module/lua/lauxlib.c

   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 */