/*

 * This project is MIT licensed. Please see the

 * COPYING file in the source package for more information.

 *

 * Copyright (C) 2016-2020 Kim Alvefur

 */

#include <lua.h>

#include <lauxlib.h>

#if (LUA_VERSION_NUM == 501)

#define luaL_setfuncs(L, R, N) luaL_register(L, NULL, R)

#endif

/* TODO Deduplicate code somehow */

int strop_and(lua_State *L) {

	luaL_Buffer buf;

	size_t a, b, i;

	const char *str_a = luaL_checklstring(L, 1, &a);

	const char *str_b = luaL_checklstring(L, 2, &b);

	if(a == 0 || b == 0) {

		lua_settop(L, 1);

		return 1;

	}

	char *cbuf = luaL_buffinitsize(L, &buf, a);

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

		cbuf[i] = str_a[i] & str_b[i % b];

	}

	luaL_addsize(&buf, a);

	luaL_pushresult(&buf);

	return 1;

}

int strop_or(lua_State *L) {

	luaL_Buffer buf;

	size_t a, b, i;

	const char *str_a = luaL_checklstring(L, 1, &a);

	const char *str_b = luaL_checklstring(L, 2, &b);

	if(a == 0 || b == 0) {

		lua_settop(L, 1);

		return 1;

	}

	char *cbuf = luaL_buffinitsize(L, &buf, a);

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

		cbuf[i] = str_a[i] | str_b[i % b];

	}

	luaL_addsize(&buf, a);

	luaL_pushresult(&buf);

	return 1;

}

int strop_xor(lua_State *L) {

	luaL_Buffer buf;

	size_t a, b, i;

	const char *str_a = luaL_checklstring(L, 1, &a);

	const char *str_b = luaL_checklstring(L, 2, &b);

	if(a == 0 || b == 0) {

		lua_settop(L, 1);

		return 1;

	}

	char *cbuf = luaL_buffinitsize(L, &buf, a);

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

		cbuf[i] = str_a[i] ^ str_b[i % b];

	}

	luaL_addsize(&buf, a);

	luaL_pushresult(&buf);

	return 1;

}

LUA_API int luaopen_util_strbitop(lua_State *L) {

	luaL_Reg exports[] = {

		{ "sand", strop_and },

		{ "sor",  strop_or },

		{ "sxor", strop_xor },

		{ NULL, NULL }

	};

	lua_newtable(L);

	luaL_setfuncs(L, exports, 0);

	return 1;

}