File

util-src/compat.c @ 10571:cfeb0077c9e9

net.server_epoll: Avoid concatenating buffer with single item Saves creating a string that'll be identical to buffer[1] anyways, as well as a C function call. Depending on Lua version and length of the string, this could be reusing an interned string, but a longer one would probably be duplicated for no reason. Having exactly one item in the buffer seems like it would be fairly common, but I have not done an extensive study. If opportunistic writes are enabled then it will be even more likely. This special case could be optimized like this in table.concat but it does not look like it is.
author Kim Alvefur <zash@zash.se>
date Sat, 28 Dec 2019 06:18:58 +0100
parent 9561:cfc7b2f7251e
child 12976:a187600ec7d6
line wrap: on
line source


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


static int lc_xpcall (lua_State *L) {
  int ret;
  int n_arg = lua_gettop(L);
  /* f, msgh, p1, p2... */
  luaL_argcheck(L, n_arg >= 2, 2, "value expected");
  lua_pushvalue(L, 1);  /* f to top */
  lua_pushvalue(L, 2);  /* msgh to top */
  lua_replace(L, 1); /* msgh to 1 */
  lua_replace(L, 2); /* f to 2 */
  /* msgh, f, p1, p2... */
  ret = lua_pcall(L, n_arg - 2, LUA_MULTRET, 1);
  lua_pushboolean(L, ret == 0);
  lua_replace(L, 1);
  return lua_gettop(L);
}

int luaopen_util_compat(lua_State *L) {
	lua_createtable(L, 0, 2);
	{
		lua_pushcfunction(L, lc_xpcall);
		lua_setfield(L, -2, "xpcall");
	}
	return 1;
}