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simpler implementation for userdata types

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This commit is contained in:
Roberto Ierusalimschy
2005-08-18 17:36:26 -03:00
parent 3b828d9e48
commit 027e9e99ca
2 changed files with 8 additions and 19 deletions
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22
lauxlib.c
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@@ -1,5 +1,5 @@
/*
** $Id: lauxlib.c,v 1.146 2005/08/17 20:09:31 roberto Exp roberto $
** $Id: lauxlib.c,v 1.147 2005/08/18 16:04:05 roberto Exp roberto $
** Auxiliary functions for building Lua libraries
** See Copyright Notice in lua.h
*/
@@ -117,28 +117,16 @@ LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
lua_newtable(L); /* create metatable */
lua_pushvalue(L, -1);
lua_setfield(L, LUA_REGISTRYINDEX, tname); /* registry.name = metatable */
lua_pushvalue(L, -1);
lua_pushstring(L, tname);
lua_rawset(L, LUA_REGISTRYINDEX); /* registry[metatable] = name */
return 1;
}
LUALIB_API void luaL_getmetatable (lua_State *L, const char *tname) {
lua_getfield(L, LUA_REGISTRYINDEX, tname);
}
LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
void *p = lua_touserdata(L, ud);
const char *tn;
if (p == NULL || /* if is not a userdata? */
!lua_getmetatable(L, ud) || /* has no metatable? */
(lua_rawget(L, LUA_REGISTRYINDEX), /* get registry[metatable] */
(tn = lua_tostring(L, -1)) == NULL) || /* metatable not registered? */
(strcmp(tn, tname) != 0)) /* or wrong? */
luaL_typerror(L, ud, tname); /* then error */
lua_pop(L, 1); /* remove registry[metatable] */
lua_getfield(L, LUA_REGISTRYINDEX, tname); /* get correct metatable */
if (p == NULL || !lua_getmetatable(L, ud) || !lua_rawequal(L, -1, -2))
luaL_typerror(L, ud, tname);
lua_pop(L, 2); /* remove both metatables */
return p;
}