1/*
2** $Id: lapi.c $
3** Lua API
4** See Copyright Notice in lua.h
5*/
6
7#define lapi_c
8#define LUA_CORE
9
10#include "lprefix.h"
11
12
13#include <limits.h>
14#include <stdarg.h>
15#include <string.h>
16
17#include "lua.h"
18
19#include "lapi.h"
20#include "ldebug.h"
21#include "ldo.h"
22#include "lfunc.h"
23#include "lgc.h"
24#include "lmem.h"
25#include "lobject.h"
26#include "lstate.h"
27#include "lstring.h"
28#include "ltable.h"
29#include "ltm.h"
30#include "lundump.h"
31#include "lvm.h"
32
33
34
35const char lua_ident[] =
36 "$LuaVersion: " LUA_COPYRIGHT " $"
37 "$LuaAuthors: " LUA_AUTHORS " $";
38
39
40
41/*
42** Test for a valid index (one that is not the 'nilvalue').
43** '!ttisnil(o)' implies 'o != &G(L)->nilvalue', so it is not needed.
44** However, it covers the most common cases in a faster way.
45*/
46#define isvalid(L, o) (!ttisnil(o) || o != &G(L)->nilvalue)
47
48
49/* test for pseudo index */
50#define ispseudo(i) ((i) <= LUA_REGISTRYINDEX)
51
52/* test for upvalue */
53#define isupvalue(i) ((i) < LUA_REGISTRYINDEX)
54
55
56/*
57** Convert an acceptable index to a pointer to its respective value.
58** Non-valid indices return the special nil value 'G(L)->nilvalue'.
59*/
60static TValue *index2value (lua_State *L, int idx) {
61 CallInfo *ci = L->ci;
62 if (idx > 0) {
63 StkId o = ci->func.p + idx;
64 api_check(L, idx <= ci->top.p - (ci->func.p + 1), "unacceptable index");
65 if (o >= L->top.p) return &G(L)->nilvalue;
66 else return s2v(o);
67 }
68 else if (!ispseudo(idx)) { /* negative index */
69 api_check(L, idx != 0 && -idx <= L->top.p - (ci->func.p + 1),
70 "invalid index");
71 return s2v(L->top.p + idx);
72 }
73 else if (idx == LUA_REGISTRYINDEX)
74 return &G(L)->l_registry;
75 else { /* upvalues */
76 idx = LUA_REGISTRYINDEX - idx;
77 api_check(L, idx <= MAXUPVAL + 1, "upvalue index too large");
78 if (ttisCclosure(s2v(ci->func.p))) { /* C closure? */
79 CClosure *func = clCvalue(s2v(ci->func.p));
80 return (idx <= func->nupvalues) ? &func->upvalue[idx-1]
81 : &G(L)->nilvalue;
82 }
83 else { /* light C function or Lua function (through a hook)?) */
84 api_check(L, ttislcf(s2v(ci->func.p)), "caller not a C function");
85 return &G(L)->nilvalue; /* no upvalues */
86 }
87 }
88}
89
90
91
92/*
93** Convert a valid actual index (not a pseudo-index) to its address.
94*/
95l_sinline StkId index2stack (lua_State *L, int idx) {
96 CallInfo *ci = L->ci;
97 if (idx > 0) {
98 StkId o = ci->func.p + idx;
99 api_check(L, o < L->top.p, "invalid index");
100 return o;
101 }
102 else { /* non-positive index */
103 api_check(L, idx != 0 && -idx <= L->top.p - (ci->func.p + 1),
104 "invalid index");
105 api_check(L, !ispseudo(idx), "invalid index");
106 return L->top.p + idx;
107 }
108}
109
110
111LUA_API int lua_checkstack (lua_State *L, int n) {
112 int res;
113 CallInfo *ci;
114 lua_lock(L);
115 ci = L->ci;
116 api_check(L, n >= 0, "negative 'n'");
117 if (L->stack_last.p - L->top.p > n) /* stack large enough? */
118 res = 1; /* yes; check is OK */
119 else /* need to grow stack */
120 res = luaD_growstack(L, n, 0);
121 if (res && ci->top.p < L->top.p + n)
122 ci->top.p = L->top.p + n; /* adjust frame top */
123 lua_unlock(L);
124 return res;
125}
126
127
128LUA_API void lua_xmove (lua_State *from, lua_State *to, int n) {
129 int i;
130 if (from == to) return;
131 lua_lock(to);
132 api_checknelems(from, n);
133 api_check(from, G(from) == G(to), "moving among independent states");
134 api_check(from, to->ci->top.p - to->top.p >= n, "stack overflow");
135 from->top.p -= n;
136 for (i = 0; i < n; i++) {
137 setobjs2s(to, to->top.p, from->top.p + i);
138 to->top.p++; /* stack already checked by previous 'api_check' */
139 }
140 lua_unlock(to);
141}
142
143
144LUA_API lua_CFunction lua_atpanic (lua_State *L, lua_CFunction panicf) {
145 lua_CFunction old;
146 lua_lock(L);
147 old = G(L)->panic;
148 G(L)->panic = panicf;
149 lua_unlock(L);
150 return old;
151}
152
153
154LUA_API lua_Number lua_version (lua_State *L) {
155 UNUSED(L);
156 return LUA_VERSION_NUM;
157}
158
159
160
161/*
162** basic stack manipulation
163*/
164
165
166/*
167** convert an acceptable stack index into an absolute index
168*/
169LUA_API int lua_absindex (lua_State *L, int idx) {
170 return (idx > 0 || ispseudo(idx))
171 ? idx
172 : cast_int(L->top.p - L->ci->func.p) + idx;
173}
174
175
176LUA_API int lua_gettop (lua_State *L) {
177 return cast_int(L->top.p - (L->ci->func.p + 1));
178}
179
180
181LUA_API void lua_settop (lua_State *L, int idx) {
182 CallInfo *ci;
183 StkId func, newtop;
184 ptrdiff_t diff; /* difference for new top */
185 lua_lock(L);
186 ci = L->ci;
187 func = ci->func.p;
188 if (idx >= 0) {
189 api_check(L, idx <= ci->top.p - (func + 1), "new top too large");
190 diff = ((func + 1) + idx) - L->top.p;
191 for (; diff > 0; diff--)
192 setnilvalue(s2v(L->top.p++)); /* clear new slots */
193 }
194 else {
195 api_check(L, -(idx+1) <= (L->top.p - (func + 1)), "invalid new top");
196 diff = idx + 1; /* will "subtract" index (as it is negative) */
197 }
198 api_check(L, L->tbclist.p < L->top.p, "previous pop of an unclosed slot");
199 newtop = L->top.p + diff;
200 if (diff < 0 && L->tbclist.p >= newtop) {
201 lua_assert(hastocloseCfunc(ci->nresults));
202 newtop = luaF_close(L, newtop, CLOSEKTOP, 0);
203 }
204 L->top.p = newtop; /* correct top only after closing any upvalue */
205 lua_unlock(L);
206}
207
208
209LUA_API void lua_closeslot (lua_State *L, int idx) {
210 StkId level;
211 lua_lock(L);
212 level = index2stack(L, idx);
213 api_check(L, hastocloseCfunc(L->ci->nresults) && L->tbclist.p == level,
214 "no variable to close at given level");
215 level = luaF_close(L, level, CLOSEKTOP, 0);
216 setnilvalue(s2v(level));
217 lua_unlock(L);
218}
219
220
221/*
222** Reverse the stack segment from 'from' to 'to'
223** (auxiliary to 'lua_rotate')
224** Note that we move(copy) only the value inside the stack.
225** (We do not move additional fields that may exist.)
226*/
227l_sinline void reverse (lua_State *L, StkId from, StkId to) {
228 for (; from < to; from++, to--) {
229 TValue temp;
230 setobj(L, &temp, s2v(from));
231 setobjs2s(L, from, to);
232 setobj2s(L, to, &temp);
233 }
234}
235
236
237/*
238** Let x = AB, where A is a prefix of length 'n'. Then,
239** rotate x n == BA. But BA == (A^r . B^r)^r.
240*/
241LUA_API void lua_rotate (lua_State *L, int idx, int n) {
242 StkId p, t, m;
243 lua_lock(L);
244 t = L->top.p - 1; /* end of stack segment being rotated */
245 p = index2stack(L, idx); /* start of segment */
246 api_check(L, (n >= 0 ? n : -n) <= (t - p + 1), "invalid 'n'");
247 m = (n >= 0 ? t - n : p - n - 1); /* end of prefix */
248 reverse(L, p, m); /* reverse the prefix with length 'n' */
249 reverse(L, m + 1, t); /* reverse the suffix */
250 reverse(L, p, t); /* reverse the entire segment */
251 lua_unlock(L);
252}
253
254
255LUA_API void lua_copy (lua_State *L, int fromidx, int toidx) {
256 TValue *fr, *to;
257 lua_lock(L);
258 fr = index2value(L, fromidx);
259 to = index2value(L, toidx);
260 api_check(L, isvalid(L, to), "invalid index");
261 setobj(L, to, fr);
262 if (isupvalue(toidx)) /* function upvalue? */
263 luaC_barrier(L, clCvalue(s2v(L->ci->func.p)), fr);
264 /* LUA_REGISTRYINDEX does not need gc barrier
265 (collector revisits it before finishing collection) */
266 lua_unlock(L);
267}
268
269
270LUA_API void lua_pushvalue (lua_State *L, int idx) {
271 lua_lock(L);
272 setobj2s(L, L->top.p, index2value(L, idx));
273 api_incr_top(L);
274 lua_unlock(L);
275}
276
277
278
279/*
280** access functions (stack -> C)
281*/
282
283
284LUA_API int lua_type (lua_State *L, int idx) {
285 const TValue *o = index2value(L, idx);
286 return (isvalid(L, o) ? ttype(o) : LUA_TNONE);
287}
288
289
290LUA_API const char *lua_typename (lua_State *L, int t) {
291 UNUSED(L);
292 api_check(L, LUA_TNONE <= t && t < LUA_NUMTYPES, "invalid type");
293 return ttypename(t);
294}
295
296
297LUA_API int lua_iscfunction (lua_State *L, int idx) {
298 const TValue *o = index2value(L, idx);
299 return (ttislcf(o) || (ttisCclosure(o)));
300}
301
302
303LUA_API int lua_isinteger (lua_State *L, int idx) {
304 const TValue *o = index2value(L, idx);
305 return ttisinteger(o);
306}
307
308
309LUA_API int lua_isnumber (lua_State *L, int idx) {
310 lua_Number n;
311 const TValue *o = index2value(L, idx);
312 return tonumber(o, &n);
313}
314
315
316LUA_API int lua_isstring (lua_State *L, int idx) {
317 const TValue *o = index2value(L, idx);
318 return (ttisstring(o) || cvt2str(o));
319}
320
321
322LUA_API int lua_isuserdata (lua_State *L, int idx) {
323 const TValue *o = index2value(L, idx);
324 return (ttisfulluserdata(o) || ttislightuserdata(o));
325}
326
327
328LUA_API int lua_rawequal (lua_State *L, int index1, int index2) {
329 const TValue *o1 = index2value(L, index1);
330 const TValue *o2 = index2value(L, index2);
331 return (isvalid(L, o1) && isvalid(L, o2)) ? luaV_rawequalobj(o1, o2) : 0;
332}
333
334
335LUA_API void lua_arith (lua_State *L, int op) {
336 lua_lock(L);
337 if (op != LUA_OPUNM && op != LUA_OPBNOT)
338 api_checknelems(L, 2); /* all other operations expect two operands */
339 else { /* for unary operations, add fake 2nd operand */
340 api_checknelems(L, 1);
341 setobjs2s(L, L->top.p, L->top.p - 1);
342 api_incr_top(L);
343 }
344 /* first operand at top - 2, second at top - 1; result go to top - 2 */
345 luaO_arith(L, op, s2v(L->top.p - 2), s2v(L->top.p - 1), L->top.p - 2);
346 L->top.p--; /* remove second operand */
347 lua_unlock(L);
348}
349
350
351LUA_API int lua_compare (lua_State *L, int index1, int index2, int op) {
352 const TValue *o1;
353 const TValue *o2;
354 int i = 0;
355 lua_lock(L); /* may call tag method */
356 o1 = index2value(L, index1);
357 o2 = index2value(L, index2);
358 if (isvalid(L, o1) && isvalid(L, o2)) {
359 switch (op) {
360 case LUA_OPEQ: i = luaV_equalobj(L, o1, o2); break;
361 case LUA_OPLT: i = luaV_lessthan(L, o1, o2); break;
362 case LUA_OPLE: i = luaV_lessequal(L, o1, o2); break;
363 default: api_check(L, 0, "invalid option");
364 }
365 }
366 lua_unlock(L);
367 return i;
368}
369
370
371LUA_API size_t lua_stringtonumber (lua_State *L, const char *s) {
372 size_t sz = luaO_str2num(s, s2v(L->top.p));
373 if (sz != 0)
374 api_incr_top(L);
375 return sz;
376}
377
378
379LUA_API lua_Number lua_tonumberx (lua_State *L, int idx, int *pisnum) {
380 lua_Number n = 0;
381 const TValue *o = index2value(L, idx);
382 int isnum = tonumber(o, &n);
383 if (pisnum)
384 *pisnum = isnum;
385 return n;
386}
387
388
389LUA_API lua_Integer lua_tointegerx (lua_State *L, int idx, int *pisnum) {
390 lua_Integer res = 0;
391 const TValue *o = index2value(L, idx);
392 int isnum = tointeger(o, &res);
393 if (pisnum)
394 *pisnum = isnum;
395 return res;
396}
397
398
399LUA_API int lua_toboolean (lua_State *L, int idx) {
400 const TValue *o = index2value(L, idx);
401 return !l_isfalse(o);
402}
403
404
405LUA_API const char *lua_tolstring (lua_State *L, int idx, size_t *len) {
406 TValue *o;
407 lua_lock(L);
408 o = index2value(L, idx);
409 if (!ttisstring(o)) {
410 if (!cvt2str(o)) { /* not convertible? */
411 if (len != NULL) *len = 0;
412 lua_unlock(L);
413 return NULL;
414 }
415 luaO_tostring(L, o);
416 luaC_checkGC(L);
417 o = index2value(L, idx); /* previous call may reallocate the stack */
418 }
419 if (len != NULL)
420 *len = tsslen(tsvalue(o));
421 lua_unlock(L);
422 return getstr(tsvalue(o));
423}
424
425
426LUA_API lua_Unsigned lua_rawlen (lua_State *L, int idx) {
427 const TValue *o = index2value(L, idx);
428 switch (ttypetag(o)) {
429 case LUA_VSHRSTR: return tsvalue(o)->shrlen;
430 case LUA_VLNGSTR: return tsvalue(o)->u.lnglen;
431 case LUA_VUSERDATA: return uvalue(o)->len;
432 case LUA_VTABLE: return luaH_getn(hvalue(o));
433 default: return 0;
434 }
435}
436
437
438LUA_API lua_CFunction lua_tocfunction (lua_State *L, int idx) {
439 const TValue *o = index2value(L, idx);
440 if (ttislcf(o)) return fvalue(o);
441 else if (ttisCclosure(o))
442 return clCvalue(o)->f;
443 else return NULL; /* not a C function */
444}
445
446
447l_sinline void *touserdata (const TValue *o) {
448 switch (ttype(o)) {
449 case LUA_TUSERDATA: return getudatamem(uvalue(o));
450 case LUA_TLIGHTUSERDATA: return pvalue(o);
451 default: return NULL;
452 }
453}
454
455
456LUA_API void *lua_touserdata (lua_State *L, int idx) {
457 const TValue *o = index2value(L, idx);
458 return touserdata(o);
459}
460
461
462LUA_API lua_State *lua_tothread (lua_State *L, int idx) {
463 const TValue *o = index2value(L, idx);
464 return (!ttisthread(o)) ? NULL : thvalue(o);
465}
466
467
468/*
469** Returns a pointer to the internal representation of an object.
470** Note that ANSI C does not allow the conversion of a pointer to
471** function to a 'void*', so the conversion here goes through
472** a 'size_t'. (As the returned pointer is only informative, this
473** conversion should not be a problem.)
474*/
475LUA_API const void *lua_topointer (lua_State *L, int idx) {
476 const TValue *o = index2value(L, idx);
477 switch (ttypetag(o)) {
478 case LUA_VLCF: return cast_voidp(cast_sizet(fvalue(o)));
479 case LUA_VUSERDATA: case LUA_VLIGHTUSERDATA:
480 return touserdata(o);
481 default: {
482 if (iscollectable(o))
483 return gcvalue(o);
484 else
485 return NULL;
486 }
487 }
488}
489
490
491
492/*
493** push functions (C -> stack)
494*/
495
496
497LUA_API void lua_pushnil (lua_State *L) {
498 lua_lock(L);
499 setnilvalue(s2v(L->top.p));
500 api_incr_top(L);
501 lua_unlock(L);
502}
503
504
505LUA_API void lua_pushnumber (lua_State *L, lua_Number n) {
506 lua_lock(L);
507 setfltvalue(s2v(L->top.p), n);
508 api_incr_top(L);
509 lua_unlock(L);
510}
511
512
513LUA_API void lua_pushinteger (lua_State *L, lua_Integer n) {
514 lua_lock(L);
515 setivalue(s2v(L->top.p), n);
516 api_incr_top(L);
517 lua_unlock(L);
518}
519
520
521/*
522** Pushes on the stack a string with given length. Avoid using 's' when
523** 'len' == 0 (as 's' can be NULL in that case), due to later use of
524** 'memcmp' and 'memcpy'.
525*/
526LUA_API const char *lua_pushlstring (lua_State *L, const char *s, size_t len) {
527 TString *ts;
528 lua_lock(L);
529 ts = (len == 0) ? luaS_new(L, "") : luaS_newlstr(L, s, len);
530 setsvalue2s(L, L->top.p, ts);
531 api_incr_top(L);
532 luaC_checkGC(L);
533 lua_unlock(L);
534 return getstr(ts);
535}
536
537
538LUA_API const char *lua_pushstring (lua_State *L, const char *s) {
539 lua_lock(L);
540 if (s == NULL)
541 setnilvalue(s2v(L->top.p));
542 else {
543 TString *ts;
544 ts = luaS_new(L, s);
545 setsvalue2s(L, L->top.p, ts);
546 s = getstr(ts); /* internal copy's address */
547 }
548 api_incr_top(L);
549 luaC_checkGC(L);
550 lua_unlock(L);
551 return s;
552}
553
554
555LUA_API const char *lua_pushvfstring (lua_State *L, const char *fmt,
556 va_list argp) {
557 const char *ret;
558 lua_lock(L);
559 ret = luaO_pushvfstring(L, fmt, argp);
560 luaC_checkGC(L);
561 lua_unlock(L);
562 return ret;
563}
564
565
566LUA_API const char *lua_pushfstring (lua_State *L, const char *fmt, ...) {
567 const char *ret;
568 va_list argp;
569 lua_lock(L);
570 va_start(argp, fmt);
571 ret = luaO_pushvfstring(L, fmt, argp);
572 va_end(argp);
573 luaC_checkGC(L);
574 lua_unlock(L);
575 return ret;
576}
577
578
579LUA_API void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
580 lua_lock(L);
581 if (n == 0) {
582 setfvalue(s2v(L->top.p), fn);
583 api_incr_top(L);
584 }
585 else {
586 CClosure *cl;
587 api_checknelems(L, n);
588 api_check(L, n <= MAXUPVAL, "upvalue index too large");
589 cl = luaF_newCclosure(L, n);
590 cl->f = fn;
591 L->top.p -= n;
592 while (n--) {
593 setobj2n(L, &cl->upvalue[n], s2v(L->top.p + n));
594 /* does not need barrier because closure is white */
595 lua_assert(iswhite(cl));
596 }
597 setclCvalue(L, s2v(L->top.p), cl);
598 api_incr_top(L);
599 luaC_checkGC(L);
600 }
601 lua_unlock(L);
602}
603
604
605LUA_API void lua_pushboolean (lua_State *L, int b) {
606 lua_lock(L);
607 if (b)
608 setbtvalue(s2v(L->top.p));
609 else
610 setbfvalue(s2v(L->top.p));
611 api_incr_top(L);
612 lua_unlock(L);
613}
614
615
616LUA_API void lua_pushlightuserdata (lua_State *L, void *p) {
617 lua_lock(L);
618 setpvalue(s2v(L->top.p), p);
619 api_incr_top(L);
620 lua_unlock(L);
621}
622
623
624LUA_API int lua_pushthread (lua_State *L) {
625 lua_lock(L);
626 setthvalue(L, s2v(L->top.p), L);
627 api_incr_top(L);
628 lua_unlock(L);
629 return (G(L)->mainthread == L);
630}
631
632
633
634/*
635** get functions (Lua -> stack)
636*/
637
638
639l_sinline int auxgetstr (lua_State *L, const TValue *t, const char *k) {
640 const TValue *slot;
641 TString *str = luaS_new(L, k);
642 if (luaV_fastget(L, t, str, slot, luaH_getstr)) {
643 setobj2s(L, L->top.p, slot);
644 api_incr_top(L);
645 }
646 else {
647 setsvalue2s(L, L->top.p, str);
648 api_incr_top(L);
649 luaV_finishget(L, t, s2v(L->top.p - 1), L->top.p - 1, slot);
650 }
651 lua_unlock(L);
652 return ttype(s2v(L->top.p - 1));
653}
654
655
656/*
657** Get the global table in the registry. Since all predefined
658** indices in the registry were inserted right when the registry
659** was created and never removed, they must always be in the array
660** part of the registry.
661*/
662#define getGtable(L) \
663 (&hvalue(&G(L)->l_registry)->array[LUA_RIDX_GLOBALS - 1])
664
665
666LUA_API int lua_getglobal (lua_State *L, const char *name) {
667 const TValue *G;
668 lua_lock(L);
669 G = getGtable(L);
670 return auxgetstr(L, G, name);
671}
672
673
674LUA_API int lua_gettable (lua_State *L, int idx) {
675 const TValue *slot;
676 TValue *t;
677 lua_lock(L);
678 t = index2value(L, idx);
679 if (luaV_fastget(L, t, s2v(L->top.p - 1), slot, luaH_get)) {
680 setobj2s(L, L->top.p - 1, slot);
681 }
682 else
683 luaV_finishget(L, t, s2v(L->top.p - 1), L->top.p - 1, slot);
684 lua_unlock(L);
685 return ttype(s2v(L->top.p - 1));
686}
687
688
689LUA_API int lua_getfield (lua_State *L, int idx, const char *k) {
690 lua_lock(L);
691 return auxgetstr(L, index2value(L, idx), k);
692}
693
694
695LUA_API int lua_geti (lua_State *L, int idx, lua_Integer n) {
696 TValue *t;
697 const TValue *slot;
698 lua_lock(L);
699 t = index2value(L, idx);
700 if (luaV_fastgeti(L, t, n, slot)) {
701 setobj2s(L, L->top.p, slot);
702 }
703 else {
704 TValue aux;
705 setivalue(&aux, n);
706 luaV_finishget(L, t, &aux, L->top.p, slot);
707 }
708 api_incr_top(L);
709 lua_unlock(L);
710 return ttype(s2v(L->top.p - 1));
711}
712
713
714l_sinline int finishrawget (lua_State *L, const TValue *val) {
715 if (isempty(val)) /* avoid copying empty items to the stack */
716 setnilvalue(s2v(L->top.p));
717 else
718 setobj2s(L, L->top.p, val);
719 api_incr_top(L);
720 lua_unlock(L);
721 return ttype(s2v(L->top.p - 1));
722}
723
724
725static Table *gettable (lua_State *L, int idx) {
726 TValue *t = index2value(L, idx);
727 api_check(L, ttistable(t), "table expected");
728 return hvalue(t);
729}
730
731
732LUA_API int lua_rawget (lua_State *L, int idx) {
733 Table *t;
734 const TValue *val;
735 lua_lock(L);
736 api_checknelems(L, 1);
737 t = gettable(L, idx);
738 val = luaH_get(t, s2v(L->top.p - 1));
739 L->top.p--; /* remove key */
740 return finishrawget(L, val);
741}
742
743
744LUA_API int lua_rawgeti (lua_State *L, int idx, lua_Integer n) {
745 Table *t;
746 lua_lock(L);
747 t = gettable(L, idx);
748 return finishrawget(L, luaH_getint(t, n));
749}
750
751
752LUA_API int lua_rawgetp (lua_State *L, int idx, const void *p) {
753 Table *t;
754 TValue k;
755 lua_lock(L);
756 t = gettable(L, idx);
757 setpvalue(&k, cast_voidp(p));
758 return finishrawget(L, luaH_get(t, &k));
759}
760
761
762LUA_API void lua_createtable (lua_State *L, int narray, int nrec) {
763 Table *t;
764 lua_lock(L);
765 t = luaH_new(L);
766 sethvalue2s(L, L->top.p, t);
767 api_incr_top(L);
768 if (narray > 0 || nrec > 0)
769 luaH_resize(L, t, narray, nrec);
770 luaC_checkGC(L);
771 lua_unlock(L);
772}
773
774
775LUA_API int lua_getmetatable (lua_State *L, int objindex) {
776 const TValue *obj;
777 Table *mt;
778 int res = 0;
779 lua_lock(L);
780 obj = index2value(L, objindex);
781 switch (ttype(obj)) {
782 case LUA_TTABLE:
783 mt = hvalue(obj)->metatable;
784 break;
785 case LUA_TUSERDATA:
786 mt = uvalue(obj)->metatable;
787 break;
788 default:
789 mt = G(L)->mt[ttype(obj)];
790 break;
791 }
792 if (mt != NULL) {
793 sethvalue2s(L, L->top.p, mt);
794 api_incr_top(L);
795 res = 1;
796 }
797 lua_unlock(L);
798 return res;
799}
800
801
802LUA_API int lua_getiuservalue (lua_State *L, int idx, int n) {
803 TValue *o;
804 int t;
805 lua_lock(L);
806 o = index2value(L, idx);
807 api_check(L, ttisfulluserdata(o), "full userdata expected");
808 if (n <= 0 || n > uvalue(o)->nuvalue) {
809 setnilvalue(s2v(L->top.p));
810 t = LUA_TNONE;
811 }
812 else {
813 setobj2s(L, L->top.p, &uvalue(o)->uv[n - 1].uv);
814 t = ttype(s2v(L->top.p));
815 }
816 api_incr_top(L);
817 lua_unlock(L);
818 return t;
819}
820
821
822/*
823** set functions (stack -> Lua)
824*/
825
826/*
827** t[k] = value at the top of the stack (where 'k' is a string)
828*/
829static void auxsetstr (lua_State *L, const TValue *t, const char *k) {
830 const TValue *slot;
831 TString *str = luaS_new(L, k);
832 api_checknelems(L, 1);
833 if (luaV_fastget(L, t, str, slot, luaH_getstr)) {
834 luaV_finishfastset(L, t, slot, s2v(L->top.p - 1));
835 L->top.p--; /* pop value */
836 }
837 else {
838 setsvalue2s(L, L->top.p, str); /* push 'str' (to make it a TValue) */
839 api_incr_top(L);
840 luaV_finishset(L, t, s2v(L->top.p - 1), s2v(L->top.p - 2), slot);
841 L->top.p -= 2; /* pop value and key */
842 }
843 lua_unlock(L); /* lock done by caller */
844}
845
846
847LUA_API void lua_setglobal (lua_State *L, const char *name) {
848 const TValue *G;
849 lua_lock(L); /* unlock done in 'auxsetstr' */
850 G = getGtable(L);
851 auxsetstr(L, G, name);
852}
853
854
855LUA_API void lua_settable (lua_State *L, int idx) {
856 TValue *t;
857 const TValue *slot;
858 lua_lock(L);
859 api_checknelems(L, 2);
860 t = index2value(L, idx);
861 if (luaV_fastget(L, t, s2v(L->top.p - 2), slot, luaH_get)) {
862 luaV_finishfastset(L, t, slot, s2v(L->top.p - 1));
863 }
864 else
865 luaV_finishset(L, t, s2v(L->top.p - 2), s2v(L->top.p - 1), slot);
866 L->top.p -= 2; /* pop index and value */
867 lua_unlock(L);
868}
869
870
871LUA_API void lua_setfield (lua_State *L, int idx, const char *k) {
872 lua_lock(L); /* unlock done in 'auxsetstr' */
873 auxsetstr(L, index2value(L, idx), k);
874}
875
876
877LUA_API void lua_seti (lua_State *L, int idx, lua_Integer n) {
878 TValue *t;
879 const TValue *slot;
880 lua_lock(L);
881 api_checknelems(L, 1);
882 t = index2value(L, idx);
883 if (luaV_fastgeti(L, t, n, slot)) {
884 luaV_finishfastset(L, t, slot, s2v(L->top.p - 1));
885 }
886 else {
887 TValue aux;
888 setivalue(&aux, n);
889 luaV_finishset(L, t, &aux, s2v(L->top.p - 1), slot);
890 }
891 L->top.p--; /* pop value */
892 lua_unlock(L);
893}
894
895
896static void aux_rawset (lua_State *L, int idx, TValue *key, int n) {
897 Table *t;
898 lua_lock(L);
899 api_checknelems(L, n);
900 t = gettable(L, idx);
901 luaH_set(L, t, key, s2v(L->top.p - 1));
902 invalidateTMcache(t);
903 luaC_barrierback(L, obj2gco(t), s2v(L->top.p - 1));
904 L->top.p -= n;
905 lua_unlock(L);
906}
907
908
909LUA_API void lua_rawset (lua_State *L, int idx) {
910 aux_rawset(L, idx, s2v(L->top.p - 2), 2);
911}
912
913
914LUA_API void lua_rawsetp (lua_State *L, int idx, const void *p) {
915 TValue k;
916 setpvalue(&k, cast_voidp(p));
917 aux_rawset(L, idx, &k, 1);
918}
919
920
921LUA_API void lua_rawseti (lua_State *L, int idx, lua_Integer n) {
922 Table *t;
923 lua_lock(L);
924 api_checknelems(L, 1);
925 t = gettable(L, idx);
926 luaH_setint(L, t, n, s2v(L->top.p - 1));
927 luaC_barrierback(L, obj2gco(t), s2v(L->top.p - 1));
928 L->top.p--;
929 lua_unlock(L);
930}
931
932
933LUA_API int lua_setmetatable (lua_State *L, int objindex) {
934 TValue *obj;
935 Table *mt;
936 lua_lock(L);
937 api_checknelems(L, 1);
938 obj = index2value(L, objindex);
939 if (ttisnil(s2v(L->top.p - 1)))
940 mt = NULL;
941 else {
942 api_check(L, ttistable(s2v(L->top.p - 1)), "table expected");
943 mt = hvalue(s2v(L->top.p - 1));
944 }
945 switch (ttype(obj)) {
946 case LUA_TTABLE: {
947 hvalue(obj)->metatable = mt;
948 if (mt) {
949 luaC_objbarrier(L, gcvalue(obj), mt);
950 luaC_checkfinalizer(L, gcvalue(obj), mt);
951 }
952 break;
953 }
954 case LUA_TUSERDATA: {
955 uvalue(obj)->metatable = mt;
956 if (mt) {
957 luaC_objbarrier(L, uvalue(obj), mt);
958 luaC_checkfinalizer(L, gcvalue(obj), mt);
959 }
960 break;
961 }
962 default: {
963 G(L)->mt[ttype(obj)] = mt;
964 break;
965 }
966 }
967 L->top.p--;
968 lua_unlock(L);
969 return 1;
970}
971
972
973LUA_API int lua_setiuservalue (lua_State *L, int idx, int n) {
974 TValue *o;
975 int res;
976 lua_lock(L);
977 api_checknelems(L, 1);
978 o = index2value(L, idx);
979 api_check(L, ttisfulluserdata(o), "full userdata expected");
980 if (!(cast_uint(n) - 1u < cast_uint(uvalue(o)->nuvalue)))
981 res = 0; /* 'n' not in [1, uvalue(o)->nuvalue] */
982 else {
983 setobj(L, &uvalue(o)->uv[n - 1].uv, s2v(L->top.p - 1));
984 luaC_barrierback(L, gcvalue(o), s2v(L->top.p - 1));
985 res = 1;
986 }
987 L->top.p--;
988 lua_unlock(L);
989 return res;
990}
991
992
993/*
994** 'load' and 'call' functions (run Lua code)
995*/
996
997
998#define checkresults(L,na,nr) \
999 api_check(L, (nr) == LUA_MULTRET \
1000 || (L->ci->top.p - L->top.p >= (nr) - (na)), \
1001 "results from function overflow current stack size")
1002
1003
1004LUA_API void lua_callk (lua_State *L, int nargs, int nresults,
1005 lua_KContext ctx, lua_KFunction k) {
1006 StkId func;
1007 lua_lock(L);
1008 api_check(L, k == NULL || !isLua(L->ci),
1009 "cannot use continuations inside hooks");
1010 api_checknelems(L, nargs+1);
1011 api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
1012 checkresults(L, nargs, nresults);
1013 func = L->top.p - (nargs+1);
1014 if (k != NULL && yieldable(L)) { /* need to prepare continuation? */
1015 L->ci->u.c.k = k; /* save continuation */
1016 L->ci->u.c.ctx = ctx; /* save context */
1017 luaD_call(L, func, nresults); /* do the call */
1018 }
1019 else /* no continuation or no yieldable */
1020 luaD_callnoyield(L, func, nresults); /* just do the call */
1021 adjustresults(L, nresults);
1022 lua_unlock(L);
1023}
1024
1025
1026
1027/*
1028** Execute a protected call.
1029*/
1030struct CallS { /* data to 'f_call' */
1031 StkId func;
1032 int nresults;
1033};
1034
1035
1036static void f_call (lua_State *L, void *ud) {
1037 struct CallS *c = cast(struct CallS *, ud);
1038 luaD_callnoyield(L, c->func, c->nresults);
1039}
1040
1041
1042
1043LUA_API int lua_pcallk (lua_State *L, int nargs, int nresults, int errfunc,
1044 lua_KContext ctx, lua_KFunction k) {
1045 struct CallS c;
1046 int status;
1047 ptrdiff_t func;
1048 lua_lock(L);
1049 api_check(L, k == NULL || !isLua(L->ci),
1050 "cannot use continuations inside hooks");
1051 api_checknelems(L, nargs+1);
1052 api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
1053 checkresults(L, nargs, nresults);
1054 if (errfunc == 0)
1055 func = 0;
1056 else {
1057 StkId o = index2stack(L, errfunc);
1058 api_check(L, ttisfunction(s2v(o)), "error handler must be a function");
1059 func = savestack(L, o);
1060 }
1061 c.func = L->top.p - (nargs+1); /* function to be called */
1062 if (k == NULL || !yieldable(L)) { /* no continuation or no yieldable? */
1063 c.nresults = nresults; /* do a 'conventional' protected call */
1064 status = luaD_pcall(L, f_call, &c, savestack(L, c.func), func);
1065 }
1066 else { /* prepare continuation (call is already protected by 'resume') */
1067 CallInfo *ci = L->ci;
1068 ci->u.c.k = k; /* save continuation */
1069 ci->u.c.ctx = ctx; /* save context */
1070 /* save information for error recovery */
1071 ci->u2.funcidx = cast_int(savestack(L, c.func));
1072 ci->u.c.old_errfunc = L->errfunc;
1073 L->errfunc = func;
1074 setoah(ci->callstatus, L->allowhook); /* save value of 'allowhook' */
1075 ci->callstatus |= CIST_YPCALL; /* function can do error recovery */
1076 luaD_call(L, c.func, nresults); /* do the call */
1077 ci->callstatus &= ~CIST_YPCALL;
1078 L->errfunc = ci->u.c.old_errfunc;
1079 status = LUA_OK; /* if it is here, there were no errors */
1080 }
1081 adjustresults(L, nresults);
1082 lua_unlock(L);
1083 return status;
1084}
1085
1086
1087LUA_API int lua_load (lua_State *L, lua_Reader reader, void *data,
1088 const char *chunkname, const char *mode) {
1089 ZIO z;
1090 int status;
1091 lua_lock(L);
1092 if (!chunkname) chunkname = "?";
1093 luaZ_init(L, &z, reader, data);
1094 status = luaD_protectedparser(L, &z, chunkname, mode);
1095 if (status == LUA_OK) { /* no errors? */
1096 LClosure *f = clLvalue(s2v(L->top.p - 1)); /* get new function */
1097 if (f->nupvalues >= 1) { /* does it have an upvalue? */
1098 /* get global table from registry */
1099 const TValue *gt = getGtable(L);
1100 /* set global table as 1st upvalue of 'f' (may be LUA_ENV) */
1101 setobj(L, f->upvals[0]->v.p, gt);
1102 luaC_barrier(L, f->upvals[0], gt);
1103 }
1104 }
1105 lua_unlock(L);
1106 return status;
1107}
1108
1109
1110LUA_API int lua_dump (lua_State *L, lua_Writer writer, void *data, int strip) {
1111 int status;
1112 TValue *o;
1113 lua_lock(L);
1114 api_checknelems(L, 1);
1115 o = s2v(L->top.p - 1);
1116 if (isLfunction(o))
1117 status = luaU_dump(L, getproto(o), writer, data, strip);
1118 else
1119 status = 1;
1120 lua_unlock(L);
1121 return status;
1122}
1123
1124
1125LUA_API int lua_status (lua_State *L) {
1126 return L->status;
1127}
1128
1129
1130/*
1131** Garbage-collection function
1132*/
1133LUA_API int lua_gc (lua_State *L, int what, ...) {
1134 va_list argp;
1135 int res = 0;
1136 global_State *g = G(L);
1137 if (g->gcstp & GCSTPGC) /* internal stop? */
1138 return -1; /* all options are invalid when stopped */
1139 lua_lock(L);
1140 va_start(argp, what);
1141 switch (what) {
1142 case LUA_GCSTOP: {
1143 g->gcstp = GCSTPUSR; /* stopped by the user */
1144 break;
1145 }
1146 case LUA_GCRESTART: {
1147 luaE_setdebt(g, 0);
1148 g->gcstp = 0; /* (GCSTPGC must be already zero here) */
1149 break;
1150 }
1151 case LUA_GCCOLLECT: {
1152 luaC_fullgc(L, 0);
1153 break;
1154 }
1155 case LUA_GCCOUNT: {
1156 /* GC values are expressed in Kbytes: #bytes/2^10 */
1157 res = cast_int(gettotalbytes(g) >> 10);
1158 break;
1159 }
1160 case LUA_GCCOUNTB: {
1161 res = cast_int(gettotalbytes(g) & 0x3ff);
1162 break;
1163 }
1164 case LUA_GCSTEP: {
1165 int data = va_arg(argp, int);
1166 l_mem debt = 1; /* =1 to signal that it did an actual step */
1167 lu_byte oldstp = g->gcstp;
1168 g->gcstp = 0; /* allow GC to run (GCSTPGC must be zero here) */
1169 if (data == 0) {
1170 luaE_setdebt(g, 0); /* do a basic step */
1171 luaC_step(L);
1172 }
1173 else { /* add 'data' to total debt */
1174 debt = cast(l_mem, data) * 1024 + g->GCdebt;
1175 luaE_setdebt(g, debt);
1176 luaC_checkGC(L);
1177 }
1178 g->gcstp = oldstp; /* restore previous state */
1179 if (debt > 0 && g->gcstate == GCSpause) /* end of cycle? */
1180 res = 1; /* signal it */
1181 break;
1182 }
1183 case LUA_GCSETPAUSE: {
1184 int data = va_arg(argp, int);
1185 res = getgcparam(g->gcpause);
1186 setgcparam(g->gcpause, data);
1187 break;
1188 }
1189 case LUA_GCSETSTEPMUL: {
1190 int data = va_arg(argp, int);
1191 res = getgcparam(g->gcstepmul);
1192 setgcparam(g->gcstepmul, data);
1193 break;
1194 }
1195 case LUA_GCISRUNNING: {
1196 res = gcrunning(g);
1197 break;
1198 }
1199 case LUA_GCGEN: {
1200 int minormul = va_arg(argp, int);
1201 int majormul = va_arg(argp, int);
1202 res = isdecGCmodegen(g) ? LUA_GCGEN : LUA_GCINC;
1203 if (minormul != 0)
1204 g->genminormul = minormul;
1205 if (majormul != 0)
1206 setgcparam(g->genmajormul, majormul);
1207 luaC_changemode(L, KGC_GEN);
1208 break;
1209 }
1210 case LUA_GCINC: {
1211 int pause = va_arg(argp, int);
1212 int stepmul = va_arg(argp, int);
1213 int stepsize = va_arg(argp, int);
1214 res = isdecGCmodegen(g) ? LUA_GCGEN : LUA_GCINC;
1215 if (pause != 0)
1216 setgcparam(g->gcpause, pause);
1217 if (stepmul != 0)
1218 setgcparam(g->gcstepmul, stepmul);
1219 if (stepsize != 0)
1220 g->gcstepsize = stepsize;
1221 luaC_changemode(L, KGC_INC);
1222 break;
1223 }
1224 default: res = -1; /* invalid option */
1225 }
1226 va_end(argp);
1227 lua_unlock(L);
1228 return res;
1229}
1230
1231
1232
1233/*
1234** miscellaneous functions
1235*/
1236
1237
1238LUA_API int lua_error (lua_State *L) {
1239 TValue *errobj;
1240 lua_lock(L);
1241 errobj = s2v(L->top.p - 1);
1242 api_checknelems(L, 1);
1243 /* error object is the memory error message? */
1244 if (ttisshrstring(errobj) && eqshrstr(tsvalue(errobj), G(L)->memerrmsg))
1245 luaM_error(L); /* raise a memory error */
1246 else
1247 luaG_errormsg(L); /* raise a regular error */
1248 /* code unreachable; will unlock when control actually leaves the kernel */
1249 return 0; /* to avoid warnings */
1250}
1251
1252
1253LUA_API int lua_next (lua_State *L, int idx) {
1254 Table *t;
1255 int more;
1256 lua_lock(L);
1257 api_checknelems(L, 1);
1258 t = gettable(L, idx);
1259 more = luaH_next(L, t, L->top.p - 1);
1260 if (more) {
1261 api_incr_top(L);
1262 }
1263 else /* no more elements */
1264 L->top.p -= 1; /* remove key */
1265 lua_unlock(L);
1266 return more;
1267}
1268
1269
1270LUA_API void lua_toclose (lua_State *L, int idx) {
1271 int nresults;
1272 StkId o;
1273 lua_lock(L);
1274 o = index2stack(L, idx);
1275 nresults = L->ci->nresults;
1276 api_check(L, L->tbclist.p < o, "given index below or equal a marked one");
1277 luaF_newtbcupval(L, o); /* create new to-be-closed upvalue */
1278 if (!hastocloseCfunc(nresults)) /* function not marked yet? */
1279 L->ci->nresults = codeNresults(nresults); /* mark it */
1280 lua_assert(hastocloseCfunc(L->ci->nresults));
1281 lua_unlock(L);
1282}
1283
1284
1285LUA_API void lua_concat (lua_State *L, int n) {
1286 lua_lock(L);
1287 api_checknelems(L, n);
1288 if (n > 0)
1289 luaV_concat(L, n);
1290 else { /* nothing to concatenate */
1291 setsvalue2s(L, L->top.p, luaS_newlstr(L, "", 0)); /* push empty string */
1292 api_incr_top(L);
1293 }
1294 luaC_checkGC(L);
1295 lua_unlock(L);
1296}
1297
1298
1299LUA_API void lua_len (lua_State *L, int idx) {
1300 TValue *t;
1301 lua_lock(L);
1302 t = index2value(L, idx);
1303 luaV_objlen(L, L->top.p, t);
1304 api_incr_top(L);
1305 lua_unlock(L);
1306}
1307
1308
1309LUA_API lua_Alloc lua_getallocf (lua_State *L, void **ud) {
1310 lua_Alloc f;
1311 lua_lock(L);
1312 if (ud) *ud = G(L)->ud;
1313 f = G(L)->frealloc;
1314 lua_unlock(L);
1315 return f;
1316}
1317
1318
1319LUA_API void lua_setallocf (lua_State *L, lua_Alloc f, void *ud) {
1320 lua_lock(L);
1321 G(L)->ud = ud;
1322 G(L)->frealloc = f;
1323 lua_unlock(L);
1324}
1325
1326
1327void lua_setwarnf (lua_State *L, lua_WarnFunction f, void *ud) {
1328 lua_lock(L);
1329 G(L)->ud_warn = ud;
1330 G(L)->warnf = f;
1331 lua_unlock(L);
1332}
1333
1334
1335void lua_warning (lua_State *L, const char *msg, int tocont) {
1336 lua_lock(L);
1337 luaE_warning(L, msg, tocont);
1338 lua_unlock(L);
1339}
1340
1341
1342
1343LUA_API void *lua_newuserdatauv (lua_State *L, size_t size, int nuvalue) {
1344 Udata *u;
1345 lua_lock(L);
1346 api_check(L, 0 <= nuvalue && nuvalue < USHRT_MAX, "invalid value");
1347 u = luaS_newudata(L, size, nuvalue);
1348 setuvalue(L, s2v(L->top.p), u);
1349 api_incr_top(L);
1350 luaC_checkGC(L);
1351 lua_unlock(L);
1352 return getudatamem(u);
1353}
1354
1355
1356
1357static const char *aux_upvalue (TValue *fi, int n, TValue **val,
1358 GCObject **owner) {
1359 switch (ttypetag(fi)) {
1360 case LUA_VCCL: { /* C closure */
1361 CClosure *f = clCvalue(fi);
1362 if (!(cast_uint(n) - 1u < cast_uint(f->nupvalues)))
1363 return NULL; /* 'n' not in [1, f->nupvalues] */
1364 *val = &f->upvalue[n-1];
1365 if (owner) *owner = obj2gco(f);
1366 return "";
1367 }
1368 case LUA_VLCL: { /* Lua closure */
1369 LClosure *f = clLvalue(fi);
1370 TString *name;
1371 Proto *p = f->p;
1372 if (!(cast_uint(n) - 1u < cast_uint(p->sizeupvalues)))
1373 return NULL; /* 'n' not in [1, p->sizeupvalues] */
1374 *val = f->upvals[n-1]->v.p;
1375 if (owner) *owner = obj2gco(f->upvals[n - 1]);
1376 name = p->upvalues[n-1].name;
1377 return (name == NULL) ? "(no name)" : getstr(name);
1378 }
1379 default: return NULL; /* not a closure */
1380 }
1381}
1382
1383
1384LUA_API const char *lua_getupvalue (lua_State *L, int funcindex, int n) {
1385 const char *name;
1386 TValue *val = NULL; /* to avoid warnings */
1387 lua_lock(L);
1388 name = aux_upvalue(index2value(L, funcindex), n, &val, NULL);
1389 if (name) {
1390 setobj2s(L, L->top.p, val);
1391 api_incr_top(L);
1392 }
1393 lua_unlock(L);
1394 return name;
1395}
1396
1397
1398LUA_API const char *lua_setupvalue (lua_State *L, int funcindex, int n) {
1399 const char *name;
1400 TValue *val = NULL; /* to avoid warnings */
1401 GCObject *owner = NULL; /* to avoid warnings */
1402 TValue *fi;
1403 lua_lock(L);
1404 fi = index2value(L, funcindex);
1405 api_checknelems(L, 1);
1406 name = aux_upvalue(fi, n, &val, &owner);
1407 if (name) {
1408 L->top.p--;
1409 setobj(L, val, s2v(L->top.p));
1410 luaC_barrier(L, owner, val);
1411 }
1412 lua_unlock(L);
1413 return name;
1414}
1415
1416
1417static UpVal **getupvalref (lua_State *L, int fidx, int n, LClosure **pf) {
1418 static const UpVal *const nullup = NULL;
1419 LClosure *f;
1420 TValue *fi = index2value(L, fidx);
1421 api_check(L, ttisLclosure(fi), "Lua function expected");
1422 f = clLvalue(fi);
1423 if (pf) *pf = f;
1424 if (1 <= n && n <= f->p->sizeupvalues)
1425 return &f->upvals[n - 1]; /* get its upvalue pointer */
1426 else
1427 return (UpVal**)&nullup;
1428}
1429
1430
1431LUA_API void *lua_upvalueid (lua_State *L, int fidx, int n) {
1432 TValue *fi = index2value(L, fidx);
1433 switch (ttypetag(fi)) {
1434 case LUA_VLCL: { /* lua closure */
1435 return *getupvalref(L, fidx, n, NULL);
1436 }
1437 case LUA_VCCL: { /* C closure */
1438 CClosure *f = clCvalue(fi);
1439 if (1 <= n && n <= f->nupvalues)
1440 return &f->upvalue[n - 1];
1441 /* else */
1442 } /* FALLTHROUGH */
1443 case LUA_VLCF:
1444 return NULL; /* light C functions have no upvalues */
1445 default: {
1446 api_check(L, 0, "function expected");
1447 return NULL;
1448 }
1449 }
1450}
1451
1452
1453LUA_API void lua_upvaluejoin (lua_State *L, int fidx1, int n1,
1454 int fidx2, int n2) {
1455 LClosure *f1;
1456 UpVal **up1 = getupvalref(L, fidx1, n1, &f1);
1457 UpVal **up2 = getupvalref(L, fidx2, n2, NULL);
1458 api_check(L, *up1 != NULL && *up2 != NULL, "invalid upvalue index");
1459 *up1 = *up2;
1460 luaC_objbarrier(L, f1, *up1);
1461}
1462
1463