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Diffstat (limited to 'lib/zstd/compress/zstd_fast.c')
| -rw-r--r-- | lib/zstd/compress/zstd_fast.c | 675 |
1 files changed, 675 insertions, 0 deletions
diff --git a/lib/zstd/compress/zstd_fast.c b/lib/zstd/compress/zstd_fast.c new file mode 100644 index 000000000000..a752e6beab52 --- /dev/null +++ b/lib/zstd/compress/zstd_fast.c @@ -0,0 +1,675 @@ +/* + * Copyright (c) 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" /* ZSTD_hashPtr, ZSTD_count, ZSTD_storeSeq */ +#include "zstd_fast.h" + + +void ZSTD_fillHashTable(ZSTD_matchState_t* ms, + const void* const end, + ZSTD_dictTableLoadMethod_e dtlm) +{ + const ZSTD_compressionParameters* const cParams = &ms->cParams; + U32* const hashTable = ms->hashTable; + U32 const hBits = cParams->hashLog; + 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 curr = (U32)(ip - base); + size_t const hash0 = ZSTD_hashPtr(ip, hBits, mls); + hashTable[hash0] = curr; + if (dtlm == ZSTD_dtlm_fast) continue; + /* Only load extra positions for ZSTD_dtlm_full */ + { U32 p; + for (p = 1; p < fastHashFillStep; ++p) { + size_t const hash = ZSTD_hashPtr(ip + p, hBits, mls); + if (hashTable[hash] == 0) { /* not yet filled */ + hashTable[hash] = curr + p; + } } } } +} + + +/* + * If you squint hard enough (and ignore repcodes), the search operation at any + * given position is broken into 4 stages: + * + * 1. Hash (map position to hash value via input read) + * 2. Lookup (map hash val to index via hashtable read) + * 3. Load (map index to value at that position via input read) + * 4. Compare + * + * Each of these steps involves a memory read at an address which is computed + * from the previous step. This means these steps must be sequenced and their + * latencies are cumulative. + * + * Rather than do 1->2->3->4 sequentially for a single position before moving + * onto the next, this implementation interleaves these operations across the + * next few positions: + * + * R = Repcode Read & Compare + * H = Hash + * T = Table Lookup + * M = Match Read & Compare + * + * Pos | Time --> + * ----+------------------- + * N | ... M + * N+1 | ... TM + * N+2 | R H T M + * N+3 | H TM + * N+4 | R H T M + * N+5 | H ... + * N+6 | R ... + * + * This is very much analogous to the pipelining of execution in a CPU. And just + * like a CPU, we have to dump the pipeline when we find a match (i.e., take a + * branch). + * + * When this happens, we throw away our current state, and do the following prep + * to re-enter the loop: + * + * Pos | Time --> + * ----+------------------- + * N | H T + * N+1 | H + * + * This is also the work we do at the beginning to enter the loop initially. + */ +FORCE_INLINE_TEMPLATE size_t +ZSTD_compressBlock_fast_noDict_generic( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize, + U32 const mls, U32 const hasStep) +{ + 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 = hasStep ? (cParams->targetLength + !(cParams->targetLength) + 1) : 2; + const BYTE* const base = ms->window.base; + const BYTE* const istart = (const BYTE*)src; + const U32 endIndex = (U32)((size_t)(istart - base) + srcSize); + const U32 prefixStartIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog); + const BYTE* const prefixStart = base + prefixStartIndex; + const BYTE* const iend = istart + srcSize; + const BYTE* const ilimit = iend - HASH_READ_SIZE; + + const BYTE* anchor = istart; + const BYTE* ip0 = istart; + const BYTE* ip1; + const BYTE* ip2; + const BYTE* ip3; + U32 current0; + + U32 rep_offset1 = rep[0]; + U32 rep_offset2 = rep[1]; + U32 offsetSaved = 0; + + size_t hash0; /* hash for ip0 */ + size_t hash1; /* hash for ip1 */ + U32 idx; /* match idx for ip0 */ + U32 mval; /* src value at match idx */ + + U32 offcode; + const BYTE* match0; + size_t mLength; + + /* ip0 and ip1 are always adjacent. The targetLength skipping and + * uncompressibility acceleration is applied to every other position, + * matching the behavior of #1562. step therefore represents the gap + * between pairs of positions, from ip0 to ip2 or ip1 to ip3. */ + size_t step; + const BYTE* nextStep; + const size_t kStepIncr = (1 << (kSearchStrength - 1)); + + DEBUGLOG(5, "ZSTD_compressBlock_fast_generic"); + ip0 += (ip0 == prefixStart); + { U32 const curr = (U32)(ip0 - base); + U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, cParams->windowLog); + U32 const maxRep = curr - windowLow; + if (rep_offset2 > maxRep) offsetSaved = rep_offset2, rep_offset2 = 0; + if (rep_offset1 > maxRep) offsetSaved = rep_offset1, rep_offset1 = 0; + } + + /* 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]; + + do { + /* load repcode match for ip[2]*/ + const U32 rval = MEM_read32(ip2 - rep_offset1); + + /* write back hash table entry */ + current0 = (U32)(ip0 - base); + hashTable[hash0] = current0; + + /* check repcode at ip[2] */ + if ((MEM_read32(ip2) == rval) & (rep_offset1 > 0)) { + ip0 = ip2; + match0 = ip0 - rep_offset1; + mLength = ip0[-1] == match0[-1]; + ip0 -= mLength; + match0 -= mLength; + offcode = STORE_REPCODE_1; + mLength += 4; + goto _match; + } + + /* load match for ip[0] */ + if (idx >= prefixStartIndex) { + mval = MEM_read32(base + 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]; + + /* 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 >= prefixStartIndex) { + mval = MEM_read32(base + 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]; + + /* 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] = rep_offset1 ? rep_offset1 : offsetSaved; + rep[1] = rep_offset2 ? rep_offset2 : offsetSaved; + + /* Return the last literals size */ + return (size_t)(iend - anchor); + +_offset: /* Requires: ip0, idx */ + + /* Compute the offset code. */ + match0 = base + idx; + rep_offset2 = rep_offset1; + rep_offset1 = (U32)(ip0-match0); + offcode = STORE_OFFSET(rep_offset1); + mLength = 4; + + /* Count the backwards match length. */ + while (((ip0>anchor) & (match0>prefixStart)) && (ip0[-1] == match0[-1])) { + ip0--; + match0--; + mLength++; + } + +_match: /* Requires: ip0, match0, offcode */ + + /* Count the forward length. */ + mLength += ZSTD_count(ip0 + mLength, match0 + mLength, iend); + + 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); + + if (rep_offset2 > 0) { /* rep_offset2==0 means rep_offset2 is invalidated */ + while ( (ip0 <= ilimit) && (MEM_read32(ip0) == MEM_read32(ip0 - rep_offset2)) ) { + /* store sequence */ + size_t const rLength = ZSTD_count(ip0+4, ip0+4-rep_offset2, iend) + 4; + { U32 const tmpOff = rep_offset2; rep_offset2 = rep_offset1; rep_offset1 = tmpOff; } /* swap rep_offset2 <=> rep_offset1 */ + hashTable[ZSTD_hashPtr(ip0, hlog, mls)] = (U32)(ip0-base); + ip0 += rLength; + ZSTD_storeSeq(seqStore, 0 /*litLen*/, anchor, iend, STORE_REPCODE_1, rLength); + anchor = ip0; + continue; /* faster when present (confirmed on gcc-8) ... (?) */ + } } } + + goto _start; +} + +#define ZSTD_GEN_FAST_FN(dictMode, mls, step) \ + static size_t ZSTD_compressBlock_fast_##dictMode##_##mls##_##step( \ + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], \ + void const* src, size_t srcSize) \ + { \ + return ZSTD_compressBlock_fast_##dictMode##_generic(ms, seqStore, rep, src, srcSize, mls, step); \ + } + +ZSTD_GEN_FAST_FN(noDict, 4, 1) +ZSTD_GEN_FAST_FN(noDict, 5, 1) +ZSTD_GEN_FAST_FN(noDict, 6, 1) +ZSTD_GEN_FAST_FN(noDict, 7, 1) + +ZSTD_GEN_FAST_FN(noDict, 4, 0) +ZSTD_GEN_FAST_FN(noDict, 5, 0) +ZSTD_GEN_FAST_FN(noDict, 6, 0) +ZSTD_GEN_FAST_FN(noDict, 7, 0) + +size_t ZSTD_compressBlock_fast( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize) +{ + U32 const mls = ms->cParams.minMatch; + assert(ms->dictMatchState == NULL); + if (ms->cParams.targetLength > 1) { + switch(mls) + { + default: /* includes case 3 */ + case 4 : + return ZSTD_compressBlock_fast_noDict_4_1(ms, seqStore, rep, src, srcSize); + case 5 : + return ZSTD_compressBlock_fast_noDict_5_1(ms, seqStore, rep, src, srcSize); + case 6 : + return ZSTD_compressBlock_fast_noDict_6_1(ms, seqStore, rep, src, srcSize); + case 7 : + return ZSTD_compressBlock_fast_noDict_7_1(ms, seqStore, rep, src, srcSize); + } + } else { + switch(mls) + { + default: /* includes case 3 */ + case 4 : + return ZSTD_compressBlock_fast_noDict_4_0(ms, seqStore, rep, src, srcSize); + case 5 : + return ZSTD_compressBlock_fast_noDict_5_0(ms, seqStore, rep, src, srcSize); + case 6 : + return ZSTD_compressBlock_fast_noDict_6_0(ms, seqStore, rep, src, srcSize); + case 7 : + return ZSTD_compressBlock_fast_noDict_7_0(ms, seqStore, rep, src, srcSize); + } + + } +} + +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, U32 const hasStep) +{ + 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; + + /* if a dictionary is still attached, it necessarily means that + * it is within window size. So we just check it. */ + const U32 maxDistance = 1U << cParams->windowLog; + const U32 endIndex = (U32)((size_t)(ip - base) + srcSize); + assert(endIndex - prefixStartIndex <= maxDistance); + (void)maxDistance; (void)endIndex; /* these variables are not used when assert() is disabled */ + + (void)hasStep; /* not currently specialized on whether it's accelerated */ + + /* ensure there will be no underflow + * when translating a dict index into a local index */ + assert(prefixStartIndex >= (U32)(dictEnd - dictBase)); + + /* init */ + DEBUGLOG(5, "ZSTD_compressBlock_fast_dictMatchState_generic"); + 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 curr = (U32)(ip-base); + U32 const matchIndex = hashTable[h]; + const BYTE* match = base + matchIndex; + const U32 repIndex = curr + 1 - offset_1; + const BYTE* repMatch = (repIndex < prefixStartIndex) ? + dictBase + (repIndex - dictIndexDelta) : + base + repIndex; + hashTable[h] = curr; /* 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, (size_t)(ip-anchor), anchor, iend, STORE_REPCODE_1, mLength); + } 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)(curr-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, (size_t)(ip-anchor), anchor, iend, STORE_OFFSET(offset), mLength); + } + } 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, (size_t)(ip-anchor), anchor, iend, STORE_OFFSET(offset), mLength); + } + + /* match found */ + ip += mLength; + anchor = ip; + + if (ip <= ilimit) { + /* Fill Table */ + assert(base+curr+2 > istart); /* check base overflow */ + hashTable[ZSTD_hashPtr(base+curr+2, hlog, mls)] = curr+2; /* here because curr+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, iend, STORE_REPCODE_1, repLength2); + 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 (size_t)(iend - anchor); +} + + +ZSTD_GEN_FAST_FN(dictMatchState, 4, 0) +ZSTD_GEN_FAST_FN(dictMatchState, 5, 0) +ZSTD_GEN_FAST_FN(dictMatchState, 6, 0) +ZSTD_GEN_FAST_FN(dictMatchState, 7, 0) + +size_t ZSTD_compressBlock_fast_dictMatchState( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize) +{ + U32 const mls = ms->cParams.minMatch; + assert(ms->dictMatchState != NULL); + switch(mls) + { + default: /* includes case 3 */ + case 4 : + return ZSTD_compressBlock_fast_dictMatchState_4_0(ms, seqStore, rep, src, srcSize); + case 5 : + return ZSTD_compressBlock_fast_dictMatchState_5_0(ms, seqStore, rep, src, srcSize); + case 6 : + return ZSTD_compressBlock_fast_dictMatchState_6_0(ms, seqStore, rep, src, srcSize); + case 7 : + return ZSTD_compressBlock_fast_dictMatchState_7_0(ms, seqStore, rep, src, srcSize); + } +} + + +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, U32 const hasStep) +{ + 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 endIndex = (U32)((size_t)(istart - base) + srcSize); + const U32 lowLimit = ZSTD_getLowestMatchIndex(ms, endIndex, cParams->windowLog); + const U32 dictStartIndex = lowLimit; + const BYTE* const dictStart = dictBase + dictStartIndex; + const U32 dictLimit = ms->window.dictLimit; + const U32 prefixStartIndex = dictLimit < lowLimit ? lowLimit : 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]; + + (void)hasStep; /* not currently specialized on whether it's accelerated */ + + DEBUGLOG(5, "ZSTD_compressBlock_fast_extDict_generic (offset_1=%u)", offset_1); + + /* switch to "regular" variant if extDict is invalidated due to maxDistance */ + 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; + 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, STORE_REPCODE_1, rLength); + ip += rLength; + anchor = ip; + } 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, STORE_OFFSET(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, STORE_REPCODE_1, repLength2); + 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 (size_t)(iend - anchor); +} + +ZSTD_GEN_FAST_FN(extDict, 4, 0) +ZSTD_GEN_FAST_FN(extDict, 5, 0) +ZSTD_GEN_FAST_FN(extDict, 6, 0) +ZSTD_GEN_FAST_FN(extDict, 7, 0) + +size_t ZSTD_compressBlock_fast_extDict( + ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], + void const* src, size_t srcSize) +{ + U32 const mls = ms->cParams.minMatch; + switch(mls) + { + default: /* includes case 3 */ + case 4 : + return ZSTD_compressBlock_fast_extDict_4_0(ms, seqStore, rep, src, srcSize); + case 5 : + return ZSTD_compressBlock_fast_extDict_5_0(ms, seqStore, rep, src, srcSize); + case 6 : + return ZSTD_compressBlock_fast_extDict_6_0(ms, seqStore, rep, src, srcSize); + case 7 : + return ZSTD_compressBlock_fast_extDict_7_0(ms, seqStore, rep, src, srcSize); + } +} |