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fixed incorrect assert

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commented Fweight instead
This commit is contained in:
Yann Collet 2022-12-28 17:23:40 -08:00
parent 4a1a79a512
commit d07e72bb13
1 changed files with 6 additions and 4 deletions
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10
lib/compress/zstd_opt.c
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@ -26,15 +26,15 @@
#if 0 /* approximation at bit level (for tests) */
# define BITCOST_ACCURACY 0
# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY)
# define WEIGHT(stat, opt) ((void)opt, ZSTD_bitWeight(stat))
# define WEIGHT(stat, opt) ((void)(opt), ZSTD_bitWeight(stat))
#elif 0 /* fractional bit accuracy (for tests) */
# define BITCOST_ACCURACY 8
# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY)
# define WEIGHT(stat,opt) ((void)opt, ZSTD_fracWeight(stat))
# define WEIGHT(stat,opt) ((void)(opt), ZSTD_fracWeight(stat))
#else /* opt==approx, ultra==accurate */
# define BITCOST_ACCURACY 8
# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY)
# define WEIGHT(stat,opt) (opt ? ZSTD_fracWeight(stat) : ZSTD_bitWeight(stat))
# define WEIGHT(stat,opt) ((opt) ? ZSTD_fracWeight(stat) : ZSTD_bitWeight(stat))
#endif
/* ZSTD_bitWeight() :
@ -52,10 +52,12 @@ MEM_STATIC U32 ZSTD_fracWeight(U32 rawStat)
U32 const stat = rawStat + 1;
U32 const hb = ZSTD_highbit32(stat);
U32 const BWeight = hb * BITCOST_MULTIPLIER;
/* Fweight was meant for "Fractional weight"
* but it's effectively a value between 1 and 2
* using fixed point arithmetic */
U32 const FWeight = (stat << BITCOST_ACCURACY) >> hb;
U32 const weight = BWeight + FWeight;
assert(hb + BITCOST_ACCURACY < 31);
assert(FWeight < BITCOST_MULTIPLIER);
return weight;
}