From 834d9408ffa61a6e372cbb875b1652c0469c3f70 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Fri, 4 Feb 2022 18:01:07 +0300
Subject: [PATCH] Add psemek_declare_enum macro for common enum utilities

---
 libs/util/include/psemek/util/enum.hpp | 95 ++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 libs/util/include/psemek/util/enum.hpp

diff --git a/libs/util/include/psemek/util/enum.hpp b/libs/util/include/psemek/util/enum.hpp
new file mode 100644
index 00000000..7bf272b2
--- /dev/null
+++ b/libs/util/include/psemek/util/enum.hpp
@@ -0,0 +1,95 @@
+#pragma once
+
+#include <boost/preprocessor/seq/for_each.hpp>
+#include <boost/preprocessor/stringize.hpp>
+
+#include <psemek/util/to_string.hpp>
+#include <psemek/util/type_name.hpp>
+
+#include <string_view>
+#include <stdexcept>
+#include <type_traits>
+#include <optional>
+#include <unordered_map>
+
+namespace psemek::util
+{
+
+	struct unknown_enum_value_exception_base
+		: std::runtime_error
+	{
+		using std::runtime_error::runtime_error;
+	};
+
+	template <typename Enum>
+	struct unknown_enum_value_exception
+		: unknown_enum_value_exception_base
+	{
+		unknown_enum_value_exception(Enum value)
+			: unknown_enum_value_exception_base(to_string("unknown ", type_name<Enum>(), " value: ", static_cast<std::int64_t>(value)))
+			, value_(value)
+		{}
+
+		Enum value() const noexcept { return value_; }
+
+	private:
+		Enum value_;
+	};
+
+	template <typename Enum>
+	struct enum_iterator
+	{
+		using underlying_type = std::underlying_type_t<Enum>;
+
+		underlying_type value;
+
+		Enum operator *() const { return static_cast<Enum>(value); }
+
+		enum_iterator operator ++() { ++value; return *this; }
+		enum_iterator operator ++ (int)
+		{
+			enum_iterator copy = *this;
+			++(*this);
+			return copy;
+		}
+
+		friend bool operator == (enum_iterator const & it1, enum_iterator const & it2) = default;
+		friend bool operator != (enum_iterator const & it1, enum_iterator const & it2) = default;
+	};
+
+	template <typename Enum>
+	struct enum_range
+	{
+		enum_iterator<Enum> first, last;
+
+		auto begin() const { return first; }
+		auto end() const { return last; }
+	};
+
+}
+
+#define psemek_declare_enum_detail_enumerator(r, data, value) value,
+
+#define psemek_declare_enum_detail_to_string(r, data, value) case data :: value : return BOOST_PP_STRINGIZE(value);
+
+#define psemek_declare_enum_detail_from_string(r, data, value) { BOOST_PP_STRINGIZE(value), data::value },
+
+#define psemek_declare_enum(name, type, values) \
+	enum class name : type { \
+		BOOST_PP_SEQ_FOR_EACH(psemek_declare_enum_detail_enumerator, _, values) \
+	}; \
+	inline ::std::string_view to_string(name value) { \
+		switch (value) { \
+			BOOST_PP_SEQ_FOR_EACH(psemek_declare_enum_detail_to_string, name, values) \
+			default: throw ::psemek::util::unknown_enum_value_exception<name>(value); \
+		} \
+	} \
+	inline std::optional<name> BOOST_PP_CAT(name, _from_string)(::std::string_view str) { \
+		static const ::std::unordered_map<::std::string_view, name> map = { \
+			BOOST_PP_SEQ_FOR_EACH(psemek_declare_enum_detail_from_string, name, values) \
+		}; \
+		auto it = map.find(str); if (it == map.end()) return std::nullopt; return it->second; \
+	} \
+	inline ::psemek::util::enum_range<name> BOOST_PP_CAT(name, _values) () { return {0, BOOST_PP_SEQ_SIZE(values)}; }
+
+