module/lua/lauxlib.c

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