mirror/magic_enum
1
0
Fork 0
mirror of https://github.com/Neargye/magic_enum.git synced 2026-01-09 23:34:23 +00:00
Code Activity

add integer_cast

Browse source
This commit is contained in:
terik23 2019-04-11 05:25:40 +05:00
parent 4a540b1a2e
commit 0c1128947b
2 changed files with 37 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

12
example/example.cpp
View file

@ -55,6 +55,18 @@ int main() {
std::cout << "GREEN = " << c3.value() << std::endl; // GREEN = 10
}
// Enum value to integer value.
auto color_underlying = magic_enum::integer_cast(Color::RED);
if (color_underlying.has_value() && color_underlying.value() == static_cast<std::underlying_type_t<Color>>(Color::RED)) {
std::cout << "RED = " << color_underlying.value() << std::endl; // RED = -10
}
// Enum value to specific type integer value.
auto color_int = magic_enum::integer_cast<int>(Color::RED);
if (color_int.has_value() && color_int.value() == static_cast<int>(Color::RED)) {
std::cout << "RED = " << color_int.value() << std::endl; // RED = -10
}
using namespace magic_enum::ops; // out-of-the-box stream operator for enums.
// ostream operator for enum.
std::cout << "Color: " << c1 << " " << c2 << " " << c3 << std::endl; // Color: RED BLUE GREEN

25
include/magic_enum.hpp
View file

@ -242,6 +242,31 @@ template <typename E, typename = detail::enable_if_enum_t<E>>
}
}
// Obtains integer value from enum value.
template <typename E, typename D = std::decay_t<E>, typename = detail::enable_if_enum_t<D>>
[[nodiscard]] constexpr std::optional<std::underlying_type_t<D>> integer_cast(E value) noexcept {
static_assert(std::is_enum_v<D>, "magic_enum::integer_cast requires enum type.");
if (detail::name_impl<D>(static_cast<int>(value)).empty()) {
return std::nullopt; // Invalid value or out of range.
} else {
return static_cast<std::underlying_type_t<D>>(value);
}
}
// Obtains specific type integer value from enum value.
template <typename I, typename E, typename D = std::decay_t<E>, typename = std::enable_if_t<std::is_enum_v<D> && std::is_arithmetic_v<I>>>
[[nodiscard]] constexpr std::optional<I> integer_cast(E value) noexcept {
static_assert(std::is_enum_v<D>, "magic_enum::integer_cast requires enum type.");
static_assert(std::is_arithmetic_v<I>, "magic_enum::integer_cast requires integer type.");
if (detail::name_impl<D>(static_cast<int>(value)).empty() || static_cast<I>(value) != static_cast<std::underlying_type_t<D>>(value)) {
return std::nullopt; // Invalid value or out of range.
} else {
return static_cast<I>(value);
}
}
// Returns enum value at specified index.
// No bounds checking is performed: the behavior is undefined if index >= number of enum values.
template<typename E, typename = detail::enable_if_enum_t<E>>