mirror/utils/enum_val_by_name.hpp

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#ifndef MIRROR_UTILS_ENUM_VAL_BY_NAME_1101180748_HPP
#define MIRROR_UTILS_ENUM_VAL_BY_NAME_1101180748_HPP

#include <mirror/meta_enum.hpp>
#include <map>
#include <cstring>

MIRROR_NAMESPACE_BEGIN

template <typename Enum>
class enum_value_by_name
{
private:
    struct ltcstr
    {
        bool operator()(const char* s1, const char* s2) const
        {
            return std::strcmp(s1, s2) < 0;
        }
    };

    template <typename ... Idx>
    static std::map<const char*, Enum, ltcstr>
    cache_vals_by_names(mp::range<Idx ...>)
    {
        return {
            std::pair<const char*, Enum>(
                mirror::_enum::_<Enum>::item_name(Idx()),
                mirror::_enum::_<Enum>::item_val_c(Idx())
            )...
        };
    }

    static const std::map<const char*, Enum, ltcstr>&
    value_by_name_cache(void)
    {
        typename mp::make_index_seq<
            typename mirror::_enum::_<Enum>::item_count
        >::type indices;
        static auto cache = cache_vals_by_names(indices);
        return cache;
    }
public:
    static bool has(const std::string& name)
    {
        auto pos = value_by_name_cache().find(name.c_str());
        return (pos != value_by_name_cache().end());
    }


    static Enum get(const std::string& name)
    {
        auto pos = value_by_name_cache().find(name.c_str());
        assert(pos != value_by_name_cache().end());
        return pos->second;
    }


    static std::pair<bool, Enum> get_opt(const std::string& name)
    {
        auto pos = value_by_name_cache().find(name.c_str());
        if(pos == value_by_name_cache().end())
            return std::pair<bool, Enum>(false, Enum());
        return std::pair<bool, Enum>(true, pos->second);
    }
};

MIRROR_NAMESPACE_END

#endif //include guard