YimMenu/BigBaseV2/src/gta/joaat.hpp

#pragma once
#include <cstddef>
#include <cstdint>
#include <string_view>
#include <type_traits>

namespace rage
{
	using joaat_t = std::uint32_t;
	inline constexpr char joaat_to_lower(char c) { return (c >= 'A' && c <= 'Z') ? c + ('a' - 'A') : c; }

	template <std::size_t CharCount>
	struct constexpr_joaat {
		char data[CharCount];
		template <std::size_t... Indices>
		constexpr constexpr_joaat(const char *str, std::index_sequence<Indices...>) : data{ (str[Indices])... } {}
		constexpr joaat_t operator()()
		{
			joaat_t hash = 0;
			for (std::size_t i = 0; i < CharCount; ++i) {
				hash += joaat_to_lower(data[i]);
				hash += (hash << 10);
				hash ^= (hash >> 6);
			}
			hash += (hash << 3);
			hash ^= (hash >> 11);
			hash += (hash << 15);
			return hash;
		}
	};

	inline joaat_t joaat(std::string_view str)
	{
		joaat_t hash = 0;
		for (auto c : str) {
			hash += joaat_to_lower(c);
			hash += (hash << 10);
			hash ^= (hash >> 6);
		}
		hash += (hash << 3);
		hash ^= (hash >> 11);
		hash += (hash << 15);
		return hash;
	}
}

#define RAGE_JOAAT_IMPL(str) (::rage::constexpr_joaat<sizeof(str) - 1>((str), std::make_index_sequence<sizeof(str) - 1>())())
#define RAGE_JOAAT(str) (std::integral_constant<rage::joaat_t, RAGE_JOAAT_IMPL(str)>::value)