1 /* 2 ** $Id: liolib.c,v 1.3 2015/02/02 14:03:05 lneto Exp $ 3 ** Standard I/O (and system) library 4 ** See Copyright Notice in lua.h 5 */ 6 7 #define liolib_c 8 #define LUA_LIB 9 10 #include "lprefix.h" 11 12 13 #include <ctype.h> 14 #include <errno.h> 15 #include <locale.h> 16 #include <stdio.h> 17 #include <stdlib.h> 18 #include <string.h> 19 20 #include "lua.h" 21 22 #include "lauxlib.h" 23 #include "lualib.h" 24 25 26 #if !defined(l_checkmode) 27 28 /* 29 ** Check whether 'mode' matches '[rwa]%+?b?'. 30 ** Change this macro to accept other modes for 'fopen' besides 31 ** the standard ones. 32 */ 33 #define l_checkmode(mode) \ 34 (*mode != '\0' && strchr("rwa", *(mode++)) != NULL && \ 35 (*mode != '+' || ++mode) && /* skip if char is '+' */ \ 36 (*mode != 'b' || ++mode) && /* skip if char is 'b' */ \ 37 (*mode == '\0')) 38 39 #endif 40 41 /* 42 ** {====================================================== 43 ** l_popen spawns a new process connected to the current 44 ** one through the file streams. 45 ** ======================================================= 46 */ 47 48 #if !defined(l_popen) /* { */ 49 50 #if defined(LUA_USE_POSIX) /* { */ 51 52 #define l_popen(L,c,m) (fflush(NULL), popen(c,m)) 53 #define l_pclose(L,file) (pclose(file)) 54 55 #elif defined(LUA_USE_WINDOWS) /* }{ */ 56 57 #define l_popen(L,c,m) (_popen(c,m)) 58 #define l_pclose(L,file) (_pclose(file)) 59 60 #else /* }{ */ 61 62 /* ISO C definitions */ 63 #define l_popen(L,c,m) \ 64 ((void)((void)c, m), \ 65 luaL_error(L, "'popen' not supported"), \ 66 (FILE*)0) 67 #define l_pclose(L,file) ((void)L, (void)file, -1) 68 69 #endif /* } */ 70 71 #endif /* } */ 72 73 /* }====================================================== */ 74 75 76 #if !defined(l_getc) /* { */ 77 78 #if defined(LUA_USE_POSIX) 79 #define l_getc(f) getc_unlocked(f) 80 #define l_lockfile(f) flockfile(f) 81 #define l_unlockfile(f) funlockfile(f) 82 #else 83 #define l_getc(f) getc(f) 84 #define l_lockfile(f) ((void)0) 85 #define l_unlockfile(f) ((void)0) 86 #endif 87 88 #endif /* } */ 89 90 91 /* 92 ** {====================================================== 93 ** l_fseek: configuration for longer offsets 94 ** ======================================================= 95 */ 96 97 #if !defined(l_fseek) /* { */ 98 99 #if defined(LUA_USE_POSIX) /* { */ 100 101 #include <sys/types.h> 102 103 #define l_fseek(f,o,w) fseeko(f,o,w) 104 #define l_ftell(f) ftello(f) 105 #define l_seeknum off_t 106 107 #elif defined(LUA_USE_WINDOWS) && !defined(_CRTIMP_TYPEINFO) \ 108 && defined(_MSC_VER) && (_MSC_VER >= 1400) /* }{ */ 109 110 /* Windows (but not DDK) and Visual C++ 2005 or higher */ 111 #define l_fseek(f,o,w) _fseeki64(f,o,w) 112 #define l_ftell(f) _ftelli64(f) 113 #define l_seeknum __int64 114 115 #else /* }{ */ 116 117 /* ISO C definitions */ 118 #define l_fseek(f,o,w) fseek(f,o,w) 119 #define l_ftell(f) ftell(f) 120 #define l_seeknum long 121 122 #endif /* } */ 123 124 #endif /* } */ 125 126 /* }====================================================== */ 127 128 129 #define IO_PREFIX "_IO_" 130 #define IOPREF_LEN (sizeof(IO_PREFIX)/sizeof(char) - 1) 131 #define IO_INPUT (IO_PREFIX "input") 132 #define IO_OUTPUT (IO_PREFIX "output") 133 134 135 typedef luaL_Stream LStream; 136 137 138 #define tolstream(L) ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE)) 139 140 #define isclosed(p) ((p)->closef == NULL) 141 142 143 static int io_type (lua_State *L) { 144 LStream *p; 145 luaL_checkany(L, 1); 146 p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE); 147 if (p == NULL) 148 lua_pushnil(L); /* not a file */ 149 else if (isclosed(p)) 150 lua_pushliteral(L, "closed file"); 151 else 152 lua_pushliteral(L, "file"); 153 return 1; 154 } 155 156 157 static int f_tostring (lua_State *L) { 158 LStream *p = tolstream(L); 159 if (isclosed(p)) 160 lua_pushliteral(L, "file (closed)"); 161 else 162 lua_pushfstring(L, "file (%p)", p->f); 163 return 1; 164 } 165 166 167 static FILE *tofile (lua_State *L) { 168 LStream *p = tolstream(L); 169 if (isclosed(p)) 170 luaL_error(L, "attempt to use a closed file"); 171 lua_assert(p->f); 172 return p->f; 173 } 174 175 176 /* 177 ** When creating file handles, always creates a 'closed' file handle 178 ** before opening the actual file; so, if there is a memory error, the 179 ** file is not left opened. 180 */ 181 static LStream *newprefile (lua_State *L) { 182 LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream)); 183 p->closef = NULL; /* mark file handle as 'closed' */ 184 luaL_setmetatable(L, LUA_FILEHANDLE); 185 return p; 186 } 187 188 189 /* 190 ** Calls the 'close' function from a file handle. The 'volatile' avoids 191 ** a bug in some versions of the Clang compiler (e.g., clang 3.0 for 192 ** 32 bits). 193 */ 194 static int aux_close (lua_State *L) { 195 LStream *p = tolstream(L); 196 volatile lua_CFunction cf = p->closef; 197 p->closef = NULL; /* mark stream as closed */ 198 return (*cf)(L); /* close it */ 199 } 200 201 202 static int io_close (lua_State *L) { 203 if (lua_isnone(L, 1)) /* no argument? */ 204 lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT); /* use standard output */ 205 tofile(L); /* make sure argument is an open stream */ 206 return aux_close(L); 207 } 208 209 210 static int f_gc (lua_State *L) { 211 LStream *p = tolstream(L); 212 if (!isclosed(p) && p->f != NULL) 213 aux_close(L); /* ignore closed and incompletely open files */ 214 return 0; 215 } 216 217 218 /* 219 ** function to close regular files 220 */ 221 static int io_fclose (lua_State *L) { 222 LStream *p = tolstream(L); 223 int res = fclose(p->f); 224 return luaL_fileresult(L, (res == 0), NULL); 225 } 226 227 228 static LStream *newfile (lua_State *L) { 229 LStream *p = newprefile(L); 230 p->f = NULL; 231 p->closef = &io_fclose; 232 return p; 233 } 234 235 236 static void opencheck (lua_State *L, const char *fname, const char *mode) { 237 LStream *p = newfile(L); 238 p->f = fopen(fname, mode); 239 if (p->f == NULL) 240 luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno)); 241 } 242 243 244 static int io_open (lua_State *L) { 245 const char *filename = luaL_checkstring(L, 1); 246 const char *mode = luaL_optstring(L, 2, "r"); 247 LStream *p = newfile(L); 248 const char *md = mode; /* to traverse/check mode */ 249 luaL_argcheck(L, l_checkmode(md), 2, "invalid mode"); 250 p->f = fopen(filename, mode); 251 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 252 } 253 254 255 /* 256 ** function to close 'popen' files 257 */ 258 static int io_pclose (lua_State *L) { 259 LStream *p = tolstream(L); 260 return luaL_execresult(L, l_pclose(L, p->f)); 261 } 262 263 264 static int io_popen (lua_State *L) { 265 const char *filename = luaL_checkstring(L, 1); 266 const char *mode = luaL_optstring(L, 2, "r"); 267 LStream *p = newprefile(L); 268 p->f = l_popen(L, filename, mode); 269 p->closef = &io_pclose; 270 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 271 } 272 273 274 static int io_tmpfile (lua_State *L) { 275 LStream *p = newfile(L); 276 p->f = tmpfile(); 277 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1; 278 } 279 280 281 static FILE *getiofile (lua_State *L, const char *findex) { 282 LStream *p; 283 lua_getfield(L, LUA_REGISTRYINDEX, findex); 284 p = (LStream *)lua_touserdata(L, -1); 285 if (isclosed(p)) 286 luaL_error(L, "standard %s file is closed", findex + IOPREF_LEN); 287 return p->f; 288 } 289 290 291 static int g_iofile (lua_State *L, const char *f, const char *mode) { 292 if (!lua_isnoneornil(L, 1)) { 293 const char *filename = lua_tostring(L, 1); 294 if (filename) 295 opencheck(L, filename, mode); 296 else { 297 tofile(L); /* check that it's a valid file handle */ 298 lua_pushvalue(L, 1); 299 } 300 lua_setfield(L, LUA_REGISTRYINDEX, f); 301 } 302 /* return current value */ 303 lua_getfield(L, LUA_REGISTRYINDEX, f); 304 return 1; 305 } 306 307 308 static int io_input (lua_State *L) { 309 return g_iofile(L, IO_INPUT, "r"); 310 } 311 312 313 static int io_output (lua_State *L) { 314 return g_iofile(L, IO_OUTPUT, "w"); 315 } 316 317 318 static int io_readline (lua_State *L); 319 320 321 static void aux_lines (lua_State *L, int toclose) { 322 int n = lua_gettop(L) - 1; /* number of arguments to read */ 323 lua_pushinteger(L, n); /* number of arguments to read */ 324 lua_pushboolean(L, toclose); /* close/not close file when finished */ 325 lua_rotate(L, 2, 2); /* move 'n' and 'toclose' to their positions */ 326 lua_pushcclosure(L, io_readline, 3 + n); 327 } 328 329 330 static int f_lines (lua_State *L) { 331 tofile(L); /* check that it's a valid file handle */ 332 aux_lines(L, 0); 333 return 1; 334 } 335 336 337 static int io_lines (lua_State *L) { 338 int toclose; 339 if (lua_isnone(L, 1)) lua_pushnil(L); /* at least one argument */ 340 if (lua_isnil(L, 1)) { /* no file name? */ 341 lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT); /* get default input */ 342 lua_replace(L, 1); /* put it at index 1 */ 343 tofile(L); /* check that it's a valid file handle */ 344 toclose = 0; /* do not close it after iteration */ 345 } 346 else { /* open a new file */ 347 const char *filename = luaL_checkstring(L, 1); 348 opencheck(L, filename, "r"); 349 lua_replace(L, 1); /* put file at index 1 */ 350 toclose = 1; /* close it after iteration */ 351 } 352 aux_lines(L, toclose); 353 return 1; 354 } 355 356 357 /* 358 ** {====================================================== 359 ** READ 360 ** ======================================================= 361 */ 362 363 364 /* maximum length of a numeral */ 365 #define MAXRN 200 366 367 /* auxiliary structure used by 'read_number' */ 368 typedef struct { 369 FILE *f; /* file being read */ 370 int c; /* current character (look ahead) */ 371 int n; /* number of elements in buffer 'buff' */ 372 char buff[MAXRN + 1]; /* +1 for ending '\0' */ 373 } RN; 374 375 376 /* 377 ** Add current char to buffer (if not out of space) and read next one 378 */ 379 static int nextc (RN *rn) { 380 if (rn->n >= MAXRN) { /* buffer overflow? */ 381 rn->buff[0] = '\0'; /* invalidate result */ 382 return 0; /* fail */ 383 } 384 else { 385 rn->buff[rn->n++] = rn->c; /* save current char */ 386 rn->c = l_getc(rn->f); /* read next one */ 387 return 1; 388 } 389 } 390 391 392 /* 393 ** Accept current char if it is in 'set' (of size 1 or 2) 394 */ 395 static int test2 (RN *rn, const char *set) { 396 if (rn->c == set[0] || (rn->c == set[1] && rn->c != '\0')) 397 return nextc(rn); 398 else return 0; 399 } 400 401 402 /* 403 ** Read a sequence of (hex)digits 404 */ 405 static int readdigits (RN *rn, int hex) { 406 int count = 0; 407 while ((hex ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn)) 408 count++; 409 return count; 410 } 411 412 413 /* access to locale "radix character" (decimal point) */ 414 #if !defined(l_getlocaledecpoint) 415 #define l_getlocaledecpoint() (localeconv()->decimal_point[0]) 416 #endif 417 418 419 /* 420 ** Read a number: first reads a valid prefix of a numeral into a buffer. 421 ** Then it calls 'lua_stringtonumber' to check whether the format is 422 ** correct and to convert it to a Lua number 423 */ 424 static int read_number (lua_State *L, FILE *f) { 425 RN rn; 426 int count = 0; 427 int hex = 0; 428 char decp[2] = "."; 429 rn.f = f; rn.n = 0; 430 decp[0] = l_getlocaledecpoint(); /* get decimal point from locale */ 431 l_lockfile(rn.f); 432 do { rn.c = l_getc(rn.f); } while (isspace(rn.c)); /* skip spaces */ 433 test2(&rn, "-+"); /* optional signal */ 434 if (test2(&rn, "0")) { 435 if (test2(&rn, "xX")) hex = 1; /* numeral is hexadecimal */ 436 else count = 1; /* count initial '0' as a valid digit */ 437 } 438 count += readdigits(&rn, hex); /* integral part */ 439 if (test2(&rn, decp)) /* decimal point? */ 440 count += readdigits(&rn, hex); /* fractional part */ 441 if (count > 0 && test2(&rn, (hex ? "pP" : "eE"))) { /* exponent mark? */ 442 test2(&rn, "-+"); /* exponent signal */ 443 readdigits(&rn, 0); /* exponent digits */ 444 } 445 ungetc(rn.c, rn.f); /* unread look-ahead char */ 446 l_unlockfile(rn.f); 447 rn.buff[rn.n] = '\0'; /* finish string */ 448 if (lua_stringtonumber(L, rn.buff)) /* is this a valid number? */ 449 return 1; /* ok */ 450 else { /* invalid format */ 451 lua_pushnil(L); /* "result" to be removed */ 452 return 0; /* read fails */ 453 } 454 } 455 456 457 static int test_eof (lua_State *L, FILE *f) { 458 int c = getc(f); 459 ungetc(c, f); /* no-op when c == EOF */ 460 lua_pushlstring(L, NULL, 0); 461 return (c != EOF); 462 } 463 464 465 static int read_line (lua_State *L, FILE *f, int chop) { 466 luaL_Buffer b; 467 int c = '\0'; 468 luaL_buffinit(L, &b); 469 while (c != EOF && c != '\n') { /* repeat until end of line */ 470 char *buff = luaL_prepbuffer(&b); /* pre-allocate buffer */ 471 int i = 0; 472 l_lockfile(f); /* no memory errors can happen inside the lock */ 473 while (i < LUAL_BUFFERSIZE && (c = l_getc(f)) != EOF && c != '\n') 474 buff[i++] = c; 475 l_unlockfile(f); 476 luaL_addsize(&b, i); 477 } 478 if (!chop && c == '\n') /* want a newline and have one? */ 479 luaL_addchar(&b, c); /* add ending newline to result */ 480 luaL_pushresult(&b); /* close buffer */ 481 /* return ok if read something (either a newline or something else) */ 482 return (c == '\n' || lua_rawlen(L, -1) > 0); 483 } 484 485 486 static void read_all (lua_State *L, FILE *f) { 487 size_t nr; 488 luaL_Buffer b; 489 luaL_buffinit(L, &b); 490 do { /* read file in chunks of LUAL_BUFFERSIZE bytes */ 491 char *p = luaL_prepbuffsize(&b, LUAL_BUFFERSIZE); 492 nr = fread(p, sizeof(char), LUAL_BUFFERSIZE, f); 493 luaL_addsize(&b, nr); 494 } while (nr == LUAL_BUFFERSIZE); 495 luaL_pushresult(&b); /* close buffer */ 496 } 497 498 499 static int read_chars (lua_State *L, FILE *f, size_t n) { 500 size_t nr; /* number of chars actually read */ 501 char *p; 502 luaL_Buffer b; 503 luaL_buffinit(L, &b); 504 p = luaL_prepbuffsize(&b, n); /* prepare buffer to read whole block */ 505 nr = fread(p, sizeof(char), n, f); /* try to read 'n' chars */ 506 luaL_addsize(&b, nr); 507 luaL_pushresult(&b); /* close buffer */ 508 return (nr > 0); /* true iff read something */ 509 } 510 511 512 static int g_read (lua_State *L, FILE *f, int first) { 513 int nargs = lua_gettop(L) - 1; 514 int success; 515 int n; 516 clearerr(f); 517 if (nargs == 0) { /* no arguments? */ 518 success = read_line(L, f, 1); 519 n = first+1; /* to return 1 result */ 520 } 521 else { /* ensure stack space for all results and for auxlib's buffer */ 522 luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments"); 523 success = 1; 524 for (n = first; nargs-- && success; n++) { 525 if (lua_type(L, n) == LUA_TNUMBER) { 526 size_t l = (size_t)luaL_checkinteger(L, n); 527 success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l); 528 } 529 else { 530 const char *p = luaL_checkstring(L, n); 531 if (*p == '*') p++; /* skip optional '*' (for compatibility) */ 532 switch (*p) { 533 case 'n': /* number */ 534 success = read_number(L, f); 535 break; 536 case 'l': /* line */ 537 success = read_line(L, f, 1); 538 break; 539 case 'L': /* line with end-of-line */ 540 success = read_line(L, f, 0); 541 break; 542 case 'a': /* file */ 543 read_all(L, f); /* read entire file */ 544 success = 1; /* always success */ 545 break; 546 default: 547 return luaL_argerror(L, n, "invalid format"); 548 } 549 } 550 } 551 } 552 if (ferror(f)) 553 return luaL_fileresult(L, 0, NULL); 554 if (!success) { 555 lua_pop(L, 1); /* remove last result */ 556 lua_pushnil(L); /* push nil instead */ 557 } 558 return n - first; 559 } 560 561 562 static int io_read (lua_State *L) { 563 return g_read(L, getiofile(L, IO_INPUT), 1); 564 } 565 566 567 static int f_read (lua_State *L) { 568 return g_read(L, tofile(L), 2); 569 } 570 571 572 static int io_readline (lua_State *L) { 573 LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1)); 574 int i; 575 int n = (int)lua_tointeger(L, lua_upvalueindex(2)); 576 if (isclosed(p)) /* file is already closed? */ 577 return luaL_error(L, "file is already closed"); 578 lua_settop(L , 1); 579 luaL_checkstack(L, n, "too many arguments"); 580 for (i = 1; i <= n; i++) /* push arguments to 'g_read' */ 581 lua_pushvalue(L, lua_upvalueindex(3 + i)); 582 n = g_read(L, p->f, 2); /* 'n' is number of results */ 583 lua_assert(n > 0); /* should return at least a nil */ 584 if (lua_toboolean(L, -n)) /* read at least one value? */ 585 return n; /* return them */ 586 else { /* first result is nil: EOF or error */ 587 if (n > 1) { /* is there error information? */ 588 /* 2nd result is error message */ 589 return luaL_error(L, "%s", lua_tostring(L, -n + 1)); 590 } 591 if (lua_toboolean(L, lua_upvalueindex(3))) { /* generator created file? */ 592 lua_settop(L, 0); 593 lua_pushvalue(L, lua_upvalueindex(1)); 594 aux_close(L); /* close it */ 595 } 596 return 0; 597 } 598 } 599 600 /* }====================================================== */ 601 602 603 static int g_write (lua_State *L, FILE *f, int arg) { 604 int nargs = lua_gettop(L) - arg; 605 int status = 1; 606 for (; nargs--; arg++) { 607 if (lua_type(L, arg) == LUA_TNUMBER) { 608 /* optimization: could be done exactly as for strings */ 609 int len = lua_isinteger(L, arg) 610 ? fprintf(f, LUA_INTEGER_FMT, lua_tointeger(L, arg)) 611 : fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)); 612 status = status && (len > 0); 613 } 614 else { 615 size_t l; 616 const char *s = luaL_checklstring(L, arg, &l); 617 status = status && (fwrite(s, sizeof(char), l, f) == l); 618 } 619 } 620 if (status) return 1; /* file handle already on stack top */ 621 else return luaL_fileresult(L, status, NULL); 622 } 623 624 625 static int io_write (lua_State *L) { 626 return g_write(L, getiofile(L, IO_OUTPUT), 1); 627 } 628 629 630 static int f_write (lua_State *L) { 631 FILE *f = tofile(L); 632 lua_pushvalue(L, 1); /* push file at the stack top (to be returned) */ 633 return g_write(L, f, 2); 634 } 635 636 637 static int f_seek (lua_State *L) { 638 static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END}; 639 static const char *const modenames[] = {"set", "cur", "end", NULL}; 640 FILE *f = tofile(L); 641 int op = luaL_checkoption(L, 2, "cur", modenames); 642 lua_Integer p3 = luaL_optinteger(L, 3, 0); 643 l_seeknum offset = (l_seeknum)p3; 644 luaL_argcheck(L, (lua_Integer)offset == p3, 3, 645 "not an integer in proper range"); 646 op = l_fseek(f, offset, mode[op]); 647 if (op) 648 return luaL_fileresult(L, 0, NULL); /* error */ 649 else { 650 lua_pushinteger(L, (lua_Integer)l_ftell(f)); 651 return 1; 652 } 653 } 654 655 656 static int f_setvbuf (lua_State *L) { 657 static const int mode[] = {_IONBF, _IOFBF, _IOLBF}; 658 static const char *const modenames[] = {"no", "full", "line", NULL}; 659 FILE *f = tofile(L); 660 int op = luaL_checkoption(L, 2, NULL, modenames); 661 lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE); 662 int res = setvbuf(f, NULL, mode[op], (size_t)sz); 663 return luaL_fileresult(L, res == 0, NULL); 664 } 665 666 667 668 static int io_flush (lua_State *L) { 669 return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL); 670 } 671 672 673 static int f_flush (lua_State *L) { 674 return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL); 675 } 676 677 678 /* 679 ** functions for 'io' library 680 */ 681 static const luaL_Reg iolib[] = { 682 {"close", io_close}, 683 {"flush", io_flush}, 684 {"input", io_input}, 685 {"lines", io_lines}, 686 {"open", io_open}, 687 {"output", io_output}, 688 {"popen", io_popen}, 689 {"read", io_read}, 690 {"tmpfile", io_tmpfile}, 691 {"type", io_type}, 692 {"write", io_write}, 693 {NULL, NULL} 694 }; 695 696 697 /* 698 ** methods for file handles 699 */ 700 static const luaL_Reg flib[] = { 701 {"close", io_close}, 702 {"flush", f_flush}, 703 {"lines", f_lines}, 704 {"read", f_read}, 705 {"seek", f_seek}, 706 {"setvbuf", f_setvbuf}, 707 {"write", f_write}, 708 {"__gc", f_gc}, 709 {"__tostring", f_tostring}, 710 {NULL, NULL} 711 }; 712 713 714 static void createmeta (lua_State *L) { 715 luaL_newmetatable(L, LUA_FILEHANDLE); /* create metatable for file handles */ 716 lua_pushvalue(L, -1); /* push metatable */ 717 lua_setfield(L, -2, "__index"); /* metatable.__index = metatable */ 718 luaL_setfuncs(L, flib, 0); /* add file methods to new metatable */ 719 lua_pop(L, 1); /* pop new metatable */ 720 } 721 722 723 /* 724 ** function to (not) close the standard files stdin, stdout, and stderr 725 */ 726 static int io_noclose (lua_State *L) { 727 LStream *p = tolstream(L); 728 p->closef = &io_noclose; /* keep file opened */ 729 lua_pushnil(L); 730 lua_pushliteral(L, "cannot close standard file"); 731 return 2; 732 } 733 734 735 static void createstdfile (lua_State *L, FILE *f, const char *k, 736 const char *fname) { 737 LStream *p = newprefile(L); 738 p->f = f; 739 p->closef = &io_noclose; 740 if (k != NULL) { 741 lua_pushvalue(L, -1); 742 lua_setfield(L, LUA_REGISTRYINDEX, k); /* add file to registry */ 743 } 744 lua_setfield(L, -2, fname); /* add file to module */ 745 } 746 747 748 LUAMOD_API int luaopen_io (lua_State *L) { 749 luaL_newlib(L, iolib); /* new module */ 750 createmeta(L); 751 /* create (and set) default files */ 752 createstdfile(L, stdin, IO_INPUT, "stdin"); 753 createstdfile(L, stdout, IO_OUTPUT, "stdout"); 754 createstdfile(L, stderr, NULL, "stderr"); 755 return 1; 756 } 757 758