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magic_enum/include/magic_enum.hpp
2019-04-06 19:44:10 +05:00

217 lines
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C++

// __ __ _ ______ _____
// | \/ | (_) | ____| / ____|_ _
// | \ / | __ _ __ _ _ ___ | |__ _ __ _ _ _ __ ___ | | _| |_ _| |_
// | |\/| |/ _` |/ _` | |/ __| | __| | '_ \| | | | '_ ` _ \ | | |_ _|_ _|
// | | | | (_| | (_| | | (__ | |____| | | | |_| | | | | | | | |____|_| |_|
// |_| |_|\__,_|\__, |_|\___| |______|_| |_|\__,_|_| |_| |_| \_____|
// __/ | https://github.com/Neargye/magic_enum
// |___/ vesion 0.2.0
//
// Licensed under the MIT License <http://opensource.org/licenses/MIT>.
// SPDX-License-Identifier: MIT
// Copyright (c) 2019 Daniil Goncharov <neargye@gmail.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#pragma once
#include <cstddef>
#include <type_traits>
#include <limits>
#include <string_view>
#include <optional>
#include <array>
#include <algorithm>
// Enum value must be in range (-MAGIC_ENUM_RANGE, MAGIC_ENUM_RANGE). If you need a larger range, redefine the macro MAGIC_ENUM_RANGE.
#if !defined(MAGIC_ENUM_RANGE)
# define MAGIC_ENUM_RANGE 128
#endif
namespace magic_enum {
static_assert(MAGIC_ENUM_RANGE > 0,
"MAGIC_ENUM_RANGE must be positive and greater than zero.");
static_assert(MAGIC_ENUM_RANGE < std::numeric_limits<int>::max(),
"MAGIC_ENUM_RANGE must be less INT_MAX.");
namespace detail {
[[nodiscard]] constexpr bool is_name_char(char c, bool front) noexcept {
return (!front && c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_';
}
template <typename E, E V>
[[nodiscard]] constexpr std::string_view enum_to_string_impl() noexcept {
static_assert(std::is_enum_v<E>, "magic_enum::enum_to_string require enum type.");
#if defined(__clang__)
std::string_view name{__PRETTY_FUNCTION__};
constexpr auto suffix = sizeof("]") - 1;
#elif defined(__GNUC__) && __GNUC__ >= 9
std::string_view name{__PRETTY_FUNCTION__};
constexpr auto suffix = sizeof("; std::string_view = std::basic_string_view<char>]") - 1;
#elif defined(_MSC_VER)
std::string_view name{__FUNCSIG__};
constexpr auto suffix = sizeof(">(void) noexcept") - 1;
#else
return {}; // Unsupported compiler.
#endif
#if defined(__clang__) || (defined(__GNUC__) && __GNUC__ >= 9) || defined(_MSC_VER)
name.remove_suffix(suffix);
for (std::size_t i = name.size(); i > 0; --i) {
if (!is_name_char(name[i - 1], false)) {
name.remove_prefix(i);
break;
}
}
if (name.length() > 0 && is_name_char(name.front(), true)) {
return name;
} else {
return {}; // Enum value does not have name.
}
#endif
}
template <typename E, int O, int... I>
[[nodiscard]] constexpr std::string_view enum_to_string_impl(int value, std::integer_sequence<int, I...>) noexcept {
static_assert(std::is_enum_v<E>, "magic_enum::enum_to_string require enum type.");
constexpr int n = sizeof...(I);
constexpr std::array<std::string_view, n> names{{enum_to_string_impl<E, static_cast<E>(I + O)>()...}};
return names[value - O];
}
template <typename E, int O, int... I>
[[nodiscard]] constexpr std::optional<E> enum_from_string_impl(std::string_view name, std::integer_sequence<int, I...>) noexcept {
static_assert(std::is_enum_v<E>, "magic_enum::enum_from_string require enum type.");
std::optional<E> value{std::nullopt};
(void)(((enum_to_string_impl<E, static_cast<E>(I + O)>() == name) ? (value = static_cast<E>(I + O), false) : true) && ...);
return value;
}
template <typename E, int O, int... I>
[[nodiscard]] constexpr decltype(auto) enum_to_sequence_impl(std::integer_sequence<int, I...>) noexcept {
static_assert(std::is_enum_v<E>, "magic_enum::enum_to_sequence require enum type.");
constexpr int n = sizeof...(I);
constexpr std::array<bool, n> valid{{!enum_to_string_impl<E, static_cast<E>(I + O)>().empty()...}};
constexpr int num_valid = ((valid[I] ? 1 : 0) + ...);
std::array<E, num_valid> sequence{};
for (int i = 0, v = 0; i < n && v < num_valid; ++i) {
if (valid[i]) {
sequence[v++] = static_cast<E>(i + O);
}
}
return sequence;
}
template <typename E, int O, int... I>
[[nodiscard]] constexpr decltype(auto) enum_to_string_sequence_impl(std::integer_sequence<int, I...> s) noexcept {
static_assert(std::is_enum_v<E>, "magic_enum::enum_to_string_sequence require enum type.");
constexpr int n = sizeof...(I);
constexpr std::array<bool, n> valid{{!enum_to_string_impl<E, static_cast<E>(I + O)>().empty()...}};
constexpr int num_valid = ((valid[I] ? 1 : 0) + ...);
std::array<std::string_view, num_valid> sequence{};
for (int i = 0, v = 0; i < n && v < num_valid; ++i) {
if (valid[i]) {
sequence[v++] = enum_to_string_impl<E, O>(i + O, s);
}
}
return sequence;
}
} // namespace detail
// enum_to_string(enum) obtains string enum name from enum variable.
template <typename T, typename = std::enable_if_t<std::is_enum_v<std::decay_t<T>>>>
[[nodiscard]] constexpr std::optional<std::string_view> enum_to_string(T value) noexcept {
using D = std::decay_t<T>;
using U = std::underlying_type_t<D>;
using C = std::common_type_t<int, U>;
constexpr int min = std::max<C>(std::is_signed_v<U> ? -MAGIC_ENUM_RANGE : 0, std::numeric_limits<U>::min());
constexpr int max = std::min<C>(MAGIC_ENUM_RANGE, std::numeric_limits<U>::max());
constexpr int range = max - min + 1;
if (static_cast<int>(value) > max || static_cast<int>(value) < min) {
return std::nullopt; // Enum value out of range.
}
const auto name = detail::enum_to_string_impl<D, min>(static_cast<int>(value), std::make_integer_sequence<int, range>{});
if (name.empty()) {
return std::nullopt;
} else {
return name; // Enum value does not have name.
}
}
// enum_to_string<enum>() obtains string enum name from static storage enum variable.
template <auto V, typename = std::enable_if_t<std::is_enum_v<std::decay_t<decltype(V)>>>>
[[nodiscard]] constexpr std::optional<std::string_view> enum_to_string() noexcept {
constexpr auto name = detail::enum_to_string_impl<decltype(V), V>();
if (name.empty()) {
return std::nullopt;
} else {
return name; // Enum value does not have name.
}
}
// enum_from_string(name) obtains enum value from enum string name.
template <typename E, typename = std::enable_if_t<std::is_enum_v<E>>>
[[nodiscard]] constexpr std::optional<E> enum_from_string(std::string_view name) noexcept {
using U = std::underlying_type_t<E>;
using C = std::common_type_t<int, U>;
constexpr int min = std::max<C>(std::is_signed_v<U> ? -MAGIC_ENUM_RANGE : 0, std::numeric_limits<U>::min());
constexpr int max = std::min<C>(MAGIC_ENUM_RANGE, std::numeric_limits<U>::max());
constexpr int range = max - min + 1;
return detail::enum_from_string_impl<E, min>(name, std::make_integer_sequence<int, range>{});
}
// enum_to_sequence<enum>() obtains value enum sequence.
template <typename E, typename = std::enable_if_t<std::is_enum_v<E>>>
[[nodiscard]] constexpr decltype(auto) enum_to_sequence() noexcept {
using U = std::underlying_type_t<E>;
using C = std::common_type_t<int, U>;
constexpr int min = std::max<C>(std::is_signed_v<U> ? -MAGIC_ENUM_RANGE : 0, std::numeric_limits<U>::min());
constexpr int max = std::min<C>(MAGIC_ENUM_RANGE, std::numeric_limits<U>::max());
constexpr int range = max - min + 1;
return detail::enum_to_sequence_impl<E, min>(std::make_integer_sequence<int, range>{});
}
// enum_to_string_sequence<enum>() obtains string enum name sequence.
template <typename E, typename = std::enable_if_t<std::is_enum_v<E>>>
[[nodiscard]] constexpr decltype(auto) enum_to_string_sequence() noexcept {
using U = std::underlying_type_t<E>;
using C = std::common_type_t<int, U>;
constexpr int min = std::max<C>(std::is_signed_v<U> ? -MAGIC_ENUM_RANGE : 0, std::numeric_limits<U>::min());
constexpr int max = std::min<C>(MAGIC_ENUM_RANGE, std::numeric_limits<U>::max());
constexpr int range = max - min + 1;
return detail::enum_to_string_sequence_impl<E, min>(std::make_integer_sequence<int, range>{});
}
} // namespace magic_enum