ba8b5c17 |
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 | |