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[opt] Only update repcodes upon arrival

dev
Nick Terrell 2020-03-04 17:57:15 -08:00
parent 0f9882deb9
commit 81fda0419e
1 changed files with 15 additions and 7 deletions
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22
lib/compress/zstd_opt.c
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@ -894,7 +894,6 @@ ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,
for (matchNb = 0; matchNb < nbMatches; matchNb++) {
U32 const offset = matches[matchNb].off;
U32 const end = matches[matchNb].len;
repcodes_t const repHistory = ZSTD_updateRep(rep, offset, ll0);
for ( ; pos <= end ; pos++ ) {
U32 const matchPrice = ZSTD_getMatchPrice(offset, pos, optStatePtr, optLevel);
U32 const sequencePrice = literalsPrice + matchPrice;
@ -904,8 +903,6 @@ ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,
opt[pos].off = offset;
opt[pos].litlen = litlen;
opt[pos].price = sequencePrice;
ZSTD_STATIC_ASSERT(sizeof(opt[pos].rep) == sizeof(repHistory));
memcpy(opt[pos].rep, &repHistory, sizeof(repHistory));
} }
last_pos = pos-1;
}
@ -932,7 +929,6 @@ ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,
opt[cur].off = 0;
opt[cur].litlen = litlen;
opt[cur].price = price;
memcpy(opt[cur].rep, opt[cur-1].rep, sizeof(opt[cur].rep));
} else {
DEBUGLOG(7, "cPos:%zi==rPos:%u : literal would cost more (%.2f>%.2f) (hist:%u,%u,%u)",
inr-istart, cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price),
@ -940,6 +936,21 @@ ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,
}
}
/* Set the repcodes of the current position. We must do it here
* because we rely on the repcodes of the 2nd to last sequence being
* correct to set the next chunks repcodes during the backward
* traversal.
*/
ZSTD_STATIC_ASSERT(sizeof(opt[cur].rep) == sizeof(repcodes_t));
assert(cur >= opt[cur].mlen);
if (opt[cur].mlen != 0) {
U32 const prev = cur - opt[cur].mlen;
repcodes_t newReps = ZSTD_updateRep(opt[prev].rep, opt[cur].off, opt[cur].litlen==0);
memcpy(opt[cur].rep, &newReps, sizeof(repcodes_t));
} else {
memcpy(opt[cur].rep, opt[cur - 1].rep, sizeof(repcodes_t));
}
/* last match must start at a minimum distance of 8 from oend */
if (inr > ilimit) continue;
@ -980,7 +991,6 @@ ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,
/* set prices using matches found at position == cur */
for (matchNb = 0; matchNb < nbMatches; matchNb++) {
U32 const offset = matches[matchNb].off;
repcodes_t const repHistory = ZSTD_updateRep(opt[cur].rep, offset, ll0);
U32 const lastML = matches[matchNb].len;
U32 const startML = (matchNb>0) ? matches[matchNb-1].len+1 : minMatch;
U32 mlen;
@ -1000,8 +1010,6 @@ ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,
opt[pos].off = offset;
opt[pos].litlen = litlen;
opt[pos].price = price;
ZSTD_STATIC_ASSERT(sizeof(opt[pos].rep) == sizeof(repHistory));
memcpy(opt[pos].rep, &repHistory, sizeof(repHistory));
} else {
DEBUGLOG(7, "rPos:%u (ml=%2u) => new price is worse (%.2f>=%.2f)",
pos, mlen, ZSTD_fCost(price), ZSTD_fCost(opt[pos].price));