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https://github.com/facebook/zstd.git
synced 2025-03-07 09:26:03 +02:00
minor refactor
This commit is contained in:
Yann Collet
parent
768c6bc705
commit
2f94d2f166
168
lib/zstd_opt.c
168
lib/zstd_opt.c
@ -1,15 +1,51 @@
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#include <stdio.h>
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#include <math.h> // log
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/*
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ZSTD Optimal mode
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Copyright (C) 2016, Przemyslaw Skibinski, Yann Collet.
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typedef struct
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{
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BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following disclaimer
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in the documentation and/or other materials provided with the
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distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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You can contact the author at :
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- Zstd source repository : https://www.zstd.net
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*/
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/* Note : this file is intended to be included within zstd_compress.c */
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/*- Dependencies -*/
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#include <stdio.h>
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#include <math.h> /* log */
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/*- Local types -*/
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typedef struct {
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U32 off;
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U32 len;
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U32 back;
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} ZSTD_match_t;
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typedef struct
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{
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typedef struct {
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U32 price;
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U32 off;
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U32 mlen;
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@ -18,7 +54,11 @@ typedef struct
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U32 rep2;
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} ZSTD_optimal_t;
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/*- Constants -*/
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#define ZSTD_OPT_NUM (1<<12)
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#define ZSTD_FREQ_THRESHOLD (256)
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/*- Debug -*/
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#define ZSTD_OPT_DEBUG 0 // 1 = tableID=0; 5 = check encoded sequences
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#if 1
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@ -33,30 +73,25 @@ typedef struct
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#define ZSTD_LOG_TRY_PRICE(fmt, args...) ;//printf(fmt, ##args)
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#define ZSTD_OPT_NUM (1<<12)
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#define ZSTD_FREQ_THRESHOLD (256)
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FORCE_INLINE U32 ZSTD_getLiteralPriceReal(seqStore_t* seqStorePtr, U32 litLength, const BYTE* literals)
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{
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U32 price = 0;
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U32 price, freq, u;
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if (litLength > 0) {
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U32 freq, u;
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/* literals */
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for (u=0; u < litLength; u++)
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price += ZSTD_highbit(seqStorePtr->litSum) - ZSTD_highbit(seqStorePtr->litFreq[literals[u]]);
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if (!litLength) return 1; /* special case */
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/* literal Length */
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price += ((litLength >= MaxLL)*8) + ((litLength >= 255+MaxLL)*16) + ((litLength>=(1<<15))*8);
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if (litLength >= MaxLL) litLength = MaxLL;
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freq = seqStorePtr->litLengthFreq[litLength];
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price += ZSTD_highbit(seqStorePtr->litLengthSum) - ZSTD_highbit(freq);
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/* note : seems that using matchLengthSum (<litLengthSum) improves compression ? */
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}
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/* literals */
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for (u=0, price=0; u < litLength; u++)
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price += ZSTD_highbit(seqStorePtr->litSum) - ZSTD_highbit(seqStorePtr->litFreq[literals[u]]);
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return price + (price == 0);
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/* literal Length */
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price += ((litLength >= MaxLL)*8) + ((litLength >= 255+MaxLL)*16) + ((litLength>=(1<<15))*8);
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if (litLength >= MaxLL) litLength = MaxLL;
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freq = seqStorePtr->litLengthFreq[litLength];
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price += ZSTD_highbit(seqStorePtr->litLengthSum) - ZSTD_highbit(freq);
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return price;
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}
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@ -73,8 +108,6 @@ FORCE_INLINE U32 ZSTD_getLiteralPrice(seqStore_t* seqStorePtr, U32 litLength, co
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FORCE_INLINE U32 ZSTD_getMatchPriceReal(seqStore_t* seqStorePtr, U32 offset, U32 matchLength)
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{
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U32 freq;
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/* offset */
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BYTE offCode = offset ? (BYTE)ZSTD_highbit(offset) + 1 : 0;
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U32 price = ZSTD_highbit(seqStorePtr->offCodeSum) - ZSTD_highbit(seqStorePtr->offCodeFreq[offCode]);
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@ -83,8 +116,7 @@ FORCE_INLINE U32 ZSTD_getMatchPriceReal(seqStore_t* seqStorePtr, U32 offset, U32
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/* match Length */
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price += ((matchLength >= MaxML)*8) + ((matchLength >= 255+MaxML)*16) + ((matchLength>=(1<<15))*8);
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if (matchLength >= MaxML) matchLength = MaxML;
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freq = seqStorePtr->matchLengthFreq[matchLength];
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price += ZSTD_highbit(seqStorePtr->matchLengthSum) - ZSTD_highbit(freq);
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price += ZSTD_highbit(seqStorePtr->matchLengthSum) - ZSTD_highbit(seqStorePtr->matchLengthFreq[matchLength]);
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return price;
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}
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@ -103,13 +135,7 @@ FORCE_INLINE U32 ZSTD_getPrice(seqStore_t* seqStorePtr, U32 litLength, const BYT
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MEM_STATIC void ZSTD_updatePrice(seqStore_t* seqStorePtr, U32 litLength, const BYTE* literals, U32 offset, U32 matchLength)
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{
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U32 u;
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#if 0
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static const BYTE* g_start = NULL;
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if (g_start==NULL) g_start = literals;
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//if (literals - g_start == 8695)
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printf("pos %6u : %3u literals & match %3u bytes at distance %6u \n",
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(U32)(literals - g_start), (U32)litLength, (U32)matchLength+4, (U32)offset);
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#endif
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/* literals */
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seqStorePtr->litSum += litLength;
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for (u=0; u < litLength; u++)
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@ -149,7 +175,7 @@ MEM_STATIC void ZSTD_updatePrice(seqStore_t* seqStorePtr, U32 litLength, const B
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/* *************************************
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/*-*************************************
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* Binary Tree search
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***************************************/
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FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */
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@ -165,8 +191,6 @@ U32 ZSTD_insertBtAndGetAllMatches (
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const size_t h = ZSTD_hashPtr(ip, hashLog, mls);
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U32* const hashTable = zc->hashTable;
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U32 matchIndex = hashTable[h];
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if (matchIndex >= current) return 0;
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U32* const bt = zc->contentTable;
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const U32 btLog = zc->params.contentLog - 1;
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const U32 btMask= (1U << btLog) - 1;
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@ -183,6 +207,7 @@ U32 ZSTD_insertBtAndGetAllMatches (
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U32 dummy32; /* to be nullified at the end */
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U32 mnum = 0;
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if (matchIndex >= current) return 0;
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bestLength = MINMATCH-1;
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hashTable[h] = current; /* Update Hash Table */
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@ -334,18 +359,14 @@ U32 ZSTD_HcGetAllMatches_generic (
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match = base + matchIndex;
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if (match[minml] == ip[minml]) /* potentially better */
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currentMl = ZSTD_count(ip, match, iHighLimit);
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if (currentMl > 0) {
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while ((match-back > base) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */
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currentMl += back;
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}
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while ((match-back > base) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */
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currentMl += back;
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} else {
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match = dictBase + matchIndex;
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if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
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currentMl = ZSTD_count_2segments(ip+MINMATCH, match+MINMATCH, iHighLimit, dictEnd, prefixStart) + MINMATCH;
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if (currentMl > 0) {
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while ((match-back > dictStart) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */
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currentMl += back;
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}
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while ((match-back > dictStart) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */
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currentMl += back;
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}
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/* save best solution */
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@ -396,7 +417,7 @@ FORCE_INLINE U32 ZSTD_HcGetAllMatches_selectMLS_extDict (
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}
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/* *******************************
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/*-*******************************
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* Optimal parser
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*********************************/
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FORCE_INLINE
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@ -836,8 +857,8 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
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const U32 repIndex = (U32)(current+1 - rep_1);
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const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
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const BYTE* const repMatch = repBase + repIndex;
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if ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
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if (MEM_read32(ip+1) == MEM_read32(repMatch)) {
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if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
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&& (MEM_read32(ip+1) == MEM_read32(repMatch)) ) {
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/* repcode detected we should take it */
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const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
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mlen = (U32)ZSTD_count_2segments(ip+1+MINMATCH, repMatch+MINMATCH, iend, repEnd, prefixStart) + MINMATCH;
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@ -879,18 +900,18 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
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goto _storeSequence;
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}
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// set prices using matches at position = 0
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for (u = 0; u < match_num; u++) {
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mlen = (u>0) ? matches[u-1].len+1 : best_mlen;
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best_mlen = (matches[u].len < ZSTD_OPT_NUM) ? matches[u].len : ZSTD_OPT_NUM;
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ZSTD_LOG_PARSER("%d: start Found mlen=%d off=%d best_mlen=%d last_pos=%d\n", (int)(ip-base), matches[u].len, matches[u].off, (int)best_mlen, (int)last_pos);
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litlen = opt[0].litlen;
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while (mlen <= best_mlen) {
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// set prices using matches at position = 0
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for (u = 0; u < match_num; u++) {
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mlen = (u>0) ? matches[u-1].len+1 : best_mlen;
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best_mlen = (matches[u].len < ZSTD_OPT_NUM) ? matches[u].len : ZSTD_OPT_NUM;
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ZSTD_LOG_PARSER("%d: start Found mlen=%d off=%d best_mlen=%d last_pos=%d\n", (int)(ip-base), matches[u].len, matches[u].off, (int)best_mlen, (int)last_pos);
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litlen = opt[0].litlen;
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while (mlen <= best_mlen) {
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price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off, mlen - MINMATCH);
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if (mlen > last_pos || price < opt[mlen].price)
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SET_PRICE(mlen, mlen, matches[u].off, litlen, price);
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mlen++;
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} }
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} }
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if (last_pos < MINMATCH) {
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// ip += ((ip-anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */
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@ -899,8 +920,7 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
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// check further positions
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for (skip_num = 0, cur = 1; cur <= last_pos; cur++)
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{
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for (skip_num = 0, cur = 1; cur <= last_pos; cur++) {
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size_t cur_rep;
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inr = ip + cur;
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@ -953,8 +973,7 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
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if (!opt[cur].off && opt[cur].mlen != 1) {
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cur_rep = opt[cur].rep2;
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ZSTD_LOG_PARSER("%d: try REP2 rep2=%d mlen=%d\n", (int)(inr-base), cur_rep, mlen);
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}
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else {
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} else {
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cur_rep = opt[cur].rep;
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ZSTD_LOG_PARSER("%d: try REP1 rep=%d mlen=%d\n", (int)(inr-base), cur_rep, mlen);
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}
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@ -969,8 +988,7 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
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mlen = (U32)ZSTD_count_2segments(inr+MINMATCH, repMatch+MINMATCH, iend, repEnd, prefixStart) + MINMATCH;
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ZSTD_LOG_PARSER("%d: Found REP mlen=%d off=%d rep=%d opt[%d].off=%d\n", (int)(inr-base), mlen, 0, opt[cur].rep, cur, opt[cur].off);
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if (mlen > sufficient_len || cur + mlen >= ZSTD_OPT_NUM)
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{
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if (mlen > sufficient_len || cur + mlen >= ZSTD_OPT_NUM) {
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best_mlen = mlen;
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best_off = 0;
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ZSTD_LOG_PARSER("%d: REP sufficient_len=%d best_mlen=%d best_off=%d last_pos=%d\n", (int)(inr-base), sufficient_len, best_mlen, best_off, last_pos);
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@ -978,20 +996,15 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
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goto _storeSequence;
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}
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if (opt[cur].mlen == 1)
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{
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if (opt[cur].mlen == 1) {
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litlen = opt[cur].litlen;
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if (cur > litlen)
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{
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if (cur > litlen) {
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price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr-litlen, 0, mlen - MINMATCH);
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ZSTD_LOG_TRY_PRICE("%d: TRY5 opt[%d].price=%d price=%d cur=%d litlen=%d\n", (int)(inr-base), cur - litlen, opt[cur - litlen].price, price, cur, litlen);
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}
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else
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} else
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price = ZSTD_getPrice(seqStorePtr, litlen, anchor, 0, mlen - MINMATCH);
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}
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else
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{
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} else {
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litlen = 0;
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price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, 0, mlen - MINMATCH);
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ZSTD_LOG_TRY_PRICE("%d: TRY7 price=%d cur=%d litlen=0 getprice=%d\n", (int)(inr-base), price, cur, (int)ZSTD_getPrice(seqStorePtr, 0, NULL, 0, mlen - MINMATCH));
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@ -1003,22 +1016,15 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
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ZSTD_LOG_PARSER("%d: Found REP mlen=%d off=%d price=%d litlen=%d price[%d]=%d\n", (int)(inr-base), mlen, 0, price, litlen, cur - litlen, opt[cur - litlen].price);
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do
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{
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do {
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if (cur + mlen > last_pos || price <= opt[cur + mlen].price) // || ((price == opt[cur + mlen].price) && (opt[cur].mlen == 1) && (cur != litlen))) // at equal price prefer REP instead of MATCH
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SET_PRICE(cur + mlen, mlen, 0, litlen, price);
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mlen--;
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}
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while (mlen >= MINMATCH);
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} while (mlen >= MINMATCH);
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}
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if (faster_get_matches && skip_num > 0)
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{
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skip_num--;
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continue;
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}
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if (faster_get_matches && skip_num > 0) { skip_num--; continue; }
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best_mlen = (best_mlen > MINMATCH) ? best_mlen : MINMATCH;
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