misc/liblua/ltm.c
author belphegorr <szabibibi@gmail.com>
Mon, 23 Jul 2012 19:15:59 +0300
changeset 7263 644eabbc9218
parent 2812 0a24853de796
permissions -rw-r--r--
Added a new function: AddNewEvent, which only adds an event to the list if it doesn't already exist. Kept the old one as it might me useful to be able to add an event more than once.

/*
** $Id: ltm.c,v 2.8.1.1 2007/12/27 13:02:25 roberto Exp $
** Tag methods
** See Copyright Notice in lua.h
*/


#include <string.h>

#define ltm_c
#define LUA_CORE

#include "lua.h"

#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"



const char *const luaT_typenames[] = {
  "nil", "boolean", "userdata", "number",
  "string", "table", "function", "userdata", "thread",
  "proto", "upval"
};


void luaT_init (lua_State *L) {
  static const char *const luaT_eventname[] = {  /* ORDER TM */
    "__index", "__newindex",
    "__gc", "__mode", "__eq",
    "__add", "__sub", "__mul", "__div", "__mod",
    "__pow", "__unm", "__len", "__lt", "__le",
    "__concat", "__call"
  };
  int i;
  for (i=0; i<TM_N; i++) {
    G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
    luaS_fix(G(L)->tmname[i]);  /* never collect these names */
  }
}


/*
** function to be used with macro "fasttm": optimized for absence of
** tag methods
*/
const TValue *luaT_gettm (Table *events, TMS event, TString *ename) {
  const TValue *tm = luaH_getstr(events, ename);
  lua_assert(event <= TM_EQ);
  if (ttisnil(tm)) {  /* no tag method? */
    events->flags |= cast_byte(1u<<event);  /* cache this fact */
    return NULL;
  }
  else return tm;
}


const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) {
  Table *mt;
  switch (ttype(o)) {
    case LUA_TTABLE:
      mt = hvalue(o)->metatable;
      break;
    case LUA_TUSERDATA:
      mt = uvalue(o)->metatable;
      break;
    default:
      mt = G(L)->mt[ttype(o)];
  }
  return (mt ? luaH_getstr(mt, G(L)->tmname[event]) : luaO_nilobject);
}