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enforce a minimum price of 1 bit per literal in the optimal parser

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Yann Collet 2022-01-07 13:51:28 -08:00
parent 5f2c3d9720
commit 9e1b4828e5
1 changed files with 4 additions and 2 deletions
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6
lib/compress/zstd_opt.c
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@ -255,11 +255,13 @@ static U32 ZSTD_rawLiteralsCost(const BYTE* const literals, U32 const litLength,
return (litLength*6) * BITCOST_MULTIPLIER; /* 6 bit per literal - no statistic used */ return (litLength*6) * BITCOST_MULTIPLIER; /* 6 bit per literal - no statistic used */
/* dynamic statistics */ /* dynamic statistics */
{ U32 price = litLength * optPtr->litSumBasePrice; { U32 price = 0;
U32 u; U32 u;
for (u=0; u < litLength; u++) { for (u=0; u < litLength; u++) {
U32 litPrice = optPtr->litSumBasePrice - WEIGHT(optPtr->litFreq[literals[u]], optLevel);
assert(WEIGHT(optPtr->litFreq[literals[u]], optLevel) <= optPtr->litSumBasePrice); /* literal cost should never be negative */ assert(WEIGHT(optPtr->litFreq[literals[u]], optLevel) <= optPtr->litSumBasePrice); /* literal cost should never be negative */
price -= WEIGHT(optPtr->litFreq[literals[u]], optLevel); if (litPrice < BITCOST_MULTIPLIER) litPrice = BITCOST_MULTIPLIER;
price += litPrice;
} }
return price; return price;
} }