#include <stdio.h>
#include <stdint.h>
#include <lua.h>
#include <lauxlib.h>

static int u64_to_num(lua_State* L) {
    #ifndef LUA_NUMBER_DOUBLE
    #error Lua must be compiled with number as a double floating point
    #endif

    const uint64_t h1 = luaL_checkint(L, 1);
    const uint64_t h2 = luaL_checkint(L, 2);

    const uint64_t stacked = (h2 << 32) | h1;

    double res = *(double *)((char *)&stacked);
    lua_pushnumber(L, res);

    return 1;
}

static const struct luaL_Reg lib[] = {
    {"u64_to_num", u64_to_num},
    {NULL, NULL}
};

int luaopen_lunaclib(lua_State *L) {
    luaL_openlib(L, "lunaclib", lib, 0);
    return 1;
}