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