File

util-src/strbitop.c @ 12469:2b3adaa6d38e

util.strbitop: Reduce scope of functions Equivalent to 'local' in Lua, these functions are exported via the luaopen_ function, which is the only one needing to be visible outside of the file. Pointed out by Link Mauve at some point, but there wasn't really any rush here.
author Kim Alvefur <zash@zash.se>
date Sat, 23 Apr 2022 14:29:43 +0200
parent 11175:235537247aa3
child 12575:1f6f05a98fcd
line wrap: on
line source

/*
 * This project is MIT licensed. Please see the
 * COPYING file in the source package for more information.
 *
 * Copyright (C) 2016 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 */

static 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);

	luaL_buffinit(L, &buf);

	if(a == 0 || b == 0) {
		lua_settop(L, 1);
		return 1;
	}

	for(i = 0; i < a; i++) {
		luaL_addchar(&buf, str_a[i] & str_b[i % b]);
	}

	luaL_pushresult(&buf);
	return 1;
}

static 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);

	luaL_buffinit(L, &buf);

	if(a == 0 || b == 0) {
		lua_settop(L, 1);
		return 1;
	}

	for(i = 0; i < a; i++) {
		luaL_addchar(&buf, str_a[i] | str_b[i % b]);
	}

	luaL_pushresult(&buf);
	return 1;
}

static 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);

	luaL_buffinit(L, &buf);

	if(a == 0 || b == 0) {
		lua_settop(L, 1);
		return 1;
	}

	for(i = 0; i < a; i++) {
		luaL_addchar(&buf, str_a[i] ^ str_b[i % b]);
	}

	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;
}