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Add scan_data::make_args

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This commit is contained in:
Victor Zverovich 2024-01-21 08:53:29 -08:00
parent e1832bcf00
commit 6f260455aa
1 changed files with 28 additions and 9 deletions
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37
test/scan.h
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@ -10,7 +10,7 @@
#include <climits>
#include <tuple>
#include "fmt/format.h"
#include "fmt/format-inl.h"
FMT_BEGIN_NAMESPACE
namespace detail {
@ -555,25 +555,45 @@ void vscan(detail::scan_buffer& buf, string_view fmt, scan_args args) {
auto h = detail::scan_handler(fmt, buf, args);
detail::parse_format_string<false>(fmt, h);
}
} // namespace detail
template <typename... T>
auto make_scan_args(T&... args) -> std::array<scan_arg, sizeof...(T)> {
return {{args...}};
template <size_t I, typename... T, FMT_ENABLE_IF(I == sizeof...(T))>
void make_args(std::array<scan_arg, sizeof...(T)>&, std::tuple<T...>&) {}
template <size_t I, typename... T, FMT_ENABLE_IF(I < sizeof...(T))>
void make_args(std::array<scan_arg, sizeof...(T)>& args,
std::tuple<T...>& values) {
using element_type = typename std::tuple_element<I, std::tuple<T...>>::type;
static_assert(std::is_same<remove_cvref_t<element_type>, element_type>::value,
"");
args[I] = std::get<I>(values);
make_args<I + 1>(args, values);
}
} // namespace detail
template <typename... T> class scan_data {
private:
std::tuple<T...> values_;
public:
scan_data() = default;
scan_data(T... values) : values_(std::move(values)...) {}
auto value() const -> decltype(std::get<0>(values_)) {
return std::get<0>(values_);
}
auto make_args() -> std::array<scan_arg, sizeof...(T)> {
auto args = std::array<scan_arg, sizeof...(T)>();
detail::make_args<0>(args, values_);
return args;
}
};
template <typename... T>
auto make_scan_args(T&... args) -> std::array<scan_arg, sizeof...(T)> {
return {{args...}};
}
class scan_error {};
// A rudimentary version of std::expected for testing the API shape.
@ -606,10 +626,9 @@ auto scan_to(string_view input, string_view fmt, T&... args)
template <typename T>
auto scan(string_view input, string_view fmt) -> scan_result<T> {
static_assert(std::is_same<remove_cvref_t<T>, T>::value, "");
auto value = T();
scan_to(input, fmt, value);
return scan_data<T>(std::move(value));
auto data = scan_data<T>();
vscan(input, fmt, data.make_args());
return data;
}
template <typename Range, typename... T,