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- Add SIMD acceleration to fast_int

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- fix MSVC warning
This commit is contained in:
Maya Warrier 2023-12-13 17:42:30 -05:00
parent 26a5b2eb16
commit bdee16bcad
1 changed files with 10 additions and 1 deletions
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11
include/fast_float/ascii_number.h
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@ -7,7 +7,6 @@
#include <iterator> #include <iterator>
#include <limits> #include <limits>
#include <type_traits> #include <type_traits>
#include <charconv>
#include "float_common.h" #include "float_common.h"
@ -472,6 +471,9 @@ from_chars_result_t<UC> parse_int_string(UC const* p, UC const* pend, T& value,
UC const* const start_digits = p; UC const* const start_digits = p;
uint64_t i = 0; uint64_t i = 0;
if (base == 10) {
loop_parse_if_eight_digits(p, pend, i); // use SIMD if possible
}
while (p != pend) { while (p != pend) {
uint8_t digit = ch_to_digit(*p); uint8_t digit = ch_to_digit(*p);
if (digit >= base) { if (digit >= base) {
@ -519,11 +521,18 @@ from_chars_result_t<UC> parse_int_string(UC const* p, UC const* pend, T& value,
} }
if (negative) { if (negative) {
#ifdef FASTFLOAT_VISUAL_STUDIO
#pragma warning(push)
#pragma warning(disable: 4146)
#endif
// this weird workaround is required because: // this weird workaround is required because:
// - converting unsigned to signed when its value is greater than signed max is UB pre-C++23. // - converting unsigned to signed when its value is greater than signed max is UB pre-C++23.
// - reinterpret_casting (~i + 1) would work, but it is not constexpr // - reinterpret_casting (~i + 1) would work, but it is not constexpr
// this is always optimized into a neg instruction. // this is always optimized into a neg instruction.
value = T(-std::numeric_limits<T>::max() - T(i - std::numeric_limits<T>::max())); value = T(-std::numeric_limits<T>::max() - T(i - std::numeric_limits<T>::max()));
#ifdef FASTFLOAT_VISUAL_STUDIO
#pragma warning(pop)
#endif
} }
else value = T(i); else value = T(i);