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restored currentMl>0 condition, as suggested by @inikep

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Yann Collet
2016-02-10 15:44:07 +01:00
parent 3b63f7fbb0
commit 62ae262771
1 changed files with 15 additions and 18 deletions
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lib/zstd_opt.h
+10 -13
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@@ -34,8 +34,7 @@
/* Note : this file is intended to be included within zstd_compress.c */ /* Note : this file is intended to be included within zstd_compress.c */
/*- Dependencies -*/ /*- Dependencies -*/
#include <stdio.h> #include <stdio.h> /* for debug */
#include <math.h> /* log */
/*- Local types -*/ /*- Local types -*/
@@ -356,15 +355,18 @@ U32 ZSTD_HcGetAllMatches_generic (
match = base + matchIndex; match = base + matchIndex;
if (match[minml] == ip[minml]) /* potentially better */ if (match[minml] == ip[minml]) /* potentially better */
currentMl = ZSTD_count(ip, match, iHighLimit); 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 */ while ((match-back > base) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */
currentMl += back; currentMl += back;
}
} else { } else {
match = dictBase + matchIndex; match = dictBase + matchIndex;
if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */ 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; currentMl = ZSTD_count_2segments(ip+MINMATCH, match+MINMATCH, iHighLimit, dictEnd, prefixStart) + MINMATCH;
while ((match-back > dictStart) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */ while ((match-back > dictStart) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */
currentMl += back; currentMl += back;
} }
}
/* save best solution */ /* save best solution */
if (currentMl > minml) { if (currentMl > minml) {
@@ -463,7 +465,6 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
inr = ip; inr = ip;
opt[0].litlen = (U32)(ip - anchor); opt[0].litlen = (U32)(ip - anchor);
/* check repCode */ /* check repCode */
if (MEM_read32(ip+1) == MEM_read32(ip+1 - rep_1)) { if (MEM_read32(ip+1) == MEM_read32(ip+1 - rep_1)) {
/* repcode : we take it */ /* repcode : we take it */
@@ -476,14 +477,12 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
} }
litlen = opt[0].litlen + 1; litlen = opt[0].litlen + 1;
do do {
{
price = ZSTD_getPrice(seqStorePtr, litlen, anchor, 0, mlen - MINMATCH); price = ZSTD_getPrice(seqStorePtr, litlen, anchor, 0, mlen - MINMATCH);
if (mlen + 1 > last_pos || price < opt[mlen + 1].price) if (mlen + 1 > last_pos || price < opt[mlen + 1].price)
SET_PRICE(mlen + 1, mlen, 0, litlen, price); SET_PRICE(mlen + 1, mlen, 0, litlen, price); /* note : macro modifies last_pos */
mlen--; mlen--;
} } while (mlen >= MINMATCH);
while (mlen >= MINMATCH);
} }
@@ -515,14 +514,12 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
best_mlen = (matches[u].len < ZSTD_OPT_NUM) ? matches[u].len : ZSTD_OPT_NUM; 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); 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; litlen = opt[0].litlen;
while (mlen <= best_mlen) while (mlen <= best_mlen) {
{
price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off, mlen - MINMATCH); price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off, mlen - MINMATCH);
if (mlen > last_pos || price < opt[mlen].price) if (mlen > last_pos || price < opt[mlen].price)
SET_PRICE(mlen, mlen, matches[u].off, litlen, price); SET_PRICE(mlen, mlen, matches[u].off, litlen, price);
mlen++; mlen++;
} } }
}
if (last_pos < MINMATCH) { if (last_pos < MINMATCH) {
// ip += ((ip-anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */ // ip += ((ip-anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */