog) !=
- ldmTagMask) {
- /* Don't insert and don't look for a match */
- ip++;
- continue;
- }
-
- /* Get the best entry and compute the match lengths */
- {
- ldmEntry_t* const bucket =
- ZSTD_ldm_getBucket(ldmState,
- ZSTD_ldm_getSmallHash(rollingHash, hBits),
- ldmParams);
- ldmEntry_t* cur;
- size_t bestMatchLength = 0;
- U32 const checksum = ZSTD_ldm_getChecksum(rollingHash, hBits);
-
- for (cur = bucket; cur < bucket + ldmBucketSize; ++cur) {
- const BYTE* const curMatchBase =
- cur->offset < dictLimit ? dictBase : base;
- const BYTE* const pMatch = curMatchBase + cur->offset;
- const BYTE* const matchEnd =
- cur->offset < dictLimit ? dictEnd : iend;
- const BYTE* const lowMatchPtr =
- cur->offset < dictLimit ? dictStart : lowPrefixPtr;
- size_t curForwardMatchLength, curBackwardMatchLength,
- curTotalMatchLength;
-
- if (cur->checksum != checksum || cur->offset <= lowestIndex) {
- continue;
- }
-
- curForwardMatchLength = ZSTD_count_2segments(
- ip, pMatch, iend,
- matchEnd, lowPrefixPtr);
- if (curForwardMatchLength < ldmParams.minMatchLength) {
- continue;
- }
- curBackwardMatchLength = ZSTD_ldm_countBackwardsMatch(
- ip, anchor, pMatch, lowMatchPtr);
- curTotalMatchLength = curForwardMatchLength +
- curBackwardMatchLength;
-
- if (curTotalMatchLength > bestMatchLength) {
- bestMatchLength = curTotalMatchLength;
- forwardMatchLength = curForwardMatchLength;
- backwardMatchLength = curBackwardMatchLength;
- bestEntry = cur;
- }
- }
- }
-
- /* No match found -- continue searching */
- if (bestEntry == NULL) {
- ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash, hBits,
- (U32)(lastHashed - base),
- ldmParams);
- ip++;
- continue;
- }
-
- /* Match found */
- mLength = forwardMatchLength + backwardMatchLength;
- ip -= backwardMatchLength;
-
- /* Call the block compressor on the remaining literals */
- {
- /* ip = current - backwardMatchLength
- * The match is at (bestEntry->offset - backwardMatchLength) */
- U32 const matchIndex = bestEntry->offset;
- U32 const offset = current - matchIndex;
-
- /* Overwrite rep codes */
- for (i = 0; i < ZSTD_REP_NUM; i++)
- seqStorePtr->rep[i] = repToConfirm[i];
-
- /* Fill the hash table for the block compressor */
- ZSTD_ldm_limitTableUpdate(ctx, anchor);
- ZSTD_ldm_fillFastTables(ctx, anchor);
-
- /* Call block compressor and get remaining literals */
- lastLiterals = blockCompressor(ctx, anchor, ip - anchor);
- ctx->nextToUpdate = (U32)(ip - base);
-
- /* Update repToConfirm with the new offset */
- for (i = ZSTD_REP_NUM - 1; i > 0; i--)
- repToConfirm[i] = repToConfirm[i-1];
- repToConfirm[0] = offset;
-
- /* Store the sequence with the leftover literals */
- ZSTD_storeSeq(seqStorePtr, lastLiterals, ip - lastLiterals,
- offset + ZSTD_REP_MOVE, mLength - MINMATCH);
- }
-
- /* Insert the current entry into the hash table */
- ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash, hBits,
- (U32)(lastHashed - base),
- ldmParams);
-
- /* Fill the hash table from lastHashed+1 to ip+mLength */
- assert(ip + backwardMatchLength == lastHashed);
- if (ip + mLength < ilimit) {
- rollingHash = ZSTD_ldm_fillLdmHashTable(
- ldmState, rollingHash, lastHashed,
- ip + mLength, base, hBits,
- ldmParams);
- lastHashed = ip + mLength - 1;
- }
- ip += mLength;
- anchor = ip;
-
- /* check immediate repcode */
- while (ip < ilimit) {
- U32 const current2 = (U32)(ip-base);
- U32 const repIndex2 = current2 - repToConfirm[1];
- const BYTE* repMatch2 = repIndex2 < dictLimit ?
- dictBase + repIndex2 : base + repIndex2;
- if ( (((U32)((dictLimit-1) - repIndex2) >= 3) &
- (repIndex2 > lowestIndex)) /* intentional overflow */
- && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
- const BYTE* const repEnd2 = repIndex2 < dictLimit ?
- dictEnd : iend;
- size_t const repLength2 =
- ZSTD_count_2segments(ip+4, repMatch2+4, iend,
- repEnd2, lowPrefixPtr) + 4;
-
- U32 tmpOffset = repToConfirm[1];
- repToConfirm[1] = repToConfirm[0];
- repToConfirm[0] = tmpOffset;
-
- ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2-MINMATCH);
-
- /* Fill the hash table from lastHashed+1 to ip+repLength2*/
- if (ip + repLength2 < ilimit) {
- rollingHash = ZSTD_ldm_fillLdmHashTable(
- ldmState, rollingHash, lastHashed,
- ip + repLength2, base, hBits,
- ldmParams);
- lastHashed = ip + repLength2 - 1;
- }
- ip += repLength2;
- anchor = ip;
- continue;
- }
- break;
- }
- }
-
- /* Overwrite rep */
- for (i = 0; i < ZSTD_REP_NUM; i++)
- seqStorePtr->rep[i] = repToConfirm[i];
-
- ZSTD_ldm_limitTableUpdate(ctx, anchor);
- ZSTD_ldm_fillFastTables(ctx, anchor);
-
- /* Call the block compressor one last time on the last literals */
- lastLiterals = blockCompressor(ctx, anchor, iend - anchor);
- ctx->nextToUpdate = (U32)(iend - base);
-
- /* Restore seqStorePtr->rep */
- for (i = 0; i < ZSTD_REP_NUM; i++)
- seqStorePtr->rep[i] = savedRep[i];
-
- /* Return the last literals size */
- return lastLiterals;
-}
-
-static size_t ZSTD_compressBlock_ldm_extDict(ZSTD_CCtx* ctx,
- const void* src, size_t srcSize)
-{
- return ZSTD_compressBlock_ldm_extDict_generic(ctx, src, srcSize);
-}
-
static void ZSTD_storeLastLiterals(seqStore_t* seqStorePtr,
const BYTE* anchor, size_t lastLLSize)
{
--- /dev/null
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+#include "zstd_ldm.h"
+
+#include "zstd_fast.h" /* ZSTD_fillHashTable() */
+#include "zstd_double_fast.h" /* ZSTD_fillDoubleHashTable() */
+
+#define LDM_BUCKET_SIZE_LOG 3
+#define LDM_MIN_MATCH_LENGTH 64
+#define LDM_HASH_LOG 20
+#define LDM_HASH_CHAR_OFFSET 10
+
+size_t ZSTD_ldm_initializeParameters(ldmParams_t* params, U32 enableLdm)
+{
+ ZSTD_STATIC_ASSERT(LDM_BUCKET_SIZE_LOG <= ZSTD_LDM_BUCKETSIZELOG_MAX);
+ params->enableLdm = enableLdm>0;
+ params->hashLog = LDM_HASH_LOG;
+ params->bucketSizeLog = LDM_BUCKET_SIZE_LOG;
+ params->minMatchLength = LDM_MIN_MATCH_LENGTH;
+ params->hashEveryLog = ZSTD_LDM_HASHEVERYLOG_NOTSET;
+ return 0;
+}
+
+void ZSTD_ldm_adjustParameters(ldmParams_t* params, U32 windowLog)
+{
+ if (params->hashEveryLog == ZSTD_LDM_HASHEVERYLOG_NOTSET) {
+ params->hashEveryLog =
+ windowLog < params->hashLog ? 0 : windowLog - params->hashLog;
+ }
+ params->bucketSizeLog = MIN(params->bucketSizeLog, params->hashLog);
+}
+
+size_t ZSTD_ldm_getTableSize(U32 hashLog, U32 bucketSizeLog) {
+ size_t const ldmHSize = ((size_t)1) << hashLog;
+ size_t const ldmBucketSizeLog = MIN(bucketSizeLog, hashLog);
+ size_t const ldmBucketSize =
+ ((size_t)1) << (hashLog - ldmBucketSizeLog);
+ return ldmBucketSize + (ldmHSize * (sizeof(ldmEntry_t)));
+}
+
+/** ZSTD_ldm_getSmallHash() :
+ * numBits should be <= 32
+ * If numBits==0, returns 0.
+ * @return : the most significant numBits of value. */
+static U32 ZSTD_ldm_getSmallHash(U64 value, U32 numBits)
+{
+ assert(numBits <= 32);
+ return numBits == 0 ? 0 : (U32)(value >> (64 - numBits));
+}
+
+/** ZSTD_ldm_getChecksum() :
+ * numBitsToDiscard should be <= 32
+ * @return : the next most significant 32 bits after numBitsToDiscard */
+static U32 ZSTD_ldm_getChecksum(U64 hash, U32 numBitsToDiscard)
+{
+ assert(numBitsToDiscard <= 32);
+ return (hash >> (64 - 32 - numBitsToDiscard)) & 0xFFFFFFFF;
+}
+
+/** ZSTD_ldm_getTag() ;
+ * Given the hash, returns the most significant numTagBits bits
+ * after (32 + hbits) bits.
+ *
+ * If there are not enough bits remaining, return the last
+ * numTagBits bits. */
+static U32 ZSTD_ldm_getTag(U64 hash, U32 hbits, U32 numTagBits)
+{
+ assert(numTagBits <= 32 && hbits <= 32);
+ if (32 - hbits < numTagBits) {
+ return hash & ((1 << numTagBits) - 1);
+ } else {
+ return (hash >> (32 - hbits - numTagBits)) & ((1 << numTagBits) - 1);
+ }
+}
+
+/** ZSTD_ldm_getBucket() :
+ * Returns a pointer to the start of the bucket associated with hash. */
+static ldmEntry_t* ZSTD_ldm_getBucket(
+ ldmState_t* ldmState, size_t hash, ldmParams_t const ldmParams)
+{
+ return ldmState->hashTable + (hash << ldmParams.bucketSizeLog);
+}
+
+/** ZSTD_ldm_insertEntry() :
+ * Insert the entry with corresponding hash into the hash table */
+static void ZSTD_ldm_insertEntry(ldmState_t* ldmState,
+ size_t const hash, const ldmEntry_t entry,
+ ldmParams_t const ldmParams)
+{
+ BYTE* const bucketOffsets = ldmState->bucketOffsets;
+ *(ZSTD_ldm_getBucket(ldmState, hash, ldmParams) + bucketOffsets[hash]) = entry;
+ bucketOffsets[hash]++;
+ bucketOffsets[hash] &= (1 << ldmParams.bucketSizeLog) - 1;
+}
+
+/** ZSTD_ldm_makeEntryAndInsertByTag() :
+ *
+ * Gets the small hash, checksum, and tag from the rollingHash.
+ *
+ * If the tag matches (1 << ldmParams.hashEveryLog)-1, then
+ * creates an ldmEntry from the offset, and inserts it into the hash table.
+ *
+ * hBits is the length of the small hash, which is the most significant hBits
+ * of rollingHash. The checksum is the next 32 most significant bits, followed
+ * by ldmParams.hashEveryLog bits that make up the tag. */
+static void ZSTD_ldm_makeEntryAndInsertByTag(ldmState_t* ldmState,
+ U64 const rollingHash,
+ U32 const hBits,
+ U32 const offset,
+ ldmParams_t const ldmParams)
+{
+ U32 const tag = ZSTD_ldm_getTag(rollingHash, hBits, ldmParams.hashEveryLog);
+ U32 const tagMask = (1 << ldmParams.hashEveryLog) - 1;
+ if (tag == tagMask) {
+ U32 const hash = ZSTD_ldm_getSmallHash(rollingHash, hBits);
+ U32 const checksum = ZSTD_ldm_getChecksum(rollingHash, hBits);
+ ldmEntry_t entry;
+ entry.offset = offset;
+ entry.checksum = checksum;
+ ZSTD_ldm_insertEntry(ldmState, hash, entry, ldmParams);
+ }
+}
+
+/** ZSTD_ldm_getRollingHash() :
+ * Get a 64-bit hash using the first len bytes from buf.
+ *
+ * Giving bytes s = s_1, s_2, ... s_k, the hash is defined to be
+ * H(s) = s_1*(a^(k-1)) + s_2*(a^(k-2)) + ... + s_k*(a^0)
+ *
+ * where the constant a is defined to be prime8bytes.
+ *
+ * The implementation adds an offset to each byte, so
+ * H(s) = (s_1 + HASH_CHAR_OFFSET)*(a^(k-1)) + ... */
+static U64 ZSTD_ldm_getRollingHash(const BYTE* buf, U32 len)
+{
+ U64 ret = 0;
+ U32 i;
+ for (i = 0; i < len; i++) {
+ ret *= prime8bytes;
+ ret += buf[i] + LDM_HASH_CHAR_OFFSET;
+ }
+ return ret;
+}
+
+/** ZSTD_ldm_ipow() :
+ * Return base^exp. */
+static U64 ZSTD_ldm_ipow(U64 base, U64 exp)
+{
+ U64 ret = 1;
+ while (exp) {
+ if (exp & 1) { ret *= base; }
+ exp >>= 1;
+ base *= base;
+ }
+ return ret;
+}
+
+U64 ZSTD_ldm_getHashPower(U32 minMatchLength) {
+ assert(minMatchLength >= ZSTD_LDM_MINMATCH_MIN);
+ return ZSTD_ldm_ipow(prime8bytes, minMatchLength - 1);
+}
+
+/** ZSTD_ldm_updateHash() :
+ * Updates hash by removing toRemove and adding toAdd. */
+static U64 ZSTD_ldm_updateHash(U64 hash, BYTE toRemove, BYTE toAdd, U64 hashPower)
+{
+ hash -= ((toRemove + LDM_HASH_CHAR_OFFSET) * hashPower);
+ hash *= prime8bytes;
+ hash += toAdd + LDM_HASH_CHAR_OFFSET;
+ return hash;
+}
+
+/** ZSTD_ldm_countBackwardsMatch() :
+ * Returns the number of bytes that match backwards before pIn and pMatch.
+ *
+ * We count only bytes where pMatch >= pBase and pIn >= pAnchor. */
+static size_t ZSTD_ldm_countBackwardsMatch(
+ const BYTE* pIn, const BYTE* pAnchor,
+ const BYTE* pMatch, const BYTE* pBase)
+{
+ size_t matchLength = 0;
+ while (pIn > pAnchor && pMatch > pBase && pIn[-1] == pMatch[-1]) {
+ pIn--;
+ pMatch--;
+ matchLength++;
+ }
+ return matchLength;
+}
+
+/** ZSTD_ldm_fillFastTables() :
+ *
+ * Fills the relevant tables for the ZSTD_fast and ZSTD_dfast strategies.
+ * This is similar to ZSTD_loadDictionaryContent.
+ *
+ * The tables for the other strategies are filled within their
+ * block compressors. */
+static size_t ZSTD_ldm_fillFastTables(ZSTD_CCtx* zc, const void* end)
+{
+ const BYTE* const iend = (const BYTE*)end;
+ const U32 mls = zc->appliedParams.cParams.searchLength;
+
+ switch(zc->appliedParams.cParams.strategy)
+ {
+ case ZSTD_fast:
+ ZSTD_fillHashTable(zc, iend, mls);
+ zc->nextToUpdate = (U32)(iend - zc->base);
+ break;
+
+ case ZSTD_dfast:
+ ZSTD_fillDoubleHashTable(zc, iend, mls);
+ zc->nextToUpdate = (U32)(iend - zc->base);
+ break;
+
+ case ZSTD_greedy:
+ case ZSTD_lazy:
+ case ZSTD_lazy2:
+ case ZSTD_btlazy2:
+ case ZSTD_btopt:
+ case ZSTD_btultra:
+ break;
+ default:
+ assert(0); /* not possible : not a valid strategy id */
+ }
+
+ return 0;
+}
+
+/** ZSTD_ldm_fillLdmHashTable() :
+ *
+ * Fills hashTable from (lastHashed + 1) to iend (non-inclusive).
+ * lastHash is the rolling hash that corresponds to lastHashed.
+ *
+ * Returns the rolling hash corresponding to position iend-1. */
+static U64 ZSTD_ldm_fillLdmHashTable(ldmState_t* state,
+ U64 lastHash, const BYTE* lastHashed,
+ const BYTE* iend, const BYTE* base,
+ U32 hBits, ldmParams_t const ldmParams)
+{
+ U64 rollingHash = lastHash;
+ const BYTE* cur = lastHashed + 1;
+
+ while (cur < iend) {
+ rollingHash = ZSTD_ldm_updateHash(rollingHash, cur[-1],
+ cur[ldmParams.minMatchLength-1],
+ state->hashPower);
+ ZSTD_ldm_makeEntryAndInsertByTag(state,
+ rollingHash, hBits,
+ (U32)(cur - base), ldmParams);
+ ++cur;
+ }
+ return rollingHash;
+}
+
+
+/** ZSTD_ldm_limitTableUpdate() :
+ *
+ * Sets cctx->nextToUpdate to a position corresponding closer to anchor
+ * if it is far way
+ * (after a long match, only update tables a limited amount). */
+static void ZSTD_ldm_limitTableUpdate(ZSTD_CCtx* cctx, const BYTE* anchor)
+{
+ U32 const current = (U32)(anchor - cctx->base);
+ if (current > cctx->nextToUpdate + 1024) {
+ cctx->nextToUpdate =
+ current - MIN(512, current - cctx->nextToUpdate - 1024);
+ }
+}
+
+typedef size_t (*ZSTD_blockCompressor) (ZSTD_CCtx* ctx, const void* src, size_t srcSize);
+/* defined in zstd_compress.c */
+ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int extDict);
+
+FORCE_INLINE_TEMPLATE
+size_t ZSTD_compressBlock_ldm_generic(ZSTD_CCtx* cctx,
+ const void* src, size_t srcSize)
+{
+ ldmState_t* const ldmState = &(cctx->ldmState);
+ const ldmParams_t ldmParams = cctx->appliedParams.ldmParams;
+ const U64 hashPower = ldmState->hashPower;
+ const U32 hBits = ldmParams.hashLog - ldmParams.bucketSizeLog;
+ const U32 ldmBucketSize = (1 << ldmParams.bucketSizeLog);
+ const U32 ldmTagMask = (1 << ldmParams.hashEveryLog) - 1;
+ seqStore_t* const seqStorePtr = &(cctx->seqStore);
+ const BYTE* const base = cctx->base;
+ const BYTE* const istart = (const BYTE*)src;
+ const BYTE* ip = istart;
+ const BYTE* anchor = istart;
+ const U32 lowestIndex = cctx->dictLimit;
+ const BYTE* const lowest = base + lowestIndex;
+ const BYTE* const iend = istart + srcSize;
+ const BYTE* const ilimit = iend - ldmParams.minMatchLength;
+
+ const ZSTD_blockCompressor blockCompressor =
+ ZSTD_selectBlockCompressor(cctx->appliedParams.cParams.strategy, 0);
+ U32* const repToConfirm = seqStorePtr->repToConfirm;
+ U32 savedRep[ZSTD_REP_NUM];
+ U64 rollingHash = 0;
+ const BYTE* lastHashed = NULL;
+ size_t i, lastLiterals;
+
+ /* Save seqStorePtr->rep and copy repToConfirm */
+ for (i = 0; i < ZSTD_REP_NUM; i++)
+ savedRep[i] = repToConfirm[i] = seqStorePtr->rep[i];
+
+ /* Main Search Loop */
+ while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
+ size_t mLength;
+ U32 const current = (U32)(ip - base);
+ size_t forwardMatchLength = 0, backwardMatchLength = 0;
+ ldmEntry_t* bestEntry = NULL;
+ if (ip != istart) {
+ rollingHash = ZSTD_ldm_updateHash(rollingHash, lastHashed[0],
+ lastHashed[ldmParams.minMatchLength],
+ hashPower);
+ } else {
+ rollingHash = ZSTD_ldm_getRollingHash(ip, ldmParams.minMatchLength);
+ }
+ lastHashed = ip;
+
+ /* Do not insert and do not look for a match */
+ if (ZSTD_ldm_getTag(rollingHash, hBits, ldmParams.hashEveryLog) !=
+ ldmTagMask) {
+ ip++;
+ continue;
+ }
+
+ /* Get the best entry and compute the match lengths */
+ {
+ ldmEntry_t* const bucket =
+ ZSTD_ldm_getBucket(ldmState,
+ ZSTD_ldm_getSmallHash(rollingHash, hBits),
+ ldmParams);
+ ldmEntry_t* cur;
+ size_t bestMatchLength = 0;
+ U32 const checksum = ZSTD_ldm_getChecksum(rollingHash, hBits);
+
+ for (cur = bucket; cur < bucket + ldmBucketSize; ++cur) {
+ const BYTE* const pMatch = cur->offset + base;
+ size_t curForwardMatchLength, curBackwardMatchLength,
+ curTotalMatchLength;
+ if (cur->checksum != checksum || cur->offset <= lowestIndex) {
+ continue;
+ }
+
+ curForwardMatchLength = ZSTD_count(ip, pMatch, iend);
+ if (curForwardMatchLength < ldmParams.minMatchLength) {
+ continue;
+ }
+ curBackwardMatchLength = ZSTD_ldm_countBackwardsMatch(
+ ip, anchor, pMatch, lowest);
+ curTotalMatchLength = curForwardMatchLength +
+ curBackwardMatchLength;
+
+ if (curTotalMatchLength > bestMatchLength) {
+ bestMatchLength = curTotalMatchLength;
+ forwardMatchLength = curForwardMatchLength;
+ backwardMatchLength = curBackwardMatchLength;
+ bestEntry = cur;
+ }
+ }
+ }
+
+ /* No match found -- continue searching */
+ if (bestEntry == NULL) {
+ ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash,
+ hBits, current,
+ ldmParams);
+ ip++;
+ continue;
+ }
+
+ /* Match found */
+ mLength = forwardMatchLength + backwardMatchLength;
+ ip -= backwardMatchLength;
+
+ /* Call the block compressor on the remaining literals */
+ {
+ U32 const matchIndex = bestEntry->offset;
+ const BYTE* const match = base + matchIndex - backwardMatchLength;
+ U32 const offset = (U32)(ip - match);
+
+ /* Overwrite rep codes */
+ for (i = 0; i < ZSTD_REP_NUM; i++)
+ seqStorePtr->rep[i] = repToConfirm[i];
+
+ /* Fill tables for block compressor */
+ ZSTD_ldm_limitTableUpdate(cctx, anchor);
+ ZSTD_ldm_fillFastTables(cctx, anchor);
+
+ /* Call block compressor and get remaining literals */
+ lastLiterals = blockCompressor(cctx, anchor, ip - anchor);
+ cctx->nextToUpdate = (U32)(ip - base);
+
+ /* Update repToConfirm with the new offset */
+ for (i = ZSTD_REP_NUM - 1; i > 0; i--)
+ repToConfirm[i] = repToConfirm[i-1];
+ repToConfirm[0] = offset;
+
+ /* Store the sequence with the leftover literals */
+ ZSTD_storeSeq(seqStorePtr, lastLiterals, ip - lastLiterals,
+ offset + ZSTD_REP_MOVE, mLength - MINMATCH);
+ }
+
+ /* Insert the current entry into the hash table */
+ ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash, hBits,
+ (U32)(lastHashed - base),
+ ldmParams);
+
+ assert(ip + backwardMatchLength == lastHashed);
+
+ /* Fill the hash table from lastHashed+1 to ip+mLength*/
+ /* Heuristic: don't need to fill the entire table at end of block */
+ if (ip + mLength < ilimit) {
+ rollingHash = ZSTD_ldm_fillLdmHashTable(
+ ldmState, rollingHash, lastHashed,
+ ip + mLength, base, hBits, ldmParams);
+ lastHashed = ip + mLength - 1;
+ }
+ ip += mLength;
+ anchor = ip;
+ /* Check immediate repcode */
+ while ( (ip < ilimit)
+ && ( (repToConfirm[1] > 0) && (repToConfirm[1] <= (U32)(ip-lowest))
+ && (MEM_read32(ip) == MEM_read32(ip - repToConfirm[1])) )) {
+
+ size_t const rLength = ZSTD_count(ip+4, ip+4-repToConfirm[1],
+ iend) + 4;
+ /* Swap repToConfirm[1] <=> repToConfirm[0] */
+ {
+ U32 const tmpOff = repToConfirm[1];
+ repToConfirm[1] = repToConfirm[0];
+ repToConfirm[0] = tmpOff;
+ }
+
+ ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength-MINMATCH);
+
+ /* Fill the hash table from lastHashed+1 to ip+rLength*/
+ if (ip + rLength < ilimit) {
+ rollingHash = ZSTD_ldm_fillLdmHashTable(
+ ldmState, rollingHash, lastHashed,
+ ip + rLength, base, hBits, ldmParams);
+ lastHashed = ip + rLength - 1;
+ }
+ ip += rLength;
+ anchor = ip;
+ }
+ }
+
+ /* Overwrite rep */
+ for (i = 0; i < ZSTD_REP_NUM; i++)
+ seqStorePtr->rep[i] = repToConfirm[i];
+
+ ZSTD_ldm_limitTableUpdate(cctx, anchor);
+ ZSTD_ldm_fillFastTables(cctx, anchor);
+
+ lastLiterals = blockCompressor(cctx, anchor, iend - anchor);
+ cctx->nextToUpdate = (U32)(iend - base);
+
+ /* Restore seqStorePtr->rep */
+ for (i = 0; i < ZSTD_REP_NUM; i++)
+ seqStorePtr->rep[i] = savedRep[i];
+
+ /* Return the last literals size */
+ return lastLiterals;
+}
+
+size_t ZSTD_compressBlock_ldm(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
+{
+ return ZSTD_compressBlock_ldm_generic(ctx, src, srcSize);
+}
+
+static size_t ZSTD_compressBlock_ldm_extDict_generic(
+ ZSTD_CCtx* ctx,
+ const void* src, size_t srcSize)
+{
+ ldmState_t* const ldmState = &(ctx->ldmState);
+ const ldmParams_t ldmParams = ctx->appliedParams.ldmParams;
+ const U64 hashPower = ldmState->hashPower;
+ const U32 hBits = ldmParams.hashLog - ldmParams.bucketSizeLog;
+ const U32 ldmBucketSize = (1 << ldmParams.bucketSizeLog);
+ const U32 ldmTagMask = (1 << ldmParams.hashEveryLog) - 1;
+ seqStore_t* const seqStorePtr = &(ctx->seqStore);
+ const BYTE* const base = ctx->base;
+ const BYTE* const dictBase = ctx->dictBase;
+ const BYTE* const istart = (const BYTE*)src;
+ const BYTE* ip = istart;
+ const BYTE* anchor = istart;
+ const U32 lowestIndex = ctx->lowLimit;
+ const BYTE* const dictStart = dictBase + lowestIndex;
+ const U32 dictLimit = ctx->dictLimit;
+ const BYTE* const lowPrefixPtr = base + dictLimit;
+ const BYTE* const dictEnd = dictBase + dictLimit;
+ const BYTE* const iend = istart + srcSize;
+ const BYTE* const ilimit = iend - ldmParams.minMatchLength;
+
+ const ZSTD_blockCompressor blockCompressor =
+ ZSTD_selectBlockCompressor(ctx->appliedParams.cParams.strategy, 1);
+ U32* const repToConfirm = seqStorePtr->repToConfirm;
+ U32 savedRep[ZSTD_REP_NUM];
+ U64 rollingHash = 0;
+ const BYTE* lastHashed = NULL;
+ size_t i, lastLiterals;
+
+ /* Save seqStorePtr->rep and copy repToConfirm */
+ for (i = 0; i < ZSTD_REP_NUM; i++) {
+ savedRep[i] = repToConfirm[i] = seqStorePtr->rep[i];
+ }
+
+ /* Search Loop */
+ while (ip < ilimit) { /* < instead of <=, because (ip+1) */
+ size_t mLength;
+ const U32 current = (U32)(ip-base);
+ size_t forwardMatchLength = 0, backwardMatchLength = 0;
+ ldmEntry_t* bestEntry = NULL;
+ if (ip != istart) {
+ rollingHash = ZSTD_ldm_updateHash(rollingHash, lastHashed[0],
+ lastHashed[ldmParams.minMatchLength],
+ hashPower);
+ } else {
+ rollingHash = ZSTD_ldm_getRollingHash(ip, ldmParams.minMatchLength);
+ }
+ lastHashed = ip;
+
+ if (ZSTD_ldm_getTag(rollingHash, hBits, ldmParams.hashEveryLog) !=
+ ldmTagMask) {
+ /* Don't insert and don't look for a match */
+ ip++;
+ continue;
+ }
+
+ /* Get the best entry and compute the match lengths */
+ {
+ ldmEntry_t* const bucket =
+ ZSTD_ldm_getBucket(ldmState,
+ ZSTD_ldm_getSmallHash(rollingHash, hBits),
+ ldmParams);
+ ldmEntry_t* cur;
+ size_t bestMatchLength = 0;
+ U32 const checksum = ZSTD_ldm_getChecksum(rollingHash, hBits);
+
+ for (cur = bucket; cur < bucket + ldmBucketSize; ++cur) {
+ const BYTE* const curMatchBase =
+ cur->offset < dictLimit ? dictBase : base;
+ const BYTE* const pMatch = curMatchBase + cur->offset;
+ const BYTE* const matchEnd =
+ cur->offset < dictLimit ? dictEnd : iend;
+ const BYTE* const lowMatchPtr =
+ cur->offset < dictLimit ? dictStart : lowPrefixPtr;
+ size_t curForwardMatchLength, curBackwardMatchLength,
+ curTotalMatchLength;
+
+ if (cur->checksum != checksum || cur->offset <= lowestIndex) {
+ continue;
+ }
+
+ curForwardMatchLength = ZSTD_count_2segments(
+ ip, pMatch, iend,
+ matchEnd, lowPrefixPtr);
+ if (curForwardMatchLength < ldmParams.minMatchLength) {
+ continue;
+ }
+ curBackwardMatchLength = ZSTD_ldm_countBackwardsMatch(
+ ip, anchor, pMatch, lowMatchPtr);
+ curTotalMatchLength = curForwardMatchLength +
+ curBackwardMatchLength;
+
+ if (curTotalMatchLength > bestMatchLength) {
+ bestMatchLength = curTotalMatchLength;
+ forwardMatchLength = curForwardMatchLength;
+ backwardMatchLength = curBackwardMatchLength;
+ bestEntry = cur;
+ }
+ }
+ }
+
+ /* No match found -- continue searching */
+ if (bestEntry == NULL) {
+ ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash, hBits,
+ (U32)(lastHashed - base),
+ ldmParams);
+ ip++;
+ continue;
+ }
+
+ /* Match found */
+ mLength = forwardMatchLength + backwardMatchLength;
+ ip -= backwardMatchLength;
+
+ /* Call the block compressor on the remaining literals */
+ {
+ /* ip = current - backwardMatchLength
+ * The match is at (bestEntry->offset - backwardMatchLength) */
+ U32 const matchIndex = bestEntry->offset;
+ U32 const offset = current - matchIndex;
+
+ /* Overwrite rep codes */
+ for (i = 0; i < ZSTD_REP_NUM; i++)
+ seqStorePtr->rep[i] = repToConfirm[i];
+
+ /* Fill the hash table for the block compressor */
+ ZSTD_ldm_limitTableUpdate(ctx, anchor);
+ ZSTD_ldm_fillFastTables(ctx, anchor);
+
+ /* Call block compressor and get remaining literals */
+ lastLiterals = blockCompressor(ctx, anchor, ip - anchor);
+ ctx->nextToUpdate = (U32)(ip - base);
+
+ /* Update repToConfirm with the new offset */
+ for (i = ZSTD_REP_NUM - 1; i > 0; i--)
+ repToConfirm[i] = repToConfirm[i-1];
+ repToConfirm[0] = offset;
+
+ /* Store the sequence with the leftover literals */
+ ZSTD_storeSeq(seqStorePtr, lastLiterals, ip - lastLiterals,
+ offset + ZSTD_REP_MOVE, mLength - MINMATCH);
+ }
+
+ /* Insert the current entry into the hash table */
+ ZSTD_ldm_makeEntryAndInsertByTag(ldmState, rollingHash, hBits,
+ (U32)(lastHashed - base),
+ ldmParams);
+
+ /* Fill the hash table from lastHashed+1 to ip+mLength */
+ assert(ip + backwardMatchLength == lastHashed);
+ if (ip + mLength < ilimit) {
+ rollingHash = ZSTD_ldm_fillLdmHashTable(
+ ldmState, rollingHash, lastHashed,
+ ip + mLength, base, hBits,
+ ldmParams);
+ lastHashed = ip + mLength - 1;
+ }
+ ip += mLength;
+ anchor = ip;
+
+ /* check immediate repcode */
+ while (ip < ilimit) {
+ U32 const current2 = (U32)(ip-base);
+ U32 const repIndex2 = current2 - repToConfirm[1];
+ const BYTE* repMatch2 = repIndex2 < dictLimit ?
+ dictBase + repIndex2 : base + repIndex2;
+ if ( (((U32)((dictLimit-1) - repIndex2) >= 3) &
+ (repIndex2 > lowestIndex)) /* intentional overflow */
+ && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
+ const BYTE* const repEnd2 = repIndex2 < dictLimit ?
+ dictEnd : iend;
+ size_t const repLength2 =
+ ZSTD_count_2segments(ip+4, repMatch2+4, iend,
+ repEnd2, lowPrefixPtr) + 4;
+
+ U32 tmpOffset = repToConfirm[1];
+ repToConfirm[1] = repToConfirm[0];
+ repToConfirm[0] = tmpOffset;
+
+ ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2-MINMATCH);
+
+ /* Fill the hash table from lastHashed+1 to ip+repLength2*/
+ if (ip + repLength2 < ilimit) {
+ rollingHash = ZSTD_ldm_fillLdmHashTable(
+ ldmState, rollingHash, lastHashed,
+ ip + repLength2, base, hBits,
+ ldmParams);
+ lastHashed = ip + repLength2 - 1;
+ }
+ ip += repLength2;
+ anchor = ip;
+ continue;
+ }
+ break;
+ }
+ }
+
+ /* Overwrite rep */
+ for (i = 0; i < ZSTD_REP_NUM; i++)
+ seqStorePtr->rep[i] = repToConfirm[i];
+
+ ZSTD_ldm_limitTableUpdate(ctx, anchor);
+ ZSTD_ldm_fillFastTables(ctx, anchor);
+
+ /* Call the block compressor one last time on the last literals */
+ lastLiterals = blockCompressor(ctx, anchor, iend - anchor);
+ ctx->nextToUpdate = (U32)(iend - base);
+
+ /* Restore seqStorePtr->rep */
+ for (i = 0; i < ZSTD_REP_NUM; i++)
+ seqStorePtr->rep[i] = savedRep[i];
+
+ /* Return the last literals size */
+ return lastLiterals;
+}
+
+size_t ZSTD_compressBlock_ldm_extDict(ZSTD_CCtx* ctx,
+ const void* src, size_t srcSize)
+{
+ return ZSTD_compressBlock_ldm_extDict_generic(ctx, src, srcSize);
+}
--- /dev/null
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+#ifndef ZSTD_LDM_H
+#define ZSTD_LDM_H
+
+#include "zstd_compress.h"
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+/*-*************************************
+* Long distance matching
+***************************************/
+
+#define ZSTD_LDM_WINDOW_LOG 27
+#define ZSTD_LDM_HASHEVERYLOG_NOTSET 9999
+
+/** ZSTD_compressBlock_ldm_generic() :
+ *
+ * This is a block compressor intended for long distance matching.
+ *
+ * The function searches for matches of length at least
+ * ldmParams.minMatchLength using a hash table in cctx->ldmState.
+ * Matches can be at a distance of up to cParams.windowLog.
+ *
+ * Upon finding a match, the unmatched literals are compressed using a
+ * ZSTD_blockCompressor (depending on the strategy in the compression
+ * parameters), which stores the matched sequences. The "long distance"
+ * match is then stored with the remaining literals from the
+ * ZSTD_blockCompressor. */
+size_t ZSTD_compressBlock_ldm(ZSTD_CCtx* cctx, const void* src, size_t srcSize);
+size_t ZSTD_compressBlock_ldm_extDict(ZSTD_CCtx* ctx,
+ const void* src, size_t srcSize);
+
+/** ZSTD_ldm_initializeParameters() :
+ * Initialize the long distance matching parameters to their default values. */
+size_t ZSTD_ldm_initializeParameters(ldmParams_t* params, U32 enableLdm);
+
+/** ZSTD_ldm_getTableSize() :
+ * Estimate the space needed for long distance matching tables. */
+size_t ZSTD_ldm_getTableSize(U32 hashLog, U32 bucketSizeLog);
+
+/** ZSTD_ldm_getTableSize() :
+ * Return prime8bytes^(minMatchLength-1) */
+U64 ZSTD_ldm_getHashPower(U32 minMatchLength);
+
+/** ZSTD_ldm_adjustParameters() :
+ * If the params->hashEveryLog is not set, set it to its default value based on
+ * windowLog and params->hashLog.
+ *
+ * Ensures that params->bucketSizeLog is <= params->hashLog (setting it to
+ * params->hashLog if it is not). */
+void ZSTD_ldm_adjustParameters(ldmParams_t* params, U32 windowLog);
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif /* ZSTD_FAST_H */
projects / thirdparty / zstd.git / commitdiff
