1 /* $NetBSD: ltm.c,v 1.4 2015/10/08 13:21:00 mbalmer Exp $ */
2
3 /*
4 ** Id: ltm.c,v 2.34 2015/03/30 15:42:27 roberto Exp
5 ** Tag methods
6 ** See Copyright Notice in lua.h
7 */
8
9 #define ltm_c
10 #define LUA_CORE
11
12 #include "lprefix.h"
13
14
15 #ifndef _KERNEL
16 #include <string.h>
17 #endif
18
19 #include "lua.h"
20
21 #include "ldebug.h"
22 #include "ldo.h"
23 #include "lobject.h"
24 #include "lstate.h"
25 #include "lstring.h"
26 #include "ltable.h"
27 #include "ltm.h"
28 #include "lvm.h"
29
30
31 static const char udatatypename[] = "userdata";
32
33 LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTAGS] = {
34 "no value",
35 "nil", "boolean", udatatypename, "number",
36 "string", "table", "function", udatatypename, "thread",
37 "proto" /* this last case is used for tests only */
38 };
39
40
luaT_init(lua_State * L)41 void luaT_init (lua_State *L) {
42 static const char *const luaT_eventname[] = { /* ORDER TM */
43 "__index", "__newindex",
44 "__gc", "__mode", "__len", "__eq",
45 #ifndef _KERNEL
46 "__add", "__sub", "__mul", "__mod", "__pow",
47 "__div", "__idiv",
48 #else
49 "__add", "__sub", "__mul", "__mod",
50 "__idiv",
51 #endif
52 "__band", "__bor", "__bxor", "__shl", "__shr",
53 "__unm", "__bnot", "__lt", "__le",
54 "__concat", "__call"
55 };
56 int i;
57 for (i=0; i<TM_N; i++) {
58 G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
59 luaC_fix(L, obj2gco(G(L)->tmname[i])); /* never collect these names */
60 }
61 }
62
63
64 /*
65 ** function to be used with macro "fasttm": optimized for absence of
66 ** tag methods
67 */
luaT_gettm(Table * events,TMS event,TString * ename)68 const TValue *luaT_gettm (Table *events, TMS event, TString *ename) {
69 const TValue *tm = luaH_getstr(events, ename);
70 lua_assert(event <= TM_EQ);
71 if (ttisnil(tm)) { /* no tag method? */
72 events->flags |= cast_byte(1u<<event); /* cache this fact */
73 return NULL;
74 }
75 else return tm;
76 }
77
78
luaT_gettmbyobj(lua_State * L,const TValue * o,TMS event)79 const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) {
80 Table *mt;
81 switch (ttnov(o)) {
82 case LUA_TTABLE:
83 mt = hvalue(o)->metatable;
84 break;
85 case LUA_TUSERDATA:
86 mt = uvalue(o)->metatable;
87 break;
88 default:
89 mt = G(L)->mt[ttnov(o)];
90 }
91 return (mt ? luaH_getstr(mt, G(L)->tmname[event]) : luaO_nilobject);
92 }
93
94
luaT_callTM(lua_State * L,const TValue * f,const TValue * p1,const TValue * p2,TValue * p3,int hasres)95 void luaT_callTM (lua_State *L, const TValue *f, const TValue *p1,
96 const TValue *p2, TValue *p3, int hasres) {
97 ptrdiff_t result = savestack(L, p3);
98 setobj2s(L, L->top++, f); /* push function (assume EXTRA_STACK) */
99 setobj2s(L, L->top++, p1); /* 1st argument */
100 setobj2s(L, L->top++, p2); /* 2nd argument */
101 if (!hasres) /* no result? 'p3' is third argument */
102 setobj2s(L, L->top++, p3); /* 3rd argument */
103 /* metamethod may yield only when called from Lua code */
104 luaD_call(L, L->top - (4 - hasres), hasres, isLua(L->ci));
105 if (hasres) { /* if has result, move it to its place */
106 p3 = restorestack(L, result);
107 setobjs2s(L, p3, --L->top);
108 }
109 }
110
111
luaT_callbinTM(lua_State * L,const TValue * p1,const TValue * p2,StkId res,TMS event)112 int luaT_callbinTM (lua_State *L, const TValue *p1, const TValue *p2,
113 StkId res, TMS event) {
114 const TValue *tm = luaT_gettmbyobj(L, p1, event); /* try first operand */
115 if (ttisnil(tm))
116 tm = luaT_gettmbyobj(L, p2, event); /* try second operand */
117 if (ttisnil(tm)) return 0;
118 luaT_callTM(L, tm, p1, p2, res, 1);
119 return 1;
120 }
121
122
luaT_trybinTM(lua_State * L,const TValue * p1,const TValue * p2,StkId res,TMS event)123 void luaT_trybinTM (lua_State *L, const TValue *p1, const TValue *p2,
124 StkId res, TMS event) {
125 if (!luaT_callbinTM(L, p1, p2, res, event)) {
126 switch (event) {
127 case TM_CONCAT:
128 luaG_concaterror(L, p1, p2);
129 /* call never returns, but to avoid warnings: *//* FALLTHROUGH */
130 case TM_BAND: case TM_BOR: case TM_BXOR:
131 case TM_SHL: case TM_SHR: case TM_BNOT: {
132 lua_Number dummy;
133 if (tonumber(p1, &dummy) && tonumber(p2, &dummy))
134 luaG_tointerror(L, p1, p2);
135 else
136 luaG_opinterror(L, p1, p2, "perform bitwise operation on");
137 }
138 /* calls never return, but to avoid warnings: *//* FALLTHROUGH */
139 default:
140 luaG_opinterror(L, p1, p2, "perform arithmetic on");
141 }
142 }
143 }
144
145
luaT_callorderTM(lua_State * L,const TValue * p1,const TValue * p2,TMS event)146 int luaT_callorderTM (lua_State *L, const TValue *p1, const TValue *p2,
147 TMS event) {
148 if (!luaT_callbinTM(L, p1, p2, L->top, event))
149 return -1; /* no metamethod */
150 else
151 return !l_isfalse(L->top);
152 }
153
154