xref: /freebsd/sys/contrib/openzfs/module/lua/lauxlib.c (revision 1f474190)
1 /* BEGIN CSTYLED */
2 /*
3 ** $Id: lauxlib.c,v 1.248.1.1 2013/04/12 18:48:47 roberto Exp $
4 ** Auxiliary functions for building Lua libraries
5 ** See Copyright Notice in lua.h
6 */
7 
8 
9 /* This file uses only the official API of Lua.
10 ** Any function declared here could be written as an application function.
11 */
12 
13 #define lauxlib_c
14 #define LUA_LIB
15 
16 #include <sys/lua/lua.h>
17 
18 #include <sys/lua/lauxlib.h>
19 
20 
21 /*
22 ** {======================================================
23 ** Traceback
24 ** =======================================================
25 */
26 
27 
28 #define LEVELS1	12	/* size of the first part of the stack */
29 #define LEVELS2	10	/* size of the second part of the stack */
30 
31 
32 
33 /*
34 ** search for 'objidx' in table at index -1.
35 ** return 1 + string at top if find a good name.
36 */
37 static int findfield (lua_State *L, int objidx, int level) {
38   if (level == 0 || !lua_istable(L, -1))
39     return 0;  /* not found */
40   lua_pushnil(L);  /* start 'next' loop */
41   while (lua_next(L, -2)) {  /* for each pair in table */
42     if (lua_type(L, -2) == LUA_TSTRING) {  /* ignore non-string keys */
43       if (lua_rawequal(L, objidx, -1)) {  /* found object? */
44         lua_pop(L, 1);  /* remove value (but keep name) */
45         return 1;
46       }
47       else if (findfield(L, objidx, level - 1)) {  /* try recursively */
48         lua_remove(L, -2);  /* remove table (but keep name) */
49         lua_pushliteral(L, ".");
50         lua_insert(L, -2);  /* place '.' between the two names */
51         lua_concat(L, 3);
52         return 1;
53       }
54     }
55     lua_pop(L, 1);  /* remove value */
56   }
57   return 0;  /* not found */
58 }
59 
60 
61 static int pushglobalfuncname (lua_State *L, lua_Debug *ar) {
62   int top = lua_gettop(L);
63   lua_getinfo(L, "f", ar);  /* push function */
64   lua_pushglobaltable(L);
65   if (findfield(L, top + 1, 2)) {
66     lua_copy(L, -1, top + 1);  /* move name to proper place */
67     lua_pop(L, 2);  /* remove pushed values */
68     return 1;
69   }
70   else {
71     lua_settop(L, top);  /* remove function and global table */
72     return 0;
73   }
74 }
75 
76 
77 static void pushfuncname (lua_State *L, lua_Debug *ar) {
78   if (*ar->namewhat != '\0')  /* is there a name? */
79     lua_pushfstring(L, "function " LUA_QS, ar->name);
80   else if (*ar->what == 'm')  /* main? */
81       lua_pushliteral(L, "main chunk");
82   else if (*ar->what == 'C') {
83     if (pushglobalfuncname(L, ar)) {
84       lua_pushfstring(L, "function " LUA_QS, lua_tostring(L, -1));
85       lua_remove(L, -2);  /* remove name */
86     }
87     else
88       lua_pushliteral(L, "?");
89   }
90   else
91     lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined);
92 }
93 
94 
95 static int countlevels (lua_State *L) {
96   lua_Debug ar;
97   int li = 1, le = 1;
98   /* find an upper bound */
99   while (lua_getstack(L, le, &ar)) { li = le; le *= 2; }
100   /* do a binary search */
101   while (li < le) {
102     int m = (li + le)/2;
103     if (lua_getstack(L, m, &ar)) li = m + 1;
104     else le = m;
105   }
106   return le - 1;
107 }
108 
109 
110 LUALIB_API void luaL_traceback (lua_State *L, lua_State *L1,
111                                 const char *msg, int level) {
112   lua_Debug ar;
113   int top = lua_gettop(L);
114   int numlevels = countlevels(L1);
115   int mark = (numlevels > LEVELS1 + LEVELS2) ? LEVELS1 : 0;
116   if (msg) lua_pushfstring(L, "%s\n", msg);
117   lua_pushliteral(L, "stack traceback:");
118   while (lua_getstack(L1, level++, &ar)) {
119     if (level == mark) {  /* too many levels? */
120       lua_pushliteral(L, "\n\t...");  /* add a '...' */
121       level = numlevels - LEVELS2;  /* and skip to last ones */
122     }
123     else {
124       lua_getinfo(L1, "Slnt", &ar);
125       lua_pushfstring(L, "\n\t%s:", ar.short_src);
126       if (ar.currentline > 0)
127         lua_pushfstring(L, "%d:", ar.currentline);
128       lua_pushliteral(L, " in ");
129       pushfuncname(L, &ar);
130       if (ar.istailcall)
131         lua_pushliteral(L, "\n\t(...tail calls...)");
132       lua_concat(L, lua_gettop(L) - top);
133     }
134   }
135   lua_concat(L, lua_gettop(L) - top);
136 }
137 
138 /* }====================================================== */
139 
140 
141 /*
142 ** {======================================================
143 ** Error-report functions
144 ** =======================================================
145 */
146 
147 LUALIB_API int luaL_argerror (lua_State *L, int narg, const char *extramsg) {
148   lua_Debug ar;
149   if (!lua_getstack(L, 0, &ar))  /* no stack frame? */
150     return luaL_error(L, "bad argument #%d (%s)", narg, extramsg);
151   lua_getinfo(L, "n", &ar);
152   if (strcmp(ar.namewhat, "method") == 0) {
153     narg--;  /* do not count `self' */
154     if (narg == 0)  /* error is in the self argument itself? */
155       return luaL_error(L, "calling " LUA_QS " on bad self (%s)",
156                            ar.name, extramsg);
157   }
158   if (ar.name == NULL)
159     ar.name = (pushglobalfuncname(L, &ar)) ? lua_tostring(L, -1) : "?";
160   return luaL_error(L, "bad argument #%d to " LUA_QS " (%s)",
161                         narg, ar.name, extramsg);
162 }
163 
164 
165 static int typeerror (lua_State *L, int narg, const char *tname) {
166   const char *msg = lua_pushfstring(L, "%s expected, got %s",
167                                     tname, luaL_typename(L, narg));
168   return luaL_argerror(L, narg, msg);
169 }
170 
171 
172 static void tag_error (lua_State *L, int narg, int tag) {
173   typeerror(L, narg, lua_typename(L, tag));
174 }
175 
176 
177 LUALIB_API void luaL_where (lua_State *L, int level) {
178   lua_Debug ar;
179   if (lua_getstack(L, level, &ar)) {  /* check function at level */
180     lua_getinfo(L, "Sl", &ar);  /* get info about it */
181     if (ar.currentline > 0) {  /* is there info? */
182       lua_pushfstring(L, "%s:%d: ", ar.short_src, ar.currentline);
183       return;
184     }
185   }
186   lua_pushliteral(L, "");  /* else, no information available... */
187 }
188 
189 
190 LUALIB_API int luaL_error (lua_State *L, const char *fmt, ...) {
191   va_list argp;
192   va_start(argp, fmt);
193   luaL_where(L, 1);
194   lua_pushvfstring(L, fmt, argp);
195   va_end(argp);
196   lua_concat(L, 2);
197   return lua_error(L);
198 }
199 
200 
201 #if !defined(inspectstat)	/* { */
202 
203 #if defined(LUA_USE_POSIX)
204 
205 #include <sys/wait.h>
206 
207 /*
208 ** use appropriate macros to interpret 'pclose' return status
209 */
210 #define inspectstat(stat,what)  \
211    if (WIFEXITED(stat)) { stat = WEXITSTATUS(stat); } \
212    else if (WIFSIGNALED(stat)) { stat = WTERMSIG(stat); what = "signal"; }
213 
214 #else
215 
216 #define inspectstat(stat,what)  /* no op */
217 
218 #endif
219 
220 #endif				/* } */
221 
222 
223 /* }====================================================== */
224 
225 
226 /*
227 ** {======================================================
228 ** Userdata's metatable manipulation
229 ** =======================================================
230 */
231 
232 LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
233   luaL_getmetatable(L, tname);  /* try to get metatable */
234   if (!lua_isnil(L, -1))  /* name already in use? */
235     return 0;  /* leave previous value on top, but return 0 */
236   lua_pop(L, 1);
237   lua_newtable(L);  /* create metatable */
238   lua_pushvalue(L, -1);
239   lua_setfield(L, LUA_REGISTRYINDEX, tname);  /* registry.name = metatable */
240   return 1;
241 }
242 
243 
244 LUALIB_API void luaL_setmetatable (lua_State *L, const char *tname) {
245   luaL_getmetatable(L, tname);
246   lua_setmetatable(L, -2);
247 }
248 
249 
250 LUALIB_API void *luaL_testudata (lua_State *L, int ud, const char *tname) {
251   void *p = lua_touserdata(L, ud);
252   if (p != NULL) {  /* value is a userdata? */
253     if (lua_getmetatable(L, ud)) {  /* does it have a metatable? */
254       luaL_getmetatable(L, tname);  /* get correct metatable */
255       if (!lua_rawequal(L, -1, -2))  /* not the same? */
256         p = NULL;  /* value is a userdata with wrong metatable */
257       lua_pop(L, 2);  /* remove both metatables */
258       return p;
259     }
260   }
261   return NULL;  /* value is not a userdata with a metatable */
262 }
263 
264 
265 LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
266   void *p = luaL_testudata(L, ud, tname);
267   if (p == NULL) typeerror(L, ud, tname);
268   return p;
269 }
270 
271 /* }====================================================== */
272 
273 
274 /*
275 ** {======================================================
276 ** Argument check functions
277 ** =======================================================
278 */
279 
280 LUALIB_API int luaL_checkoption (lua_State *L, int narg, const char *def,
281                                  const char *const lst[]) {
282   const char *name = (def) ? luaL_optstring(L, narg, def) :
283                              luaL_checkstring(L, narg);
284   int i;
285   for (i=0; lst[i]; i++)
286     if (strcmp(lst[i], name) == 0)
287       return i;
288   return luaL_argerror(L, narg,
289                        lua_pushfstring(L, "invalid option " LUA_QS, name));
290 }
291 
292 
293 LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *msg) {
294   /* keep some extra space to run error routines, if needed */
295   const int extra = LUA_MINSTACK;
296   if (!lua_checkstack(L, space + extra)) {
297     if (msg)
298       luaL_error(L, "stack overflow (%s)", msg);
299     else
300       luaL_error(L, "stack overflow");
301   }
302 }
303 
304 
305 LUALIB_API void luaL_checktype (lua_State *L, int narg, int t) {
306   if (lua_type(L, narg) != t)
307     tag_error(L, narg, t);
308 }
309 
310 
311 LUALIB_API void luaL_checkany (lua_State *L, int narg) {
312   if (lua_type(L, narg) == LUA_TNONE)
313     luaL_argerror(L, narg, "value expected");
314 }
315 
316 
317 LUALIB_API const char *luaL_checklstring (lua_State *L, int narg, size_t *len) {
318   const char *s = lua_tolstring(L, narg, len);
319   if (!s) tag_error(L, narg, LUA_TSTRING);
320   return s;
321 }
322 
323 
324 LUALIB_API const char *luaL_optlstring (lua_State *L, int narg,
325                                         const char *def, size_t *len) {
326   if (lua_isnoneornil(L, narg)) {
327     if (len)
328       *len = (def ? strlen(def) : 0);
329     return def;
330   }
331   else return luaL_checklstring(L, narg, len);
332 }
333 
334 
335 LUALIB_API lua_Number luaL_checknumber (lua_State *L, int narg) {
336   int isnum;
337   lua_Number d = lua_tonumberx(L, narg, &isnum);
338   if (!isnum)
339     tag_error(L, narg, LUA_TNUMBER);
340   return d;
341 }
342 
343 
344 LUALIB_API lua_Number luaL_optnumber (lua_State *L, int narg, lua_Number def) {
345   return luaL_opt(L, luaL_checknumber, narg, def);
346 }
347 
348 
349 LUALIB_API lua_Integer luaL_checkinteger (lua_State *L, int narg) {
350   int isnum;
351   lua_Integer d = lua_tointegerx(L, narg, &isnum);
352   if (!isnum)
353     tag_error(L, narg, LUA_TNUMBER);
354   return d;
355 }
356 
357 
358 LUALIB_API lua_Unsigned luaL_checkunsigned (lua_State *L, int narg) {
359   int isnum;
360   lua_Unsigned d = lua_tounsignedx(L, narg, &isnum);
361   if (!isnum)
362     tag_error(L, narg, LUA_TNUMBER);
363   return d;
364 }
365 
366 
367 LUALIB_API lua_Integer luaL_optinteger (lua_State *L, int narg,
368                                                       lua_Integer def) {
369   return luaL_opt(L, luaL_checkinteger, narg, def);
370 }
371 
372 
373 LUALIB_API lua_Unsigned luaL_optunsigned (lua_State *L, int narg,
374                                                         lua_Unsigned def) {
375   return luaL_opt(L, luaL_checkunsigned, narg, def);
376 }
377 
378 /* }====================================================== */
379 
380 
381 /*
382 ** {======================================================
383 ** Generic Buffer manipulation
384 ** =======================================================
385 */
386 
387 /*
388 ** check whether buffer is using a userdata on the stack as a temporary
389 ** buffer
390 */
391 #define buffonstack(B)	((B)->b != (B)->initb)
392 
393 
394 /*
395 ** returns a pointer to a free area with at least 'sz' bytes
396 */
397 LUALIB_API char *luaL_prepbuffsize (luaL_Buffer *B, size_t sz) {
398   lua_State *L = B->L;
399   if (B->size - B->n < sz) {  /* not enough space? */
400     char *newbuff;
401     size_t newsize = B->size * 2;  /* double buffer size */
402     if (newsize - B->n < sz)  /* not big enough? */
403       newsize = B->n + sz;
404     if (newsize < B->n || newsize - B->n < sz)
405       luaL_error(L, "buffer too large");
406     /* create larger buffer */
407     newbuff = (char *)lua_newuserdata(L, newsize * sizeof(char));
408     /* move content to new buffer */
409     memcpy(newbuff, B->b, B->n * sizeof(char));
410     if (buffonstack(B))
411       lua_remove(L, -2);  /* remove old buffer */
412     B->b = newbuff;
413     B->size = newsize;
414   }
415   return &B->b[B->n];
416 }
417 
418 
419 LUALIB_API void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l) {
420   char *b = luaL_prepbuffsize(B, l);
421   memcpy(b, s, l * sizeof(char));
422   luaL_addsize(B, l);
423 }
424 
425 
426 LUALIB_API void luaL_addstring (luaL_Buffer *B, const char *s) {
427   luaL_addlstring(B, s, strlen(s));
428 }
429 
430 
431 LUALIB_API void luaL_pushresult (luaL_Buffer *B) {
432   lua_State *L = B->L;
433   lua_pushlstring(L, B->b, B->n);
434   if (buffonstack(B))
435     lua_remove(L, -2);  /* remove old buffer */
436 }
437 
438 
439 LUALIB_API void luaL_pushresultsize (luaL_Buffer *B, size_t sz) {
440   luaL_addsize(B, sz);
441   luaL_pushresult(B);
442 }
443 
444 
445 LUALIB_API void luaL_addvalue (luaL_Buffer *B) {
446   lua_State *L = B->L;
447   size_t l;
448   const char *s = lua_tolstring(L, -1, &l);
449   if (buffonstack(B))
450     lua_insert(L, -2);  /* put value below buffer */
451   luaL_addlstring(B, s, l);
452   lua_remove(L, (buffonstack(B)) ? -2 : -1);  /* remove value */
453 }
454 
455 
456 LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {
457   B->L = L;
458   B->b = B->initb;
459   B->n = 0;
460   B->size = LUAL_BUFFERSIZE;
461 }
462 
463 
464 LUALIB_API char *luaL_buffinitsize (lua_State *L, luaL_Buffer *B, size_t sz) {
465   luaL_buffinit(L, B);
466   return luaL_prepbuffsize(B, sz);
467 }
468 
469 /* }====================================================== */
470 
471 
472 /*
473 ** {======================================================
474 ** Reference system
475 ** =======================================================
476 */
477 
478 /* index of free-list header */
479 #define freelist	0
480 
481 
482 LUALIB_API int luaL_ref (lua_State *L, int t) {
483   int ref;
484   if (lua_isnil(L, -1)) {
485     lua_pop(L, 1);  /* remove from stack */
486     return LUA_REFNIL;  /* `nil' has a unique fixed reference */
487   }
488   t = lua_absindex(L, t);
489   lua_rawgeti(L, t, freelist);  /* get first free element */
490   ref = (int)lua_tointeger(L, -1);  /* ref = t[freelist] */
491   lua_pop(L, 1);  /* remove it from stack */
492   if (ref != 0) {  /* any free element? */
493     lua_rawgeti(L, t, ref);  /* remove it from list */
494     lua_rawseti(L, t, freelist);  /* (t[freelist] = t[ref]) */
495   }
496   else  /* no free elements */
497     ref = (int)lua_rawlen(L, t) + 1;  /* get a new reference */
498   lua_rawseti(L, t, ref);
499   return ref;
500 }
501 
502 
503 LUALIB_API void luaL_unref (lua_State *L, int t, int ref) {
504   if (ref >= 0) {
505     t = lua_absindex(L, t);
506     lua_rawgeti(L, t, freelist);
507     lua_rawseti(L, t, ref);  /* t[ref] = t[freelist] */
508     lua_pushinteger(L, ref);
509     lua_rawseti(L, t, freelist);  /* t[freelist] = ref */
510   }
511 }
512 
513 /* }====================================================== */
514 
515 
516 /*
517 ** {======================================================
518 ** Load functions
519 ** =======================================================
520 */
521 
522 typedef struct LoadS {
523   const char *s;
524   size_t size;
525 } LoadS;
526 
527 
528 static const char *getS (lua_State *L, void *ud, size_t *size) {
529   LoadS *ls = (LoadS *)ud;
530   (void)L;  /* not used */
531   if (ls->size == 0) return NULL;
532   *size = ls->size;
533   ls->size = 0;
534   return ls->s;
535 }
536 
537 
538 LUALIB_API int luaL_loadbufferx (lua_State *L, const char *buff, size_t size,
539                                  const char *name, const char *mode) {
540   LoadS ls;
541   ls.s = buff;
542   ls.size = size;
543   return lua_load(L, getS, &ls, name, mode);
544 }
545 
546 
547 LUALIB_API int luaL_loadstring (lua_State *L, const char *s) {
548   return luaL_loadbuffer(L, s, strlen(s), s);
549 }
550 
551 /* }====================================================== */
552 
553 
554 
555 LUALIB_API int luaL_getmetafield (lua_State *L, int obj, const char *event) {
556   if (!lua_getmetatable(L, obj))  /* no metatable? */
557     return 0;
558   lua_pushstring(L, event);
559   lua_rawget(L, -2);
560   if (lua_isnil(L, -1)) {
561     lua_pop(L, 2);  /* remove metatable and metafield */
562     return 0;
563   }
564   else {
565     lua_remove(L, -2);  /* remove only metatable */
566     return 1;
567   }
568 }
569 
570 
571 LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) {
572   obj = lua_absindex(L, obj);
573   if (!luaL_getmetafield(L, obj, event))  /* no metafield? */
574     return 0;
575   lua_pushvalue(L, obj);
576   lua_call(L, 1, 1);
577   return 1;
578 }
579 
580 
581 LUALIB_API int luaL_len (lua_State *L, int idx) {
582   int l;
583   int isnum;
584   lua_len(L, idx);
585   l = (int)lua_tointegerx(L, -1, &isnum);
586   if (!isnum)
587     luaL_error(L, "object length is not a number");
588   lua_pop(L, 1);  /* remove object */
589   return l;
590 }
591 
592 
593 LUALIB_API const char *luaL_tolstring (lua_State *L, int idx, size_t *len) {
594   if (!luaL_callmeta(L, idx, "__tostring")) {  /* no metafield? */
595     switch (lua_type(L, idx)) {
596       case LUA_TNUMBER:
597       case LUA_TSTRING:
598         lua_pushvalue(L, idx);
599         break;
600       case LUA_TBOOLEAN:
601         lua_pushstring(L, (lua_toboolean(L, idx) ? "true" : "false"));
602         break;
603       case LUA_TNIL:
604         lua_pushliteral(L, "nil");
605         break;
606       default:
607         lua_pushfstring(L, "%s: %p", luaL_typename(L, idx),
608                                             lua_topointer(L, idx));
609         break;
610     }
611   }
612   return lua_tolstring(L, -1, len);
613 }
614 
615 
616 /*
617 ** {======================================================
618 ** Compatibility with 5.1 module functions
619 ** =======================================================
620 */
621 #if defined(LUA_COMPAT_MODULE)
622 
623 static const char *luaL_findtable (lua_State *L, int idx,
624                                    const char *fname, int szhint) {
625   const char *e;
626   if (idx) lua_pushvalue(L, idx);
627   do {
628     e = strchr(fname, '.');
629     if (e == NULL) e = fname + strlen(fname);
630     lua_pushlstring(L, fname, e - fname);
631     lua_rawget(L, -2);
632     if (lua_isnil(L, -1)) {  /* no such field? */
633       lua_pop(L, 1);  /* remove this nil */
634       lua_createtable(L, 0, (*e == '.' ? 1 : szhint)); /* new table for field */
635       lua_pushlstring(L, fname, e - fname);
636       lua_pushvalue(L, -2);
637       lua_settable(L, -4);  /* set new table into field */
638     }
639     else if (!lua_istable(L, -1)) {  /* field has a non-table value? */
640       lua_pop(L, 2);  /* remove table and value */
641       return fname;  /* return problematic part of the name */
642     }
643     lua_remove(L, -2);  /* remove previous table */
644     fname = e + 1;
645   } while (*e == '.');
646   return NULL;
647 }
648 
649 
650 /*
651 ** Count number of elements in a luaL_Reg list.
652 */
653 static int libsize (const luaL_Reg *l) {
654   int size = 0;
655   for (; l && l->name; l++) size++;
656   return size;
657 }
658 
659 
660 /*
661 ** Find or create a module table with a given name. The function
662 ** first looks at the _LOADED table and, if that fails, try a
663 ** global variable with that name. In any case, leaves on the stack
664 ** the module table.
665 */
666 LUALIB_API void luaL_pushmodule (lua_State *L, const char *modname,
667                                  int sizehint) {
668   luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 1);  /* get _LOADED table */
669   lua_getfield(L, -1, modname);  /* get _LOADED[modname] */
670   if (!lua_istable(L, -1)) {  /* not found? */
671     lua_pop(L, 1);  /* remove previous result */
672     /* try global variable (and create one if it does not exist) */
673     lua_pushglobaltable(L);
674     if (luaL_findtable(L, 0, modname, sizehint) != NULL)
675       luaL_error(L, "name conflict for module " LUA_QS, modname);
676     lua_pushvalue(L, -1);
677     lua_setfield(L, -3, modname);  /* _LOADED[modname] = new table */
678   }
679   lua_remove(L, -2);  /* remove _LOADED table */
680 }
681 
682 
683 LUALIB_API void luaL_openlib (lua_State *L, const char *libname,
684                                const luaL_Reg *l, int nup) {
685   luaL_checkversion(L);
686   if (libname) {
687     luaL_pushmodule(L, libname, libsize(l));  /* get/create library table */
688     lua_insert(L, -(nup + 1));  /* move library table to below upvalues */
689   }
690   if (l)
691     luaL_setfuncs(L, l, nup);
692   else
693     lua_pop(L, nup);  /* remove upvalues */
694 }
695 
696 #endif
697 /* }====================================================== */
698 
699 /*
700 ** set functions from list 'l' into table at top - 'nup'; each
701 ** function gets the 'nup' elements at the top as upvalues.
702 ** Returns with only the table at the stack.
703 */
704 LUALIB_API void luaL_setfuncs (lua_State *L, const luaL_Reg *l, int nup) {
705   luaL_checkversion(L);
706   luaL_checkstack(L, nup, "too many upvalues");
707   for (; l->name != NULL; l++) {  /* fill the table with given functions */
708     int i;
709     for (i = 0; i < nup; i++)  /* copy upvalues to the top */
710       lua_pushvalue(L, -nup);
711     lua_pushcclosure(L, l->func, nup);  /* closure with those upvalues */
712     lua_setfield(L, -(nup + 2), l->name);
713   }
714   lua_pop(L, nup);  /* remove upvalues */
715 }
716 
717 
718 /*
719 ** ensure that stack[idx][fname] has a table and push that table
720 ** into the stack
721 */
722 LUALIB_API int luaL_getsubtable (lua_State *L, int idx, const char *fname) {
723   lua_getfield(L, idx, fname);
724   if (lua_istable(L, -1)) return 1;  /* table already there */
725   else {
726     lua_pop(L, 1);  /* remove previous result */
727     idx = lua_absindex(L, idx);
728     lua_newtable(L);
729     lua_pushvalue(L, -1);  /* copy to be left at top */
730     lua_setfield(L, idx, fname);  /* assign new table to field */
731     return 0;  /* false, because did not find table there */
732   }
733 }
734 
735 
736 /*
737 ** stripped-down 'require'. Calls 'openf' to open a module,
738 ** registers the result in 'package.loaded' table and, if 'glb'
739 ** is true, also registers the result in the global table.
740 ** Leaves resulting module on the top.
741 */
742 LUALIB_API void luaL_requiref (lua_State *L, const char *modname,
743                                lua_CFunction openf, int glb) {
744   lua_pushcfunction(L, openf);
745   lua_pushstring(L, modname);  /* argument to open function */
746   lua_call(L, 1, 1);  /* open module */
747   luaL_getsubtable(L, LUA_REGISTRYINDEX, "_LOADED");
748   lua_pushvalue(L, -2);  /* make copy of module (call result) */
749   lua_setfield(L, -2, modname);  /* _LOADED[modname] = module */
750   lua_pop(L, 1);  /* remove _LOADED table */
751   if (glb) {
752     lua_pushvalue(L, -1);  /* copy of 'mod' */
753     lua_setglobal(L, modname);  /* _G[modname] = module */
754   }
755 }
756 
757 
758 LUALIB_API const char *luaL_gsub (lua_State *L, const char *s, const char *p,
759                                                                const char *r) {
760   const char *wild;
761   size_t l = strlen(p);
762   luaL_Buffer b;
763   luaL_buffinit(L, &b);
764   while ((wild = strstr(s, p)) != NULL) {
765     luaL_addlstring(&b, s, wild - s);  /* push prefix */
766     luaL_addstring(&b, r);  /* push replacement in place of pattern */
767     s = wild + l;  /* continue after `p' */
768   }
769   luaL_addstring(&b, s);  /* push last suffix */
770   luaL_pushresult(&b);
771   return lua_tostring(L, -1);
772 }
773 
774 
775 LUALIB_API void luaL_checkversion_ (lua_State *L, lua_Number ver) {
776   const lua_Number *v = lua_version(L);
777   if (v != lua_version(NULL))
778     luaL_error(L, "multiple Lua VMs detected");
779   else if (*v != ver)
780     luaL_error(L, "version mismatch: app. needs %f, Lua core provides %f",
781                   ver, *v);
782   /* check conversions number -> integer types */
783   lua_pushnumber(L, -(lua_Number)0x1234);
784   if (lua_tointeger(L, -1) != -0x1234 ||
785       lua_tounsigned(L, -1) != (lua_Unsigned)-0x1234)
786     luaL_error(L, "bad conversion number->int;"
787                   " must recompile Lua with proper settings");
788   lua_pop(L, 1);
789 }
790 
791 #if defined(_KERNEL)
792 
793 EXPORT_SYMBOL(luaL_argerror);
794 EXPORT_SYMBOL(luaL_error);
795 EXPORT_SYMBOL(luaL_loadbufferx);
796 EXPORT_SYMBOL(luaL_newmetatable);
797 EXPORT_SYMBOL(luaL_traceback);
798 
799 #endif
800 /* END CSTYLED */
801