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Improve std::complex formatter (#4050)

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Signed-off-by: Vladislav Shchapov <vladislav@shchapov.ru>
This commit is contained in:
Vladislav Shchapov
2024-07-05 05:24:01 +05:00
committed by GitHub
parent 232c6bc481
commit a96259701e
2 changed files with 78 additions and 20 deletions
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74
include/fmt/std.h
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@@ -631,33 +631,67 @@ struct formatter<std::atomic_flag, Char> : formatter<bool, Char> {
#endif // __cpp_lib_atomic_flag_test
FMT_EXPORT
template <typename F, typename Char>
struct formatter<std::complex<F>, Char> : nested_formatter<F, Char> {
template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
private:
// Functor because C++11 doesn't support generic lambdas.
struct writer {
const formatter<std::complex<F>, Char>* f;
const std::complex<F>& c;
detail::dynamic_format_specs<Char> specs_;
template <typename OutputIt>
FMT_CONSTEXPR auto operator()(OutputIt out) -> OutputIt {
if (c.real() != 0) {
auto format_full = detail::string_literal<Char, '(', '{', '}', '+', '{',
'}', 'i', ')'>{};
return fmt::format_to(out, basic_string_view<Char>(format_full),
f->nested(c.real()), f->nested(c.imag()));
}
auto format_imag = detail::string_literal<Char, '{', '}', 'i'>{};
return fmt::format_to(out, basic_string_view<Char>(format_imag),
f->nested(c.imag()));
template <typename FormatContext, typename OutputIt>
FMT_CONSTEXPR auto do_format(const std::complex<T>& c,
detail::dynamic_format_specs<Char>& specs,
FormatContext& ctx, OutputIt out) const
-> OutputIt {
if (c.real() != 0) {
*out++ = Char('(');
out = detail::write<Char>(out, c.real(), specs, ctx.locale());
specs.sign = sign::plus;
out = detail::write<Char>(out, c.imag(), specs, ctx.locale());
if (!detail::isfinite(c.imag())) *out++ = Char(' ');
*out++ = Char('i');
*out++ = Char(')');
return out;
}
};
out = detail::write<Char>(out, c.imag(), specs, ctx.locale());
if (!detail::isfinite(c.imag())) *out++ = Char(' ');
*out++ = Char('i');
return out;
}
public:
FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
-> decltype(ctx.begin()) {
if (ctx.begin() == ctx.end() || *ctx.begin() == '}') return ctx.begin();
return parse_format_specs(ctx.begin(), ctx.end(), specs_, ctx,
detail::type_constant<T, Char>::value);
}
template <typename FormatContext>
auto format(const std::complex<F>& c, FormatContext& ctx) const
auto format(const std::complex<T>& c, FormatContext& ctx) const
-> decltype(ctx.out()) {
return this->write_padded(ctx, writer{this, c});
auto specs = specs_;
if (specs.width_ref.kind != detail::arg_id_kind::none ||
specs.precision_ref.kind != detail::arg_id_kind::none) {
detail::handle_dynamic_spec<detail::width_checker>(specs.width,
specs.width_ref, ctx);
detail::handle_dynamic_spec<detail::precision_checker>(
specs.precision, specs.precision_ref, ctx);
}
if (specs.width == 0) return do_format(c, specs, ctx, ctx.out());
auto buf = basic_memory_buffer<Char>();
auto outer_specs = format_specs();
outer_specs.width = specs.width;
outer_specs.fill = specs.fill;
outer_specs.align = specs.align;
specs.width = 0;
specs.fill = {};
specs.align = align::none;
do_format(c, specs, ctx, basic_appender<Char>(buf));
return detail::write<Char>(ctx.out(),
basic_string_view<Char>(buf.data(), buf.size()),
outer_specs);
}
};