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1 | /* | |
2 | ** $Id: ltm.c,v 2.14 2011/06/02 19:31:40 roberto Exp $ | |
3 | ** Tag methods | |
4 | ** See Copyright Notice in lua.h | |
5 | */ | |
6 | ||
7 | ||
8 | #include <string.h> | |
9 | ||
10 | #define ltm_c | |
11 | #define LUA_CORE | |
12 | ||
13 | #include "lua.h" | |
14 | ||
15 | #include "lobject.h" | |
16 | #include "lstate.h" | |
17 | #include "lstring.h" | |
18 | #include "ltable.h" | |
19 | #include "ltm.h" | |
20 | ||
21 | ||
22 | static const char udatatypename[] = "userdata"; | |
23 | ||
24 | LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTAGS] = { | |
25 | "no value", | |
26 | "nil", "boolean", udatatypename, "number", | |
27 | "string", "table", "function", udatatypename, "thread", | |
28 | "proto", "upval" /* these last two cases are used for tests only */ | |
29 | }; | |
30 | ||
31 | ||
32 | void luaT_init (lua_State *L) { | |
33 | static const char *const luaT_eventname[] = { /* ORDER TM */ | |
34 | "__index", "__newindex", | |
35 | "__gc", "__mode", "__len", "__eq", | |
36 | "__add", "__sub", "__mul", "__div", "__mod", | |
37 | "__pow", "__unm", "__lt", "__le", | |
38 | "__concat", "__call" | |
39 | }; | |
40 | int i; | |
41 | for (i=0; i<TM_N; i++) { | |
42 | G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]); | |
43 | luaS_fix(G(L)->tmname[i]); /* never collect these names */ | |
44 | } | |
45 | } | |
46 | ||
47 | ||
48 | /* | |
49 | ** function to be used with macro "fasttm": optimized for absence of | |
50 | ** tag methods | |
51 | */ | |
52 | const TValue *luaT_gettm (Table *events, TMS event, TString *ename) { | |
53 | const TValue *tm = luaH_getstr(events, ename); | |
54 | lua_assert(event <= TM_EQ); | |
55 | if (ttisnil(tm)) { /* no tag method? */ | |
56 | events->flags |= cast_byte(1u<<event); /* cache this fact */ | |
57 | return NULL; | |
58 | } | |
59 | else return tm; | |
60 | } | |
61 | ||
62 | ||
63 | const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) { | |
64 | Table *mt; | |
65 | switch (ttypenv(o)) { | |
66 | case LUA_TTABLE: | |
67 | mt = hvalue(o)->metatable; | |
68 | break; | |
69 | case LUA_TUSERDATA: | |
70 | mt = uvalue(o)->metatable; | |
71 | break; | |
72 | default: | |
73 | mt = G(L)->mt[ttypenv(o)]; | |
74 | } | |
75 | return (mt ? luaH_getstr(mt, G(L)->tmname[event]) : luaO_nilobject); | |
76 | } | |
77 |