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Move pshufb_fill_patterns from snappy-internal.h to snappy.cc. 

The array of constants is only used in the SSSE3 fast-path in IncrementalCopy.
This commit is contained in:
costan 2018-08-09 10:58:55 -07:00 committed by Victor Costan
parent 73c31e824c
commit ad82620f6f
2 changed files with 17 additions and 14 deletions
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13
snappy-internal.h
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@ -218,19 +218,6 @@ static const uint16 char_table[256] = {
0x1801, 0x0f0a, 0x103f, 0x203f, 0x2001, 0x0f0b, 0x1040, 0x2040
};
// This is a table of shuffle control masks that can be used as the source
// operand for PSHUFB to permute the contents of the destination XMM register
// into a repeating byte pattern.
alignas(16) static const char pshufb_fill_patterns[7][16] = {
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1},
{0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0},
{0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3},
{0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0},
{0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3},
{0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 0, 1},
};
} // end namespace internal
} // end namespace snappy

18
snappy.cc
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@ -61,7 +61,6 @@ using internal::COPY_2_BYTE_OFFSET;
using internal::LITERAL;
using internal::char_table;
using internal::kMaximumTagLength;
using internal::pshufb_fill_patterns;
// Any hash function will produce a valid compressed bitstream, but a good
// hash function reduces the number of collisions and thus yields better
@ -140,6 +139,23 @@ inline char* IncrementalCopySlow(const char* src, char* op,
return op_limit;
}
#if SNAPPY_HAVE_SSSE3
// This is a table of shuffle control masks that can be used as the source
// operand for PSHUFB to permute the contents of the destination XMM register
// into a repeating byte pattern.
alignas(16) const char pshufb_fill_patterns[7][16] = {
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1},
{0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0},
{0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3},
{0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0},
{0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3},
{0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 0, 1},
};
#endif // SNAPPY_HAVE_SSSE3
// Copy [src, src+(op_limit-op)) to [op, (op_limit-op)) but faster than
// IncrementalCopySlow. buf_limit is the address past the end of the writable
// region of the buffer.