introduce bitmask support and std::format specialization

.vscode/settings.json

@@ -1,6 +1,7 @@
 {
-    "files.associations": {
-        "cmath": "cpp",
-        "string_view": "cpp"
-    }
-}
+  "files.associations": {
+    "cmath": "cpp",
+    "string_view": "cpp",
+    "sstream": "cpp"
+  }
+}

README.md

@@ -9,27 +9,44 @@ Converting (scoped)enum values to/from string names written in C++>=11.
 ## Features
 * Supports `enum` and `enum class`
 * Supports enums in namespaces, classes or structs even templated or not
-* Supports compile-time as much as possible using with C++14 and later
+* Supports compile-time as much as possible using with C++17 and later
 * Changing enum range with template parameter <sub>(default range: `[0, 256)`)</sub> on each call or with your special function for types or adding specialized `enum_range<Enum>` struct
 * Supports and automatically overloaded `operator<<` for Enum types to direct using with ostream objects
 * Supports custom enum name output by explicit specialization of `constexpr inline auto mgutility::detail::enum_type::name<Enum, EnumValue>() noexcept` function
+* Supports bitmasked enums and auto detect them
 * Supports iterate over enum (names and values) with `mgutility::enum_for_each<T>()` class and it is compatible with standard ranges and views
 
 ## Limitations
 * Compiler versions
 * Wider range can increase compile time so user responsible to adjusting for enum's range
 
 
-## Usage ([try it!](https://godbolt.org/z/YM5EvY1Y5))
+## Usage ([try it!](https://godbolt.org/z/dfeYxscvT))
 ```C++
 #include <iostream>
 #include "enum_name.hpp"
 
-num class rgb_color { red, green, blue, unknown = -1 };
+enum class rgb_color {
+    red = 1 << 0,
+    green = 1 << 1,
+    blue = 1 << 2,
+    unknown = -1
+};
+
+auto operator|(rgb_color lhs, rgb_color rhs) -> rgb_color {
+    return static_cast<rgb_color>(mgutility::enum_to_underlying(lhs) |
+                                  mgutility::enum_to_underlying(rhs));
+}
+
+auto operator&(rgb_color lhs, rgb_color rhs) -> rgb_color {
+    return static_cast<rgb_color>(mgutility::enum_to_underlying(lhs) &
+                                  mgutility::enum_to_underlying(rhs));
+}
 
 // specialize rgb_color::unknown to make output "UNKNOWN" instead of "unknown"
 template <>
-constexpr auto mgutility::detail::enum_type::name<rgb_color, rgb_color::unknown>() noexcept
+constexpr inline auto
+mgutility::detail::enum_type::name<rgb_color, rgb_color::unknown>() noexcept
     -> string_view {
     return "UNKNOWN";
 }
@@ -38,38 +55,41 @@ constexpr auto mgutility::detail::enum_type::name<rgb_color, rgb_color::unknown>
 template <>
 struct mgutility::enum_range<rgb_color> {
     static constexpr auto min = -1;
-    static constexpr auto max = 3;
+    static constexpr auto max = 5;
 };
 
 // you can specialize enum ranges with overload per enum types (option 2)
-auto enum_name = [](rgb_color c) { return mgutility::enum_name<-1, 3>(c); };
+auto enum_name = [](rgb_color c) { return mgutility::enum_name<-1, 5>(c); };
 
 #if defined(__cpp_lib_print)
 #include <print>
 #include <ranges>
 #endif
 
-
 int main() {
     auto x = rgb_color::blue;
-    auto y = mgutility::to_enum<rgb_color>("greenn");
+    auto y = mgutility::to_enum<rgb_color>("green|red");
 
 #if defined(__cpp_lib_print)
 
-// enum_for_each<T> can usable with views and range algorithms
-auto colors = mgutility::enum_for_each<rgb_color>() |
-                  std::ranges::views::filter(
-                      [](auto &&pair) { return pair.second != "UNKNOWN"; });
+    // enum_for_each<T> can usable with views and range algorithms
+    auto colors = mgutility::enum_for_each<rgb_color>() |
+                  std::ranges::views::filter([](auto &&pair) {
+                      return !pair.second.empty() && pair.second != "UNKNOWN";
+                  });
 
     std::ranges::for_each(colors, [](auto &&color) {
-        std::println("{} \t: {}", color.second, mgutility::enum_to_underlying(color.first));
+        std::println("{} \t: {}", color.second,
+                     mgutility::enum_to_underlying(color.first));
     });
 
 #else
 
     for (auto&& e : mgutility::enum_for_each<rgb_color>()) {
-        if(e.second != "UNKNOWN"){
-            std::cout << e.second << " \t: " << mgutility::enum_to_underlying(e.first) << '\n';
+        if (!e.second.empty() && e.second != "UNKNOWN") {
+            std::cout << e.second
+                      << " \t: " << mgutility::enum_to_underlying(e.first)
+                      << '\n';
         }
         // std::pair<Enum, string_view> {enum_type, name_of_enum}
     }
@@ -78,8 +98,6 @@ auto colors = mgutility::enum_for_each<rgb_color>() |
     // default signature: enum_name<min_value = -128, max_value = 128, Enum
     // typename>(Enum&&) Changing max_value to not too much greater than enum's
     // max value, it will compiles faster
-    std::cout << mgutility::enum_name(x) << '\n';  // will print "blue" to output
-    // or
     std::cout << x << '\n';  // will print "blue" to output
 
     // calling specialized enum ranges function for rgb_color type

include/enum_name.hpp

@@ -33,7 +33,6 @@
 #include <string>
 #include <type_traits>
 #include <utility>
-#include <vector>
 
 #if defined(_MSC_VER) && _MSC_VER < 1910
 #error "Requires MSVC 2017 or newer!"
@@ -59,6 +58,18 @@
 #error "Standards older than C++11 is not supported!"
 #endif
 
+#if MG_ENUM_NAME_CPLUSPLUS > 201703L
+#define MG_ENUM_NAME_CNSTXPR_FUNC constexpr
+#else
+#define MG_ENUM_NAME_CNSTXPR_FUNC
+#endif
+
+#if MG_ENUM_NAME_CPLUSPLUS > 201703L
+#define MG_ENUM_NAME_CNSTEVL consteval
+#else
+#define MG_ENUM_NAME_CNSTEVL
+#endif
+
 #if MG_ENUM_NAME_CPLUSPLUS > 201702L
 #include <optional>
 #endif
@@ -72,6 +83,13 @@ struct is_scoped_enum {
         std::is_enum<E>::value &&
         !std::is_convertible<E, typename std::underlying_type<E>::type>::value;
 };
+
+template <typename T, typename = void>
+struct has_bit_or : std::false_type {};
+
+template <typename T>
+struct has_bit_or<T, decltype((T{} | T{}), void())> : std::true_type {};
+
 #if MG_ENUM_NAME_CPLUSPLUS > 201103L
 template <typename E>
 static constexpr bool is_scoped_enum_v = is_scoped_enum<E>::value;
@@ -131,8 +149,14 @@ class basic_string_view {
                                                     size_t len) const noexcept {
         return basic_string_view<Char>(data_ + begin, len);
     }
-    constexpr inline size_t rfind(Char c, size_t pos = 0) const noexcept {
-        return c == data_[pos] ? pos : rfind(c, --pos);
+    constexpr inline size_t rfind(Char c, size_t pos = npos) const noexcept {
+        return (pos == npos ? pos = size_ : pos = pos), c == data_[pos] ? pos
+                                                        : pos == 0U
+                                                            ? npos
+                                                            : rfind(c, --pos);
+    }
+    constexpr inline size_t find(Char c, size_t pos = 0) const noexcept {
+        return c == data_[pos] ? pos : pos < size_ ? find(c, ++pos) : npos;
     }
 
     constexpr friend inline bool operator==(
@@ -168,6 +192,8 @@ class basic_string_view {
         return os;
     }
 
+    static constexpr auto npos = -1;
+
    private:
     size_t size_;
     const Char* data_;
@@ -297,6 +323,11 @@ using enable_if_t = std::enable_if_t<B, T>;
 
 #endif
 
+template <typename T>
+using string_or_view_t =
+    typename std::conditional<has_bit_or<T>::value, std::string,
+                              detail::string_view>::type;
+
 template <typename Enum, Enum...>
 struct enum_sequence {};
 
@@ -362,20 +393,21 @@ struct enum_type {
 };
 
 template <typename Enum>
-using enum_pair = std::pair<Enum, detail::string_view>;
+using enum_pair = std::pair<Enum, detail::string_or_view_t<Enum>>;
 
 template <typename Enum, Enum... Is>
-inline auto get_enum_array(detail::enum_sequence<Enum, Is...>) noexcept
+MG_ENUM_NAME_CNSTXPR inline auto get_enum_array(
+    detail::enum_sequence<Enum, Is...>) noexcept
     -> std::array<detail::string_view, sizeof...(Is) + 1> {
-    static std::array<detail::string_view, sizeof...(Is) + 1>
-        arr{"", enum_type::template name<Enum, Is>()...};
-    return arr;
+    return std::array<detail::string_view, sizeof...(Is) + 1>{
+        "", enum_type::template name<Enum, Is>()...};
 }
 
 template <typename Enum, int Min, int Max>
-inline auto to_enum_impl(detail::string_view str) noexcept
+MG_ENUM_NAME_CNSTXPR inline auto to_enum_impl(detail::string_view str) noexcept
     -> detail::optional<Enum> {
-    auto arr = get_enum_array<Enum>(detail::make_enum_sequence<Enum, Min, Max>());
+    MG_ENUM_NAME_CNSTXPR auto arr =
+        get_enum_array<Enum>(detail::make_enum_sequence<Enum, Min, Max>());
     const auto index{std::find(arr.begin() + 1, arr.end(), str)};
     return index == arr.end()
                ? detail::nullopt
@@ -384,11 +416,85 @@ inline auto to_enum_impl(detail::string_view str) noexcept
 }
 
 template <typename Enum, int Min, int Max>
-inline auto enum_name_impl(Enum e) noexcept -> detail::string_view {
-    auto arr = get_enum_array<Enum>(detail::make_enum_sequence<Enum, Min, Max>());
-    const auto index{std::abs(Min) + static_cast<int>(e) + (Min < 0 ? 1 : 1)};
+MG_ENUM_NAME_CNSTXPR inline auto to_enum_bitmask_impl(
+    detail::string_view str) noexcept -> detail::optional<Enum> {
+    if (str.find('|') == detail::string_view::npos) {
+        return to_enum_impl<Enum, Min, Max>(str);
+    } else {
+        auto index = std::size_t{};
+        auto result = detail::optional<Enum>{detail::nullopt};
+        for (std::size_t i{}; i < str.size(); ++i) {
+            if (str[i] == '|') {
+                const auto name = str.substr(index, i - index);
+                auto maybe_enum =
+                    to_enum_impl<Enum, Min, Max>(str.substr(index, i - index));
+                if (!name.empty() && maybe_enum) {
+                    result.emplace(
+                        result ? static_cast<Enum>(*result | *maybe_enum)
+                               : *maybe_enum);
+                }
+
+                index = i + 1U;
+            }
+        }
+        if (result) {
+            auto maybe_enum = to_enum_impl<Enum, Min, Max>(
+                str.substr(index, str.size() - index));
+            if (maybe_enum) {
+                result.emplace(static_cast<Enum>(*result | *maybe_enum));
+            } else {
+                result.reset();
+            }
+        }
+
+        return result;
+    }
+}
+
+template <typename Enum, int Min, int Max,
+          detail::enable_if_t<!detail::has_bit_or<Enum>::value, bool> = true>
+MG_ENUM_NAME_CNSTXPR inline auto enum_name_impl(Enum e) noexcept
+    -> detail::string_view {
+    MG_ENUM_NAME_CNSTXPR auto arr =
+        get_enum_array<Enum>(detail::make_enum_sequence<Enum, Min, Max>());
+    const auto index{(Min < 0 ? Min * -1 : Min) + static_cast<int>(e) +
+                     (Min < 0 ? 1 : 1)};
     return arr[(index < Min || index > arr.size() - 1) ? 0 : index];
 }
+
+template <typename Enum, int Min, int Max,
+          detail::enable_if_t<detail::has_bit_or<Enum>::value, bool> = true>
+MG_ENUM_NAME_CNSTXPR_FUNC inline auto enum_name_impl(Enum e) noexcept
+    -> detail::string_or_view_t<Enum> {
+    MG_ENUM_NAME_CNSTXPR auto arr =
+        get_enum_array<Enum>(detail::make_enum_sequence<Enum, Min, Max>());
+    const auto index{(Min < 0 ? Min * -1 : Min) + static_cast<int>(e) +
+                     (Min < 0 ? 1 : 1)};
+    const auto name = arr[(index < Min || index > arr.size() - 1) ? 0 : index];
+
+    const auto isdigit = [](char c) {
+        return static_cast<int>(c) < 58 && static_cast<int>(c) > 47;
+    };
+
+    if (!name.empty() && !isdigit(name[0])) {
+        return std::string{name};
+    } else {
+        auto bitmasked_name = std::string{};
+
+        for (auto i{Min}; i < Max; ++i) {
+            const auto idx = (Min < 0 ? Min * -1 : Min) + i + (Min < 0 ? 1 : 1);
+            if (!(idx < Min || idx > arr.size() - 1) && !arr[idx].empty() &&
+                !isdigit(arr[idx][0]) &&
+                (e & static_cast<Enum>(i)) == static_cast<Enum>(i)) {
+                bitmasked_name.append(arr[idx]).append("|");
+            }
+        }
+
+        const auto result =
+            bitmasked_name.substr(0U, bitmasked_name.size() - 1U);
+        return result.find('|') != std::string::npos ? result : std::string{""};
+    }
+}
 }  // namespace detail
 }  // namespace mgutility
 
@@ -462,7 +568,7 @@ constexpr inline auto enum_to_underlying(Enum e) noexcept
 
 template <int Min, int Max, typename Enum>
 MG_ENUM_NAME_CNSTXPR inline auto enum_name(Enum e) noexcept
-    -> detail::string_view {
+    -> detail::string_or_view_t<Enum> {
     static_assert(Min < Max - 1, "Max must be greater than (Min + 1)!");
     static_assert(std::is_enum<Enum>::value, "Value is not an Enum type!");
     return detail::enum_name_impl<Enum, Min, Max>(e);
@@ -471,7 +577,7 @@ MG_ENUM_NAME_CNSTXPR inline auto enum_name(Enum e) noexcept
 template <typename Enum, int Min = enum_range<Enum>::min,
           int Max = enum_range<Enum>::max>
 MG_ENUM_NAME_CNSTXPR inline auto enum_name(Enum e) noexcept
-    -> detail::string_view {
+    -> detail::string_or_view_t<Enum> {
     static_assert(Min < Max - 1, "Max must be greater than (Min + 1)!");
     static_assert(std::is_enum<Enum>::value, "Value is not an Enum type!");
     return detail::enum_name_impl<Enum, Min, Max>(e);
@@ -484,13 +590,24 @@ auto enum_for_each<Enum>::enum_iter::operator*() const -> value_type {
 }
 
 template <typename Enum, int Min = enum_range<Enum>::min,
-          int Max = enum_range<Enum>::max>
+          int Max = enum_range<Enum>::max,
+          detail::enable_if_t<!detail::has_bit_or<Enum>::value, bool> = true>
 MG_ENUM_NAME_CNSTXPR inline auto to_enum(detail::string_view str) noexcept
     -> detail::optional<Enum> {
     static_assert(Min < Max - 1, "Max must be greater than (Min + 1)!");
     static_assert(std::is_enum<Enum>::value, "Type is not an Enum type!");
     return detail::to_enum_impl<Enum, Min, Max>(str);
 }
+
+template <typename Enum, int Min = enum_range<Enum>::min,
+          int Max = enum_range<Enum>::max,
+          detail::enable_if_t<detail::has_bit_or<Enum>::value, bool> = true>
+MG_ENUM_NAME_CNSTXPR inline auto to_enum(detail::string_view str) noexcept
+    -> detail::optional<Enum> {
+    static_assert(Min < Max - 1, "Max must be greater than (Min + 1)!");
+    static_assert(std::is_enum<Enum>::value, "Type is not an Enum type!");
+    return detail::to_enum_bitmask_impl<Enum, Min, Max>(str);
+}
 }  // namespace mgutility
 
 template <typename Enum,
@@ -501,4 +618,19 @@ auto operator<<(std::ostream& os, Enum e) -> std::ostream& {
     return os;
 }
 
-#endif  // MGUTILITY_ENUM_NAME_HPP
+#if defined(__cpp_lib_format)
+
+#include <format>
+
+template <typename Enum>
+    requires std::is_enum_v<Enum>
+struct std::formatter<Enum> : formatter<std::string_view> {
+    auto constexpr format(Enum e, format_context& ctx) const {
+        return formatter<std::string_view>::format(mgutility::enum_name(e),
+                                                   ctx);
+    }
+};
+
+#endif
+
+#endif  // MGUTILITY_ENUM_NAME_HPP