1 /* 2 ** $Id: liolib.c,v 2.151 2016/12/20 18:37:00 roberto 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 27 28 /* 29 ** Change this macro to accept other modes for 'fopen' besides 30 ** the standard ones. 31 */ 32 #if !defined(l_checkmode) 33 34 /* accepted extensions to 'mode' in 'fopen' */ 35 #if !defined(L_MODEEXT) 36 #define L_MODEEXT "b" 37 #endif 38 39 /* Check whether 'mode' matches '[rwa]%+?[L_MODEEXT]*' */ 40 static int l_checkmode (const char *mode) { 41 return (*mode != '\0' && strchr("rwa", *(mode++)) != NULL && 42 (*mode != '+' || (++mode, 1)) && /* skip if char is '+' */ 43 (strspn(mode, L_MODEEXT) == strlen(mode))); /* check extensions */ 44 } 45 46 #endif 47 48 /* 49 ** {====================================================== 50 ** l_popen spawns a new process connected to the current 51 ** one through the file streams. 52 ** ======================================================= 53 */ 54 55 #if !defined(l_popen) /* { */ 56 57 #if defined(LUA_USE_POSIX) /* { */ 58 59 #define l_popen(L,c,m) (fflush(NULL), popen(c,m)) 60 #define l_pclose(L,file) (pclose(file)) 61 62 #elif defined(LUA_USE_WINDOWS) /* }{ */ 63 64 #define l_popen(L,c,m) (_popen(c,m)) 65 #define l_pclose(L,file) (_pclose(file)) 66 67 #else /* }{ */ 68 69 /* ISO C definitions */ 70 #define l_popen(L,c,m) \ 71 ((void)((void)c, m), \ 72 luaL_error(L, "'popen' not supported"), \ 73 (FILE*)0) 74 #define l_pclose(L,file) ((void)L, (void)file, -1) 75 76 #endif /* } */ 77 78 #endif /* } */ 79 80 /* }====================================================== */ 81 82 83 #if !defined(l_getc) /* { */ 84 85 #if defined(LUA_USE_POSIX) 86 #define l_getc(f) getc_unlocked(f) 87 #define l_lockfile(f) flockfile(f) 88 #define l_unlockfile(f) funlockfile(f) 89 #else 90 #define l_getc(f) getc(f) 91 #define l_lockfile(f) ((void)0) 92 #define l_unlockfile(f) ((void)0) 93 #endif 94 95 #endif /* } */ 96 97 98 /* 99 ** {====================================================== 100 ** l_fseek: configuration for longer offsets 101 ** ======================================================= 102 */ 103 104 #if !defined(l_fseek) /* { */ 105 106 #if defined(LUA_USE_POSIX) /* { */ 107 108 #include <sys/types.h> 109 110 #define l_fseek(f,o,w) fseeko(f,o,w) 111 #define l_ftell(f) ftello(f) 112 #define l_seeknum off_t 113 114 #elif defined(LUA_USE_WINDOWS) && !defined(_CRTIMP_TYPEINFO) \ 115 && defined(_MSC_VER) && (_MSC_VER >= 1400) /* }{ */ 116 117 /* Windows (but not DDK) and Visual C++ 2005 or higher */ 118 #define l_fseek(f,o,w) _fseeki64(f,o,w) 119 #define l_ftell(f) _ftelli64(f) 120 #define l_seeknum __int64 121 122 #else /* }{ */ 123 124 /* ISO C definitions */ 125 #define l_fseek(f,o,w) fseek(f,o,w) 126 #define l_ftell(f) ftell(f) 127 #define l_seeknum long 128 129 #endif /* } */ 130 131 #endif /* } */ 132 133 /* }====================================================== */ 134 135 136 #define IO_PREFIX "_IO_" 137 #define IOPREF_LEN (sizeof(IO_PREFIX)/sizeof(char) - 1) 138 #define IO_INPUT (IO_PREFIX "input") 139 #define IO_OUTPUT (IO_PREFIX "output") 140 141 142 typedef luaL_Stream LStream; 143 144 145 #define tolstream(L) ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE)) 146 147 #define isclosed(p) ((p)->closef == NULL) 148 149 150 static int io_type (lua_State *L) { 151 LStream *p; 152 luaL_checkany(L, 1); 153 p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE); 154 if (p == NULL) 155 lua_pushnil(L); /* not a file */ 156 else if (isclosed(p)) 157 lua_pushliteral(L, "closed file"); 158 else 159 lua_pushliteral(L, "file"); 160 return 1; 161 } 162 163 164 static int f_tostring (lua_State *L) { 165 LStream *p = tolstream(L); 166 if (isclosed(p)) 167 lua_pushliteral(L, "file (closed)"); 168 else 169 lua_pushfstring(L, "file (%p)", p->f); 170 return 1; 171 } 172 173 174 static FILE *tofile (lua_State *L) { 175 LStream *p = tolstream(L); 176 if (isclosed(p)) 177 luaL_error(L, "attempt to use a closed file"); 178 lua_assert(p->f); 179 return p->f; 180 } 181 182 183 /* 184 ** When creating file handles, always creates a 'closed' file handle 185 ** before opening the actual file; so, if there is a memory error, the 186 ** handle is in a consistent state. 187 */ 188 static LStream *newprefile (lua_State *L) { 189 LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream)); 190 p->closef = NULL; /* mark file handle as 'closed' */ 191 luaL_setmetatable(L, LUA_FILEHANDLE); 192 return p; 193 } 194 195 196 /* 197 ** Calls the 'close' function from a file handle. The 'volatile' avoids 198 ** a bug in some versions of the Clang compiler (e.g., clang 3.0 for 199 ** 32 bits). 200 */ 201 static int aux_close (lua_State *L) { 202 LStream *p = tolstream(L); 203 volatile lua_CFunction cf = p->closef; 204 p->closef = NULL; /* mark stream as closed */ 205 return (*cf)(L); /* close it */ 206 } 207 208 209 static int io_close (lua_State *L) { 210 if (lua_isnone(L, 1)) /* no argument? */ 211 lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT); /* use standard output */ 212 tofile(L); /* make sure argument is an open stream */ 213 return aux_close(L); 214 } 215 216 217 static int f_gc (lua_State *L) { 218 LStream *p = tolstream(L); 219 if (!isclosed(p) && p->f != NULL) 220 aux_close(L); /* ignore closed and incompletely open files */ 221 return 0; 222 } 223 224 225 /* 226 ** function to close regular files 227 */ 228 static int io_fclose (lua_State *L) { 229 LStream *p = tolstream(L); 230 int res = fclose(p->f); 231 return luaL_fileresult(L, (res == 0), NULL); 232 } 233 234 235 static LStream *newfile (lua_State *L) { 236 LStream *p = newprefile(L); 237 p->f = NULL; 238 p->closef = &io_fclose; 239 return p; 240 } 241 242 243 static void opencheck (lua_State *L, const char *fname, const char *mode) { 244 LStream *p = newfile(L); 245 p->f = fopen(fname, mode); 246 if (p->f == NULL) 247 luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno)); 248 } 249 250 251 static int io_open (lua_State *L) { 252 const char *filename = luaL_checkstring(L, 1); 253 const char *mode = luaL_optstring(L, 2, "r"); 254 LStream *p = newfile(L); 255 const char *md = mode; /* to traverse/check mode */ 256 luaL_argcheck(L, l_checkmode(md), 2, "invalid mode"); 257 p->f = fopen(filename, mode); 258 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 259 } 260 261 262 /* 263 ** function to close 'popen' files 264 */ 265 static int io_pclose (lua_State *L) { 266 LStream *p = tolstream(L); 267 return luaL_execresult(L, l_pclose(L, p->f)); 268 } 269 270 271 static int io_popen (lua_State *L) { 272 const char *filename = luaL_checkstring(L, 1); 273 const char *mode = luaL_optstring(L, 2, "r"); 274 LStream *p = newprefile(L); 275 p->f = l_popen(L, filename, mode); 276 p->closef = &io_pclose; 277 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 278 } 279 280 281 static int io_tmpfile (lua_State *L) { 282 LStream *p = newfile(L); 283 p->f = tmpfile(); 284 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1; 285 } 286 287 288 static FILE *getiofile (lua_State *L, const char *findex) { 289 LStream *p; 290 lua_getfield(L, LUA_REGISTRYINDEX, findex); 291 p = (LStream *)lua_touserdata(L, -1); 292 if (isclosed(p)) 293 luaL_error(L, "standard %s file is closed", findex + IOPREF_LEN); 294 return p->f; 295 } 296 297 298 static int g_iofile (lua_State *L, const char *f, const char *mode) { 299 if (!lua_isnoneornil(L, 1)) { 300 const char *filename = lua_tostring(L, 1); 301 if (filename) 302 opencheck(L, filename, mode); 303 else { 304 tofile(L); /* check that it's a valid file handle */ 305 lua_pushvalue(L, 1); 306 } 307 lua_setfield(L, LUA_REGISTRYINDEX, f); 308 } 309 /* return current value */ 310 lua_getfield(L, LUA_REGISTRYINDEX, f); 311 return 1; 312 } 313 314 315 static int io_input (lua_State *L) { 316 return g_iofile(L, IO_INPUT, "r"); 317 } 318 319 320 static int io_output (lua_State *L) { 321 return g_iofile(L, IO_OUTPUT, "w"); 322 } 323 324 325 static int io_readline (lua_State *L); 326 327 328 /* 329 ** maximum number of arguments to 'f:lines'/'io.lines' (it + 3 must fit 330 ** in the limit for upvalues of a closure) 331 */ 332 #define MAXARGLINE 250 333 334 static void aux_lines (lua_State *L, int toclose) { 335 int n = lua_gettop(L) - 1; /* number of arguments to read */ 336 luaL_argcheck(L, n <= MAXARGLINE, MAXARGLINE + 2, "too many arguments"); 337 lua_pushinteger(L, n); /* number of arguments to read */ 338 lua_pushboolean(L, toclose); /* close/not close file when finished */ 339 lua_rotate(L, 2, 2); /* move 'n' and 'toclose' to their positions */ 340 lua_pushcclosure(L, io_readline, 3 + n); 341 } 342 343 344 static int f_lines (lua_State *L) { 345 tofile(L); /* check that it's a valid file handle */ 346 aux_lines(L, 0); 347 return 1; 348 } 349 350 351 static int io_lines (lua_State *L) { 352 int toclose; 353 if (lua_isnone(L, 1)) lua_pushnil(L); /* at least one argument */ 354 if (lua_isnil(L, 1)) { /* no file name? */ 355 lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT); /* get default input */ 356 lua_replace(L, 1); /* put it at index 1 */ 357 tofile(L); /* check that it's a valid file handle */ 358 toclose = 0; /* do not close it after iteration */ 359 } 360 else { /* open a new file */ 361 const char *filename = luaL_checkstring(L, 1); 362 opencheck(L, filename, "r"); 363 lua_replace(L, 1); /* put file at index 1 */ 364 toclose = 1; /* close it after iteration */ 365 } 366 aux_lines(L, toclose); 367 return 1; 368 } 369 370 371 /* 372 ** {====================================================== 373 ** READ 374 ** ======================================================= 375 */ 376 377 378 /* maximum length of a numeral */ 379 #if !defined (L_MAXLENNUM) 380 #define L_MAXLENNUM 200 381 #endif 382 383 384 /* auxiliary structure used by 'read_number' */ 385 typedef struct { 386 FILE *f; /* file being read */ 387 int c; /* current character (look ahead) */ 388 int n; /* number of elements in buffer 'buff' */ 389 char buff[L_MAXLENNUM + 1]; /* +1 for ending '\0' */ 390 } RN; 391 392 393 /* 394 ** Add current char to buffer (if not out of space) and read next one 395 */ 396 static int nextc (RN *rn) { 397 if (rn->n >= L_MAXLENNUM) { /* buffer overflow? */ 398 rn->buff[0] = '\0'; /* invalidate result */ 399 return 0; /* fail */ 400 } 401 else { 402 rn->buff[rn->n++] = rn->c; /* save current char */ 403 rn->c = l_getc(rn->f); /* read next one */ 404 return 1; 405 } 406 } 407 408 409 /* 410 ** Accept current char if it is in 'set' (of size 2) 411 */ 412 static int test2 (RN *rn, const char *set) { 413 if (rn->c == set[0] || rn->c == set[1]) 414 return nextc(rn); 415 else return 0; 416 } 417 418 419 /* 420 ** Read a sequence of (hex)digits 421 */ 422 static int readdigits (RN *rn, int hex) { 423 int count = 0; 424 while ((hex ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn)) 425 count++; 426 return count; 427 } 428 429 430 /* 431 ** Read a number: first reads a valid prefix of a numeral into a buffer. 432 ** Then it calls 'lua_stringtonumber' to check whether the format is 433 ** correct and to convert it to a Lua number 434 */ 435 static int read_number (lua_State *L, FILE *f) { 436 RN rn; 437 int count = 0; 438 int hex = 0; 439 char decp[2]; 440 rn.f = f; rn.n = 0; 441 decp[0] = lua_getlocaledecpoint(); /* get decimal point from locale */ 442 decp[1] = '.'; /* always accept a dot */ 443 l_lockfile(rn.f); 444 do { rn.c = l_getc(rn.f); } while (isspace(rn.c)); /* skip spaces */ 445 test2(&rn, "-+"); /* optional signal */ 446 if (test2(&rn, "00")) { 447 if (test2(&rn, "xX")) hex = 1; /* numeral is hexadecimal */ 448 else count = 1; /* count initial '0' as a valid digit */ 449 } 450 count += readdigits(&rn, hex); /* integral part */ 451 if (test2(&rn, decp)) /* decimal point? */ 452 count += readdigits(&rn, hex); /* fractional part */ 453 if (count > 0 && test2(&rn, (hex ? "pP" : "eE"))) { /* exponent mark? */ 454 test2(&rn, "-+"); /* exponent signal */ 455 readdigits(&rn, 0); /* exponent digits */ 456 } 457 ungetc(rn.c, rn.f); /* unread look-ahead char */ 458 l_unlockfile(rn.f); 459 rn.buff[rn.n] = '\0'; /* finish string */ 460 if (lua_stringtonumber(L, rn.buff)) /* is this a valid number? */ 461 return 1; /* ok */ 462 else { /* invalid format */ 463 lua_pushnil(L); /* "result" to be removed */ 464 return 0; /* read fails */ 465 } 466 } 467 468 469 static int test_eof (lua_State *L, FILE *f) { 470 int c = getc(f); 471 ungetc(c, f); /* no-op when c == EOF */ 472 lua_pushliteral(L, ""); 473 return (c != EOF); 474 } 475 476 477 static int read_line (lua_State *L, FILE *f, int chop) { 478 luaL_Buffer b; 479 int c = '\0'; 480 luaL_buffinit(L, &b); 481 while (c != EOF && c != '\n') { /* repeat until end of line */ 482 char *buff = luaL_prepbuffer(&b); /* preallocate buffer */ 483 int i = 0; 484 l_lockfile(f); /* no memory errors can happen inside the lock */ 485 while (i < LUAL_BUFFERSIZE && (c = l_getc(f)) != EOF && c != '\n') 486 buff[i++] = c; 487 l_unlockfile(f); 488 luaL_addsize(&b, i); 489 } 490 if (!chop && c == '\n') /* want a newline and have one? */ 491 luaL_addchar(&b, c); /* add ending newline to result */ 492 luaL_pushresult(&b); /* close buffer */ 493 /* return ok if read something (either a newline or something else) */ 494 return (c == '\n' || lua_rawlen(L, -1) > 0); 495 } 496 497 498 static void read_all (lua_State *L, FILE *f) { 499 size_t nr; 500 luaL_Buffer b; 501 luaL_buffinit(L, &b); 502 do { /* read file in chunks of LUAL_BUFFERSIZE bytes */ 503 char *p = luaL_prepbuffer(&b); 504 nr = fread(p, sizeof(char), LUAL_BUFFERSIZE, f); 505 luaL_addsize(&b, nr); 506 } while (nr == LUAL_BUFFERSIZE); 507 luaL_pushresult(&b); /* close buffer */ 508 } 509 510 511 static int read_chars (lua_State *L, FILE *f, size_t n) { 512 size_t nr; /* number of chars actually read */ 513 char *p; 514 luaL_Buffer b; 515 luaL_buffinit(L, &b); 516 p = luaL_prepbuffsize(&b, n); /* prepare buffer to read whole block */ 517 nr = fread(p, sizeof(char), n, f); /* try to read 'n' chars */ 518 luaL_addsize(&b, nr); 519 luaL_pushresult(&b); /* close buffer */ 520 return (nr > 0); /* true iff read something */ 521 } 522 523 524 static int g_read (lua_State *L, FILE *f, int first) { 525 int nargs = lua_gettop(L) - 1; 526 int success; 527 int n; 528 clearerr(f); 529 if (nargs == 0) { /* no arguments? */ 530 success = read_line(L, f, 1); 531 n = first+1; /* to return 1 result */ 532 } 533 else { /* ensure stack space for all results and for auxlib's buffer */ 534 luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments"); 535 success = 1; 536 for (n = first; nargs-- && success; n++) { 537 if (lua_type(L, n) == LUA_TNUMBER) { 538 size_t l = (size_t)luaL_checkinteger(L, n); 539 success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l); 540 } 541 else { 542 const char *p = luaL_checkstring(L, n); 543 if (*p == '*') p++; /* skip optional '*' (for compatibility) */ 544 switch (*p) { 545 case 'n': /* number */ 546 success = read_number(L, f); 547 break; 548 case 'l': /* line */ 549 success = read_line(L, f, 1); 550 break; 551 case 'L': /* line with end-of-line */ 552 success = read_line(L, f, 0); 553 break; 554 case 'a': /* file */ 555 read_all(L, f); /* read entire file */ 556 success = 1; /* always success */ 557 break; 558 default: 559 return luaL_argerror(L, n, "invalid format"); 560 } 561 } 562 } 563 } 564 if (ferror(f)) 565 return luaL_fileresult(L, 0, NULL); 566 if (!success) { 567 lua_pop(L, 1); /* remove last result */ 568 lua_pushnil(L); /* push nil instead */ 569 } 570 return n - first; 571 } 572 573 574 static int io_read (lua_State *L) { 575 return g_read(L, getiofile(L, IO_INPUT), 1); 576 } 577 578 579 static int f_read (lua_State *L) { 580 return g_read(L, tofile(L), 2); 581 } 582 583 584 static int io_readline (lua_State *L) { 585 LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1)); 586 int i; 587 int n = (int)lua_tointeger(L, lua_upvalueindex(2)); 588 if (isclosed(p)) /* file is already closed? */ 589 return luaL_error(L, "file is already closed"); 590 lua_settop(L , 1); 591 luaL_checkstack(L, n, "too many arguments"); 592 for (i = 1; i <= n; i++) /* push arguments to 'g_read' */ 593 lua_pushvalue(L, lua_upvalueindex(3 + i)); 594 n = g_read(L, p->f, 2); /* 'n' is number of results */ 595 lua_assert(n > 0); /* should return at least a nil */ 596 if (lua_toboolean(L, -n)) /* read at least one value? */ 597 return n; /* return them */ 598 else { /* first result is nil: EOF or error */ 599 if (n > 1) { /* is there error information? */ 600 /* 2nd result is error message */ 601 return luaL_error(L, "%s", lua_tostring(L, -n + 1)); 602 } 603 if (lua_toboolean(L, lua_upvalueindex(3))) { /* generator created file? */ 604 lua_settop(L, 0); 605 lua_pushvalue(L, lua_upvalueindex(1)); 606 aux_close(L); /* close it */ 607 } 608 return 0; 609 } 610 } 611 612 /* }====================================================== */ 613 614 615 static int g_write (lua_State *L, FILE *f, int arg) { 616 int nargs = lua_gettop(L) - arg; 617 int status = 1; 618 for (; nargs--; arg++) { 619 if (lua_type(L, arg) == LUA_TNUMBER) { 620 /* optimization: could be done exactly as for strings */ 621 int len = lua_isinteger(L, arg) 622 ? fprintf(f, LUA_INTEGER_FMT, 623 (LUAI_UACINT)lua_tointeger(L, arg)) 624 : fprintf(f, LUA_NUMBER_FMT, 625 (LUAI_UACNUMBER)lua_tonumber(L, arg)); 626 status = status && (len > 0); 627 } 628 else { 629 size_t l; 630 const char *s = luaL_checklstring(L, arg, &l); 631 status = status && (fwrite(s, sizeof(char), l, f) == l); 632 } 633 } 634 if (status) return 1; /* file handle already on stack top */ 635 else return luaL_fileresult(L, status, NULL); 636 } 637 638 639 static int io_write (lua_State *L) { 640 return g_write(L, getiofile(L, IO_OUTPUT), 1); 641 } 642 643 644 static int f_write (lua_State *L) { 645 FILE *f = tofile(L); 646 lua_pushvalue(L, 1); /* push file at the stack top (to be returned) */ 647 return g_write(L, f, 2); 648 } 649 650 651 static int f_seek (lua_State *L) { 652 static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END}; 653 static const char *const modenames[] = {"set", "cur", "end", NULL}; 654 FILE *f = tofile(L); 655 int op = luaL_checkoption(L, 2, "cur", modenames); 656 lua_Integer p3 = luaL_optinteger(L, 3, 0); 657 l_seeknum offset = (l_seeknum)p3; 658 luaL_argcheck(L, (lua_Integer)offset == p3, 3, 659 "not an integer in proper range"); 660 op = l_fseek(f, offset, mode[op]); 661 if (op) 662 return luaL_fileresult(L, 0, NULL); /* error */ 663 else { 664 lua_pushinteger(L, (lua_Integer)l_ftell(f)); 665 return 1; 666 } 667 } 668 669 670 static int f_setvbuf (lua_State *L) { 671 static const int mode[] = {_IONBF, _IOFBF, _IOLBF}; 672 static const char *const modenames[] = {"no", "full", "line", NULL}; 673 FILE *f = tofile(L); 674 int op = luaL_checkoption(L, 2, NULL, modenames); 675 lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE); 676 int res = setvbuf(f, NULL, mode[op], (size_t)sz); 677 return luaL_fileresult(L, res == 0, NULL); 678 } 679 680 681 682 static int io_flush (lua_State *L) { 683 return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL); 684 } 685 686 687 static int f_flush (lua_State *L) { 688 return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL); 689 } 690 691 692 /* 693 ** functions for 'io' library 694 */ 695 static const luaL_Reg iolib[] = { 696 {"close", io_close}, 697 {"flush", io_flush}, 698 {"input", io_input}, 699 {"lines", io_lines}, 700 {"open", io_open}, 701 {"output", io_output}, 702 {"popen", io_popen}, 703 {"read", io_read}, 704 {"tmpfile", io_tmpfile}, 705 {"type", io_type}, 706 {"write", io_write}, 707 {NULL, NULL} 708 }; 709 710 711 /* 712 ** methods for file handles 713 */ 714 static const luaL_Reg flib[] = { 715 {"close", io_close}, 716 {"flush", f_flush}, 717 {"lines", f_lines}, 718 {"read", f_read}, 719 {"seek", f_seek}, 720 {"setvbuf", f_setvbuf}, 721 {"write", f_write}, 722 {"__gc", f_gc}, 723 {"__tostring", f_tostring}, 724 {NULL, NULL} 725 }; 726 727 728 static void createmeta (lua_State *L) { 729 luaL_newmetatable(L, LUA_FILEHANDLE); /* create metatable for file handles */ 730 lua_pushvalue(L, -1); /* push metatable */ 731 lua_setfield(L, -2, "__index"); /* metatable.__index = metatable */ 732 luaL_setfuncs(L, flib, 0); /* add file methods to new metatable */ 733 lua_pop(L, 1); /* pop new metatable */ 734 } 735 736 737 /* 738 ** function to (not) close the standard files stdin, stdout, and stderr 739 */ 740 static int io_noclose (lua_State *L) { 741 LStream *p = tolstream(L); 742 p->closef = &io_noclose; /* keep file opened */ 743 lua_pushnil(L); 744 lua_pushliteral(L, "cannot close standard file"); 745 return 2; 746 } 747 748 749 static void createstdfile (lua_State *L, FILE *f, const char *k, 750 const char *fname) { 751 LStream *p = newprefile(L); 752 p->f = f; 753 p->closef = &io_noclose; 754 if (k != NULL) { 755 lua_pushvalue(L, -1); 756 lua_setfield(L, LUA_REGISTRYINDEX, k); /* add file to registry */ 757 } 758 lua_setfield(L, -2, fname); /* add file to module */ 759 } 760 761 762 LUAMOD_API int luaopen_io (lua_State *L) { 763 luaL_newlib(L, iolib); /* new module */ 764 createmeta(L); 765 /* create (and set) default files */ 766 createstdfile(L, stdin, IO_INPUT, "stdin"); 767 createstdfile(L, stdout, IO_OUTPUT, "stdout"); 768 createstdfile(L, stderr, NULL, "stderr"); 769 return 1; 770 } 771 772