Sophiar2/src/utility/string_map.hpp

#ifndef SOPHIAR2_STRING_MAP_HPP
#define SOPHIAR2_STRING_MAP_HPP

#include <cassert>
#include <string>
#include <string_view>
#include <type_traits>
#include <unordered_map>

namespace sophiar {

    template<typename T>
    class string_map {
    public:
        template<typename ...Args>
        void insert(std::string_view str, Args... args) {
            insert(hash_sv(str), std::forward<Args>(args)...);
        }

        bool contains(std::string_view str) const {
            return m.contains(hash_sv(str));
        }

        T &query(std::string_view str) {
            assert(contains(str));
            return m.at(hash_sv(str));
        }

        const T &query(std::string_view str) const {
            assert(contains(str));
            return m.at(hash_sv(str));
        }

        void clear() {
            m.clear();
        }

    private:
        static constexpr auto hash_sv = std::hash<std::string_view>{};
        std::unordered_map<std::size_t, T> m;

        template<typename ...Args>
        void insert(size_t index, Args... args) {
            static_assert(std::is_constructible_v<T, Args...>);
            assert(!m.contains(index));
            m.emplace(std::piecewise_construct,
                      std::forward_as_tuple(index),
                      std::forward_as_tuple(std::forward<Args>(args)...));
        }
    };

}

#endif //SOPHIAR2_STRING_MAP_HPP