1 /* $NetBSD: ltm.c,v 1.11 2023/06/08 21:12:08 nikita Exp $ */
2
3 /*
4 ** Id: ltm.c
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 /* _KERNEL */
18
19 #include "lua.h"
20
21 #include "ldebug.h"
22 #include "ldo.h"
23 #include "lgc.h"
24 #include "lobject.h"
25 #include "lstate.h"
26 #include "lstring.h"
27 #include "ltable.h"
28 #include "ltm.h"
29 #include "lvm.h"
30
31
32 static const char udatatypename[] = "userdata";
33
34 LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTYPES] = {
35 "no value",
36 "nil", "boolean", udatatypename, "number",
37 "string", "table", "function", udatatypename, "thread",
38 "upvalue", "proto" /* these last cases are used for tests only */
39 };
40
41
luaT_init(lua_State * L)42 void luaT_init (lua_State *L) {
43 static const char *const luaT_eventname[] = { /* ORDER TM */
44 "__index", "__newindex",
45 "__gc", "__mode", "__len", "__eq",
46 #ifndef _KERNEL
47 "__add", "__sub", "__mul", "__mod", "__pow",
48 "__div", "__idiv",
49 #else /* _KERNEL */
50 "__add", "__sub", "__mul", "__mod",
51 "__idiv",
52 #endif /* _KERNEL */
53 "__band", "__bor", "__bxor", "__shl", "__shr",
54 "__unm", "__bnot", "__lt", "__le",
55 "__concat", "__call", "__close"
56 };
57 int i;
58 for (i=0; i<TM_N; i++) {
59 G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
60 luaC_fix(L, obj2gco(G(L)->tmname[i])); /* never collect these names */
61 }
62 }
63
64
65 /*
66 ** function to be used with macro "fasttm": optimized for absence of
67 ** tag methods
68 */
luaT_gettm(Table * events,TMS event,TString * ename)69 const TValue *luaT_gettm (Table *events, TMS event, TString *ename) {
70 const TValue *tm = luaH_getshortstr(events, ename);
71 lua_assert(event <= TM_EQ);
72 if (notm(tm)) { /* no tag method? */
73 events->flags |= cast_byte(1u<<event); /* cache this fact */
74 return NULL;
75 }
76 else return tm;
77 }
78
79
luaT_gettmbyobj(lua_State * L,const TValue * o,TMS event)80 const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) {
81 Table *mt;
82 switch (ttype(o)) {
83 case LUA_TTABLE:
84 mt = hvalue(o)->metatable;
85 break;
86 case LUA_TUSERDATA:
87 mt = uvalue(o)->metatable;
88 break;
89 default:
90 mt = G(L)->mt[ttype(o)];
91 }
92 return (mt ? luaH_getshortstr(mt, G(L)->tmname[event]) : &G(L)->nilvalue);
93 }
94
95
96 /*
97 ** Return the name of the type of an object. For tables and userdata
98 ** with metatable, use their '__name' metafield, if present.
99 */
luaT_objtypename(lua_State * L,const TValue * o)100 const char *luaT_objtypename (lua_State *L, const TValue *o) {
101 Table *mt;
102 if ((ttistable(o) && (mt = hvalue(o)->metatable) != NULL) ||
103 (ttisfulluserdata(o) && (mt = uvalue(o)->metatable) != NULL)) {
104 const TValue *name = luaH_getshortstr(mt, luaS_new(L, "__name"));
105 if (ttisstring(name)) /* is '__name' a string? */
106 return getstr(tsvalue(name)); /* use it as type name */
107 }
108 return ttypename(ttype(o)); /* else use standard type name */
109 }
110
111
luaT_callTM(lua_State * L,const TValue * f,const TValue * p1,const TValue * p2,const TValue * p3)112 void luaT_callTM (lua_State *L, const TValue *f, const TValue *p1,
113 const TValue *p2, const TValue *p3) {
114 StkId func = L->top.p;
115 setobj2s(L, func, f); /* push function (assume EXTRA_STACK) */
116 setobj2s(L, func + 1, p1); /* 1st argument */
117 setobj2s(L, func + 2, p2); /* 2nd argument */
118 setobj2s(L, func + 3, p3); /* 3rd argument */
119 L->top.p = func + 4;
120 /* metamethod may yield only when called from Lua code */
121 if (isLuacode(L->ci))
122 luaD_call(L, func, 0);
123 else
124 luaD_callnoyield(L, func, 0);
125 }
126
127
luaT_callTMres(lua_State * L,const TValue * f,const TValue * p1,const TValue * p2,StkId res)128 void luaT_callTMres (lua_State *L, const TValue *f, const TValue *p1,
129 const TValue *p2, StkId res) {
130 ptrdiff_t result = savestack(L, res);
131 StkId func = L->top.p;
132 setobj2s(L, func, f); /* push function (assume EXTRA_STACK) */
133 setobj2s(L, func + 1, p1); /* 1st argument */
134 setobj2s(L, func + 2, p2); /* 2nd argument */
135 L->top.p += 3;
136 /* metamethod may yield only when called from Lua code */
137 if (isLuacode(L->ci))
138 luaD_call(L, func, 1);
139 else
140 luaD_callnoyield(L, func, 1);
141 res = restorestack(L, result);
142 setobjs2s(L, res, --L->top.p); /* move result to its place */
143 }
144
145
callbinTM(lua_State * L,const TValue * p1,const TValue * p2,StkId res,TMS event)146 static int callbinTM (lua_State *L, const TValue *p1, const TValue *p2,
147 StkId res, TMS event) {
148 const TValue *tm = luaT_gettmbyobj(L, p1, event); /* try first operand */
149 if (notm(tm))
150 tm = luaT_gettmbyobj(L, p2, event); /* try second operand */
151 if (notm(tm)) return 0;
152 luaT_callTMres(L, tm, p1, p2, res);
153 return 1;
154 }
155
156
luaT_trybinTM(lua_State * L,const TValue * p1,const TValue * p2,StkId res,TMS event)157 void luaT_trybinTM (lua_State *L, const TValue *p1, const TValue *p2,
158 StkId res, TMS event) {
159 if (l_unlikely(!callbinTM(L, p1, p2, res, event))) {
160 switch (event) {
161 case TM_BAND: case TM_BOR: case TM_BXOR:
162 case TM_SHL: case TM_SHR: case TM_BNOT: {
163 if (ttisnumber(p1) && ttisnumber(p2))
164 luaG_tointerror(L, p1, p2);
165 else
166 luaG_opinterror(L, p1, p2, "perform bitwise operation on");
167 }
168 /* calls never return, but to avoid warnings: *//* FALLTHROUGH */
169 default:
170 luaG_opinterror(L, p1, p2, "perform arithmetic on");
171 }
172 }
173 }
174
175
luaT_tryconcatTM(lua_State * L)176 void luaT_tryconcatTM (lua_State *L) {
177 StkId top = L->top.p;
178 if (l_unlikely(!callbinTM(L, s2v(top - 2), s2v(top - 1), top - 2,
179 TM_CONCAT)))
180 luaG_concaterror(L, s2v(top - 2), s2v(top - 1));
181 }
182
183
luaT_trybinassocTM(lua_State * L,const TValue * p1,const TValue * p2,int flip,StkId res,TMS event)184 void luaT_trybinassocTM (lua_State *L, const TValue *p1, const TValue *p2,
185 int flip, StkId res, TMS event) {
186 if (flip)
187 luaT_trybinTM(L, p2, p1, res, event);
188 else
189 luaT_trybinTM(L, p1, p2, res, event);
190 }
191
192
luaT_trybiniTM(lua_State * L,const TValue * p1,lua_Integer i2,int flip,StkId res,TMS event)193 void luaT_trybiniTM (lua_State *L, const TValue *p1, lua_Integer i2,
194 int flip, StkId res, TMS event) {
195 TValue aux;
196 setivalue(&aux, i2);
197 luaT_trybinassocTM(L, p1, &aux, flip, res, event);
198 }
199
200
201 /*
202 ** Calls an order tag method.
203 ** For lessequal, LUA_COMPAT_LT_LE keeps compatibility with old
204 ** behavior: if there is no '__le', try '__lt', based on l <= r iff
205 ** !(r < l) (assuming a total order). If the metamethod yields during
206 ** this substitution, the continuation has to know about it (to negate
207 ** the result of r<l); bit CIST_LEQ in the call status keeps that
208 ** information.
209 */
luaT_callorderTM(lua_State * L,const TValue * p1,const TValue * p2,TMS event)210 int luaT_callorderTM (lua_State *L, const TValue *p1, const TValue *p2,
211 TMS event) {
212 if (callbinTM(L, p1, p2, L->top.p, event)) /* try original event */
213 return !l_isfalse(s2v(L->top.p));
214 #if defined(LUA_COMPAT_LT_LE)
215 else if (event == TM_LE) {
216 /* try '!(p2 < p1)' for '(p1 <= p2)' */
217 L->ci->callstatus |= CIST_LEQ; /* mark it is doing 'lt' for 'le' */
218 if (callbinTM(L, p2, p1, L->top.p, TM_LT)) {
219 L->ci->callstatus ^= CIST_LEQ; /* clear mark */
220 return l_isfalse(s2v(L->top.p));
221 }
222 /* else error will remove this 'ci'; no need to clear mark */
223 }
224 #endif
225 luaG_ordererror(L, p1, p2); /* no metamethod found */
226 return 0; /* to avoid warnings */
227 }
228
229
luaT_callorderiTM(lua_State * L,const TValue * p1,int v2,int flip,int isfloat,TMS event)230 int luaT_callorderiTM (lua_State *L, const TValue *p1, int v2,
231 int flip, int isfloat, TMS event) {
232 TValue aux; const TValue *p2;
233 #ifndef _KERNEL
234 if (isfloat) {
235 setfltvalue(&aux, cast_num(v2));
236 }
237 else
238 #endif /* _KERNEL */
239 setivalue(&aux, v2);
240 if (flip) { /* arguments were exchanged? */
241 p2 = p1; p1 = &aux; /* correct them */
242 }
243 else
244 p2 = &aux;
245 return luaT_callorderTM(L, p1, p2, event);
246 }
247
248
luaT_adjustvarargs(lua_State * L,int nfixparams,CallInfo * ci,const Proto * p)249 void luaT_adjustvarargs (lua_State *L, int nfixparams, CallInfo *ci,
250 const Proto *p) {
251 int i;
252 int actual = cast_int(L->top.p - ci->func.p) - 1; /* number of arguments */
253 int nextra = actual - nfixparams; /* number of extra arguments */
254 ci->u.l.nextraargs = nextra;
255 luaD_checkstack(L, p->maxstacksize + 1);
256 /* copy function to the top of the stack */
257 setobjs2s(L, L->top.p++, ci->func.p);
258 /* move fixed parameters to the top of the stack */
259 for (i = 1; i <= nfixparams; i++) {
260 setobjs2s(L, L->top.p++, ci->func.p + i);
261 setnilvalue(s2v(ci->func.p + i)); /* erase original parameter (for GC) */
262 }
263 ci->func.p += actual + 1;
264 ci->top.p += actual + 1;
265 lua_assert(L->top.p <= ci->top.p && ci->top.p <= L->stack_last.p);
266 }
267
268
luaT_getvarargs(lua_State * L,CallInfo * ci,StkId where,int wanted)269 void luaT_getvarargs (lua_State *L, CallInfo *ci, StkId where, int wanted) {
270 int i;
271 int nextra = ci->u.l.nextraargs;
272 if (wanted < 0) {
273 wanted = nextra; /* get all extra arguments available */
274 checkstackGCp(L, nextra, where); /* ensure stack space */
275 L->top.p = where + nextra; /* next instruction will need top */
276 }
277 for (i = 0; i < wanted && i < nextra; i++)
278 setobjs2s(L, where + i, ci->func.p - nextra + i);
279 for (; i < wanted; i++) /* complete required results with nil */
280 setnilvalue(s2v(where + i));
281 }
282
283