diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c index 92010fd8a..b1bb9fa10 100644 --- a/lib/compress/zstd_compress.c +++ b/lib/compress/zstd_compress.c @@ -2413,7 +2413,7 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize) src, srcSize); assert(zc->externSeqStore.pos <= zc->externSeqStore.size); } else if (zc->appliedParams.ldmParams.enableLdm) { - rawSeqStore_t ldmSeqStore = {NULL, 0, 0, 0}; + rawSeqStore_t ldmSeqStore = kNullRawSeqStore; ldmSeqStore.seq = zc->ldmSequences; ldmSeqStore.capacity = zc->maxNbLdmSequences; @@ -2430,6 +2430,7 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize) assert(ldmSeqStore.pos == ldmSeqStore.size); } else { /* not long range mode */ ZSTD_blockCompressor const blockCompressor = ZSTD_selectBlockCompressor(zc->appliedParams.cParams.strategy, dictMode); + ms->ldmSeqStore = NULL; lastLLSize = blockCompressor(ms, &zc->seqStore, zc->blockState.nextCBlock->rep, src, srcSize); } { const BYTE* const lastLiterals = (const BYTE*)src + srcSize - lastLLSize; diff --git a/lib/compress/zstd_compress_internal.h b/lib/compress/zstd_compress_internal.h index 1fc9180aa..a0a9d53ba 100644 --- a/lib/compress/zstd_compress_internal.h +++ b/lib/compress/zstd_compress_internal.h @@ -82,10 +82,27 @@ typedef struct { } ZSTD_entropyCTables_t; typedef struct { - U32 off; - U32 len; + U32 off; /* Offset code (offset + ZSTD_REP_MOVE) for the match */ + U32 len; /* Raw length of match */ } ZSTD_match_t; +typedef struct { + U32 offset; /* Offset of sequence */ + U32 litLength; /* Length of literals prior to match */ + U32 matchLength; /* Raw length of match */ +} rawSeq; + +typedef struct { + rawSeq* seq; /* The start of the sequences */ + size_t pos; /* The index in seq where reading stopped. pos <= size. */ + size_t posInSequence; /* The position within the sequence at seq[pos] where reading + stopped. posInSequence <= seq[pos].litLength + seq[pos].matchLength */ + size_t size; /* The number of sequences. <= capacity. */ + size_t capacity; /* The capacity starting from `seq` pointer */ +} rawSeqStore_t; + +UNUSED_ATTR static const rawSeqStore_t kNullRawSeqStore = {NULL, 0, 0, 0, 0}; + typedef struct { int price; U32 off; @@ -152,6 +169,7 @@ struct ZSTD_matchState_t { optState_t opt; /* optimal parser state */ const ZSTD_matchState_t* dictMatchState; ZSTD_compressionParameters cParams; + const rawSeqStore_t* ldmSeqStore; }; typedef struct { @@ -183,19 +201,6 @@ typedef struct { U32 windowLog; /* Window log for the LDM */ } ldmParams_t; -typedef struct { - U32 offset; - U32 litLength; - U32 matchLength; -} rawSeq; - -typedef struct { - rawSeq* seq; /* The start of the sequences */ - size_t pos; /* The position where reading stopped. <= size. */ - size_t size; /* The number of sequences. <= capacity. */ - size_t capacity; /* The capacity starting from `seq` pointer */ -} rawSeqStore_t; - typedef struct { int collectSequences; ZSTD_Sequence* seqStart; diff --git a/lib/compress/zstd_ldm.c b/lib/compress/zstd_ldm.c index dbfce3dce..cc338e697 100644 --- a/lib/compress/zstd_ldm.c +++ b/lib/compress/zstd_ldm.c @@ -27,13 +27,6 @@ void ZSTD_ldm_adjustParameters(ldmParams_t* params, DEBUGLOG(4, "ZSTD_ldm_adjustParameters"); if (!params->bucketSizeLog) params->bucketSizeLog = LDM_BUCKET_SIZE_LOG; if (!params->minMatchLength) params->minMatchLength = LDM_MIN_MATCH_LENGTH; - if (cParams->strategy >= ZSTD_btopt) { - /* Get out of the way of the optimal parser */ - U32 const minMatch = MAX(cParams->targetLength, params->minMatchLength); - assert(minMatch >= ZSTD_LDM_MINMATCH_MIN); - assert(minMatch <= ZSTD_LDM_MINMATCH_MAX); - params->minMatchLength = minMatch; - } if (params->hashLog == 0) { params->hashLog = MAX(ZSTD_HASHLOG_MIN, params->windowLog - LDM_HASH_RLOG); assert(params->hashLog <= ZSTD_HASHLOG_MAX); @@ -562,6 +555,26 @@ static rawSeq maybeSplitSequence(rawSeqStore_t* rawSeqStore, return sequence; } +/* ZSTD_ldm_skipRawSeqStoreBytes(): + * Moves forward in rawSeqStore by nbBytes, updating fields 'pos' and 'posInSequence'. + */ +static void ZSTD_ldm_skipRawSeqStoreBytes(rawSeqStore_t* rawSeqStore, size_t nbBytes) { + U32 currPos = (U32)(rawSeqStore->posInSequence + nbBytes); + while (currPos && rawSeqStore->pos < rawSeqStore->size) { + rawSeq currSeq = rawSeqStore->seq[rawSeqStore->pos]; + if (currPos >= currSeq.litLength + currSeq.matchLength) { + currPos -= currSeq.litLength + currSeq.matchLength; + rawSeqStore->pos++; + } else { + rawSeqStore->posInSequence = currPos; + break; + } + } + if (currPos == 0 || rawSeqStore->pos == rawSeqStore->size) { + rawSeqStore->posInSequence = 0; + } +} + size_t ZSTD_ldm_blockCompress(rawSeqStore_t* rawSeqStore, ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], void const* src, size_t srcSize) @@ -577,6 +590,15 @@ size_t ZSTD_ldm_blockCompress(rawSeqStore_t* rawSeqStore, BYTE const* ip = istart; DEBUGLOG(5, "ZSTD_ldm_blockCompress: srcSize=%zu", srcSize); + /* If using opt parser, use LDMs only as candidates rather than always accepting them */ + if (cParams->strategy >= ZSTD_btopt) { + size_t lastLLSize; + ms->ldmSeqStore = rawSeqStore; + lastLLSize = blockCompressor(ms, seqStore, rep, src, srcSize); + ZSTD_ldm_skipRawSeqStoreBytes(rawSeqStore, srcSize); + return lastLLSize; + } + assert(rawSeqStore->pos <= rawSeqStore->size); assert(rawSeqStore->size <= rawSeqStore->capacity); /* Loop through each sequence and apply the block compressor to the lits */ diff --git a/lib/compress/zstd_opt.c b/lib/compress/zstd_opt.c index 5acc9e0b6..e55c459de 100644 --- a/lib/compress/zstd_opt.c +++ b/lib/compress/zstd_opt.c @@ -764,6 +764,140 @@ FORCE_INLINE_TEMPLATE U32 ZSTD_BtGetAllMatches ( } } +/************************* +* LDM helper functions * +*************************/ + +/* Struct containing info needed to make decision about ldm inclusion */ +typedef struct { + rawSeqStore_t seqStore; /* External match candidates store for this block */ + U32 startPosInBlock; /* Start position of the current match candidate */ + U32 endPosInBlock; /* End position of the current match candidate */ + U32 offset; /* Offset of the match candidate */ +} ZSTD_optLdm_t; + +/* ZSTD_optLdm_skipRawSeqStoreBytes(): + * Moves forward in rawSeqStore by nbBytes, which will update the fields 'pos' and 'posInSequence'. + */ +static void ZSTD_optLdm_skipRawSeqStoreBytes(rawSeqStore_t* rawSeqStore, size_t nbBytes) { + U32 currPos = (U32)(rawSeqStore->posInSequence + nbBytes); + while (currPos && rawSeqStore->pos < rawSeqStore->size) { + rawSeq currSeq = rawSeqStore->seq[rawSeqStore->pos]; + if (currPos >= currSeq.litLength + currSeq.matchLength) { + currPos -= currSeq.litLength + currSeq.matchLength; + rawSeqStore->pos++; + } else { + rawSeqStore->posInSequence = currPos; + break; + } + } + if (currPos == 0 || rawSeqStore->pos == rawSeqStore->size) { + rawSeqStore->posInSequence = 0; + } +} + +/* ZSTD_opt_getNextMatchAndUpdateSeqStore(): + * Calculates the beginning and end of the next match in the current block. + * Updates 'pos' and 'posInSequence' of the ldmSeqStore. + */ +static void ZSTD_opt_getNextMatchAndUpdateSeqStore(ZSTD_optLdm_t* optLdm, U32 currPosInBlock, + U32 blockBytesRemaining) { + rawSeq currSeq; + U32 currBlockEndPos; + U32 literalsBytesRemaining; + U32 matchBytesRemaining; + + /* Setting match end position to MAX to ensure we never use an LDM during this block */ + if (optLdm->seqStore.size == 0 || optLdm->seqStore.pos >= optLdm->seqStore.size) { + optLdm->startPosInBlock = UINT_MAX; + optLdm->endPosInBlock = UINT_MAX; + return; + } + /* Calculate appropriate bytes left in matchLength and litLength after adjusting + based on ldmSeqStore->posInSequence */ + currSeq = optLdm->seqStore.seq[optLdm->seqStore.pos]; + assert(optLdm->seqStore.posInSequence <= currSeq.litLength + currSeq.matchLength); + currBlockEndPos = currPosInBlock + blockBytesRemaining; + literalsBytesRemaining = (optLdm->seqStore.posInSequence < currSeq.litLength) ? + currSeq.litLength - (U32)optLdm->seqStore.posInSequence : + 0; + matchBytesRemaining = (literalsBytesRemaining == 0) ? + currSeq.matchLength - ((U32)optLdm->seqStore.posInSequence - currSeq.litLength) : + currSeq.matchLength; + + /* If there are more literal bytes than bytes remaining in block, no ldm is possible */ + if (literalsBytesRemaining >= blockBytesRemaining) { + optLdm->startPosInBlock = UINT_MAX; + optLdm->endPosInBlock = UINT_MAX; + ZSTD_optLdm_skipRawSeqStoreBytes(&optLdm->seqStore, blockBytesRemaining); + return; + } + + /* Matches may be < MINMATCH by this process. In that case, we will reject them + when we are deciding whether or not to add the ldm */ + optLdm->startPosInBlock = currPosInBlock + literalsBytesRemaining; + optLdm->endPosInBlock = optLdm->startPosInBlock + matchBytesRemaining; + optLdm->offset = currSeq.offset; + + if (optLdm->endPosInBlock > currBlockEndPos) { + /* Match ends after the block ends, we can't use the whole match */ + optLdm->endPosInBlock = currBlockEndPos; + ZSTD_optLdm_skipRawSeqStoreBytes(&optLdm->seqStore, currBlockEndPos - currPosInBlock); + } else { + /* Consume nb of bytes equal to size of sequence left */ + ZSTD_optLdm_skipRawSeqStoreBytes(&optLdm->seqStore, literalsBytesRemaining + matchBytesRemaining); + } +} + +/* ZSTD_optLdm_maybeAddMatch(): + * Adds a match if it's long enough, based on it's 'matchStartPosInBlock' + * and 'matchEndPosInBlock', into 'matches'. Maintains the correct ordering of 'matches' + */ +static void ZSTD_optLdm_maybeAddMatch(ZSTD_match_t* matches, U32* nbMatches, + ZSTD_optLdm_t* optLdm, U32 currPosInBlock) { + U32 posDiff = currPosInBlock - optLdm->startPosInBlock; + /* Note: ZSTD_match_t actually contains offCode and matchLength (before subtracting MINMATCH) */ + U32 candidateMatchLength = optLdm->endPosInBlock - optLdm->startPosInBlock - posDiff; + U32 candidateOffCode = optLdm->offset + ZSTD_REP_MOVE; + + /* Ensure that current block position is not outside of the match */ + if (currPosInBlock < optLdm->startPosInBlock + || currPosInBlock >= optLdm->endPosInBlock + || candidateMatchLength < MINMATCH) { + return; + } + + if (*nbMatches == 0 || ((candidateMatchLength > matches[*nbMatches-1].len) && *nbMatches < ZSTD_OPT_NUM)) { + DEBUGLOG(6, "ZSTD_optLdm_maybeAddMatch(): Adding ldm candidate match (offCode: %u matchLength %u) at block position=%u", + candidateOffCode, candidateMatchLength, currPosInBlock); + matches[*nbMatches].len = candidateMatchLength; + matches[*nbMatches].off = candidateOffCode; + (*nbMatches)++; + } +} + +/* ZSTD_optLdm_processMatchCandidate(): + * Wrapper function to update ldm seq store and call ldm functions as necessary. + */ +static void ZSTD_optLdm_processMatchCandidate(ZSTD_optLdm_t* optLdm, ZSTD_match_t* matches, U32* nbMatches, + U32 currPosInBlock, U32 remainingBytes) { + if (optLdm->seqStore.size == 0 || optLdm->seqStore.pos >= optLdm->seqStore.size) { + return; + } + + if (currPosInBlock >= optLdm->endPosInBlock) { + if (currPosInBlock > optLdm->endPosInBlock) { + /* The position at which ZSTD_optLdm_processMatchCandidate() is called is not necessarily + * at the end of a match from the ldm seq store, and will often be some bytes + * over beyond matchEndPosInBlock. As such, we need to correct for these "overshoots" + */ + U32 posOvershoot = currPosInBlock - optLdm->endPosInBlock; + ZSTD_optLdm_skipRawSeqStoreBytes(&optLdm->seqStore, posOvershoot); + } + ZSTD_opt_getNextMatchAndUpdateSeqStore(optLdm, currPosInBlock, remainingBytes); + } + ZSTD_optLdm_maybeAddMatch(matches, nbMatches, optLdm, currPosInBlock); +} /*-******************************* * Optimal parser @@ -817,6 +951,11 @@ ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms, ZSTD_optimal_t* const opt = optStatePtr->priceTable; ZSTD_match_t* const matches = optStatePtr->matchTable; ZSTD_optimal_t lastSequence; + ZSTD_optLdm_t optLdm; + + optLdm.seqStore = ms->ldmSeqStore ? *ms->ldmSeqStore : kNullRawSeqStore; + optLdm.endPosInBlock = optLdm.startPosInBlock = optLdm.offset = 0; + ZSTD_opt_getNextMatchAndUpdateSeqStore(&optLdm, (U32)(ip-istart), (U32)(iend-ip)); /* init */ DEBUGLOG(5, "ZSTD_compressBlock_opt_generic: current=%u, prefix=%u, nextToUpdate=%u", @@ -832,7 +971,9 @@ ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms, /* find first match */ { U32 const litlen = (U32)(ip - anchor); U32 const ll0 = !litlen; - U32 const nbMatches = ZSTD_BtGetAllMatches(matches, ms, &nextToUpdate3, ip, iend, dictMode, rep, ll0, minMatch); + U32 nbMatches = ZSTD_BtGetAllMatches(matches, ms, &nextToUpdate3, ip, iend, dictMode, rep, ll0, minMatch); + ZSTD_optLdm_processMatchCandidate(&optLdm, matches, &nbMatches, + (U32)(ip-istart), (U32)(iend - ip)); if (!nbMatches) { ip++; continue; } /* initialize opt[0] */ @@ -945,8 +1086,12 @@ ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms, U32 const litlen = (opt[cur].mlen == 0) ? opt[cur].litlen : 0; U32 const previousPrice = opt[cur].price; U32 const basePrice = previousPrice + ZSTD_litLengthPrice(0, optStatePtr, optLevel); - U32 const nbMatches = ZSTD_BtGetAllMatches(matches, ms, &nextToUpdate3, inr, iend, dictMode, opt[cur].rep, ll0, minMatch); + U32 nbMatches = ZSTD_BtGetAllMatches(matches, ms, &nextToUpdate3, inr, iend, dictMode, opt[cur].rep, ll0, minMatch); U32 matchNb; + + ZSTD_optLdm_processMatchCandidate(&optLdm, matches, &nbMatches, + (U32)(inr-istart), (U32)(iend-inr)); + if (!nbMatches) { DEBUGLOG(7, "rPos:%u : no match found", cur); continue; diff --git a/lib/compress/zstdmt_compress.c b/lib/compress/zstdmt_compress.c index 7bd8db484..d68f47189 100644 --- a/lib/compress/zstdmt_compress.c +++ b/lib/compress/zstdmt_compress.c @@ -266,8 +266,6 @@ static void ZSTDMT_releaseBuffer(ZSTDMT_bufferPool* bufPool, buffer_t buf) /* ===== Seq Pool Wrapper ====== */ -static rawSeqStore_t kNullRawSeqStore = {NULL, 0, 0, 0}; - typedef ZSTDMT_bufferPool ZSTDMT_seqPool; static size_t ZSTDMT_sizeof_seqPool(ZSTDMT_seqPool* seqPool) @@ -277,7 +275,7 @@ static size_t ZSTDMT_sizeof_seqPool(ZSTDMT_seqPool* seqPool) static rawSeqStore_t bufferToSeq(buffer_t buffer) { - rawSeqStore_t seq = {NULL, 0, 0, 0}; + rawSeqStore_t seq = kNullRawSeqStore; seq.seq = (rawSeq*)buffer.start; seq.capacity = buffer.capacity / sizeof(rawSeq); return seq; diff --git a/tests/fuzzer.c b/tests/fuzzer.c index 838772c09..302bfaf62 100644 --- a/tests/fuzzer.c +++ b/tests/fuzzer.c @@ -793,6 +793,44 @@ static int basicUnitTests(U32 const seed, double compressibility) } DISPLAYLEVEL(3, "OK \n"); + DISPLAYLEVEL(3, "test%3i : testing ldm no regressions in size for opt parser : ", testNb++); + { + size_t cSizeLdm; + size_t cSizeNoLdm; + ZSTD_CCtx* const cctx = ZSTD_createCCtx(); + + RDG_genBuffer(CNBuffer, CNBuffSize, 0.5, 0.5, seed); + + /* Enable checksum to verify round trip. */ + CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, 1)); + CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_enableLongDistanceMatching, 1)); + CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, 19)); + + /* Round trip once with ldm. */ + cSizeLdm = ZSTD_compress2(cctx, compressedBuffer, compressedBufferSize, CNBuffer, CNBuffSize); + CHECK_Z(cSizeLdm); + CHECK_Z(ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSizeLdm)); + + ZSTD_CCtx_reset(cctx, ZSTD_reset_session_and_parameters); + CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, 1)); + CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_enableLongDistanceMatching, 0)); + CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, 19)); + + /* Round trip once without ldm. */ + cSizeNoLdm = ZSTD_compress2(cctx, compressedBuffer, compressedBufferSize, CNBuffer, CNBuffSize); + CHECK_Z(cSizeNoLdm); + CHECK_Z(ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSizeNoLdm)); + + if (cSizeLdm > cSizeNoLdm) { + DISPLAY("Using long mode should not cause regressions for btopt+\n"); + testResult = 1; + goto _end; + } + + ZSTD_freeCCtx(cctx); + } + DISPLAYLEVEL(3, "OK \n"); + /* Note: this test takes 0.5 seconds to run */ DISPLAYLEVEL(3, "test%3i : testing refPrefx vs refPrefx + ldm (size comparison) : ", testNb++); { diff --git a/tests/playTests.sh b/tests/playTests.sh index fd602e7ae..b0a5ffc69 100755 --- a/tests/playTests.sh +++ b/tests/playTests.sh @@ -1206,6 +1206,7 @@ roundTripTest -g1000K "1 --single-thread --long" roundTripTest -g517K "6 --single-thread --long" roundTripTest -g516K "16 --single-thread --long" roundTripTest -g518K "19 --single-thread --long" +roundTripTest -g2M "22 --single-thread --ultra --long" fileRoundTripTest -g5M "3 --single-thread --long" @@ -1215,6 +1216,7 @@ then println "\n===> zstdmt round-trip tests " roundTripTest -g4M "1 -T0" roundTripTest -g8M "3 -T2" + roundTripTest -g8M "19 -T0 --long" roundTripTest -g8000K "2 --threads=2" fileRoundTripTest -g4M "19 -T2 -B1M" @@ -1333,6 +1335,28 @@ roundTripTest -g1M -P50 "1 --single-thread --long=29" " --long=28 --memory=512MB roundTripTest -g1M -P50 "1 --single-thread --long=29" " --zstd=wlog=28 --memory=512MB" +println "\n===> zstd long distance matching with optimal parser compressed size tests " +optCSize16=$(datagen -g511K | zstd -16 -c | wc -c) +longCSize16=$(datagen -g511K | zstd -16 --long -c | wc -c) +optCSize19=$(datagen -g2M | zstd -19 -c | wc -c) +longCSize19=$(datagen -g2M | zstd -19 --long -c | wc -c) +optCSize19wlog23=$(datagen -g2M | zstd -19 -c --zstd=wlog=23 | wc -c) +longCSize19wlog23=$(datagen -g2M | zstd -19 -c --long=23 | wc -c) +optCSize22=$(datagen -g900K | zstd -22 --ultra -c | wc -c) +longCSize22=$(datagen -g900K | zstd -22 --ultra --long -c | wc -c) +if [ "$longCSize16" -gt "$optCSize16" ]; then + echo using --long on compression level 16 should not cause compressed size regression + exit 1 +elif [ "$longCSize19" -gt "$optCSize19" ]; then + echo using --long on compression level 19 should not cause compressed size regression + exit 1 +elif [ "$longCSize19wlog23" -gt "$optCSize19wlog23" ]; then + echo using --long on compression level 19 with wLog=23 should not cause compressed size regression + exit 1 +elif [ "$longCSize22" -gt "$optCSize22" ]; then + echo using --long on compression level 22 should not cause compressed size regression + exit 1 +fi if [ "$1" != "--test-large-data" ]; then