77 lines · 1.8 KB · C
RawDownload
/*** $Id: ltm.c,v 2.14 2011/06/02 19:31:40 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"  static const char udatatypename[] = "userdata"; LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTAGS] = {  "no value",  "nil", "boolean", udatatypename, "number",  "string", "table", "function", udatatypename, "thread",  "proto", "upval"  /* these last two cases are used for tests only */};  void luaT_init (lua_State *L) {  static const char *const luaT_eventname[] = {  /* ORDER TM */    "__index", "__newindex",    "__gc", "__mode", "__len", "__eq",    "__add", "__sub", "__mul", "__div", "__mod",    "__pow", "__unm", "__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 (ttypenv(o)) {    case LUA_TTABLE:      mt = hvalue(o)->metatable;      break;    case LUA_TUSERDATA:      mt = uvalue(o)->metatable;      break;    default:      mt = G(L)->mt[ttypenv(o)];  }  return (mt ? luaH_getstr(mt, G(L)->tmname[event]) : luaO_nilobject);}