385 lines
18 KiB
C
385 lines
18 KiB
C
/*
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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"
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#include "zstd_fast.h"
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void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
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ZSTD_compressionParameters const* cParams,
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void const* end, ZSTD_dictTableLoadMethod_e dtlm)
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{
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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->searchLength;
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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 - 1 <= iend; ip += fastHashFillStep) {
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U32 const current = (U32)(ip - base);
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U32 i;
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for (i = 0; i < fastHashFillStep; ++i) {
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size_t const hash = ZSTD_hashPtr(ip + i, hBits, mls);
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if (i == 0 || hashTable[hash] == 0)
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hashTable[hash] = current + i;
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/* Only load extra positions for ZSTD_dtlm_full */
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if (dtlm == ZSTD_dtlm_fast)
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break;
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}
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}
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}
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FORCE_INLINE_TEMPLATE
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size_t 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 hlog, U32 stepSize, U32 const mls,
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ZSTD_dictMode_e const dictMode)
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{
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U32* const hashTable = ms->hashTable;
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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 U32* const dictHashTable = dictMode == ZSTD_dictMatchState ?
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dms->hashTable : NULL;
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const U32 dictStartIndex = dictMode == ZSTD_dictMatchState ?
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dms->window.dictLimit : 0;
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const BYTE* const dictBase = dictMode == ZSTD_dictMatchState ?
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dms->window.base : NULL;
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const BYTE* const dictStart = dictMode == ZSTD_dictMatchState ?
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dictBase + dictStartIndex : NULL;
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const BYTE* const dictEnd = dictMode == ZSTD_dictMatchState ?
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dms->window.nextSrc : NULL;
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const U32 dictIndexDelta = dictMode == ZSTD_dictMatchState ?
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prefixStartIndex - (U32)(dictEnd - dictBase) :
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0;
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const U32 dictAndPrefixLength = (U32)(ip - prefixStart + dictEnd - dictStart);
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assert(dictMode == ZSTD_noDict || dictMode == ZSTD_dictMatchState);
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/* otherwise, we would get index underflow when translating a dict index
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* into a local index */
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assert(dictMode != ZSTD_dictMatchState
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|| prefixStartIndex >= (U32)(dictEnd - dictBase));
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/* init */
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stepSize += !stepSize; /* support stepSize of 0 */
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ip += (dictAndPrefixLength == 0);
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if (dictMode == ZSTD_noDict) {
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U32 const maxRep = (U32)(ip - 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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if (dictMode == ZSTD_dictMatchState) {
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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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}
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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 = (dictMode == ZSTD_dictMatchState
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&& 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 ( (dictMode == ZSTD_dictMatchState)
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&& ((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, ip-anchor, anchor, 0, mLength-MINMATCH);
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} else if ( dictMode == ZSTD_noDict
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&& ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
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mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
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ip++;
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ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH);
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} else if ( (matchIndex <= prefixStartIndex) ) {
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if (dictMode == ZSTD_dictMatchState) {
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U32 const dictMatchIndex = dictHashTable[h];
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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, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
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}
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} else {
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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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}
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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, ip-anchor, anchor, 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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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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if (dictMode == ZSTD_dictMatchState) {
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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, 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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if (dictMode == ZSTD_noDict) {
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while ( (ip <= ilimit)
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&& ( (offset_2>0)
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& (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
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/* store sequence */
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size_t const rLength = ZSTD_count(ip+4, ip+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(ip, hlog, mls)] = (U32)(ip-base);
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ZSTD_storeSeq(seqStore, 0, anchor, 0, rLength-MINMATCH);
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ip += rLength;
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anchor = ip;
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continue; /* faster when present ... (?) */
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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 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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ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize)
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{
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U32 const hlog = cParams->hashLog;
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U32 const mls = cParams->searchLength;
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U32 const stepSize = cParams->targetLength;
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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, hlog, stepSize, 4, ZSTD_noDict);
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case 5 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 5, ZSTD_noDict);
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case 6 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 6, ZSTD_noDict);
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case 7 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 7, ZSTD_noDict);
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}
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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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ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize)
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{
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U32 const hlog = cParams->hashLog;
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U32 const mls = cParams->searchLength;
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U32 const stepSize = cParams->targetLength;
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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, hlog, stepSize, 4, ZSTD_dictMatchState);
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case 5 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 5, ZSTD_dictMatchState);
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case 6 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 6, ZSTD_dictMatchState);
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case 7 :
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return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 7, ZSTD_dictMatchState);
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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],
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void const* src, size_t srcSize,
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U32 const hlog, U32 stepSize, U32 const mls)
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{
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U32* hashTable = ms->hashTable;
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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 dictStartIndex = ms->window.lowLimit;
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const BYTE* const dictStart = dictBase + dictStartIndex;
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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 dictEnd = dictBase + prefixStartIndex;
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const BYTE* const iend = istart + srcSize;
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const BYTE* const ilimit = iend - 8;
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U32 offset_1=rep[0], offset_2=rep[1];
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stepSize += !stepSize; /* support stepSize == 0 */
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/* Search Loop */
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while (ip < ilimit) { /* < instead of <=, because (ip+1) */
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const size_t h = ZSTD_hashPtr(ip, hlog, mls);
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const U32 matchIndex = hashTable[h];
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const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base;
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const BYTE* match = matchBase + matchIndex;
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const U32 current = (U32)(ip-base);
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const U32 repIndex = current + 1 - offset_1;
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const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base;
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const BYTE* const repMatch = repBase + repIndex;
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size_t mLength;
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hashTable[h] = current; /* update hash table */
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assert(offset_1 <= current +1); /* check repIndex */
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if ( (((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > dictStartIndex))
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&& (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
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const BYTE* 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, ip-anchor, anchor, 0, mLength-MINMATCH);
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} else {
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if ( (matchIndex < dictStartIndex) ||
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(MEM_read32(match) != 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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}
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{ const BYTE* matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend;
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const BYTE* lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart;
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U32 offset;
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mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, prefixStart) + 4;
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while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
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offset = current - matchIndex;
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offset_2 = offset_1;
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offset_1 = offset;
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ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
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} }
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/* found a match : store it */
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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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hashTable[ZSTD_hashPtr(base+current+2, hlog, mls)] = current+2;
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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 ? dictBase + repIndex2 : base + repIndex2;
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if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (repIndex2 > dictStartIndex)) /* 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, 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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/* save reps for next block */
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rep[0] = offset_1;
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rep[1] = offset_2;
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/* Return the last literals size */
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return iend - anchor;
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}
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size_t ZSTD_compressBlock_fast_extDict(
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ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
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ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize)
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{
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U32 const hlog = cParams->hashLog;
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U32 const mls = cParams->searchLength;
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U32 const stepSize = cParams->targetLength;
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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_extDict_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 4);
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case 5 :
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return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 5);
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case 6 :
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return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 6);
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case 7 :
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return ZSTD_compressBlock_fast_extDict_generic(ms, seqStore, rep, src, srcSize, hlog, stepSize, 7);
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}
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}
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