1 /* BEGIN CSTYLED */ 2 /* 3 ** $Id: ltm.c,v 2.14.1.1 2013/04/12 18:48:47 roberto Exp $ 4 ** Tag methods 5 ** See Copyright Notice in lua.h 6 */ 7 8 9 #define ltm_c 10 #define LUA_CORE 11 12 #include <sys/lua/lua.h> 13 14 #include "lobject.h" 15 #include "lstate.h" 16 #include "lstring.h" 17 #include "ltable.h" 18 #include "ltm.h" 19 20 21 static const char udatatypename[] = "userdata"; 22 23 LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTAGS] = { 24 "no value", 25 "nil", "boolean", udatatypename, "number", 26 "string", "table", "function", udatatypename, "thread", 27 "proto", "upval" /* these last two cases are used for tests only */ 28 }; 29 30 31 void luaT_init (lua_State *L) { 32 static const char *const luaT_eventname[] = { /* ORDER TM */ 33 "__index", "__newindex", 34 "__gc", "__mode", "__len", "__eq", 35 "__add", "__sub", "__mul", "__div", "__mod", 36 "__pow", "__unm", "__lt", "__le", 37 "__concat", "__call" 38 }; 39 int i; 40 for (i=0; i<TM_N; i++) { 41 G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]); 42 luaS_fix(G(L)->tmname[i]); /* never collect these names */ 43 } 44 } 45 46 47 /* 48 ** function to be used with macro "fasttm": optimized for absence of 49 ** tag methods 50 */ 51 const TValue *luaT_gettm (Table *events, TMS event, TString *ename) { 52 const TValue *tm = luaH_getstr(events, ename); 53 lua_assert(event <= TM_EQ); 54 if (ttisnil(tm)) { /* no tag method? */ 55 events->flags |= cast_byte(1u<<event); /* cache this fact */ 56 return NULL; 57 } 58 else return tm; 59 } 60 61 62 const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) { 63 Table *mt; 64 switch (ttypenv(o)) { 65 case LUA_TTABLE: 66 mt = hvalue(o)->metatable; 67 break; 68 case LUA_TUSERDATA: 69 mt = uvalue(o)->metatable; 70 break; 71 default: 72 mt = G(L)->mt[ttypenv(o)]; 73 } 74 return (mt ? luaH_getstr(mt, G(L)->tmname[event]) : luaO_nilobject); 75 } 76 /* END CSTYLED */ 77