Mercurial > public > mercurial-scm > hg
diff contrib/python-zstandard/zstd/common/bitstream.h @ 42070:675775c33ab6
zstandard: vendor python-zstandard 0.11
The upstream source distribution from PyPI was extracted. Unwanted
files were removed.
The clang-format ignore list was updated to reflect the new source
of files.
The project contains a vendored copy of zstandard 1.3.8. The old
version was 1.3.6. This should result in some minor performance wins.
test-check-py3-compat.t was updated to reflect now-passing tests on
Python 3.8.
Some HTTP tests were updated to reflect new zstd compression output.
# no-check-commit because 3rd party code has different style guidelines
Differential Revision: https://phab.mercurial-scm.org/D6199
| author | Gregory Szorc <gregory.szorc@gmail.com> |
|---|---|
| date | Thu, 04 Apr 2019 17:34:43 -0700 |
| parents | 73fef626dae3 |
| children | 69de49c4e39c |
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--- a/contrib/python-zstandard/zstd/common/bitstream.h Thu Apr 04 15:24:03 2019 -0700 +++ b/contrib/python-zstandard/zstd/common/bitstream.h Thu Apr 04 17:34:43 2019 -0700 @@ -339,17 +339,10 @@ MEM_STATIC size_t BIT_getMiddleBits(size_t bitContainer, U32 const start, U32 const nbBits) { -#if defined(__BMI__) && defined(__GNUC__) && __GNUC__*1000+__GNUC_MINOR__ >= 4008 /* experimental */ -# if defined(__x86_64__) - if (sizeof(bitContainer)==8) - return _bextr_u64(bitContainer, start, nbBits); - else -# endif - return _bextr_u32(bitContainer, start, nbBits); -#else + U32 const regMask = sizeof(bitContainer)*8 - 1; + /* if start > regMask, bitstream is corrupted, and result is undefined */ assert(nbBits < BIT_MASK_SIZE); - return (bitContainer >> start) & BIT_mask[nbBits]; -#endif + return (bitContainer >> (start & regMask)) & BIT_mask[nbBits]; } MEM_STATIC size_t BIT_getLowerBits(size_t bitContainer, U32 const nbBits) @@ -366,9 +359,13 @@ * @return : value extracted */ MEM_STATIC size_t BIT_lookBits(const BIT_DStream_t* bitD, U32 nbBits) { -#if defined(__BMI__) && defined(__GNUC__) /* experimental; fails if bitD->bitsConsumed + nbBits > sizeof(bitD->bitContainer)*8 */ + /* arbitrate between double-shift and shift+mask */ +#if 1 + /* 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); #else + /* this code path is slower on my os-x laptop */ U32 const regMask = sizeof(bitD->bitContainer)*8 - 1; return ((bitD->bitContainer << (bitD->bitsConsumed & regMask)) >> 1) >> ((regMask-nbBits) & regMask); #endif @@ -392,7 +389,7 @@ * Read (consume) next n bits from local register and update. * Pay attention to not read more than nbBits contained into local register. * @return : extracted value. */ -MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, U32 nbBits) +MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, unsigned nbBits) { size_t const value = BIT_lookBits(bitD, nbBits); BIT_skipBits(bitD, nbBits); @@ -401,7 +398,7 @@ /*! BIT_readBitsFast() : * unsafe version; only works only if nbBits >= 1 */ -MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, U32 nbBits) +MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits) { size_t const value = BIT_lookBitsFast(bitD, nbBits); assert(nbBits >= 1);