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/*
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* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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*/
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#include "zstd_compress_internal.h" /* ZSTD_hashPtr, ZSTD_count, ZSTD_storeSeq */
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#include "zstd_fast.h"
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void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
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const void* const end,
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ZSTD_dictTableLoadMethod_e dtlm)
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{
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const ZSTD_compressionParameters* const cParams = &ms->cParams;
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U32* const hashTable = ms->hashTable;
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U32 const hBits = cParams->hashLog;
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U32 const mls = cParams->minMatch;
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const BYTE* const base = ms->window.base;
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const BYTE* ip = base + ms->nextToUpdate;
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const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
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const U32 fastHashFillStep = 3;
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/* Always insert every fastHashFillStep position into the hash table.
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* Insert the other positions if their hash entry is empty.
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*/
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for ( ; ip + fastHashFillStep < iend + 2; ip += fastHashFillStep) {
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U32 const current = (U32)(ip - base);
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size_t const hash0 = ZSTD_hashPtr(ip, hBits, mls);
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hashTable[hash0] = current;
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if (dtlm == ZSTD_dtlm_fast) continue;
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/* Only load extra positions for ZSTD_dtlm_full */
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{ U32 p;
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for (p = 1; p < fastHashFillStep; ++p) {
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size_t const hash = ZSTD_hashPtr(ip + p, hBits, mls);
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if (hashTable[hash] == 0) { /* not yet filled */
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hashTable[hash] = current + p;
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} } } }
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}
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FORCE_INLINE_TEMPLATE size_t
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ZSTD_compressBlock_fast_generic(
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ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
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void const* src, size_t srcSize,
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U32 const mls)
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{
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const ZSTD_compressionParameters* const cParams = &ms->cParams;
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U32* const hashTable = ms->hashTable;
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U32 const hlog = cParams->hashLog;
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/* support stepSize of 0 */
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size_t const stepSize = cParams->targetLength + !(cParams->targetLength) + 1;
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const BYTE* const base = ms->window.base;
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const BYTE* const istart = (const BYTE*)src;
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/* We check ip0 (ip + 0) and ip1 (ip + 1) each loop */
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const BYTE* ip0 = istart;
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const BYTE* ip1;
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const BYTE* anchor = istart;
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const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
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const U32 maxDistance = 1U << cParams->windowLog;
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const U32 validStartIndex = ms->window.dictLimit;
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const U32 prefixStartIndex = (endIndex - validStartIndex > maxDistance) ? endIndex - maxDistance : validStartIndex;
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const BYTE* const prefixStart = base + prefixStartIndex;
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const BYTE* const iend = istart + srcSize;
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const BYTE* const ilimit = iend - HASH_READ_SIZE;
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U32 offset_1=rep[0], offset_2=rep[1];
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U32 offsetSaved = 0;
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/* init */
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DEBUGLOG(5, "ZSTD_compressBlock_fast_generic");
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ip0 += (ip0 == prefixStart);
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ip1 = ip0 + 1;
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{ U32 const maxRep = (U32)(ip0 - prefixStart);
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if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
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if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
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}
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/* Main Search Loop */
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while (ip1 < ilimit) { /* < instead of <=, because check at ip0+2 */
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size_t mLength;
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BYTE const* ip2 = ip0 + 2;
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size_t const h0 = ZSTD_hashPtr(ip0, hlog, mls);
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U32 const val0 = MEM_read32(ip0);
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size_t const h1 = ZSTD_hashPtr(ip1, hlog, mls);
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U32 const val1 = MEM_read32(ip1);
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U32 const current0 = (U32)(ip0-base);
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U32 const current1 = (U32)(ip1-base);
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U32 const matchIndex0 = hashTable[h0];
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U32 const matchIndex1 = hashTable[h1];
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BYTE const* repMatch = ip2-offset_1;
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const BYTE* match0 = base + matchIndex0;
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const BYTE* match1 = base + matchIndex1;
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U32 offcode;
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hashTable[h0] = current0; /* update hash table */
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hashTable[h1] = current1; /* update hash table */
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assert(ip0 + 1 == ip1);
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if ((offset_1 > 0) & (MEM_read32(repMatch) == MEM_read32(ip2))) {
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mLength = ip2[-1] == repMatch[-1] ? 1 : 0;
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ip0 = ip2 - mLength;
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match0 = repMatch - mLength;
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offcode = 0;
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goto _match;
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}
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if ((matchIndex0 > prefixStartIndex) && MEM_read32(match0) == val0) {
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/* found a regular match */
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goto _offset;
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}
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if ((matchIndex1 > prefixStartIndex) && MEM_read32(match1) == val1) {
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/* found a regular match after one literal */
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ip0 = ip1;
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match0 = match1;
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goto _offset;
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}
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{ size_t const step = ((size_t)(ip0-anchor) >> (kSearchStrength - 1)) + stepSize;
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assert(step >= 2);
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ip0 += step;
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ip1 += step;
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continue;
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}
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_offset: /* Requires: ip0, match0 */
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/* Compute the offset code */
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offset_2 = offset_1;
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offset_1 = (U32)(ip0-match0);
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offcode = offset_1 + ZSTD_REP_MOVE;
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mLength = 0;
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/* Count the backwards match length */
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while (((ip0>anchor) & (match0>prefixStart))
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&& (ip0[-1] == match0[-1])) { ip0--; match0--; mLength++; } /* catch up */
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_match: /* Requires: ip0, match0, offcode */
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/* Count the forward length */
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mLength += ZSTD_count(ip0+mLength+4, match0+mLength+4, iend) + 4;
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ZSTD_storeSeq(seqStore, (size_t)(ip0-anchor), anchor, iend, offcode, mLength-MINMATCH);
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/* match found */
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ip0 += mLength;
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anchor = ip0;
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ip1 = ip0 + 1;
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if (ip0 <= ilimit) {
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/* Fill Table */
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assert(base+current0+2 > istart); /* check base overflow */
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hashTable[ZSTD_hashPtr(base+current0+2, hlog, mls)] = current0+2; /* here because current+2 could be > iend-8 */
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hashTable[ZSTD_hashPtr(ip0-2, hlog, mls)] = (U32)(ip0-2-base);
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while ( ((ip0 <= ilimit) & (offset_2>0)) /* offset_2==0 means offset_2 is invalidated */
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&& (MEM_read32(ip0) == MEM_read32(ip0 - offset_2)) ) {
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/* store sequence */
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size_t const rLength = ZSTD_count(ip0+4, ip0+4-offset_2, iend) + 4;
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{ U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; } /* swap offset_2 <=> offset_1 */
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hashTable[ZSTD_hashPtr(ip0, hlog, mls)] = (U32)(ip0-base);
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ip0 += rLength;
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ip1 = ip0 + 1;
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ZSTD_storeSeq(seqStore, 0 /*litLen*/, anchor, iend, 0 /*offCode*/, rLength-MINMATCH);
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anchor = ip0;
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continue; /* faster when present (confirmed on gcc-8) ... (?) */
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}
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}
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}
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/* save reps for next block */
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rep[0] = offset_1 ? offset_1 : offsetSaved;
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rep[1] = offset_2 ? offset_2 : offsetSaved;
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/* Return the last literals size */
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return (size_t)(iend - anchor);
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}
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size_t ZSTD_compressBlock_fast(
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ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
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void const* src, size_t srcSize)
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{
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U32 const mls = ms->cParams.minMatch;
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assert(ms->dictMatchState == NULL);
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switch(mls)
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{
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default: /* includes case 3 */
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case 4 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 4);
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case 5 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 5);
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case 6 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 6);
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case 7 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 7);
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}
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}
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FORCE_INLINE_TEMPLATE
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size_t ZSTD_compressBlock_fast_dictMatchState_generic(
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ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
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void const* src, size_t srcSize, U32 const mls)
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{
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const ZSTD_compressionParameters* const cParams = &ms->cParams;
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U32* const hashTable = ms->hashTable;
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U32 const hlog = cParams->hashLog;
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/* support stepSize of 0 */
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U32 const stepSize = cParams->targetLength + !(cParams->targetLength);
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const BYTE* const base = ms->window.base;
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const BYTE* const istart = (const BYTE*)src;
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const BYTE* ip = istart;
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const BYTE* anchor = istart;
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const U32 prefixStartIndex = ms->window.dictLimit;
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const BYTE* const prefixStart = base + prefixStartIndex;
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const BYTE* const iend = istart + srcSize;
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const BYTE* const ilimit = iend - HASH_READ_SIZE;
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U32 offset_1=rep[0], offset_2=rep[1];
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U32 offsetSaved = 0;
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const ZSTD_matchState_t* const dms = ms->dictMatchState;
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const ZSTD_compressionParameters* const dictCParams = &dms->cParams ;
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const U32* const dictHashTable = dms->hashTable;
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const U32 dictStartIndex = dms->window.dictLimit;
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const BYTE* const dictBase = dms->window.base;
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const BYTE* const dictStart = dictBase + dictStartIndex;
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const BYTE* const dictEnd = dms->window.nextSrc;
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const U32 dictIndexDelta = prefixStartIndex - (U32)(dictEnd - dictBase);
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const U32 dictAndPrefixLength = (U32)(ip - prefixStart + dictEnd - dictStart);
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const U32 dictHLog = dictCParams->hashLog;
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/* if a dictionary is still attached, it necessarily means that
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* it is within window size. So we just check it. */
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const U32 maxDistance = 1U << cParams->windowLog;
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const U32 endIndex = (U32)((size_t)(ip - base) + srcSize);
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assert(endIndex - prefixStartIndex <= maxDistance);
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(void)maxDistance; (void)endIndex; /* these variables are not used when assert() is disabled */
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/* ensure there will be no no underflow
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* when translating a dict index into a local index */
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assert(prefixStartIndex >= (U32)(dictEnd - dictBase));
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/* init */
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DEBUGLOG(5, "ZSTD_compressBlock_fast_dictMatchState_generic");
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ip += (dictAndPrefixLength == 0);
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/* dictMatchState repCode checks don't currently handle repCode == 0
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* disabling. */
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assert(offset_1 <= dictAndPrefixLength);
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assert(offset_2 <= dictAndPrefixLength);
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/* Main Search Loop */
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while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
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size_t mLength;
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size_t const h = ZSTD_hashPtr(ip, hlog, mls);
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U32 const current = (U32)(ip-base);
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U32 const matchIndex = hashTable[h];
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const BYTE* match = base + matchIndex;
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const U32 repIndex = current + 1 - offset_1;
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const BYTE* repMatch = (repIndex < prefixStartIndex) ?
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dictBase + (repIndex - dictIndexDelta) :
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base + repIndex;
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hashTable[h] = current; /* update hash table */
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if ( ((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex isn't overlapping dict + prefix */
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&& (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
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const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
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mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4;
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ip++;
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ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
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} else if ( (matchIndex <= prefixStartIndex) ) {
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size_t const dictHash = ZSTD_hashPtr(ip, dictHLog, mls);
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U32 const dictMatchIndex = dictHashTable[dictHash];
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const BYTE* dictMatch = dictBase + dictMatchIndex;
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if (dictMatchIndex <= dictStartIndex ||
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MEM_read32(dictMatch) != MEM_read32(ip)) {
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assert(stepSize >= 1);
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ip += ((ip-anchor) >> kSearchStrength) + stepSize;
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continue;
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} else {
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/* found a dict match */
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U32 const offset = (U32)(current-dictMatchIndex-dictIndexDelta);
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mLength = ZSTD_count_2segments(ip+4, dictMatch+4, iend, dictEnd, prefixStart) + 4;
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while (((ip>anchor) & (dictMatch>dictStart))
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&& (ip[-1] == dictMatch[-1])) {
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ip--; dictMatch--; mLength++;
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} /* catch up */
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offset_2 = offset_1;
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offset_1 = offset;
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ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
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}
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} else if (MEM_read32(match) != MEM_read32(ip)) {
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/* it's not a match, and we're not going to check the dictionary */
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assert(stepSize >= 1);
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ip += ((ip-anchor) >> kSearchStrength) + stepSize;
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continue;
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} else {
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/* found a regular match */
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U32 const offset = (U32)(ip-match);
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mLength = ZSTD_count(ip+4, match+4, iend) + 4;
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while (((ip>anchor) & (match>prefixStart))
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&& (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
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offset_2 = offset_1;
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offset_1 = offset;
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ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
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}
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/* match found */
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ip += mLength;
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anchor = ip;
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if (ip <= ilimit) {
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/* Fill Table */
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assert(base+current+2 > istart); /* check base overflow */
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hashTable[ZSTD_hashPtr(base+current+2, hlog, mls)] = current+2; /* here because current+2 could be > iend-8 */
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hashTable[ZSTD_hashPtr(ip-2, hlog, mls)] = (U32)(ip-2-base);
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/* check immediate repcode */
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while (ip <= ilimit) {
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U32 const current2 = (U32)(ip-base);
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U32 const repIndex2 = current2 - offset_2;
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const BYTE* repMatch2 = repIndex2 < prefixStartIndex ?
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dictBase - dictIndexDelta + repIndex2 :
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base + repIndex2;
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if ( ((U32)((prefixStartIndex-1) - (U32)repIndex2) >= 3 /* intentional overflow */)
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&& (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
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const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
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size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
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U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
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ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, repLength2-MINMATCH);
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hashTable[ZSTD_hashPtr(ip, hlog, mls)] = current2;
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ip += repLength2;
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anchor = ip;
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continue;
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}
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break;
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}
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}
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}
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/* save reps for next block */
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rep[0] = offset_1 ? offset_1 : offsetSaved;
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rep[1] = offset_2 ? offset_2 : offsetSaved;
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/* Return the last literals size */
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return (size_t)(iend - anchor);
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}
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size_t ZSTD_compressBlock_fast_dictMatchState(
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ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
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void const* src, size_t srcSize)
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{
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U32 const mls = ms->cParams.minMatch;
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assert(ms->dictMatchState != NULL);
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switch(mls)
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{
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default: /* includes case 3 */
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case 4 :
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return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 4);
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case 5 :
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return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 5);
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case 6 :
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return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 6);
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|
case 7 :
|
|
|
return ZSTD_compressBlock_fast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 7);
|
|
|
}
|
|
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}
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|
|
|
|
|
|
|
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static size_t ZSTD_compressBlock_fast_extDict_generic(
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|
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
|
|
|
void const* src, size_t srcSize, U32 const mls)
|
|
|
{
|
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|
const ZSTD_compressionParameters* const cParams = &ms->cParams;
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|
U32* const hashTable = ms->hashTable;
|
|
|
U32 const hlog = cParams->hashLog;
|
|
|
/* support stepSize of 0 */
|
|
|
U32 const stepSize = cParams->targetLength + !(cParams->targetLength);
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const BYTE* const base = ms->window.base;
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|
const BYTE* const dictBase = ms->window.dictBase;
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|
const BYTE* const istart = (const BYTE*)src;
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const BYTE* ip = istart;
|
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|
const BYTE* anchor = istart;
|
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|
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;
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|
|
const BYTE* const dictEnd = dictBase + prefixStartIndex;
|
|
|
const BYTE* const iend = istart + srcSize;
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|
|
const BYTE* const ilimit = iend - 8;
|
|
|
U32 offset_1=rep[0], offset_2=rep[1];
|
|
|
|
|
|
DEBUGLOG(5, "ZSTD_compressBlock_fast_extDict_generic");
|
|
|
|
|
|
/* switch to "regular" variant if extDict is invalidated due to maxDistance */
|
|
|
if (prefixStartIndex == dictStartIndex)
|
|
|
return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, mls);
|
|
|
|
|
|
/* 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;
|
|
|
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* 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, 0, rLength-MINMATCH);
|
|
|
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 = current - 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 + ZSTD_REP_MOVE, mLength-MINMATCH);
|
|
|
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* const 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 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; } /* swap offset_2 <=> offset_1 */
|
|
|
ZSTD_storeSeq(seqStore, 0 /*litlen*/, anchor, iend, 0 /*offcode*/, 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 (size_t)(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)
|
|
|
{
|
|
|
U32 const mls = ms->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);
|
|
|
}
|
|
|
}
|
|
|
|
