diff options
Diffstat (limited to 'vendor/github.com/DataDog/zstd/zstd_fast.c')
| -rw-r--r-- | vendor/github.com/DataDog/zstd/zstd_fast.c | 470 |
1 files changed, 470 insertions, 0 deletions
diff --git a/vendor/github.com/DataDog/zstd/zstd_fast.c b/vendor/github.com/DataDog/zstd/zstd_fast.c new file mode 100644 index 000000000..ed997b441 --- /dev/null +++ b/vendor/github.com/DataDog/zstd/zstd_fast.c @@ -0,0 +1,470 @@ +/* + * 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). + * You may select, at your option, one of the above-listed licenses. + */ + +#include "zstd_compress_internal.h" +#include "zstd_fast.h" + + +void ZSTD_fillHashTable(ZSTD_matchState_t* ms, + void const* end, ZSTD_dictTableLoadMethod_e dtlm) +{ + const ZSTD_compressionParameters* const cParams = &ms->cParams; + U32* const hashTable = ms->hashTable; + U32 const hBits = cParams->hashLog; + 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; + + /* 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 current = (U32)(ip - base); + size_t const hash0 = ZSTD_hashPtr(ip, hBits, mls); + hashTable[hash0] = current; + 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 hash = ZSTD_hashPtr(ip + p, hBits, mls); + if (hashTable[hash] == 0) { /* not yet filled */ + hashTable[hash] = current + p; + } } } } +} + +FORCE_INLINE_TEMPLATE +size_t ZSTD_compressBlock_fast_generic( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize, + U32 const mls) +{ + const ZSTD_compressionParameters* const cParams = &ms->cParams; + U32* const hashTable = ms->hashTable; + U32 const hlog = cParams->hashLog; + /* support stepSize of 0 */ + size_t const stepSize = cParams->targetLength + !(cParams->targetLength) + 1; + const BYTE* const base = ms->window.base; + const BYTE* const istart = (const BYTE*)src; + /* We check ip0 (ip + 0) and ip1 (ip + 1) each loop */ + const BYTE* ip0 = istart; + const BYTE* ip1; + const BYTE* anchor = istart; + const U32 prefixStartIndex = ms->window.dictLimit; + const BYTE* const prefixStart = base + prefixStartIndex; + const BYTE* const iend = istart + srcSize; + const BYTE* const ilimit = iend - HASH_READ_SIZE; + U32 offset_1=rep[0], offset_2=rep[1]; + U32 offsetSaved = 0; + + /* init */ + ip0 += (ip0 == prefixStart); + ip1 = ip0 + 1; + { + U32 const maxRep = (U32)(ip0 - prefixStart); + if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0; + if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0; + } + + /* Main Search Loop */ + while (ip1 < ilimit) { /* < instead of <=, because check at ip0+2 */ + size_t mLength; + BYTE const* ip2 = ip0 + 2; + size_t const h0 = ZSTD_hashPtr(ip0, hlog, mls); + U32 const val0 = MEM_read32(ip0); + size_t const h1 = ZSTD_hashPtr(ip1, hlog, mls); + U32 const val1 = MEM_read32(ip1); + U32 const current0 = (U32)(ip0-base); + U32 const current1 = (U32)(ip1-base); + U32 const matchIndex0 = hashTable[h0]; + U32 const matchIndex1 = hashTable[h1]; + BYTE const* repMatch = ip2-offset_1; + const BYTE* match0 = base + matchIndex0; + const BYTE* match1 = base + matchIndex1; + U32 offcode; + hashTable[h0] = current0; /* update hash table */ + hashTable[h1] = current1; /* update hash table */ + + assert(ip0 + 1 == ip1); + + if ((offset_1 > 0) & (MEM_read32(repMatch) == MEM_read32(ip2))) { + mLength = ip2[-1] == repMatch[-1] ? 1 : 0; + ip0 = ip2 - mLength; + match0 = repMatch - mLength; + offcode = 0; + goto _match; + } + if ((matchIndex0 > prefixStartIndex) && MEM_read32(match0) == val0) { + /* found a regular match */ + goto _offset; + } + if ((matchIndex1 > prefixStartIndex) && MEM_read32(match1) == val1) { + /* found a regular match after one literal */ + ip0 = ip1; + match0 = match1; + goto _offset; + } + { + size_t const step = ((ip0-anchor) >> (kSearchStrength - 1)) + stepSize; + assert(step >= 2); + ip0 += step; + ip1 += step; + continue; + } +_offset: /* Requires: ip0, match0 */ + /* Compute the offset code */ + offset_2 = offset_1; + offset_1 = (U32)(ip0-match0); + offcode = offset_1 + ZSTD_REP_MOVE; + mLength = 0; + /* Count the backwards match length */ + while (((ip0>anchor) & (match0>prefixStart)) + && (ip0[-1] == match0[-1])) { ip0--; match0--; mLength++; } /* catch up */ + +_match: /* Requires: ip0, match0, offcode */ + /* Count the forward length */ + mLength += ZSTD_count(ip0+mLength+4, match0+mLength+4, iend) + 4; + ZSTD_storeSeq(seqStore, ip0-anchor, anchor, offcode, mLength-MINMATCH); + /* match found */ + ip0 += mLength; + anchor = ip0; + ip1 = ip0 + 1; + + 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); + + while ( (ip0 <= ilimit) + && ( (offset_2>0) + & (MEM_read32(ip0) == MEM_read32(ip0 - offset_2)) )) { + /* store sequence */ + size_t const rLength = ZSTD_count(ip0+4, ip0+4-offset_2, iend) + 4; + U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; /* swap offset_2 <=> offset_1 */ + hashTable[ZSTD_hashPtr(ip0, hlog, mls)] = (U32)(ip0-base); + ip0 += rLength; + ip1 = ip0 + 1; + ZSTD_storeSeq(seqStore, 0, anchor, 0, rLength-MINMATCH); + anchor = ip0; + continue; /* faster when present (confirmed on gcc-8) ... (?) */ + } + } + } + + /* save reps for next block */ + rep[0] = offset_1 ? offset_1 : offsetSaved; + rep[1] = offset_2 ? offset_2 : offsetSaved; + + /* Return the last literals size */ + return iend - anchor; +} + + +size_t ZSTD_compressBlock_fast( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize) +{ + ZSTD_compressionParameters const* cParams = &ms->cParams; + U32 const mls = cParams->minMatch; + assert(ms->dictMatchState == NULL); + switch(mls) + { + default: /* includes case 3 */ + case 4 : + return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 4); + case 5 : + return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 5); + case 6 : + return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 6); + case 7 : + return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 7); + } +} + +FORCE_INLINE_TEMPLATE +size_t ZSTD_compressBlock_fast_dictMatchState_generic( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize, U32 const mls) +{ + const ZSTD_compressionParameters* const cParams = &ms->cParams; + U32* const hashTable = ms->hashTable; + U32 const hlog = cParams->hashLog; + /* support stepSize of 0 */ + U32 const stepSize = cParams->targetLength + !(cParams->targetLength); + const BYTE* const base = ms->window.base; + const BYTE* const istart = (const BYTE*)src; + const BYTE* ip = istart; + const BYTE* anchor = istart; + const U32 prefixStartIndex = ms->window.dictLimit; + const BYTE* const prefixStart = base + prefixStartIndex; + const BYTE* const iend = istart + srcSize; + const BYTE* const ilimit = iend - HASH_READ_SIZE; + U32 offset_1=rep[0], offset_2=rep[1]; + U32 offsetSaved = 0; + + const ZSTD_matchState_t* const dms = ms->dictMatchState; + const ZSTD_compressionParameters* const dictCParams = &dms->cParams ; + const U32* const dictHashTable = dms->hashTable; + const U32 dictStartIndex = dms->window.dictLimit; + const BYTE* const dictBase = dms->window.base; + const BYTE* const dictStart = dictBase + dictStartIndex; + const BYTE* const dictEnd = dms->window.nextSrc; + const U32 dictIndexDelta = prefixStartIndex - (U32)(dictEnd - dictBase); + const U32 dictAndPrefixLength = (U32)(ip - prefixStart + dictEnd - dictStart); + const U32 dictHLog = dictCParams->hashLog; + + /* otherwise, we would get index underflow when translating a dict index + * into a local index */ + assert(prefixStartIndex >= (U32)(dictEnd - dictBase)); + + /* init */ + ip += (dictAndPrefixLength == 0); + /* dictMatchState repCode checks don't currently handle repCode == 0 + * disabling. */ + assert(offset_1 <= dictAndPrefixLength); + assert(offset_2 <= dictAndPrefixLength); + + /* Main Search Loop */ + while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */ + size_t mLength; + size_t const h = ZSTD_hashPtr(ip, hlog, mls); + U32 const current = (U32)(ip-base); + U32 const matchIndex = hashTable[h]; + const BYTE* match = base + matchIndex; + const U32 repIndex = current + 1 - offset_1; + const BYTE* repMatch = (repIndex < prefixStartIndex) ? + dictBase + (repIndex - dictIndexDelta) : + base + repIndex; + hashTable[h] = current; /* update hash table */ + + if ( ((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex isn't overlapping dict + prefix */ + && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) { + const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend; + mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4; + ip++; + ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH); + } else if ( (matchIndex <= prefixStartIndex) ) { + size_t const dictHash = ZSTD_hashPtr(ip, dictHLog, mls); + U32 const dictMatchIndex = dictHashTable[dictHash]; + const BYTE* dictMatch = dictBase + dictMatchIndex; + if (dictMatchIndex <= dictStartIndex || + MEM_read32(dictMatch) != MEM_read32(ip)) { + assert(stepSize >= 1); + ip += ((ip-anchor) >> kSearchStrength) + stepSize; + continue; + } else { + /* found a dict match */ + U32 const offset = (U32)(current-dictMatchIndex-dictIndexDelta); + mLength = ZSTD_count_2segments(ip+4, dictMatch+4, iend, dictEnd, prefixStart) + 4; + while (((ip>anchor) & (dictMatch>dictStart)) + && (ip[-1] == dictMatch[-1])) { + ip--; dictMatch--; mLength++; + } /* catch up */ + offset_2 = offset_1; + offset_1 = offset; + ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); + } + } else if (MEM_read32(match) != MEM_read32(ip)) { + /* it's not a match, and we're not going to check the dictionary */ + assert(stepSize >= 1); + ip += ((ip-anchor) >> kSearchStrength) + stepSize; + continue; + } else { + /* found a regular match */ + U32 const offset = (U32)(ip-match); + mLength = ZSTD_count(ip+4, match+4, iend) + 4; + while (((ip>anchor) & (match>prefixStart)) + && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ + offset_2 = offset_1; + offset_1 = offset; + ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); + } + + /* match found */ + ip += mLength; + anchor = ip; + + if (ip <= ilimit) { + /* Fill Table */ + assert(base+current+2 > istart); /* check base overflow */ + hashTable[ZSTD_hashPtr(base+current+2, hlog, mls)] = current+2; /* here because current+2 could be > iend-8 */ + 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* repMatch2 = repIndex2 < prefixStartIndex ? + dictBase - dictIndexDelta + repIndex2 : + base + repIndex2; + if ( ((U32)((prefixStartIndex-1) - (U32)repIndex2) >= 3 /* 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 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */ + ZSTD_storeSeq(seqStore, 0, anchor, 0, repLength2-MINMATCH); + hashTable[ZSTD_hashPtr(ip, hlog, mls)] = current2; + ip += repLength2; + anchor = ip; + continue; + } + break; + } + } + } + + /* save reps for next block */ + rep[0] = offset_1 ? offset_1 : offsetSaved; + rep[1] = offset_2 ? offset_2 : offsetSaved; + + /* Return the last literals size */ + return iend - anchor; +} + +size_t ZSTD_compressBlock_fast_dictMatchState( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize) +{ + ZSTD_compressionParameters const* cParams = &ms->cParams; + U32 const mls = cParams->minMatch; + assert(ms->dictMatchState != NULL); + switch(mls) + { + default: /* includes case 3 */ + case 4 : + return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 4); + case 5 : + return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 5); + case 6 : + return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 6); + case 7 : + return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 7); + } +} + + +static size_t ZSTD_compressBlock_fast_extDict_generic( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize, U32 const mls) +{ + const ZSTD_compressionParameters* const cParams = &ms->cParams; + U32* const hashTable = ms->hashTable; + U32 const hlog = cParams->hashLog; + /* support stepSize of 0 */ + U32 const stepSize = cParams->targetLength + !(cParams->targetLength); + 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 dictStartIndex = ms->window.lowLimit; + const BYTE* const dictStart = dictBase + dictStartIndex; + const U32 prefixStartIndex = ms->window.dictLimit; + const BYTE* const prefixStart = base + prefixStartIndex; + const BYTE* const dictEnd = dictBase + prefixStartIndex; + const BYTE* const iend = istart + srcSize; + const BYTE* const ilimit = iend - 8; + U32 offset_1=rep[0], offset_2=rep[1]; + + /* 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 current = (U32)(ip-base); + const U32 repIndex = current + 1 - offset_1; + const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base; + const BYTE* const repMatch = repBase + repIndex; + size_t mLength; + hashTable[h] = current; /* update hash table */ + assert(offset_1 <= current +1); /* check repIndex */ + + if ( (((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > dictStartIndex)) + && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) { + const BYTE* repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend; + mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4; + ip++; + ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH); + } else { + if ( (matchIndex < dictStartIndex) || + (MEM_read32(match) != MEM_read32(ip)) ) { + assert(stepSize >= 1); + ip += ((ip-anchor) >> kSearchStrength) + stepSize; + continue; + } + { const BYTE* matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend; + const BYTE* lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart; + U32 offset; + 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 = current - matchIndex; + offset_2 = offset_1; + offset_1 = offset; + ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); + } } + + /* found a match : store it */ + ip += mLength; + anchor = ip; + + if (ip <= ilimit) { + /* Fill Table */ + hashTable[ZSTD_hashPtr(base+current+2, hlog, mls)] = current+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* repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2; + if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (repIndex2 > 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 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */ + ZSTD_storeSeq(seqStore, 0, anchor, 0, repLength2-MINMATCH); + hashTable[ZSTD_hashPtr(ip, hlog, mls)] = current2; + ip += repLength2; + anchor = ip; + continue; + } + break; + } } } + + /* save reps for next block */ + rep[0] = offset_1; + rep[1] = offset_2; + + /* Return the last literals size */ + return iend - anchor; +} + + +size_t ZSTD_compressBlock_fast_extDict( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize) +{ + ZSTD_compressionParameters const* cParams = &ms->cParams; + U32 const mls = cParams->minMatch; + switch(mls) + { + default: /* includes case 3 */ + case 4 : + return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, 4); + case 5 : + return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, 5); + case 6 : + return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, 6); + case 7 : + return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, 7); + } +} |