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Adding new is_made_of_eight_digits_fast implementation. [skip ci]

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RealTimeChris 2024-11-22 00:24:47 -05:00
parent cb1d42aaa1
commit 04034f79c6
1 changed files with 10 additions and 3 deletions
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13
include/fast_float/ascii_number.h
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@ -137,11 +137,18 @@ parse_eight_digits_unrolled(UC const *chars) noexcept {
return parse_eight_digits_unrolled(simd_read8_to_u64(chars));
}
// credit @aqrit
// credit @realtimechris
fastfloat_really_inline constexpr bool
is_made_of_eight_digits_fast(uint64_t val) noexcept {
return !((((val + 0x4646464646464646) | (val - 0x3030303030303030)) &
0x8080808080808080));
constexpr uint64_t byte_mask = ~uint64_t(0) / 255ull;
constexpr uint64_t msb_mask = byte_mask * 128ull;
constexpr uint64_t sub_mask =
byte_mask * (127ull - 10ull) - 0x3030303030303030ull;
#if !defined(__clang__)
return !bool((val + sub_mask | val) & msb_mask);
#else
return ((val + sub_mask | val) & msb_mask) == 0;
#endif
}
#ifdef FASTFLOAT_HAS_SIMD