lauxlib.c (35966B)
1 /* 2 ** $Id: lauxlib.c $ 3 ** Auxiliary functions for building Lua libraries 4 ** See Copyright Notice in lua.h 5 */ 6 7 #define lauxlib_c 8 #define LUA_LIB 9 10 #include "lprefix.h" 11 12 13 #include <errno.h> 14 #include <stdarg.h> 15 #include <stdio.h> 16 #include <stdlib.h> 17 #include <string.h> 18 19 20 /* 21 ** This file uses only the official API of Lua. 22 ** Any function declared here could be written as an application function. 23 */ 24 25 #include "lua.h" 26 27 #include "lauxlib.h" 28 #include "llimits.h" 29 30 31 /* 32 ** {====================================================== 33 ** Traceback 34 ** ======================================================= 35 */ 36 37 38 #define LEVELS1 10 /* size of the first part of the stack */ 39 #define LEVELS2 11 /* size of the second part of the stack */ 40 41 42 43 /* 44 ** Search for 'objidx' in table at index -1. ('objidx' must be an 45 ** absolute index.) Return 1 + string at top if it found a good name. 46 */ 47 static int findfield (lua_State *L, int objidx, int level) { 48 if (level == 0 || !lua_istable(L, -1)) 49 return 0; /* not found */ 50 lua_pushnil(L); /* start 'next' loop */ 51 while (lua_next(L, -2)) { /* for each pair in table */ 52 if (lua_type(L, -2) == LUA_TSTRING) { /* ignore non-string keys */ 53 if (lua_rawequal(L, objidx, -1)) { /* found object? */ 54 lua_pop(L, 1); /* remove value (but keep name) */ 55 return 1; 56 } 57 else if (findfield(L, objidx, level - 1)) { /* try recursively */ 58 /* stack: lib_name, lib_table, field_name (top) */ 59 lua_pushliteral(L, "."); /* place '.' between the two names */ 60 lua_replace(L, -3); /* (in the slot occupied by table) */ 61 lua_concat(L, 3); /* lib_name.field_name */ 62 return 1; 63 } 64 } 65 lua_pop(L, 1); /* remove value */ 66 } 67 return 0; /* not found */ 68 } 69 70 71 /* 72 ** Search for a name for a function in all loaded modules 73 */ 74 static int pushglobalfuncname (lua_State *L, lua_Debug *ar) { 75 int top = lua_gettop(L); 76 lua_getinfo(L, "f", ar); /* push function */ 77 lua_getfield(L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE); 78 luaL_checkstack(L, 6, "not enough stack"); /* slots for 'findfield' */ 79 if (findfield(L, top + 1, 2)) { 80 const char *name = lua_tostring(L, -1); 81 if (strncmp(name, LUA_GNAME ".", 3) == 0) { /* name start with '_G.'? */ 82 lua_pushstring(L, name + 3); /* push name without prefix */ 83 lua_remove(L, -2); /* remove original name */ 84 } 85 lua_copy(L, -1, top + 1); /* copy name to proper place */ 86 lua_settop(L, top + 1); /* remove table "loaded" and name copy */ 87 return 1; 88 } 89 else { 90 lua_settop(L, top); /* remove function and global table */ 91 return 0; 92 } 93 } 94 95 96 static void pushfuncname (lua_State *L, lua_Debug *ar) { 97 if (pushglobalfuncname(L, ar)) { /* try first a global name */ 98 lua_pushfstring(L, "function '%s'", lua_tostring(L, -1)); 99 lua_remove(L, -2); /* remove name */ 100 } 101 else if (*ar->namewhat != '\0') /* is there a name from code? */ 102 lua_pushfstring(L, "%s '%s'", ar->namewhat, ar->name); /* use it */ 103 else if (*ar->what == 'm') /* main? */ 104 lua_pushliteral(L, "main chunk"); 105 else if (*ar->what != 'C') /* for Lua functions, use <file:line> */ 106 lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined); 107 else /* nothing left... */ 108 lua_pushliteral(L, "?"); 109 } 110 111 112 static int lastlevel (lua_State *L) { 113 lua_Debug ar; 114 int li = 1, le = 1; 115 /* find an upper bound */ 116 while (lua_getstack(L, le, &ar)) { li = le; le *= 2; } 117 /* do a binary search */ 118 while (li < le) { 119 int m = (li + le)/2; 120 if (lua_getstack(L, m, &ar)) li = m + 1; 121 else le = m; 122 } 123 return le - 1; 124 } 125 126 127 LUALIB_API void luaL_traceback (lua_State *L, lua_State *L1, 128 const char *msg, int level) { 129 luaL_Buffer b; 130 lua_Debug ar; 131 int last = lastlevel(L1); 132 int limit2show = (last - level > LEVELS1 + LEVELS2) ? LEVELS1 : -1; 133 luaL_buffinit(L, &b); 134 if (msg) { 135 luaL_addstring(&b, msg); 136 luaL_addchar(&b, '\n'); 137 } 138 luaL_addstring(&b, "stack traceback:"); 139 while (lua_getstack(L1, level++, &ar)) { 140 if (limit2show-- == 0) { /* too many levels? */ 141 int n = last - level - LEVELS2 + 1; /* number of levels to skip */ 142 lua_pushfstring(L, "\n\t...\t(skipping %d levels)", n); 143 luaL_addvalue(&b); /* add warning about skip */ 144 level += n; /* and skip to last levels */ 145 } 146 else { 147 lua_getinfo(L1, "Slnt", &ar); 148 if (ar.currentline <= 0) 149 lua_pushfstring(L, "\n\t%s: in ", ar.short_src); 150 else 151 lua_pushfstring(L, "\n\t%s:%d: in ", ar.short_src, ar.currentline); 152 luaL_addvalue(&b); 153 pushfuncname(L, &ar); 154 luaL_addvalue(&b); 155 if (ar.istailcall) 156 luaL_addstring(&b, "\n\t(...tail calls...)"); 157 } 158 } 159 luaL_pushresult(&b); 160 } 161 162 /* }====================================================== */ 163 164 165 /* 166 ** {====================================================== 167 ** Error-report functions 168 ** ======================================================= 169 */ 170 171 LUALIB_API int luaL_argerror (lua_State *L, int arg, const char *extramsg) { 172 lua_Debug ar; 173 const char *argword; 174 if (!lua_getstack(L, 0, &ar)) /* no stack frame? */ 175 return luaL_error(L, "bad argument #%d (%s)", arg, extramsg); 176 lua_getinfo(L, "nt", &ar); 177 if (arg <= ar.extraargs) /* error in an extra argument? */ 178 argword = "extra argument"; 179 else { 180 arg -= ar.extraargs; /* do not count extra arguments */ 181 if (strcmp(ar.namewhat, "method") == 0) { /* colon syntax? */ 182 arg--; /* do not count (extra) self argument */ 183 if (arg == 0) /* error in self argument? */ 184 return luaL_error(L, "calling '%s' on bad self (%s)", 185 ar.name, extramsg); 186 /* else go through; error in a regular argument */ 187 } 188 argword = "argument"; 189 } 190 if (ar.name == NULL) 191 ar.name = (pushglobalfuncname(L, &ar)) ? lua_tostring(L, -1) : "?"; 192 return luaL_error(L, "bad %s #%d to '%s' (%s)", 193 argword, arg, ar.name, extramsg); 194 } 195 196 197 LUALIB_API int luaL_typeerror (lua_State *L, int arg, const char *tname) { 198 const char *msg; 199 const char *typearg; /* name for the type of the actual argument */ 200 if (luaL_getmetafield(L, arg, "__name") == LUA_TSTRING) 201 typearg = lua_tostring(L, -1); /* use the given type name */ 202 else if (lua_type(L, arg) == LUA_TLIGHTUSERDATA) 203 typearg = "light userdata"; /* special name for messages */ 204 else 205 typearg = luaL_typename(L, arg); /* standard name */ 206 msg = lua_pushfstring(L, "%s expected, got %s", tname, typearg); 207 return luaL_argerror(L, arg, msg); 208 } 209 210 211 static void tag_error (lua_State *L, int arg, int tag) { 212 luaL_typeerror(L, arg, lua_typename(L, tag)); 213 } 214 215 216 /* 217 ** The use of 'lua_pushfstring' ensures this function does not 218 ** need reserved stack space when called. 219 */ 220 LUALIB_API void luaL_where (lua_State *L, int level) { 221 lua_Debug ar; 222 if (lua_getstack(L, level, &ar)) { /* check function at level */ 223 lua_getinfo(L, "Sl", &ar); /* get info about it */ 224 if (ar.currentline > 0) { /* is there info? */ 225 lua_pushfstring(L, "%s:%d: ", ar.short_src, ar.currentline); 226 return; 227 } 228 } 229 lua_pushfstring(L, ""); /* else, no information available... */ 230 } 231 232 233 /* 234 ** Again, the use of 'lua_pushvfstring' ensures this function does 235 ** not need reserved stack space when called. (At worst, it generates 236 ** a memory error instead of the given message.) 237 */ 238 LUALIB_API int luaL_error (lua_State *L, const char *fmt, ...) { 239 va_list argp; 240 va_start(argp, fmt); 241 luaL_where(L, 1); 242 lua_pushvfstring(L, fmt, argp); 243 va_end(argp); 244 lua_concat(L, 2); 245 return lua_error(L); 246 } 247 248 249 LUALIB_API int luaL_fileresult (lua_State *L, int stat, const char *fname) { 250 int en = errno; /* calls to Lua API may change this value */ 251 if (stat) { 252 lua_pushboolean(L, 1); 253 return 1; 254 } 255 else { 256 const char *msg; 257 luaL_pushfail(L); 258 msg = (en != 0) ? strerror(en) : "(no extra info)"; 259 if (fname) 260 lua_pushfstring(L, "%s: %s", fname, msg); 261 else 262 lua_pushstring(L, msg); 263 lua_pushinteger(L, en); 264 return 3; 265 } 266 } 267 268 269 #if !defined(l_inspectstat) /* { */ 270 271 #if defined(LUA_USE_POSIX) 272 273 #include <sys/wait.h> 274 275 /* 276 ** use appropriate macros to interpret 'pclose' return status 277 */ 278 #define l_inspectstat(stat,what) \ 279 if (WIFEXITED(stat)) { stat = WEXITSTATUS(stat); } \ 280 else if (WIFSIGNALED(stat)) { stat = WTERMSIG(stat); what = "signal"; } 281 282 #else 283 284 #define l_inspectstat(stat,what) /* no op */ 285 286 #endif 287 288 #endif /* } */ 289 290 291 LUALIB_API int luaL_execresult (lua_State *L, int stat) { 292 if (stat != 0 && errno != 0) /* error with an 'errno'? */ 293 return luaL_fileresult(L, 0, NULL); 294 else { 295 const char *what = "exit"; /* type of termination */ 296 l_inspectstat(stat, what); /* interpret result */ 297 if (*what == 'e' && stat == 0) /* successful termination? */ 298 lua_pushboolean(L, 1); 299 else 300 luaL_pushfail(L); 301 lua_pushstring(L, what); 302 lua_pushinteger(L, stat); 303 return 3; /* return true/fail,what,code */ 304 } 305 } 306 307 /* }====================================================== */ 308 309 310 311 /* 312 ** {====================================================== 313 ** Userdata's metatable manipulation 314 ** ======================================================= 315 */ 316 317 LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) { 318 if (luaL_getmetatable(L, tname) != LUA_TNIL) /* name already in use? */ 319 return 0; /* leave previous value on top, but return 0 */ 320 lua_pop(L, 1); 321 lua_createtable(L, 0, 2); /* create metatable */ 322 lua_pushstring(L, tname); 323 lua_setfield(L, -2, "__name"); /* metatable.__name = tname */ 324 lua_pushvalue(L, -1); 325 lua_setfield(L, LUA_REGISTRYINDEX, tname); /* registry.name = metatable */ 326 return 1; 327 } 328 329 330 LUALIB_API void luaL_setmetatable (lua_State *L, const char *tname) { 331 luaL_getmetatable(L, tname); 332 lua_setmetatable(L, -2); 333 } 334 335 336 LUALIB_API void *luaL_testudata (lua_State *L, int ud, const char *tname) { 337 void *p = lua_touserdata(L, ud); 338 if (p != NULL) { /* value is a userdata? */ 339 if (lua_getmetatable(L, ud)) { /* does it have a metatable? */ 340 luaL_getmetatable(L, tname); /* get correct metatable */ 341 if (!lua_rawequal(L, -1, -2)) /* not the same? */ 342 p = NULL; /* value is a userdata with wrong metatable */ 343 lua_pop(L, 2); /* remove both metatables */ 344 return p; 345 } 346 } 347 return NULL; /* value is not a userdata with a metatable */ 348 } 349 350 351 LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) { 352 void *p = luaL_testudata(L, ud, tname); 353 luaL_argexpected(L, p != NULL, ud, tname); 354 return p; 355 } 356 357 /* }====================================================== */ 358 359 360 /* 361 ** {====================================================== 362 ** Argument check functions 363 ** ======================================================= 364 */ 365 366 LUALIB_API int luaL_checkoption (lua_State *L, int arg, const char *def, 367 const char *const lst[]) { 368 const char *name = (def) ? luaL_optstring(L, arg, def) : 369 luaL_checkstring(L, arg); 370 int i; 371 for (i=0; lst[i]; i++) 372 if (strcmp(lst[i], name) == 0) 373 return i; 374 return luaL_argerror(L, arg, 375 lua_pushfstring(L, "invalid option '%s'", name)); 376 } 377 378 379 /* 380 ** Ensures the stack has at least 'space' extra slots, raising an error 381 ** if it cannot fulfill the request. (The error handling needs a few 382 ** extra slots to format the error message. In case of an error without 383 ** this extra space, Lua will generate the same 'stack overflow' error, 384 ** but without 'msg'.) 385 */ 386 LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *msg) { 387 if (l_unlikely(!lua_checkstack(L, space))) { 388 if (msg) 389 luaL_error(L, "stack overflow (%s)", msg); 390 else 391 luaL_error(L, "stack overflow"); 392 } 393 } 394 395 396 LUALIB_API void luaL_checktype (lua_State *L, int arg, int t) { 397 if (l_unlikely(lua_type(L, arg) != t)) 398 tag_error(L, arg, t); 399 } 400 401 402 LUALIB_API void luaL_checkany (lua_State *L, int arg) { 403 if (l_unlikely(lua_type(L, arg) == LUA_TNONE)) 404 luaL_argerror(L, arg, "value expected"); 405 } 406 407 408 LUALIB_API const char *luaL_checklstring (lua_State *L, int arg, size_t *len) { 409 const char *s = lua_tolstring(L, arg, len); 410 if (l_unlikely(!s)) tag_error(L, arg, LUA_TSTRING); 411 return s; 412 } 413 414 415 LUALIB_API const char *luaL_optlstring (lua_State *L, int arg, 416 const char *def, size_t *len) { 417 if (lua_isnoneornil(L, arg)) { 418 if (len) 419 *len = (def ? strlen(def) : 0); 420 return def; 421 } 422 else return luaL_checklstring(L, arg, len); 423 } 424 425 426 LUALIB_API lua_Number luaL_checknumber (lua_State *L, int arg) { 427 int isnum; 428 lua_Number d = lua_tonumberx(L, arg, &isnum); 429 if (l_unlikely(!isnum)) 430 tag_error(L, arg, LUA_TNUMBER); 431 return d; 432 } 433 434 435 LUALIB_API lua_Number luaL_optnumber (lua_State *L, int arg, lua_Number def) { 436 return luaL_opt(L, luaL_checknumber, arg, def); 437 } 438 439 440 static void interror (lua_State *L, int arg) { 441 if (lua_isnumber(L, arg)) 442 luaL_argerror(L, arg, "number has no integer representation"); 443 else 444 tag_error(L, arg, LUA_TNUMBER); 445 } 446 447 448 LUALIB_API lua_Integer luaL_checkinteger (lua_State *L, int arg) { 449 int isnum; 450 lua_Integer d = lua_tointegerx(L, arg, &isnum); 451 if (l_unlikely(!isnum)) { 452 interror(L, arg); 453 } 454 return d; 455 } 456 457 458 LUALIB_API lua_Integer luaL_optinteger (lua_State *L, int arg, 459 lua_Integer def) { 460 return luaL_opt(L, luaL_checkinteger, arg, def); 461 } 462 463 /* }====================================================== */ 464 465 466 /* 467 ** {====================================================== 468 ** Generic Buffer manipulation 469 ** ======================================================= 470 */ 471 472 /* userdata to box arbitrary data */ 473 typedef struct UBox { 474 void *box; 475 size_t bsize; 476 } UBox; 477 478 479 /* Resize the buffer used by a box. Optimize for the common case of 480 ** resizing to the old size. (For instance, __gc will resize the box 481 ** to 0 even after it was closed. 'pushresult' may also resize it to a 482 ** final size that is equal to the one set when the buffer was created.) 483 */ 484 static void *resizebox (lua_State *L, int idx, size_t newsize) { 485 UBox *box = (UBox *)lua_touserdata(L, idx); 486 if (box->bsize == newsize) /* not changing size? */ 487 return box->box; /* keep the buffer */ 488 else { 489 void *ud; 490 lua_Alloc allocf = lua_getallocf(L, &ud); 491 void *temp = allocf(ud, box->box, box->bsize, newsize); 492 if (l_unlikely(temp == NULL && newsize > 0)) { /* allocation error? */ 493 lua_pushliteral(L, "not enough memory"); 494 lua_error(L); /* raise a memory error */ 495 } 496 box->box = temp; 497 box->bsize = newsize; 498 return temp; 499 } 500 } 501 502 503 static int boxgc (lua_State *L) { 504 resizebox(L, 1, 0); 505 return 0; 506 } 507 508 509 static const luaL_Reg boxmt[] = { /* box metamethods */ 510 {"__gc", boxgc}, 511 {"__close", boxgc}, 512 {NULL, NULL} 513 }; 514 515 516 static void newbox (lua_State *L) { 517 UBox *box = (UBox *)lua_newuserdatauv(L, sizeof(UBox), 0); 518 box->box = NULL; 519 box->bsize = 0; 520 if (luaL_newmetatable(L, "_UBOX*")) /* creating metatable? */ 521 luaL_setfuncs(L, boxmt, 0); /* set its metamethods */ 522 lua_setmetatable(L, -2); 523 } 524 525 526 /* 527 ** check whether buffer is using a userdata on the stack as a temporary 528 ** buffer 529 */ 530 #define buffonstack(B) ((B)->b != (B)->init.b) 531 532 533 /* 534 ** Whenever buffer is accessed, slot 'idx' must either be a box (which 535 ** cannot be NULL) or it is a placeholder for the buffer. 536 */ 537 #define checkbufferlevel(B,idx) \ 538 lua_assert(buffonstack(B) ? lua_touserdata(B->L, idx) != NULL \ 539 : lua_touserdata(B->L, idx) == (void*)B) 540 541 542 /* 543 ** Compute new size for buffer 'B', enough to accommodate extra 'sz' 544 ** bytes plus one for a terminating zero. (The test for "not big enough" 545 ** also gets the case when the computation of 'newsize' overflows.) 546 */ 547 static size_t newbuffsize (luaL_Buffer *B, size_t sz) { 548 size_t newsize = (B->size / 2) * 3; /* buffer size * 1.5 */ 549 if (l_unlikely(sz > MAX_SIZE - B->n - 1)) 550 return cast_sizet(luaL_error(B->L, "resulting string too large")); 551 if (newsize < B->n + sz + 1 || newsize > MAX_SIZE) { 552 /* newsize was not big enough or too big */ 553 newsize = B->n + sz + 1; 554 } 555 return newsize; 556 } 557 558 559 /* 560 ** Returns a pointer to a free area with at least 'sz' bytes in buffer 561 ** 'B'. 'boxidx' is the relative position in the stack where is the 562 ** buffer's box or its placeholder. 563 */ 564 static char *prepbuffsize (luaL_Buffer *B, size_t sz, int boxidx) { 565 checkbufferlevel(B, boxidx); 566 if (B->size - B->n >= sz) /* enough space? */ 567 return B->b + B->n; 568 else { 569 lua_State *L = B->L; 570 char *newbuff; 571 size_t newsize = newbuffsize(B, sz); 572 /* create larger buffer */ 573 if (buffonstack(B)) /* buffer already has a box? */ 574 newbuff = (char *)resizebox(L, boxidx, newsize); /* resize it */ 575 else { /* no box yet */ 576 lua_remove(L, boxidx); /* remove placeholder */ 577 newbox(L); /* create a new box */ 578 lua_insert(L, boxidx); /* move box to its intended position */ 579 lua_toclose(L, boxidx); 580 newbuff = (char *)resizebox(L, boxidx, newsize); 581 memcpy(newbuff, B->b, B->n * sizeof(char)); /* copy original content */ 582 } 583 B->b = newbuff; 584 B->size = newsize; 585 return newbuff + B->n; 586 } 587 } 588 589 /* 590 ** returns a pointer to a free area with at least 'sz' bytes 591 */ 592 LUALIB_API char *luaL_prepbuffsize (luaL_Buffer *B, size_t sz) { 593 return prepbuffsize(B, sz, -1); 594 } 595 596 597 LUALIB_API void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l) { 598 if (l > 0) { /* avoid 'memcpy' when 's' can be NULL */ 599 char *b = prepbuffsize(B, l, -1); 600 memcpy(b, s, l * sizeof(char)); 601 luaL_addsize(B, l); 602 } 603 } 604 605 606 LUALIB_API void luaL_addstring (luaL_Buffer *B, const char *s) { 607 luaL_addlstring(B, s, strlen(s)); 608 } 609 610 611 LUALIB_API void luaL_pushresult (luaL_Buffer *B) { 612 lua_State *L = B->L; 613 checkbufferlevel(B, -1); 614 if (!buffonstack(B)) /* using static buffer? */ 615 lua_pushlstring(L, B->b, B->n); /* save result as regular string */ 616 else { /* reuse buffer already allocated */ 617 UBox *box = (UBox *)lua_touserdata(L, -1); 618 void *ud; 619 lua_Alloc allocf = lua_getallocf(L, &ud); /* function to free buffer */ 620 size_t len = B->n; /* final string length */ 621 char *s; 622 resizebox(L, -1, len + 1); /* adjust box size to content size */ 623 s = (char*)box->box; /* final buffer address */ 624 s[len] = '\0'; /* add ending zero */ 625 /* clear box, as Lua will take control of the buffer */ 626 box->bsize = 0; box->box = NULL; 627 lua_pushexternalstring(L, s, len, allocf, ud); 628 lua_closeslot(L, -2); /* close the box */ 629 lua_gc(L, LUA_GCSTEP, len); 630 } 631 lua_remove(L, -2); /* remove box or placeholder from the stack */ 632 } 633 634 635 LUALIB_API void luaL_pushresultsize (luaL_Buffer *B, size_t sz) { 636 luaL_addsize(B, sz); 637 luaL_pushresult(B); 638 } 639 640 641 /* 642 ** 'luaL_addvalue' is the only function in the Buffer system where the 643 ** box (if existent) is not on the top of the stack. So, instead of 644 ** calling 'luaL_addlstring', it replicates the code using -2 as the 645 ** last argument to 'prepbuffsize', signaling that the box is (or will 646 ** be) below the string being added to the buffer. (Box creation can 647 ** trigger an emergency GC, so we should not remove the string from the 648 ** stack before we have the space guaranteed.) 649 */ 650 LUALIB_API void luaL_addvalue (luaL_Buffer *B) { 651 lua_State *L = B->L; 652 size_t len; 653 const char *s = lua_tolstring(L, -1, &len); 654 char *b = prepbuffsize(B, len, -2); 655 memcpy(b, s, len * sizeof(char)); 656 luaL_addsize(B, len); 657 lua_pop(L, 1); /* pop string */ 658 } 659 660 661 LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) { 662 B->L = L; 663 B->b = B->init.b; 664 B->n = 0; 665 B->size = LUAL_BUFFERSIZE; 666 lua_pushlightuserdata(L, (void*)B); /* push placeholder */ 667 } 668 669 670 LUALIB_API char *luaL_buffinitsize (lua_State *L, luaL_Buffer *B, size_t sz) { 671 luaL_buffinit(L, B); 672 return prepbuffsize(B, sz, -1); 673 } 674 675 /* }====================================================== */ 676 677 678 /* 679 ** {====================================================== 680 ** Reference system 681 ** ======================================================= 682 */ 683 684 /* 685 ** The previously freed references form a linked list: t[1] is the index 686 ** of a first free index, t[t[1]] is the index of the second element, 687 ** etc. A zero signals the end of the list. 688 */ 689 LUALIB_API int luaL_ref (lua_State *L, int t) { 690 int ref; 691 if (lua_isnil(L, -1)) { 692 lua_pop(L, 1); /* remove from stack */ 693 return LUA_REFNIL; /* 'nil' has a unique fixed reference */ 694 } 695 t = lua_absindex(L, t); 696 if (lua_rawgeti(L, t, 1) == LUA_TNUMBER) /* already initialized? */ 697 ref = (int)lua_tointeger(L, -1); /* ref = t[1] */ 698 else { /* first access */ 699 lua_assert(!lua_toboolean(L, -1)); /* must be nil or false */ 700 ref = 0; /* list is empty */ 701 lua_pushinteger(L, 0); /* initialize as an empty list */ 702 lua_rawseti(L, t, 1); /* ref = t[1] = 0 */ 703 } 704 lua_pop(L, 1); /* remove element from stack */ 705 if (ref != 0) { /* any free element? */ 706 lua_rawgeti(L, t, ref); /* remove it from list */ 707 lua_rawseti(L, t, 1); /* (t[1] = t[ref]) */ 708 } 709 else /* no free elements */ 710 ref = (int)lua_rawlen(L, t) + 1; /* get a new reference */ 711 lua_rawseti(L, t, ref); 712 return ref; 713 } 714 715 716 LUALIB_API void luaL_unref (lua_State *L, int t, int ref) { 717 if (ref >= 0) { 718 t = lua_absindex(L, t); 719 lua_rawgeti(L, t, 1); 720 lua_assert(lua_isinteger(L, -1)); 721 lua_rawseti(L, t, ref); /* t[ref] = t[1] */ 722 lua_pushinteger(L, ref); 723 lua_rawseti(L, t, 1); /* t[1] = ref */ 724 } 725 } 726 727 /* }====================================================== */ 728 729 730 /* 731 ** {====================================================== 732 ** Load functions 733 ** ======================================================= 734 */ 735 736 typedef struct LoadF { 737 unsigned n; /* number of pre-read characters */ 738 FILE *f; /* file being read */ 739 char buff[BUFSIZ]; /* area for reading file */ 740 } LoadF; 741 742 743 static const char *getF (lua_State *L, void *ud, size_t *size) { 744 LoadF *lf = (LoadF *)ud; 745 (void)L; /* not used */ 746 if (lf->n > 0) { /* are there pre-read characters to be read? */ 747 *size = lf->n; /* return them (chars already in buffer) */ 748 lf->n = 0; /* no more pre-read characters */ 749 } 750 else { /* read a block from file */ 751 /* 'fread' can return > 0 *and* set the EOF flag. If next call to 752 'getF' called 'fread', it might still wait for user input. 753 The next check avoids this problem. */ 754 if (feof(lf->f)) return NULL; 755 *size = fread(lf->buff, 1, sizeof(lf->buff), lf->f); /* read block */ 756 } 757 return lf->buff; 758 } 759 760 761 static int errfile (lua_State *L, const char *what, int fnameindex) { 762 int err = errno; 763 const char *filename = lua_tostring(L, fnameindex) + 1; 764 if (err != 0) 765 lua_pushfstring(L, "cannot %s %s: %s", what, filename, strerror(err)); 766 else 767 lua_pushfstring(L, "cannot %s %s", what, filename); 768 lua_remove(L, fnameindex); 769 return LUA_ERRFILE; 770 } 771 772 773 /* 774 ** Skip an optional BOM at the start of a stream. If there is an 775 ** incomplete BOM (the first character is correct but the rest is 776 ** not), returns the first character anyway to force an error 777 ** (as no chunk can start with 0xEF). 778 */ 779 static int skipBOM (FILE *f) { 780 int c = getc(f); /* read first character */ 781 if (c == 0xEF && getc(f) == 0xBB && getc(f) == 0xBF) /* correct BOM? */ 782 return getc(f); /* ignore BOM and return next char */ 783 else /* no (valid) BOM */ 784 return c; /* return first character */ 785 } 786 787 788 /* 789 ** reads the first character of file 'f' and skips an optional BOM mark 790 ** in its beginning plus its first line if it starts with '#'. Returns 791 ** true if it skipped the first line. In any case, '*cp' has the 792 ** first "valid" character of the file (after the optional BOM and 793 ** a first-line comment). 794 */ 795 static int skipcomment (FILE *f, int *cp) { 796 int c = *cp = skipBOM(f); 797 if (c == '#') { /* first line is a comment (Unix exec. file)? */ 798 do { /* skip first line */ 799 c = getc(f); 800 } while (c != EOF && c != '\n'); 801 *cp = getc(f); /* next character after comment, if present */ 802 return 1; /* there was a comment */ 803 } 804 else return 0; /* no comment */ 805 } 806 807 808 LUALIB_API int luaL_loadfilex (lua_State *L, const char *filename, 809 const char *mode) { 810 LoadF lf; 811 int status, readstatus; 812 int c; 813 int fnameindex = lua_gettop(L) + 1; /* index of filename on the stack */ 814 if (filename == NULL) { 815 lua_pushliteral(L, "=stdin"); 816 lf.f = stdin; 817 } 818 else { 819 lua_pushfstring(L, "@%s", filename); 820 errno = 0; 821 lf.f = fopen(filename, "r"); 822 if (lf.f == NULL) return errfile(L, "open", fnameindex); 823 } 824 lf.n = 0; 825 if (skipcomment(lf.f, &c)) /* read initial portion */ 826 lf.buff[lf.n++] = '\n'; /* add newline to correct line numbers */ 827 if (c == LUA_SIGNATURE[0]) { /* binary file? */ 828 lf.n = 0; /* remove possible newline */ 829 if (filename) { /* "real" file? */ 830 errno = 0; 831 lf.f = freopen(filename, "rb", lf.f); /* reopen in binary mode */ 832 if (lf.f == NULL) return errfile(L, "reopen", fnameindex); 833 skipcomment(lf.f, &c); /* re-read initial portion */ 834 } 835 } 836 if (c != EOF) 837 lf.buff[lf.n++] = cast_char(c); /* 'c' is the first character */ 838 status = lua_load(L, getF, &lf, lua_tostring(L, -1), mode); 839 readstatus = ferror(lf.f); 840 errno = 0; /* no useful error number until here */ 841 if (filename) fclose(lf.f); /* close file (even in case of errors) */ 842 if (readstatus) { 843 lua_settop(L, fnameindex); /* ignore results from 'lua_load' */ 844 return errfile(L, "read", fnameindex); 845 } 846 lua_remove(L, fnameindex); 847 return status; 848 } 849 850 851 typedef struct LoadS { 852 const char *s; 853 size_t size; 854 } LoadS; 855 856 857 static const char *getS (lua_State *L, void *ud, size_t *size) { 858 LoadS *ls = (LoadS *)ud; 859 (void)L; /* not used */ 860 if (ls->size == 0) return NULL; 861 *size = ls->size; 862 ls->size = 0; 863 return ls->s; 864 } 865 866 867 LUALIB_API int luaL_loadbufferx (lua_State *L, const char *buff, size_t size, 868 const char *name, const char *mode) { 869 LoadS ls; 870 ls.s = buff; 871 ls.size = size; 872 return lua_load(L, getS, &ls, name, mode); 873 } 874 875 876 LUALIB_API int luaL_loadstring (lua_State *L, const char *s) { 877 return luaL_loadbuffer(L, s, strlen(s), s); 878 } 879 880 /* }====================================================== */ 881 882 883 884 LUALIB_API int luaL_getmetafield (lua_State *L, int obj, const char *event) { 885 if (!lua_getmetatable(L, obj)) /* no metatable? */ 886 return LUA_TNIL; 887 else { 888 int tt; 889 lua_pushstring(L, event); 890 tt = lua_rawget(L, -2); 891 if (tt == LUA_TNIL) /* is metafield nil? */ 892 lua_pop(L, 2); /* remove metatable and metafield */ 893 else 894 lua_remove(L, -2); /* remove only metatable */ 895 return tt; /* return metafield type */ 896 } 897 } 898 899 900 LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) { 901 obj = lua_absindex(L, obj); 902 if (luaL_getmetafield(L, obj, event) == LUA_TNIL) /* no metafield? */ 903 return 0; 904 lua_pushvalue(L, obj); 905 lua_call(L, 1, 1); 906 return 1; 907 } 908 909 910 LUALIB_API lua_Integer luaL_len (lua_State *L, int idx) { 911 lua_Integer l; 912 int isnum; 913 lua_len(L, idx); 914 l = lua_tointegerx(L, -1, &isnum); 915 if (l_unlikely(!isnum)) 916 luaL_error(L, "object length is not an integer"); 917 lua_pop(L, 1); /* remove object */ 918 return l; 919 } 920 921 922 LUALIB_API const char *luaL_tolstring (lua_State *L, int idx, size_t *len) { 923 idx = lua_absindex(L,idx); 924 if (luaL_callmeta(L, idx, "__tostring")) { /* metafield? */ 925 if (!lua_isstring(L, -1)) 926 luaL_error(L, "'__tostring' must return a string"); 927 } 928 else { 929 switch (lua_type(L, idx)) { 930 case LUA_TNUMBER: { 931 char buff[LUA_N2SBUFFSZ]; 932 lua_numbertocstring(L, idx, buff); 933 lua_pushstring(L, buff); 934 break; 935 } 936 case LUA_TSTRING: 937 lua_pushvalue(L, idx); 938 break; 939 case LUA_TBOOLEAN: 940 lua_pushstring(L, (lua_toboolean(L, idx) ? "true" : "false")); 941 break; 942 case LUA_TNIL: 943 lua_pushliteral(L, "nil"); 944 break; 945 default: { 946 int tt = luaL_getmetafield(L, idx, "__name"); /* try name */ 947 const char *kind = (tt == LUA_TSTRING) ? lua_tostring(L, -1) : 948 luaL_typename(L, idx); 949 lua_pushfstring(L, "%s: %p", kind, lua_topointer(L, idx)); 950 if (tt != LUA_TNIL) 951 lua_remove(L, -2); /* remove '__name' */ 952 break; 953 } 954 } 955 } 956 return lua_tolstring(L, -1, len); 957 } 958 959 960 /* 961 ** set functions from list 'l' into table at top - 'nup'; each 962 ** function gets the 'nup' elements at the top as upvalues. 963 ** Returns with only the table at the stack. 964 */ 965 LUALIB_API void luaL_setfuncs (lua_State *L, const luaL_Reg *l, int nup) { 966 luaL_checkstack(L, nup, "too many upvalues"); 967 for (; l->name != NULL; l++) { /* fill the table with given functions */ 968 if (l->func == NULL) /* placeholder? */ 969 lua_pushboolean(L, 0); 970 else { 971 int i; 972 for (i = 0; i < nup; i++) /* copy upvalues to the top */ 973 lua_pushvalue(L, -nup); 974 lua_pushcclosure(L, l->func, nup); /* closure with those upvalues */ 975 } 976 lua_setfield(L, -(nup + 2), l->name); 977 } 978 lua_pop(L, nup); /* remove upvalues */ 979 } 980 981 982 /* 983 ** ensure that stack[idx][fname] has a table and push that table 984 ** into the stack 985 */ 986 LUALIB_API int luaL_getsubtable (lua_State *L, int idx, const char *fname) { 987 if (lua_getfield(L, idx, fname) == LUA_TTABLE) 988 return 1; /* table already there */ 989 else { 990 lua_pop(L, 1); /* remove previous result */ 991 idx = lua_absindex(L, idx); 992 lua_newtable(L); 993 lua_pushvalue(L, -1); /* copy to be left at top */ 994 lua_setfield(L, idx, fname); /* assign new table to field */ 995 return 0; /* false, because did not find table there */ 996 } 997 } 998 999 1000 /* 1001 ** Stripped-down 'require': After checking "loaded" table, calls 'openf' 1002 ** to open a module, registers the result in 'package.loaded' table and, 1003 ** if 'glb' is true, also registers the result in the global table. 1004 ** Leaves resulting module on the top. 1005 */ 1006 LUALIB_API void luaL_requiref (lua_State *L, const char *modname, 1007 lua_CFunction openf, int glb) { 1008 luaL_getsubtable(L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE); 1009 lua_getfield(L, -1, modname); /* LOADED[modname] */ 1010 if (!lua_toboolean(L, -1)) { /* package not already loaded? */ 1011 lua_pop(L, 1); /* remove field */ 1012 lua_pushcfunction(L, openf); 1013 lua_pushstring(L, modname); /* argument to open function */ 1014 lua_call(L, 1, 1); /* call 'openf' to open module */ 1015 lua_pushvalue(L, -1); /* make copy of module (call result) */ 1016 lua_setfield(L, -3, modname); /* LOADED[modname] = module */ 1017 } 1018 lua_remove(L, -2); /* remove LOADED table */ 1019 if (glb) { 1020 lua_pushvalue(L, -1); /* copy of module */ 1021 lua_setglobal(L, modname); /* _G[modname] = module */ 1022 } 1023 } 1024 1025 1026 LUALIB_API void luaL_addgsub (luaL_Buffer *b, const char *s, 1027 const char *p, const char *r) { 1028 const char *wild; 1029 size_t l = strlen(p); 1030 while ((wild = strstr(s, p)) != NULL) { 1031 luaL_addlstring(b, s, ct_diff2sz(wild - s)); /* push prefix */ 1032 luaL_addstring(b, r); /* push replacement in place of pattern */ 1033 s = wild + l; /* continue after 'p' */ 1034 } 1035 luaL_addstring(b, s); /* push last suffix */ 1036 } 1037 1038 1039 LUALIB_API const char *luaL_gsub (lua_State *L, const char *s, 1040 const char *p, const char *r) { 1041 luaL_Buffer b; 1042 luaL_buffinit(L, &b); 1043 luaL_addgsub(&b, s, p, r); 1044 luaL_pushresult(&b); 1045 return lua_tostring(L, -1); 1046 } 1047 1048 1049 static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) { 1050 (void)ud; (void)osize; /* not used */ 1051 if (nsize == 0) { 1052 free(ptr); 1053 return NULL; 1054 } 1055 else 1056 return realloc(ptr, nsize); 1057 } 1058 1059 1060 /* 1061 ** Standard panic function just prints an error message. The test 1062 ** with 'lua_type' avoids possible memory errors in 'lua_tostring'. 1063 */ 1064 static int panic (lua_State *L) { 1065 const char *msg = (lua_type(L, -1) == LUA_TSTRING) 1066 ? lua_tostring(L, -1) 1067 : "error object is not a string"; 1068 lua_writestringerror("PANIC: unprotected error in call to Lua API (%s)\n", 1069 msg); 1070 return 0; /* return to Lua to abort */ 1071 } 1072 1073 1074 /* 1075 ** Warning functions: 1076 ** warnfoff: warning system is off 1077 ** warnfon: ready to start a new message 1078 ** warnfcont: previous message is to be continued 1079 */ 1080 static void warnfoff (void *ud, const char *message, int tocont); 1081 static void warnfon (void *ud, const char *message, int tocont); 1082 static void warnfcont (void *ud, const char *message, int tocont); 1083 1084 1085 /* 1086 ** Check whether message is a control message. If so, execute the 1087 ** control or ignore it if unknown. 1088 */ 1089 static int checkcontrol (lua_State *L, const char *message, int tocont) { 1090 if (tocont || *(message++) != '@') /* not a control message? */ 1091 return 0; 1092 else { 1093 if (strcmp(message, "off") == 0) 1094 lua_setwarnf(L, warnfoff, L); /* turn warnings off */ 1095 else if (strcmp(message, "on") == 0) 1096 lua_setwarnf(L, warnfon, L); /* turn warnings on */ 1097 return 1; /* it was a control message */ 1098 } 1099 } 1100 1101 1102 static void warnfoff (void *ud, const char *message, int tocont) { 1103 checkcontrol((lua_State *)ud, message, tocont); 1104 } 1105 1106 1107 /* 1108 ** Writes the message and handle 'tocont', finishing the message 1109 ** if needed and setting the next warn function. 1110 */ 1111 static void warnfcont (void *ud, const char *message, int tocont) { 1112 lua_State *L = (lua_State *)ud; 1113 lua_writestringerror("%s", message); /* write message */ 1114 if (tocont) /* not the last part? */ 1115 lua_setwarnf(L, warnfcont, L); /* to be continued */ 1116 else { /* last part */ 1117 lua_writestringerror("%s", "\n"); /* finish message with end-of-line */ 1118 lua_setwarnf(L, warnfon, L); /* next call is a new message */ 1119 } 1120 } 1121 1122 1123 static void warnfon (void *ud, const char *message, int tocont) { 1124 if (checkcontrol((lua_State *)ud, message, tocont)) /* control message? */ 1125 return; /* nothing else to be done */ 1126 lua_writestringerror("%s", "Lua warning: "); /* start a new warning */ 1127 warnfcont(ud, message, tocont); /* finish processing */ 1128 } 1129 1130 1131 1132 /* 1133 ** A function to compute an unsigned int with some level of 1134 ** randomness. Rely on Address Space Layout Randomization (if present) 1135 ** and the current time. 1136 */ 1137 #if !defined(luai_makeseed) 1138 1139 #include <time.h> 1140 1141 1142 /* Size for the buffer, in bytes */ 1143 #define BUFSEEDB (sizeof(void*) + sizeof(time_t)) 1144 1145 /* Size for the buffer in int's, rounded up */ 1146 #define BUFSEED ((BUFSEEDB + sizeof(int) - 1) / sizeof(int)) 1147 1148 /* 1149 ** Copy the contents of variable 'v' into the buffer pointed by 'b'. 1150 ** (The '&b[0]' disguises 'b' to fix an absurd warning from clang.) 1151 */ 1152 #define addbuff(b,v) (memcpy(&b[0], &(v), sizeof(v)), b += sizeof(v)) 1153 1154 1155 static unsigned int luai_makeseed (void) { 1156 unsigned int buff[BUFSEED]; 1157 unsigned int res; 1158 unsigned int i; 1159 time_t t = time(NULL); 1160 char *b = (char*)buff; 1161 addbuff(b, b); /* local variable's address */ 1162 addbuff(b, t); /* time */ 1163 /* fill (rare but possible) remain of the buffer with zeros */ 1164 memset(b, 0, sizeof(buff) - BUFSEEDB); 1165 res = buff[0]; 1166 for (i = 1; i < BUFSEED; i++) 1167 res ^= (res >> 3) + (res << 7) + buff[i]; 1168 return res; 1169 } 1170 1171 #endif 1172 1173 1174 LUALIB_API unsigned int luaL_makeseed (lua_State *L) { 1175 (void)L; /* unused */ 1176 return luai_makeseed(); 1177 } 1178 1179 1180 LUALIB_API lua_State *luaL_newstate (void) { 1181 lua_State *L = lua_newstate(l_alloc, NULL, luai_makeseed()); 1182 if (l_likely(L)) { 1183 lua_atpanic(L, &panic); 1184 lua_setwarnf(L, warnfoff, L); /* default is warnings off */ 1185 } 1186 return L; 1187 } 1188 1189 1190 LUALIB_API void luaL_checkversion_ (lua_State *L, lua_Number ver, size_t sz) { 1191 lua_Number v = lua_version(L); 1192 if (sz != LUAL_NUMSIZES) /* check numeric types */ 1193 luaL_error(L, "core and library have incompatible numeric types"); 1194 else if (v != ver) 1195 luaL_error(L, "version mismatch: app. needs %f, Lua core provides %f", 1196 (LUAI_UACNUMBER)ver, (LUAI_UACNUMBER)v); 1197 } 1198