1 /* 2 ** $Id: ltm.c,v 2.14.1.1 2013/04/12 18:48:47 roberto Exp $ 3 ** Tag methods 4 ** See Copyright Notice in lua.h 5 */ 6 7 8 #define ltm_c 9 #define LUA_CORE 10 11 #include <sys/lua/lua.h> 12 13 #include "lobject.h" 14 #include "lstate.h" 15 #include "lstring.h" 16 #include "ltable.h" 17 #include "ltm.h" 18 19 20 static const char udatatypename[] = "userdata"; 21 22 LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTAGS] = { 23 "no value", 24 "nil", "boolean", udatatypename, "number", 25 "string", "table", "function", udatatypename, "thread", 26 "proto", "upval" /* these last two cases are used for tests only */ 27 }; 28 29 30 void luaT_init (lua_State *L) { 31 static const char *const luaT_eventname[] = { /* ORDER TM */ 32 "__index", "__newindex", 33 "__gc", "__mode", "__len", "__eq", 34 "__add", "__sub", "__mul", "__div", "__mod", 35 "__pow", "__unm", "__lt", "__le", 36 "__concat", "__call" 37 }; 38 int i; 39 for (i=0; i<TM_N; i++) { 40 G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]); 41 luaS_fix(G(L)->tmname[i]); /* never collect these names */ 42 } 43 } 44 45 46 /* 47 ** function to be used with macro "fasttm": optimized for absence of 48 ** tag methods 49 */ 50 const TValue *luaT_gettm (Table *events, TMS event, TString *ename) { 51 const TValue *tm = luaH_getstr(events, ename); 52 lua_assert(event <= TM_EQ); 53 if (ttisnil(tm)) { /* no tag method? */ 54 events->flags |= cast_byte(1u<<event); /* cache this fact */ 55 return NULL; 56 } 57 else return tm; 58 } 59 60 61 const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) { 62 Table *mt; 63 switch (ttypenv(o)) { 64 case LUA_TTABLE: 65 mt = hvalue(o)->metatable; 66 break; 67 case LUA_TUSERDATA: 68 mt = uvalue(o)->metatable; 69 break; 70 default: 71 mt = G(L)->mt[ttypenv(o)]; 72 } 73 return (mt ? luaH_getstr(mt, G(L)->tmname[event]) : luaO_nilobject); 74 } 75