reducing the overhead of 'json' and 'allow plus' options

This commit is contained in:
Daniel Lemire 2025-03-09 14:51:50 -04:00
parent 1504792a9f
commit 13ba430893
3 changed files with 15 additions and 12 deletions

View File

@ -279,7 +279,7 @@ report_parse_error(UC const *p, parse_error error) {
// Assuming that you use no more than 19 digits, this will
// parse an ASCII string.
template <typename UC>
template <bool allow_leading_plus, bool basic_json_fmt, typename UC>
fastfloat_really_inline FASTFLOAT_CONSTEXPR20 parsed_number_string_t<UC>
parse_number_string(UC const *p, UC const *pend,
parse_options_t<UC> options) noexcept {
@ -293,14 +293,14 @@ parse_number_string(UC const *p, UC const *pend,
answer.negative = (*p == UC('-'));
// C++17 20.19.3.(7.1) explicitly forbids '+' sign here
if ((*p == UC('-')) ||
(uint64_t(fmt & chars_format::allow_leading_plus) &&
!uint64_t(fmt & detail::basic_json_fmt) && *p == UC('+'))) {
(allow_leading_plus &&
!basic_json_fmt && *p == UC('+'))) {
++p;
if (p == pend) {
return report_parse_error<UC>(
p, parse_error::missing_integer_or_dot_after_sign);
}
if (uint64_t(fmt & detail::basic_json_fmt)) {
if (basic_json_fmt) {
if (!is_integer(*p)) { // a sign must be followed by an integer
return report_parse_error<UC>(p,
parse_error::missing_integer_after_sign);
@ -329,7 +329,7 @@ parse_number_string(UC const *p, UC const *pend,
UC const *const end_of_integer_part = p;
int64_t digit_count = int64_t(end_of_integer_part - start_digits);
answer.integer = span<UC const>(start_digits, size_t(digit_count));
if (uint64_t(fmt & detail::basic_json_fmt)) {
if (basic_json_fmt) {
// at least 1 digit in integer part, without leading zeros
if (digit_count == 0) {
return report_parse_error<UC>(p, parse_error::no_digits_in_integer_part);
@ -358,7 +358,7 @@ parse_number_string(UC const *p, UC const *pend,
answer.fraction = span<UC const>(before, size_t(p - before));
digit_count -= exponent;
}
if (uint64_t(fmt & detail::basic_json_fmt)) {
if (basic_json_fmt) {
// at least 1 digit in fractional part
if (has_decimal_point && exponent == 0) {
return report_parse_error<UC>(p,
@ -470,11 +470,11 @@ parse_number_string(UC const *p, UC const *pend,
return answer;
}
template <typename T, typename UC>
template <bool allow_leading_plus = false, typename T, typename UC>
fastfloat_really_inline FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
parse_int_string(UC const *p, UC const *pend, T &value,
parse_options_t<UC> options) {
chars_format const fmt = detail::adjust_for_feature_macros(options.format);
//chars_format const fmt = detail::adjust_for_feature_macros(options.format);
int const base = options.base;
from_chars_result_t<UC> answer;
@ -495,7 +495,7 @@ parse_int_string(UC const *p, UC const *pend, T &value,
return answer;
}
if ((*p == UC('-')) ||
(uint64_t(fmt & chars_format::allow_leading_plus) && (*p == UC('+')))) {
(allow_leading_plus && (*p == UC('+')))) {
++p;
}

View File

@ -304,8 +304,11 @@ from_chars_float_advanced(UC const *first, UC const *last, T &value,
answer.ptr = first;
return answer;
}
parsed_number_string_t<UC> pns =
parse_number_string<UC>(first, last, options);
bool allow_leading_plus = uint64_t(fmt & chars_format::allow_leading_plus);
bool basic_json_fmt = uint64_t(fmt & detail::basic_json_fmt);
parsed_number_string_t<UC> pns = allow_leading_plus ?
(basic_json_fmt ? parse_number_string<true, true, UC>(first, last, options): parse_number_string<true, false, UC>(first, last, options)) :
(basic_json_fmt ? parse_number_string<false, true, UC>(first, last, options): parse_number_string<false, false, UC>(first, last, options));
if (!pns.valid) {
if (uint64_t(fmt & chars_format::no_infnan)) {
answer.ec = std::errc::invalid_argument;

View File

@ -131,7 +131,7 @@ int main() {
for (std::size_t i = 0; i < reject.size(); ++i) {
auto const &f = reject[i].input;
auto const &expected_reason = reject[i].reason;
auto answer = fast_float::parse_number_string(
auto answer = fast_float::parse_number_string<true, true>(
f.data(), f.data() + f.size(),
fast_float::parse_options(
fast_float::chars_format::json |