liblua/lauxlib.c

   1 /*
   2 ** $Id: lauxlib.c,v 1.248 2013/03/21 13:54:57 roberto Exp $
   3 ** Auxiliary functions for building Lua libraries
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <errno.h>
   9 #include <stdarg.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13
  14
  15 /* This file uses only the official API of Lua.
  16 ** Any function declared here could be written as an application function.
  17 */
  18
  19 #define lauxlib_c
  20 #define LUA_LIB
  21
  22 #include "lua.h"
  23
  24 #include "lauxlib.h"
  25
  26
  27 /*
  28 ** {======================================================
  29 ** Traceback
  30 ** =======================================================
  31 */
  32
  33
  34 #define LEVELS1 12      /* size of the first part of the stack */
  35 #define LEVELS2 10      /* size of the second part of the stack */
  36
  37
  38
  39 /*
  40 ** search for 'objidx' in table at index -1.
  41 ** return 1 + string at top if find a good name.
  42 */
  43 static int findfield (lua_State *L, int objidx, int level) {
  44   if (level == 0 || !lua_istable(L, -1))
  45     return 0;  /* not found */
  46   lua_pushnil(L);  /* start 'next' loop */
  47   while (lua_next(L, -2)) {  /* for each pair in table */
  48     if (lua_type(L, -2) == LUA_TSTRING) {  /* ignore non-string keys */
  49       if (lua_rawequal(L, objidx, -1)) {  /* found object? */
  50         lua_pop(L, 1);  /* remove value (but keep name) */
  51         return 1;
  52       }
  53       else if (findfield(L, objidx, level - 1)) {  /* try recursively */
  54         lua_remove(L, -2);  /* remove table (but keep name) */
  55         lua_pushliteral(L, ".");
  56         lua_insert(L, -2);  /* place '.' between the two names */
  57         lua_concat(L, 3);
  58         return 1;
  59       }
  60     }
  61     lua_pop(L, 1);  /* remove value */
  62   }
  63   return 0;  /* not found */
  64 }
  65
  66
  67 static int pushglobalfuncname (lua_State *L, lua_Debug *ar) {
  68   int top = lua_gettop(L);
  69   lua_getinfo(L, "f", ar);  /* push function */
  70   lua_pushglobaltable(L);
  71   if (findfield(L, top + 1, 2)) {
  72     lua_copy(L, -1, top + 1);  /* move name to proper place */
  73     lua_pop(L, 2);  /* remove pushed values */
  74     return 1;
  75   }
  76   else {
  77     lua_settop(L, top);  /* remove function and global table */
  78     return 0;
  79   }
  80 }
  81
  82
  83 static void pushfuncname (lua_State *L, lua_Debug *ar) {
  84   if (*ar->namewhat != '\0')  /* is there a name? */
  85     lua_pushfstring(L, "function " LUA_QS, ar->name);
  86   else if (*ar->what == 'm')  /* main? */
  87       lua_pushliteral(L, "main chunk");
  88   else if (*ar->what == 'C') {
  89     if (pushglobalfuncname(L, ar)) {
  90       lua_pushfstring(L, "function " LUA_QS, lua_tostring(L, -1));
  91       lua_remove(L, -2);  /* remove name */
  92     }
  93     else
  94       lua_pushliteral(L, "?");
  95   }
  96   else
  97     lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined);
  98 }
  99
 100
 101 static int countlevels (lua_State *L) {
 102   lua_Debug ar;
 103   int li = 1, le = 1;
 104   /* find an upper bound */
 105   while (lua_getstack(L, le, &ar)) { li = le; le *= 2; }
 106   /* do a binary search */
 107   while (li < le) {
 108     int m = (li + le)/2;
 109     if (lua_getstack(L, m, &ar)) li = m + 1;
 110     else le = m;
 111   }
 112   return le - 1;
 113 }
 114
 115
 116 LUALIB_API void luaL_traceback (lua_State *L, lua_State *L1,
 117                                 const char *msg, int level) {
 118   lua_Debug ar;
 119   int top = lua_gettop(L);
 120   int numlevels = countlevels(L1);
 121   int mark = (numlevels > LEVELS1 + LEVELS2) ? LEVELS1 : 0;
 122   if (msg) lua_pushfstring(L, "%s\n", msg);
 123   lua_pushliteral(L, "stack traceback:");
 124   while (lua_getstack(L1, level++, &ar)) {
 125     if (level == mark) {  /* too many levels? */
 126       lua_pushliteral(L, "\n\t...");  /* add a '...' */
 127       level = numlevels - LEVELS2;  /* and skip to last ones */
 128     }
 129     else {
 130       lua_getinfo(L1, "Slnt", &ar);
 131       lua_pushfstring(L, "\n\t%s:", ar.short_src);
 132       if (ar.currentline > 0)
 133         lua_pushfstring(L, "%d:", ar.currentline);
 134       lua_pushliteral(L, " in ");
 135       pushfuncname(L, &ar);
 136       if (ar.istailcall)
 137         lua_pushliteral(L, "\n\t(...tail calls...)");
 138       lua_concat(L, lua_gettop(L) - top);
 139     }
 140   }
 141   lua_concat(L, lua_gettop(L) - top);
 142 }
 143
 144 /* }====================================================== */
 145
 146
 147 /*
 148 ** {======================================================
 149 ** Error-report functions
 150 ** =======================================================
 151 */
 152
 153 LUALIB_API int luaL_argerror (lua_State *L, int narg, const char *extramsg) {
 154   lua_Debug ar;
 155   if (!lua_getstack(L, 0, &ar))  /* no stack frame? */
 156     return luaL_error(L, "bad argument #%d (%s)", narg, extramsg);
 157   lua_getinfo(L, "n", &ar);
 158   if (strcmp(ar.namewhat, "method") == 0) {
 159     narg--;  /* do not count `self' */
 160     if (narg == 0)  /* error is in the self argument itself? */
 161       return luaL_error(L, "calling " LUA_QS " on bad self (%s)",
 162                            ar.name, extramsg);
 163   }
 164   if (ar.name == NULL)
 165     ar.name = (pushglobalfuncname(L, &ar)) ? lua_tostring(L, -1) : "?";
 166   return luaL_error(L, "bad argument #%d to " LUA_QS " (%s)",
 167                         narg, ar.name, extramsg);
 168 }
 169
 170
 171 static int typeerror (lua_State *L, int narg, const char *tname) {
 172   const char *msg = lua_pushfstring(L, "%s expected, got %s",
 173                                     tname, luaL_typename(L, narg));
 174   return luaL_argerror(L, narg, msg);
 175 }
 176
 177
 178 static void tag_error (lua_State *L, int narg, int tag) {
 179   typeerror(L, narg, lua_typename(L, tag));
 180 }
 181
 182
 183 LUALIB_API void luaL_where (lua_State *L, int level) {
 184   lua_Debug ar;
 185   if (lua_getstack(L, level, &ar)) {  /* check function at level */
 186     lua_getinfo(L, "Sl", &ar);  /* get info about it */
 187     if (ar.currentline > 0) {  /* is there info? */
 188       lua_pushfstring(L, "%s:%d: ", ar.short_src, ar.currentline);
 189       return;
 190     }
 191   }
 192   lua_pushliteral(L, "");  /* else, no information available... */
 193 }
 194
 195
 196 LUALIB_API int luaL_error (lua_State *L, const char *fmt, ...) {
 197   va_list argp;
 198   va_start(argp, fmt);
 199   luaL_where(L, 1);
 200   lua_pushvfstring(L, fmt, argp);
 201   va_end(argp);
 202   lua_concat(L, 2);
 203   return lua_error(L);
 204 }
 205
 206
 207 LUALIB_API int luaL_fileresult (lua_State *L, int stat, const char *fname) {
 208   int en = errno;  /* calls to Lua API may change this value */
 209   if (stat) {
 210     lua_pushboolean(L, 1);
 211     return 1;
 212   }
 213   else {
 214     lua_pushnil(L);
 215     if (fname)
 216       lua_pushfstring(L, "%s: %s", fname, strerror(en));
 217     else
 218       lua_pushstring(L, strerror(en));
 219     lua_pushinteger(L, en);
 220     return 3;
 221   }
 222 }
 223
 224
 225 #if !defined(inspectstat)       /* { */
 226
 227 #if defined(LUA_USE_POSIX)
 228
 229 #include <sys/wait.h>
 230
 231 /*
 232 ** use appropriate macros to interpret 'pclose' return status
 233 */
 234 #define inspectstat(stat,what)  \
 235    if (WIFEXITED(stat)) { stat = WEXITSTATUS(stat); } \
 236    else if (WIFSIGNALED(stat)) { stat = WTERMSIG(stat); what = "signal"; }
 237
 238 #else
 239
 240 #define inspectstat(stat,what)  /* no op */
 241
 242 #endif
 243
 244 #endif                          /* } */
 245
 246
 247 LUALIB_API int luaL_execresult (lua_State *L, int stat) {
 248   const char *what = "exit";  /* type of termination */
 249   if (stat == -1)  /* error? */
 250     return luaL_fileresult(L, 0, NULL);
 251   else {
 252     inspectstat(stat, what);  /* interpret result */
 253     if (*what == 'e' && stat == 0)  /* successful termination? */
 254       lua_pushboolean(L, 1);
 255     else
 256       lua_pushnil(L);
 257     lua_pushstring(L, what);
 258     lua_pushinteger(L, stat);
 259     return 3;  /* return true/nil,what,code */
 260   }
 261 }
 262
 263 /* }====================================================== */
 264
 265
 266 /*
 267 ** {======================================================
 268 ** Userdata's metatable manipulation
 269 ** =======================================================
 270 */
 271
 272 LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
 273   luaL_getmetatable(L, tname);  /* try to get metatable */
 274   if (!lua_isnil(L, -1))  /* name already in use? */
 275     return 0;  /* leave previous value on top, but return 0 */
 276   lua_pop(L, 1);
 277   lua_newtable(L);  /* create metatable */
 278   lua_pushvalue(L, -1);
 279   lua_setfield(L, LUA_REGISTRYINDEX, tname);  /* registry.name = metatable */
 280   return 1;
 281 }
 282
 283
 284 LUALIB_API void luaL_setmetatable (lua_State *L, const char *tname) {
 285   luaL_getmetatable(L, tname);
 286   lua_setmetatable(L, -2);
 287 }
 288
 289
 290 LUALIB_API void *luaL_testudata (lua_State *L, int ud, const char *tname) {
 291   void *p = lua_touserdata(L, ud);
 292   if (p != NULL) {  /* value is a userdata? */
 293     if (lua_getmetatable(L, ud)) {  /* does it have a metatable? */
 294       luaL_getmetatable(L, tname);  /* get correct metatable */
 295       if (!lua_rawequal(L, -1, -2))  /* not the same? */
 296         p = NULL;  /* value is a userdata with wrong metatable */
 297       lua_pop(L, 2);  /* remove both metatables */
 298       return p;
 299     }
 300   }
 301   return NULL;  /* value is not a userdata with a metatable */
 302 }
 303
 304
 305 LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
 306   void *p = luaL_testudata(L, ud, tname);
 307   if (p == NULL) typeerror(L, ud, tname);
 308   return p;
 309 }
 310
 311 /* }====================================================== */
 312
 313
 314 /*
 315 ** {======================================================
 316 ** Argument check functions
 317 ** =======================================================
 318 */
 319
 320 LUALIB_API int luaL_checkoption (lua_State *L, int narg, const char *def,
 321                                  const char *const lst[]) {
 322   const char *name = (def) ? luaL_optstring(L, narg, def) :
 323                              luaL_checkstring(L, narg);
 324   int i;
 325   for (i=0; lst[i]; i++)
 326     if (strcmp(lst[i], name) == 0)
 327       return i;
 328   return luaL_argerror(L, narg,
 329                        lua_pushfstring(L, "invalid option " LUA_QS, name));
 330 }
 331
 332
 333 LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *msg) {
 334   /* keep some extra space to run error routines, if needed */
 335   const int extra = LUA_MINSTACK;
 336   if (!lua_checkstack(L, space + extra)) {
 337     if (msg)
 338       luaL_error(L, "stack overflow (%s)", msg);
 339     else
 340       luaL_error(L, "stack overflow");
 341   }
 342 }
 343
 344
 345 LUALIB_API void luaL_checktype (lua_State *L, int narg, int t) {
 346   if (lua_type(L, narg) != t)
 347     tag_error(L, narg, t);
 348 }
 349
 350
 351 LUALIB_API void luaL_checkany (lua_State *L, int narg) {
 352   if (lua_type(L, narg) == LUA_TNONE)
 353     luaL_argerror(L, narg, "value expected");
 354 }
 355
 356
 357 LUALIB_API const char *luaL_checklstring (lua_State *L, int narg, size_t *len) {
 358   const char *s = lua_tolstring(L, narg, len);
 359   if (!s) tag_error(L, narg, LUA_TSTRING);
 360   return s;
 361 }
 362
 363
 364 LUALIB_API const char *luaL_optlstring (lua_State *L, int narg,
 365                                         const char *def, size_t *len) {
 366   if (lua_isnoneornil(L, narg)) {
 367     if (len)
 368       *len = (def ? strlen(def) : 0);
 369     return def;
 370   }
 371   else return luaL_checklstring(L, narg, len);
 372 }
 373
 374
 375 LUALIB_API lua_Number luaL_checknumber (lua_State *L, int narg) {
 376   int isnum;
 377   lua_Number d = lua_tonumberx(L, narg, &isnum);
 378   if (!isnum)
 379     tag_error(L, narg, LUA_TNUMBER);
 380   return d;
 381 }
 382
 383
 384 LUALIB_API lua_Number luaL_optnumber (lua_State *L, int narg, lua_Number def) {
 385   return luaL_opt(L, luaL_checknumber, narg, def);
 386 }
 387
 388
 389 LUALIB_API lua_Integer luaL_checkinteger (lua_State *L, int narg) {
 390   int isnum;
 391   lua_Integer d = lua_tointegerx(L, narg, &isnum);
 392   if (!isnum)
 393     tag_error(L, narg, LUA_TNUMBER);
 394   return d;
 395 }
 396
 397
 398 LUALIB_API lua_Unsigned luaL_checkunsigned (lua_State *L, int narg) {
 399   int isnum;
 400   lua_Unsigned d = lua_tounsignedx(L, narg, &isnum);
 401   if (!isnum)
 402     tag_error(L, narg, LUA_TNUMBER);
 403   return d;
 404 }
 405
 406
 407 LUALIB_API lua_Integer luaL_optinteger (lua_State *L, int narg,
 408                                                       lua_Integer def) {
 409   return luaL_opt(L, luaL_checkinteger, narg, def);
 410 }
 411
 412
 413 LUALIB_API lua_Unsigned luaL_optunsigned (lua_State *L, int narg,
 414                                                         lua_Unsigned def) {
 415   return luaL_opt(L, luaL_checkunsigned, narg, def);
 416 }
 417
 418 /* }====================================================== */
 419
 420
 421 /*
 422 ** {======================================================
 423 ** Generic Buffer manipulation
 424 ** =======================================================
 425 */
 426
 427 /*
 428 ** check whether buffer is using a userdata on the stack as a temporary
 429 ** buffer
 430 */
 431 #define buffonstack(B)  ((B)->b != (B)->initb)
 432
 433
 434 /*
 435 ** returns a pointer to a free area with at least 'sz' bytes
 436 */
 437 LUALIB_API char *luaL_prepbuffsize (luaL_Buffer *B, size_t sz) {
 438   lua_State *L = B->L;
 439   if (B->size - B->n < sz) {  /* not enough space? */
 440     char *newbuff;
 441     size_t newsize = B->size * 2;  /* double buffer size */
 442     if (newsize - B->n < sz)  /* not big enough? */
 443       newsize = B->n + sz;
 444     if (newsize < B->n || newsize - B->n < sz)
 445       luaL_error(L, "buffer too large");
 446     /* create larger buffer */
 447     newbuff = (char *)lua_newuserdata(L, newsize * sizeof(char));
 448     /* move content to new buffer */
 449     memcpy(newbuff, B->b, B->n * sizeof(char));
 450     if (buffonstack(B))
 451       lua_remove(L, -2);  /* remove old buffer */
 452     B->b = newbuff;
 453     B->size = newsize;
 454   }
 455   return &B->b[B->n];
 456 }
 457
 458
 459 LUALIB_API void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l) {
 460   char *b = luaL_prepbuffsize(B, l);
 461   memcpy(b, s, l * sizeof(char));
 462   luaL_addsize(B, l);
 463 }
 464
 465
 466 LUALIB_API void luaL_addstring (luaL_Buffer *B, const char *s) {
 467   luaL_addlstring(B, s, strlen(s));
 468 }
 469
 470
 471 LUALIB_API void luaL_pushresult (luaL_Buffer *B) {
 472   lua_State *L = B->L;
 473   lua_pushlstring(L, B->b, B->n);
 474   if (buffonstack(B))
 475     lua_remove(L, -2);  /* remove old buffer */
 476 }
 477
 478
 479 LUALIB_API void luaL_pushresultsize (luaL_Buffer *B, size_t sz) {
 480   luaL_addsize(B, sz);
 481   luaL_pushresult(B);
 482 }
 483
 484
 485 LUALIB_API void luaL_addvalue (luaL_Buffer *B) {
 486   lua_State *L = B->L;
 487   size_t l;
 488   const char *s = lua_tolstring(L, -1, &l);
 489   if (buffonstack(B))
 490     lua_insert(L, -2);  /* put value below buffer */
 491   luaL_addlstring(B, s, l);
 492   lua_remove(L, (buffonstack(B)) ? -2 : -1);  /* remove value */
 493 }
 494
 495
 496 LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {
 497   B->L = L;
 498   B->b = B->initb;
 499   B->n = 0;
 500   B->size = LUAL_BUFFERSIZE;
 501 }
 502
 503
 504 LUALIB_API char *luaL_buffinitsize (lua_State *L, luaL_Buffer *B, size_t sz) {
 505   luaL_buffinit(L, B);
 506   return luaL_prepbuffsize(B, sz);
 507 }
 508
 509 /* }====================================================== */
 510
 511
 512 /*
 513 ** {======================================================
 514 ** Reference system
 515 ** =======================================================
 516 */
 517
 518 /* index of free-list header */
 519 #define freelist        0
 520
 521
 522 LUALIB_API int luaL_ref (lua_State *L, int t) {
 523   int ref;
 524   if (lua_isnil(L, -1)) {
 525     lua_pop(L, 1);  /* remove from stack */
 526     return LUA_REFNIL;  /* `nil' has a unique fixed reference */
 527   }
 528   t = lua_absindex(L, t);
 529   lua_rawgeti(L, t, freelist);  /* get first free element */
 530   ref = (int)lua_tointeger(L, -1);  /* ref = t[freelist] */
 531   lua_pop(L, 1);  /* remove it from stack */
 532   if (ref != 0) {  /* any free element? */
 533     lua_rawgeti(L, t, ref);  /* remove it from list */
 534     lua_rawseti(L, t, freelist);  /* (t[freelist] = t[ref]) */
 535   }
 536   else  /* no free elements */
 537     ref = (int)lua_rawlen(L, t) + 1;  /* get a new reference */
 538   lua_rawseti(L, t, ref);
 539   return ref;
 540 }
 541
 542
 543 LUALIB_API void luaL_unref (lua_State *L, int t, int ref) {
 544   if (ref >= 0) {
 545     t = lua_absindex(L, t);
 546     lua_rawgeti(L, t, freelist);
 547     lua_rawseti(L, t, ref);  /* t[ref] = t[freelist] */
 548     lua_pushinteger(L, ref);
 549     lua_rawseti(L, t, freelist);  /* t[freelist] = ref */
 550   }
 551 }
 552
 553 /* }====================================================== */
 554
 555
 556 /*
 557 ** {======================================================
 558 ** Load functions
 559 ** =======================================================
 560 */
 561
 562 typedef struct LoadF {
 563   int n;  /* number of pre-read characters */
 564   FILE *f;  /* file being read */
 565   char buff[LUAL_BUFFERSIZE];  /* area for reading file */
 566 } LoadF;
 567
 568
 569 static const char *getF (lua_State *L, void *ud, size_t *size) {
 570   LoadF *lf = (LoadF *)ud;
 571   (void)L;  /* not used */
 572   if (lf->n > 0) {  /* are there pre-read characters to be read? */
 573     *size = lf->n;  /* return them (chars already in buffer) */
 574     lf->n = 0;  /* no more pre-read characters */
 575   }
 576   else {  /* read a block from file */
 577     /* 'fread' can return > 0 *and* set the EOF flag. If next call to
 578        'getF' called 'fread', it might still wait for user input.
 579        The next check avoids this problem. */
 580     if (feof(lf->f)) return NULL;
 581     *size = fread(lf->buff, 1, sizeof(lf->buff), lf->f);  /* read block */
 582   }
 583   return lf->buff;
 584 }
 585
 586
 587 static int errfile (lua_State *L, const char *what, int fnameindex) {
 588   const char *serr = strerror(errno);
 589   const char *filename = lua_tostring(L, fnameindex) + 1;
 590   lua_pushfstring(L, "cannot %s %s: %s", what, filename, serr);
 591   lua_remove(L, fnameindex);
 592   return LUA_ERRFILE;
 593 }
 594
 595
 596 static int skipBOM (LoadF *lf) {
 597   const char *p = "\xEF\xBB\xBF";  /* Utf8 BOM mark */
 598   int c;
 599   lf->n = 0;
 600   do {
 601     c = getc(lf->f);
 602     if (c == EOF || c != *(const unsigned char *)p++) return c;
 603     lf->buff[lf->n++] = c;  /* to be read by the parser */
 604   } while (*p != '\0');
 605   lf->n = 0;  /* prefix matched; discard it */
 606   return getc(lf->f);  /* return next character */
 607 }
 608
 609
 610 /*
 611 ** reads the first character of file 'f' and skips an optional BOM mark
 612 ** in its beginning plus its first line if it starts with '#'. Returns
 613 ** true if it skipped the first line.  In any case, '*cp' has the
 614 ** first "valid" character of the file (after the optional BOM and
 615 ** a first-line comment).
 616 */
 617 static int skipcomment (LoadF *lf, int *cp) {
 618   int c = *cp = skipBOM(lf);
 619   if (c == '#') {  /* first line is a comment (Unix exec. file)? */
 620     do {  /* skip first line */
 621       c = getc(lf->f);
 622     } while (c != EOF && c != '\n') ;
 623     *cp = getc(lf->f);  /* skip end-of-line, if present */
 624     return 1;  /* there was a comment */
 625   }
 626   else return 0;  /* no comment */
 627 }
 628
 629
 630 LUALIB_API int luaL_loadfilex (lua_State *L, const char *filename,
 631                                              const char *mode) {
 632   LoadF lf;
 633   int status, readstatus;
 634   int c;
 635   int fnameindex = lua_gettop(L) + 1;  /* index of filename on the stack */
 636   if (filename == NULL) {
 637     lua_pushliteral(L, "=stdin");
 638     lf.f = stdin;
 639   }
 640   else {
 641     lua_pushfstring(L, "@%s", filename);
 642     lf.f = fopen(filename, "r");
 643     if (lf.f == NULL) return errfile(L, "open", fnameindex);
 644   }
 645   if (skipcomment(&lf, &c))  /* read initial portion */
 646     lf.buff[lf.n++] = '\n';  /* add line to correct line numbers */
 647   if (c == LUA_SIGNATURE[0] && filename) {  /* binary file? */
 648     lf.f = freopen(filename, "rb", lf.f);  /* reopen in binary mode */
 649     if (lf.f == NULL) return errfile(L, "reopen", fnameindex);
 650     skipcomment(&lf, &c);  /* re-read initial portion */
 651   }
 652   if (c != EOF)
 653     lf.buff[lf.n++] = c;  /* 'c' is the first character of the stream */
 654   status = lua_load(L, getF, &lf, lua_tostring(L, -1), mode);
 655   readstatus = ferror(lf.f);
 656   if (filename) fclose(lf.f);  /* close file (even in case of errors) */
 657   if (readstatus) {
 658     lua_settop(L, fnameindex);  /* ignore results from `lua_load' */
 659     return errfile(L, "read", fnameindex);
 660   }
 661   lua_remove(L, fnameindex);
 662   return status;
 663 }
 664
 665
 666 typedef struct LoadS {
 667   const char *s;
 668   size_t size;
 669 } LoadS;
 670
 671
 672 static const char *getS (lua_State *L, void *ud, size_t *size) {
 673   LoadS *ls = (LoadS *)ud;
 674   (void)L;  /* not used */
 675   if (ls->size == 0) return NULL;
 676   *size = ls->size;
 677   ls->size = 0;
 678   return ls->s;
 679 }
 680
 681
 682 LUALIB_API int luaL_loadbufferx (lua_State *L, const char *buff, size_t size,
 683                                  const char *name, const char *mode) {
 684   LoadS ls;
 685   ls.s = buff;
 686   ls.size = size;
 687   return lua_load(L, getS, &ls, name, mode);
 688 }
 689
 690
 691 LUALIB_API int luaL_loadstring (lua_State *L, const char *s) {
 692   return luaL_loadbuffer(L, s, strlen(s), s);
 693 }
 694
 695 /* }====================================================== */
 696
 697
 698
 699 LUALIB_API int luaL_getmetafield (lua_State *L, int obj, const char *event) {
 700   if (!lua_getmetatable(L, obj))  /* no metatable? */
 701     return 0;
 702   lua_pushstring(L, event);
 703   lua_rawget(L, -2);
 704   if (lua_isnil(L, -1)) {
 705     lua_pop(L, 2);  /* remove metatable and metafield */
 706     return 0;
 707   }
 708   else {
 709     lua_remove(L, -2);  /* remove only metatable */
 710     return 1;
 711   }
 712 }
 713
 714
 715 LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) {
 716   obj = lua_absindex(L, obj);
 717   if (!luaL_getmetafield(L, obj, event))  /* no metafield? */
 718     return 0;
 719   lua_pushvalue(L, obj);
 720   lua_call(L, 1, 1);
 721   return 1;
 722 }
 723
 724
 725 LUALIB_API int luaL_len (lua_State *L, int idx) {
 726   int l;
 727   int isnum;
 728   lua_len(L, idx);
 729   l = (int)lua_tointegerx(L, -1, &isnum);
 730   if (!isnum)
 731     luaL_error(L, "object length is not a number");
 732   lua_pop(L, 1);  /* remove object */
 733   return l;
 734 }
 735
 736
 737 LUALIB_API const char *luaL_tolstring (lua_State *L, int idx, size_t *len) {
 738   if (!luaL_callmeta(L, idx, "__tostring")) {  /* no metafield? */
 739     switch (lua_type(L, idx)) {
 740       case LUA_TNUMBER:
 741       case LUA_TSTRING:
 742         lua_pushvalue(L, idx);
 743         break;
 744       case LUA_TBOOLEAN:
 745         lua_pushstring(L, (lua_toboolean(L, idx) ? "true" : "false"));
 746         break;
 747       case LUA_TNIL:
 748         lua_pushliteral(L, "nil");
 749         break;
 750       default:
 751         lua_pushfstring(L, "%s: %p", luaL_typename(L, idx),
 752                                             lua_topointer(L, idx));
 753         break;
 754     }
 755   }
 756   return lua_tolstring(L, -1, len);
 757 }
 758
 759
 760 /*
 761 ** {======================================================
 762 ** Compatibility with 5.1 module functions
 763 ** =======================================================
 764 */
 765 #if defined(LUA_COMPAT_MODULE)
 766
 767 static const char *luaL_findtable (lua_State *L, int idx,
 768                                    const char *fname, int szhint) {
 769   const char *e;
 770   if (idx) lua_pushvalue(L, idx);
 771   do {
 772     e = strchr(fname, '.');
 773     if (e == NULL) e = fname + strlen(fname);
 774     lua_pushlstring(L, fname, e - fname);
 775     lua_rawget(L, -2);
 776     if (lua_isnil(L, -1)) {  /* no such field? */
 777       lua_pop(L, 1);  /* remove this nil */
 778       lua_createtable(L, 0, (*e == '.' ? 1 : szhint)); /* new table for field */
 779       lua_pushlstring(L, fname, e - fname);
 780       lua_pushvalue(L, -2);
 781       lua_settable(L, -4);  /* set new table into field */
 782     }
 783     else if (!lua_istable(L, -1)) {  /* field has a non-table value? */
 784       lua_pop(L, 2);  /* remove table and value */
 785       return fname;  /* return problematic part of the name */
 786     }
 787     lua_remove(L, -2);  /* remove previous table */
 788     fname = e + 1;
 789   } while (*e == '.');
 790   return NULL;
 791 }
 792
 793
 794 /*
 795 ** Count number of elements in a luaL_Reg list.
 796 */
 797 static int libsize (const luaL_Reg *l) {
 798   int size = 0;
 799   for (; l && l->name; l++) size++;
 800   return size;
 801 }
 802
 803
 804 /*
 805 ** Find or create a module table with a given name. The function
 806 ** first looks at the _LOADED table and, if that fails, try a
 807 ** global variable with that name. In any case, leaves on the stack
 808 ** the module table.
 809 */
 810 LUALIB_API void luaL_pushmodule (lua_State *L, const char *modname,
 811                                  int sizehint) {
 812   luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 1);  /* get _LOADED table */
 813   lua_getfield(L, -1, modname);  /* get _LOADED[modname] */
 814   if (!lua_istable(L, -1)) {  /* not found? */
 815     lua_pop(L, 1);  /* remove previous result */
 816     /* try global variable (and create one if it does not exist) */
 817     lua_pushglobaltable(L);
 818     if (luaL_findtable(L, 0, modname, sizehint) != NULL)
 819       luaL_error(L, "name conflict for module " LUA_QS, modname);
 820     lua_pushvalue(L, -1);
 821     lua_setfield(L, -3, modname);  /* _LOADED[modname] = new table */
 822   }
 823   lua_remove(L, -2);  /* remove _LOADED table */
 824 }
 825
 826
 827 LUALIB_API void luaL_openlib (lua_State *L, const char *libname,
 828                                const luaL_Reg *l, int nup) {
 829   luaL_checkversion(L);
 830   if (libname) {
 831     luaL_pushmodule(L, libname, libsize(l));  /* get/create library table */
 832     lua_insert(L, -(nup + 1));  /* move library table to below upvalues */
 833   }
 834   if (l)
 835     luaL_setfuncs(L, l, nup);
 836   else
 837     lua_pop(L, nup);  /* remove upvalues */
 838 }
 839
 840 #endif
 841 /* }====================================================== */
 842
 843 /*
 844 ** set functions from list 'l' into table at top - 'nup'; each
 845 ** function gets the 'nup' elements at the top as upvalues.
 846 ** Returns with only the table at the stack.
 847 */
 848 LUALIB_API void luaL_setfuncs (lua_State *L, const luaL_Reg *l, int nup) {
 849   luaL_checkversion(L);
 850   luaL_checkstack(L, nup, "too many upvalues");
 851   for (; l->name != NULL; l++) {  /* fill the table with given functions */
 852     int i;
 853     for (i = 0; i < nup; i++)  /* copy upvalues to the top */
 854       lua_pushvalue(L, -nup);
 855     lua_pushcclosure(L, l->func, nup);  /* closure with those upvalues */
 856     lua_setfield(L, -(nup + 2), l->name);
 857   }
 858   lua_pop(L, nup);  /* remove upvalues */
 859 }
 860
 861
 862 /*
 863 ** ensure that stack[idx][fname] has a table and push that table
 864 ** into the stack
 865 */
 866 LUALIB_API int luaL_getsubtable (lua_State *L, int idx, const char *fname) {
 867   lua_getfield(L, idx, fname);
 868   if (lua_istable(L, -1)) return 1;  /* table already there */
 869   else {
 870     lua_pop(L, 1);  /* remove previous result */
 871     idx = lua_absindex(L, idx);
 872     lua_newtable(L);
 873     lua_pushvalue(L, -1);  /* copy to be left at top */
 874     lua_setfield(L, idx, fname);  /* assign new table to field */
 875     return 0;  /* false, because did not find table there */
 876   }
 877 }
 878
 879
 880 /*
 881 ** stripped-down 'require'. Calls 'openf' to open a module,
 882 ** registers the result in 'package.loaded' table and, if 'glb'
 883 ** is true, also registers the result in the global table.
 884 ** Leaves resulting module on the top.
 885 */
 886 LUALIB_API void luaL_requiref (lua_State *L, const char *modname,
 887                                lua_CFunction openf, int glb) {
 888   lua_pushcfunction(L, openf);
 889   lua_pushstring(L, modname);  /* argument to open function */
 890   lua_call(L, 1, 1);  /* open module */
 891   luaL_getsubtable(L, LUA_REGISTRYINDEX, "_LOADED");
 892   lua_pushvalue(L, -2);  /* make copy of module (call result) */
 893   lua_setfield(L, -2, modname);  /* _LOADED[modname] = module */
 894   lua_pop(L, 1);  /* remove _LOADED table */
 895   if (glb) {
 896     lua_pushvalue(L, -1);  /* copy of 'mod' */
 897     lua_setglobal(L, modname);  /* _G[modname] = module */
 898   }
 899 }
 900
 901
 902 LUALIB_API const char *luaL_gsub (lua_State *L, const char *s, const char *p,
 903                                                                const char *r) {
 904   const char *wild;
 905   size_t l = strlen(p);
 906   luaL_Buffer b;
 907   luaL_buffinit(L, &b);
 908   while ((wild = strstr(s, p)) != NULL) {
 909     luaL_addlstring(&b, s, wild - s);  /* push prefix */
 910     luaL_addstring(&b, r);  /* push replacement in place of pattern */
 911     s = wild + l;  /* continue after `p' */
 912   }
 913   luaL_addstring(&b, s);  /* push last suffix */
 914   luaL_pushresult(&b);
 915   return lua_tostring(L, -1);
 916 }
 917
 918
 919 static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
 920   (void)ud; (void)osize;  /* not used */
 921   if (nsize == 0) {
 922     free(ptr);
 923     return NULL;
 924   }
 925   else
 926     return realloc(ptr, nsize);
 927 }
 928
 929
 930 static int panic (lua_State *L) {
 931   luai_writestringerror("PANIC: unprotected error in call to Lua API (%s)\n",
 932                    lua_tostring(L, -1));
 933   return 0;  /* return to Lua to abort */
 934 }
 935
 936
 937 LUALIB_API lua_State *luaL_newstate (void) {
 938   lua_State *L = lua_newstate(l_alloc, NULL);
 939   if (L) lua_atpanic(L, &panic);
 940   return L;
 941 }
 942
 943
 944 LUALIB_API void luaL_checkversion_ (lua_State *L, lua_Number ver) {
 945   const lua_Number *v = lua_version(L);
 946   if (v != lua_version(NULL))
 947     luaL_error(L, "multiple Lua VMs detected");
 948   else if (*v != ver)
 949     luaL_error(L, "version mismatch: app. needs %f, Lua core provides %f",
 950                   ver, *v);
 951   /* check conversions number -> integer types */
 952   lua_pushnumber(L, -(lua_Number)0x1234);
 953   if (lua_tointeger(L, -1) != -0x1234 ||
 954       lua_tounsigned(L, -1) != (lua_Unsigned)-0x1234)
 955     luaL_error(L, "bad conversion number->int;"
 956                   " must recompile Lua with proper settings");
 957   lua_pop(L, 1);
 958 }
 959