diff --git a/lib/compress/zstd_fast.c b/lib/compress/zstd_fast.c index 5da108c622a..7b1d0dd43e6 100644 --- a/lib/compress/zstd_fast.c +++ b/lib/compress/zstd_fast.c @@ -587,11 +587,10 @@ static size_t ZSTD_compressBlock_fast_extDict_generic( U32* const hashTable = ms->hashTable; U32 const hlog = cParams->hashLog; /* support stepSize of 0 */ - U32 const stepSize = cParams->targetLength + !(cParams->targetLength); + U32 const stepSize = cParams->targetLength + !(cParams->targetLength) + 1; const BYTE* const base = ms->window.base; const BYTE* const dictBase = ms->window.dictBase; const BYTE* const istart = (const BYTE*)src; - const BYTE* ip = istart; const BYTE* anchor = istart; const U32 endIndex = (U32)((size_t)(istart - base) + srcSize); const U32 lowLimit = ZSTD_getLowestMatchIndex(ms, endIndex, cParams->windowLog); @@ -604,6 +603,29 @@ static size_t ZSTD_compressBlock_fast_extDict_generic( const BYTE* const iend = istart + srcSize; const BYTE* const ilimit = iend - 8; U32 offset_1=rep[0], offset_2=rep[1]; + U32 offsetSaved = 0; + + const BYTE* ip0 = istart; + const BYTE* ip1; + const BYTE* ip2; + const BYTE* ip3; + U32 current0; + + + size_t hash0; /* hash for ip0 */ + size_t hash1; /* hash for ip1 */ + U32 idx; /* match idx for ip0 */ + const BYTE* idxBase; /* base pointer for idx */ + U32 mval; /* src or dict value at match idx */ + + U32 offcode; + const BYTE* match0; + size_t mLength; + const BYTE* matchEnd = 0; /* initialize to avoid warning, assert != 0 later */ + + size_t step; + const BYTE* nextStep; + const size_t kStepIncr = (1 << (kSearchStrength - 1)); (void)hasStep; /* not currently specialized on whether it's accelerated */ @@ -613,75 +635,200 @@ static size_t ZSTD_compressBlock_fast_extDict_generic( if (prefixStartIndex == dictStartIndex) return ZSTD_compressBlock_fast(ms, seqStore, rep, src, srcSize); - /* Search Loop */ - while (ip < ilimit) { /* < instead of <=, because (ip+1) */ - const size_t h = ZSTD_hashPtr(ip, hlog, mls); - const U32 matchIndex = hashTable[h]; - const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base; - const BYTE* match = matchBase + matchIndex; - const U32 curr = (U32)(ip-base); - const U32 repIndex = curr + 1 - offset_1; + /* start each op */ +_start: /* Requires: ip0 */ + + step = stepSize; + nextStep = ip0 + kStepIncr; + + /* calculate positions, ip0 - anchor == 0, so we skip step calc */ + ip1 = ip0 + 1; + ip2 = ip0 + step; + ip3 = ip2 + 1; + + if (ip3 >= ilimit) { + goto _cleanup; + } + + hash0 = ZSTD_hashPtr(ip0, hlog, mls); + hash1 = ZSTD_hashPtr(ip1, hlog, mls); + + idx = hashTable[hash0]; + idxBase = idx < prefixStartIndex ? dictBase : base; + + do { + /* load repcode match for ip[2]*/ + const U32 current2 = (U32)(ip2 - base); + const U32 repIndex = current2 - offset_1; const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base; - const BYTE* const repMatch = repBase + repIndex; - hashTable[h] = curr; /* update hash table */ - DEBUGLOG(7, "offset_1 = %u , curr = %u", offset_1, curr); - - if ( ( ((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow */ - & (offset_1 <= curr+1 - dictStartIndex) ) /* note: we are searching at curr+1 */ - && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) { - const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend; - size_t const rLength = ZSTD_count_2segments(ip+1 +4, repMatch +4, iend, repMatchEnd, prefixStart) + 4; - ip++; - ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, REPCODE1_TO_OFFBASE, rLength); - ip += rLength; - anchor = ip; + U32 rval; + + /* load repcode match for ip[2] */ + assert(offset_1 > 0); + if ( ( ((U32)(prefixStartIndex - repIndex) >= 4) /* intentional underflow */ + & (offset_1 < current2 - dictStartIndex) ) ) { + rval = MEM_read32(repBase + repIndex); } else { - if ( (matchIndex < dictStartIndex) || - (MEM_read32(match) != MEM_read32(ip)) ) { - assert(stepSize >= 1); - ip += ((ip-anchor) >> kSearchStrength) + stepSize; - continue; - } - { const BYTE* const matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend; - const BYTE* const lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart; - U32 const offset = curr - matchIndex; - size_t mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, prefixStart) + 4; - while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ - offset_2 = offset_1; offset_1 = offset; /* update offset history */ - ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength); - ip += mLength; - anchor = ip; - } } - - if (ip <= ilimit) { - /* Fill Table */ - hashTable[ZSTD_hashPtr(base+curr+2, hlog, mls)] = curr+2; - hashTable[ZSTD_hashPtr(ip-2, hlog, mls)] = (U32)(ip-2-base); - /* check immediate repcode */ - while (ip <= ilimit) { - U32 const current2 = (U32)(ip-base); - U32 const repIndex2 = current2 - offset_2; - const BYTE* const repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2; - if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (offset_2 <= curr - dictStartIndex)) /* intentional overflow */ - && (MEM_read32(repMatch2) == MEM_read32(ip)) ) { - const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend; - size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4; - { U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; } /* swap offset_2 <=> offset_1 */ - ZSTD_storeSeq(seqStore, 0 /*litlen*/, anchor, iend, REPCODE1_TO_OFFBASE, repLength2); - hashTable[ZSTD_hashPtr(ip, hlog, mls)] = current2; - ip += repLength2; - anchor = ip; - continue; - } - break; - } } } + rval = MEM_read32(ip2) ^ 1; /* guaranteed to not match. */ + } + + /* write back hash table entry */ + current0 = (U32)(ip0 - base); + hashTable[hash0] = current0; + + /* check repcode at ip[2] */ + if (MEM_read32(ip2) == rval) { + ip0 = ip2; + match0 = repBase + repIndex; + matchEnd = repIndex < prefixStartIndex ? dictEnd : iend; + assert((match0 != prefixStart) & (match0 != dictStart)); + mLength = ip0[-1] == match0[-1]; + ip0 -= mLength; + match0 -= mLength; + offcode = REPCODE1_TO_OFFBASE; + mLength += 4; + goto _match; + } + + /* load match for ip[0] */ + if (idx >= dictStartIndex) { + mval = MEM_read32(idxBase + idx); + } else { + mval = MEM_read32(ip0) ^ 1; /* guaranteed to not match. */ + } + + /* check match at ip[0] */ + if (MEM_read32(ip0) == mval) { + /* found a match! */ + goto _offset; + } + + /* lookup ip[1] */ + idx = hashTable[hash1]; + idxBase = idx < prefixStartIndex ? dictBase : base; + + /* hash ip[2] */ + hash0 = hash1; + hash1 = ZSTD_hashPtr(ip2, hlog, mls); + + /* advance to next positions */ + ip0 = ip1; + ip1 = ip2; + ip2 = ip3; + + /* write back hash table entry */ + current0 = (U32)(ip0 - base); + hashTable[hash0] = current0; + + /* load match for ip[0] */ + if (idx >= dictStartIndex) { + mval = MEM_read32(idxBase + idx); + } else { + mval = MEM_read32(ip0) ^ 1; /* guaranteed to not match. */ + } + + /* check match at ip[0] */ + if (MEM_read32(ip0) == mval) { + /* found a match! */ + goto _offset; + } + + /* lookup ip[1] */ + idx = hashTable[hash1]; + idxBase = idx < prefixStartIndex ? dictBase : base; + + /* hash ip[2] */ + hash0 = hash1; + hash1 = ZSTD_hashPtr(ip2, hlog, mls); + + /* advance to next positions */ + ip0 = ip1; + ip1 = ip2; + ip2 = ip0 + step; + ip3 = ip1 + step; + + /* calculate step */ + if (ip2 >= nextStep) { + step++; + PREFETCH_L1(ip1 + 64); + PREFETCH_L1(ip1 + 128); + nextStep += kStepIncr; + } + } while (ip3 < ilimit); + +_cleanup: + /* Note that there are probably still a couple positions we could search. + * However, it seems to be a meaningful performance hit to try to search + * them. So let's not. */ /* save reps for next block */ - rep[0] = offset_1; - rep[1] = offset_2; + rep[0] = offset_1 ? offset_1 : offsetSaved; + rep[1] = offset_2 ? offset_2 : offsetSaved; /* Return the last literals size */ return (size_t)(iend - anchor); + +_offset: /* Requires: ip0, idx */ + + /* Compute the offset code. */ + { U32 const offset = current0 - idx; + const BYTE* const lowMatchPtr = idx < prefixStartIndex ? dictStart : prefixStart; + matchEnd = idx < prefixStartIndex ? dictEnd : iend; + match0 = idxBase + idx; + offset_2 = offset_1; + offset_1 = offset; + offcode = OFFSET_TO_OFFBASE(offset); + mLength = 4; + + /* Count the backwards match length. */ + while (((ip0>anchor) & (match0>lowMatchPtr)) && (ip0[-1] == match0[-1])) { + ip0--; + match0--; + mLength++; + } } + +_match: /* Requires: ip0, match0, offcode */ + + /* Count the forward length. */ + assert(matchEnd != 0); + mLength += ZSTD_count_2segments(ip0 + mLength, match0 + mLength, iend, matchEnd, prefixStart); + + ZSTD_storeSeq(seqStore, (size_t)(ip0 - anchor), anchor, iend, offcode, mLength); + + ip0 += mLength; + anchor = ip0; + + /* write next hash table entry */ + if (ip1 < ip0) { + hashTable[hash1] = (U32)(ip1 - base); + } + + /* Fill table and check for immediate repcode. */ + if (ip0 <= ilimit) { + /* Fill Table */ + assert(base+current0+2 > istart); /* check base overflow */ + hashTable[ZSTD_hashPtr(base+current0+2, hlog, mls)] = current0+2; /* here because current+2 could be > iend-8 */ + hashTable[ZSTD_hashPtr(ip0-2, hlog, mls)] = (U32)(ip0-2-base); + + assert(offset_2 > 0); + while (ip0 <= ilimit) { + U32 const repIndex2 = (U32)(ip0-base) - offset_2; + const BYTE* const repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2; + if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (offset_2 <= (U32)(ip0-base) - dictStartIndex)) /* intentional overflow */ + && (MEM_read32(repMatch2) == MEM_read32(ip0)) ) { + const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend; + size_t const repLength2 = ZSTD_count_2segments(ip0+4, repMatch2+4, iend, repEnd2, prefixStart) + 4; + { U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; } /* swap offset_2 <=> offset_1 */ + ZSTD_storeSeq(seqStore, 0 /*litlen*/, anchor, iend, REPCODE1_TO_OFFBASE, repLength2); + hashTable[ZSTD_hashPtr(ip0, hlog, mls)] = (U32)(ip0-base); + ip0 += repLength2; + anchor = ip0; + continue; + } + break; + } } + + goto _start; } ZSTD_GEN_FAST_FN(extDict, 4, 0)