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zstd_opt.h: small improvement in compression ratio

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Przemyslaw Skibinski 2016-10-20 11:49:02 +02:00
parent 575ab00db7
commit d365ae3497
1 changed files with 13 additions and 16 deletions
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29
lib/compress/zstd_opt.h
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@ -1,5 +1,5 @@
/** /**
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc. * Copyright (c) 2016-present, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
* All rights reserved. * All rights reserved.
* *
* This source code is licensed under the BSD-style license found in the * This source code is licensed under the BSD-style license found in the
@ -401,7 +401,6 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
ZSTD_rescaleFreqs(seqStorePtr); ZSTD_rescaleFreqs(seqStorePtr);
ip += (ip==prefixStart); ip += (ip==prefixStart);
{ U32 i; for (i=0; i<ZSTD_REP_NUM; i++) rep[i]=ctx->rep[i]; } { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) rep[i]=ctx->rep[i]; }
//inr = ip;
/* Match Loop */ /* Match Loop */
while (ip < ilimit) { while (ip < ilimit) {
@ -511,20 +510,20 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
best_off = i - (opt[cur].mlen != 1); best_off = i - (opt[cur].mlen != 1);
if (opt[cur].mlen == 1) { if (mlen > best_mlen) best_mlen = mlen;
litlen = opt[cur].litlen;
if (cur > litlen) {
price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr-litlen, best_off, mlen - MINMATCH);
} else
price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH);
} else {
litlen = 0;
price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, best_off, mlen - MINMATCH);
}
if (mlen > best_mlen) best_mlen = mlen; do {
if (opt[cur].mlen == 1) {
litlen = opt[cur].litlen;
if (cur > litlen) {
price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr-litlen, best_off, mlen - MINMATCH);
} else
price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH);
} else {
litlen = 0;
price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, best_off, mlen - MINMATCH);
}
do {
if (cur + mlen > last_pos || price <= opt[cur + mlen].price) if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
SET_PRICE(cur + mlen, mlen, i, litlen, price); SET_PRICE(cur + mlen, mlen, i, litlen, price);
mlen--; mlen--;
@ -657,7 +656,6 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
ctx->nextToUpdate3 = ctx->nextToUpdate; ctx->nextToUpdate3 = ctx->nextToUpdate;
ZSTD_rescaleFreqs(seqStorePtr); ZSTD_rescaleFreqs(seqStorePtr);
ip += (ip==prefixStart); ip += (ip==prefixStart);
//inr = ip;
/* Match Loop */ /* Match Loop */
while (ip < ilimit) { while (ip < ilimit) {
@ -666,7 +664,6 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
U32 current = (U32)(ip-base); U32 current = (U32)(ip-base);
memset(opt, 0, sizeof(ZSTD_optimal_t)); memset(opt, 0, sizeof(ZSTD_optimal_t));
last_pos = 0; last_pos = 0;
//inr = ip;
opt[0].litlen = (U32)(ip - anchor); opt[0].litlen = (U32)(ip - anchor);
/* check repCode */ /* check repCode */