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removed one assert()

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which can be triggered when input is corrupted.
This commit is contained in:
Yann Collet 2018-10-10 16:36:11 -07:00
parent d3ec23313d
commit 7791f192ee
1 changed files with 5 additions and 2 deletions
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7
lib/common/bitstream.h
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@ -340,6 +340,7 @@ MEM_STATIC size_t BIT_getUpperBits(size_t bitContainer, U32 const start)
MEM_STATIC size_t BIT_getMiddleBits(size_t bitContainer, U32 const start, U32 const nbBits) MEM_STATIC size_t BIT_getMiddleBits(size_t bitContainer, U32 const start, U32 const nbBits)
{ {
assert(nbBits < BIT_MASK_SIZE); assert(nbBits < BIT_MASK_SIZE);
assert(start < sizeof(bitContainer)*8);
return (bitContainer >> start) & BIT_mask[nbBits]; return (bitContainer >> start) & BIT_mask[nbBits];
} }
@ -357,11 +358,13 @@ MEM_STATIC size_t BIT_getLowerBits(size_t bitContainer, U32 const nbBits)
* @return : value extracted */ * @return : value extracted */
MEM_STATIC size_t BIT_lookBits(const BIT_DStream_t* bitD, U32 nbBits) MEM_STATIC size_t BIT_lookBits(const BIT_DStream_t* bitD, U32 nbBits)
{ {
/* arbitrate between double-shift and shift+mask */
#if 1 #if 1
assert(bitD->bitsConsumed + nbBits <= sizeof(bitD->bitContainer)*8); /* if bitD->bitsConsumed + nbBits > sizeof(bitD->bitContainer)*8,
* bitstream is likely corrupted, and result is undefined */
return BIT_getMiddleBits(bitD->bitContainer, (sizeof(bitD->bitContainer)*8) - bitD->bitsConsumed - nbBits, nbBits); return BIT_getMiddleBits(bitD->bitContainer, (sizeof(bitD->bitContainer)*8) - bitD->bitsConsumed - nbBits, nbBits);
#else #else
/* previous code path, seems slower */ /* this code path is slower on my os-x laptop */
U32 const regMask = sizeof(bitD->bitContainer)*8 - 1; U32 const regMask = sizeof(bitD->bitContainer)*8 - 1;
return ((bitD->bitContainer << (bitD->bitsConsumed & regMask)) >> 1) >> ((regMask-nbBits) & regMask); return ((bitD->bitContainer << (bitD->bitsConsumed & regMask)) >> 1) >> ((regMask-nbBits) & regMask);
#endif #endif