/*
** $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);
}