#include <lua.h>

#include <lauxlib.h>

#ifndef LUA_MAXINTEGER

#include <stdint.h>

#define LUA_MAXINTEGER PTRDIFF_MAX

#endif

static int Lcreate_table(lua_State *L) {

	lua_createtable(L, luaL_checkinteger(L, 1), luaL_checkinteger(L, 2));

	return 1;

}

/* COMPAT: w/ Lua pre-5.2 */

static int Lpack(lua_State *L) {

	unsigned int n_args = lua_gettop(L);

	lua_createtable(L, n_args, 1);

	lua_insert(L, 1);

	for(int arg = n_args; arg >= 1; arg--) {

		lua_rawseti(L, 1, arg);

	}

	lua_pushinteger(L, n_args);

	lua_setfield(L, -2, "n");

	return 1;

}

/* COMPAT: w/ Lua pre-5.4 */

static int Lmove (lua_State *L) {

	lua_Integer f = luaL_checkinteger(L, 2);

	lua_Integer e = luaL_checkinteger(L, 3);

	lua_Integer t = luaL_checkinteger(L, 4);

	int tt = !lua_isnoneornil(L, 5) ? 5 : 1;  /* destination table */

	luaL_checktype(L, 1, LUA_TTABLE);

	luaL_checktype(L, tt, LUA_TTABLE);

	if (e >= f) {  /* otherwise, nothing to move */

		lua_Integer n, i;

		luaL_argcheck(L, f > 0 || e < LUA_MAXINTEGER + f, 3,

		  "too many elements to move");

		n = e - f + 1;  /* number of elements to move */

		luaL_argcheck(L, t <= LUA_MAXINTEGER - n + 1, 4,

		"destination wrap around");

		if (t > e || t <= f || (tt != 1 && !lua_compare(L, 1, tt, LUA_OPEQ))) {

			for (i = 0; i < n; i++) {

				lua_rawgeti(L, 1, f + i);

				lua_rawseti(L, tt, t + i);

			}

		} else {

			for (i = n - 1; i >= 0; i--) {

				lua_rawgeti(L, 1, f + i);

				lua_rawseti(L, tt, t + i);

			}

		}

	}

	lua_pushvalue(L, tt);  /* return destination table */

	return 1;

}

int luaopen_util_table(lua_State *L) {

	luaL_checkversion(L);

	lua_createtable(L, 0, 2);

	lua_pushcfunction(L, Lcreate_table);

	lua_setfield(L, -2, "create");

	lua_pushcfunction(L, Lpack);

	lua_setfield(L, -2, "pack");

	lua_pushcfunction(L, Lmove);

	lua_setfield(L, -2, "move");

	return 1;

}