1 /* $NetBSD: liolib.c,v 1.8 2017/04/26 13:17:33 mbalmer Exp $ */ 2 3 /* 4 ** Id: liolib.c,v 2.151 2016/12/20 18:37:00 roberto Exp 5 ** Standard I/O (and system) library 6 ** See Copyright Notice in lua.h 7 */ 8 9 #define liolib_c 10 #define LUA_LIB 11 12 #include "lprefix.h" 13 14 15 #include <ctype.h> 16 #include <errno.h> 17 #include <locale.h> 18 #include <stdio.h> 19 #include <stdlib.h> 20 #include <string.h> 21 22 #include "lua.h" 23 24 #include "lauxlib.h" 25 #include "lualib.h" 26 27 28 29 30 /* 31 ** Change this macro to accept other modes for 'fopen' besides 32 ** the standard ones. 33 */ 34 #if !defined(l_checkmode) 35 36 /* accepted extensions to 'mode' in 'fopen' */ 37 #if !defined(L_MODEEXT) 38 #define L_MODEEXT "b" 39 #endif 40 41 /* Check whether 'mode' matches '[rwa]%+?[L_MODEEXT]*' */ 42 static int l_checkmode (const char *mode) { 43 return (*mode != '\0' && strchr("rwa", *(mode++)) != NULL && 44 (*mode != '+' || (++mode, 1)) && /* skip if char is '+' */ 45 (strspn(mode, L_MODEEXT) == strlen(mode))); /* check extensions */ 46 } 47 48 #endif 49 50 /* 51 ** {====================================================== 52 ** l_popen spawns a new process connected to the current 53 ** one through the file streams. 54 ** ======================================================= 55 */ 56 57 #if !defined(l_popen) /* { */ 58 59 #if defined(LUA_USE_POSIX) /* { */ 60 61 #define l_popen(L,c,m) (fflush(NULL), popen(c,m)) 62 #define l_pclose(L,file) (pclose(file)) 63 64 #elif defined(LUA_USE_WINDOWS) /* }{ */ 65 66 #define l_popen(L,c,m) (_popen(c,m)) 67 #define l_pclose(L,file) (_pclose(file)) 68 69 #else /* }{ */ 70 71 /* ISO C definitions */ 72 #define l_popen(L,c,m) \ 73 ((void)((void)c, m), \ 74 luaL_error(L, "'popen' not supported"), \ 75 (FILE*)0) 76 #define l_pclose(L,file) ((void)L, (void)file, -1) 77 78 #endif /* } */ 79 80 #endif /* } */ 81 82 /* }====================================================== */ 83 84 85 #if !defined(l_getc) /* { */ 86 87 #if defined(LUA_USE_POSIX) 88 #define l_getc(f) getc_unlocked(f) 89 #define l_lockfile(f) flockfile(f) 90 #define l_unlockfile(f) funlockfile(f) 91 #else 92 #define l_getc(f) getc(f) 93 #define l_lockfile(f) ((void)0) 94 #define l_unlockfile(f) ((void)0) 95 #endif 96 97 #endif /* } */ 98 99 100 /* 101 ** {====================================================== 102 ** l_fseek: configuration for longer offsets 103 ** ======================================================= 104 */ 105 106 #if !defined(l_fseek) /* { */ 107 108 #if defined(LUA_USE_POSIX) /* { */ 109 110 #include <sys/types.h> 111 112 #define l_fseek(f,o,w) fseeko(f,o,w) 113 #define l_ftell(f) ftello(f) 114 #define l_seeknum off_t 115 116 #elif defined(LUA_USE_WINDOWS) && !defined(_CRTIMP_TYPEINFO) \ 117 && defined(_MSC_VER) && (_MSC_VER >= 1400) /* }{ */ 118 119 /* Windows (but not DDK) and Visual C++ 2005 or higher */ 120 #define l_fseek(f,o,w) _fseeki64(f,o,w) 121 #define l_ftell(f) _ftelli64(f) 122 #define l_seeknum __int64 123 124 #else /* }{ */ 125 126 /* ISO C definitions */ 127 #define l_fseek(f,o,w) fseek(f,o,w) 128 #define l_ftell(f) ftell(f) 129 #define l_seeknum long 130 131 #endif /* } */ 132 133 #endif /* } */ 134 135 /* }====================================================== */ 136 137 138 #define IO_PREFIX "_IO_" 139 #define IOPREF_LEN (sizeof(IO_PREFIX)/sizeof(char) - 1) 140 #define IO_INPUT (IO_PREFIX "input") 141 #define IO_OUTPUT (IO_PREFIX "output") 142 143 144 typedef luaL_Stream LStream; 145 146 147 #define tolstream(L) ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE)) 148 149 #define isclosed(p) ((p)->closef == NULL) 150 151 152 static int io_type (lua_State *L) { 153 LStream *p; 154 luaL_checkany(L, 1); 155 p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE); 156 if (p == NULL) 157 lua_pushnil(L); /* not a file */ 158 else if (isclosed(p)) 159 lua_pushliteral(L, "closed file"); 160 else 161 lua_pushliteral(L, "file"); 162 return 1; 163 } 164 165 166 static int f_tostring (lua_State *L) { 167 LStream *p = tolstream(L); 168 if (isclosed(p)) 169 lua_pushliteral(L, "file (closed)"); 170 else 171 lua_pushfstring(L, "file (%p)", p->f); 172 return 1; 173 } 174 175 176 static FILE *tofile (lua_State *L) { 177 LStream *p = tolstream(L); 178 if (isclosed(p)) 179 luaL_error(L, "attempt to use a closed file"); 180 lua_assert(p->f); 181 return p->f; 182 } 183 184 185 /* 186 ** When creating file handles, always creates a 'closed' file handle 187 ** before opening the actual file; so, if there is a memory error, the 188 ** handle is in a consistent state. 189 */ 190 static LStream *newprefile (lua_State *L) { 191 LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream)); 192 p->closef = NULL; /* mark file handle as 'closed' */ 193 luaL_setmetatable(L, LUA_FILEHANDLE); 194 return p; 195 } 196 197 198 /* 199 ** Calls the 'close' function from a file handle. The 'volatile' avoids 200 ** a bug in some versions of the Clang compiler (e.g., clang 3.0 for 201 ** 32 bits). 202 */ 203 static int aux_close (lua_State *L) { 204 LStream *p = tolstream(L); 205 volatile lua_CFunction cf = p->closef; 206 p->closef = NULL; /* mark stream as closed */ 207 return (*cf)(L); /* close it */ 208 } 209 210 211 static int io_close (lua_State *L) { 212 if (lua_isnone(L, 1)) /* no argument? */ 213 lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT); /* use standard output */ 214 tofile(L); /* make sure argument is an open stream */ 215 return aux_close(L); 216 } 217 218 219 static int f_gc (lua_State *L) { 220 LStream *p = tolstream(L); 221 if (!isclosed(p) && p->f != NULL) 222 aux_close(L); /* ignore closed and incompletely open files */ 223 return 0; 224 } 225 226 227 /* 228 ** function to close regular files 229 */ 230 static int io_fclose (lua_State *L) { 231 LStream *p = tolstream(L); 232 int res = fclose(p->f); 233 return luaL_fileresult(L, (res == 0), NULL); 234 } 235 236 237 static LStream *newfile (lua_State *L) { 238 LStream *p = newprefile(L); 239 p->f = NULL; 240 p->closef = &io_fclose; 241 return p; 242 } 243 244 245 static void opencheck (lua_State *L, const char *fname, const char *mode) { 246 LStream *p = newfile(L); 247 p->f = fopen(fname, mode); 248 if (p->f == NULL) 249 luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno)); 250 } 251 252 253 static int io_open (lua_State *L) { 254 const char *filename = luaL_checkstring(L, 1); 255 const char *mode = luaL_optstring(L, 2, "r"); 256 LStream *p = newfile(L); 257 const char *md = mode; /* to traverse/check mode */ 258 luaL_argcheck(L, l_checkmode(md), 2, "invalid mode"); 259 p->f = fopen(filename, mode); 260 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 261 } 262 263 264 /* 265 ** function to close 'popen' files 266 */ 267 static int io_pclose (lua_State *L) { 268 LStream *p = tolstream(L); 269 return luaL_execresult(L, l_pclose(L, p->f)); 270 } 271 272 273 static int io_popen (lua_State *L) { 274 const char *filename = luaL_checkstring(L, 1); 275 const char *mode = luaL_optstring(L, 2, "r"); 276 LStream *p = newprefile(L); 277 p->f = l_popen(L, filename, mode); 278 p->closef = &io_pclose; 279 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 280 } 281 282 283 static int io_tmpfile (lua_State *L) { 284 LStream *p = newfile(L); 285 p->f = tmpfile(); 286 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1; 287 } 288 289 290 static FILE *getiofile (lua_State *L, const char *findex) { 291 LStream *p; 292 lua_getfield(L, LUA_REGISTRYINDEX, findex); 293 p = (LStream *)lua_touserdata(L, -1); 294 if (isclosed(p)) 295 luaL_error(L, "standard %s file is closed", findex + IOPREF_LEN); 296 return p->f; 297 } 298 299 300 static int g_iofile (lua_State *L, const char *f, const char *mode) { 301 if (!lua_isnoneornil(L, 1)) { 302 const char *filename = lua_tostring(L, 1); 303 if (filename) 304 opencheck(L, filename, mode); 305 else { 306 tofile(L); /* check that it's a valid file handle */ 307 lua_pushvalue(L, 1); 308 } 309 lua_setfield(L, LUA_REGISTRYINDEX, f); 310 } 311 /* return current value */ 312 lua_getfield(L, LUA_REGISTRYINDEX, f); 313 return 1; 314 } 315 316 317 static int io_input (lua_State *L) { 318 return g_iofile(L, IO_INPUT, "r"); 319 } 320 321 322 static int io_output (lua_State *L) { 323 return g_iofile(L, IO_OUTPUT, "w"); 324 } 325 326 327 static int io_readline (lua_State *L); 328 329 330 /* 331 ** maximum number of arguments to 'f:lines'/'io.lines' (it + 3 must fit 332 ** in the limit for upvalues of a closure) 333 */ 334 #define MAXARGLINE 250 335 336 static void aux_lines (lua_State *L, int toclose) { 337 int n = lua_gettop(L) - 1; /* number of arguments to read */ 338 luaL_argcheck(L, n <= MAXARGLINE, MAXARGLINE + 2, "too many arguments"); 339 lua_pushinteger(L, n); /* number of arguments to read */ 340 lua_pushboolean(L, toclose); /* close/not close file when finished */ 341 lua_rotate(L, 2, 2); /* move 'n' and 'toclose' to their positions */ 342 lua_pushcclosure(L, io_readline, 3 + n); 343 } 344 345 346 static int f_lines (lua_State *L) { 347 tofile(L); /* check that it's a valid file handle */ 348 aux_lines(L, 0); 349 return 1; 350 } 351 352 353 static int io_lines (lua_State *L) { 354 int toclose; 355 if (lua_isnone(L, 1)) lua_pushnil(L); /* at least one argument */ 356 if (lua_isnil(L, 1)) { /* no file name? */ 357 lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT); /* get default input */ 358 lua_replace(L, 1); /* put it at index 1 */ 359 tofile(L); /* check that it's a valid file handle */ 360 toclose = 0; /* do not close it after iteration */ 361 } 362 else { /* open a new file */ 363 const char *filename = luaL_checkstring(L, 1); 364 opencheck(L, filename, "r"); 365 lua_replace(L, 1); /* put file at index 1 */ 366 toclose = 1; /* close it after iteration */ 367 } 368 aux_lines(L, toclose); 369 return 1; 370 } 371 372 373 /* 374 ** {====================================================== 375 ** READ 376 ** ======================================================= 377 */ 378 379 380 /* maximum length of a numeral */ 381 #if !defined (L_MAXLENNUM) 382 #define L_MAXLENNUM 200 383 #endif 384 385 386 /* auxiliary structure used by 'read_number' */ 387 typedef struct { 388 FILE *f; /* file being read */ 389 int c; /* current character (look ahead) */ 390 int n; /* number of elements in buffer 'buff' */ 391 char buff[L_MAXLENNUM + 1]; /* +1 for ending '\0' */ 392 } RN; 393 394 395 /* 396 ** Add current char to buffer (if not out of space) and read next one 397 */ 398 static int nextc (RN *rn) { 399 if (rn->n >= L_MAXLENNUM) { /* buffer overflow? */ 400 rn->buff[0] = '\0'; /* invalidate result */ 401 return 0; /* fail */ 402 } 403 else { 404 rn->buff[rn->n++] = rn->c; /* save current char */ 405 rn->c = l_getc(rn->f); /* read next one */ 406 return 1; 407 } 408 } 409 410 411 /* 412 ** Accept current char if it is in 'set' (of size 2) 413 */ 414 static int test2 (RN *rn, const char *set) { 415 if (rn->c == set[0] || rn->c == set[1]) 416 return nextc(rn); 417 else return 0; 418 } 419 420 421 /* 422 ** Read a sequence of (hex)digits 423 */ 424 static int readdigits (RN *rn, int hex) { 425 int count = 0; 426 while ((hex ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn)) 427 count++; 428 return count; 429 } 430 431 432 /* 433 ** Read a number: first reads a valid prefix of a numeral into a buffer. 434 ** Then it calls 'lua_stringtonumber' to check whether the format is 435 ** correct and to convert it to a Lua number 436 */ 437 static int read_number (lua_State *L, FILE *f) { 438 RN rn; 439 int count = 0; 440 int hex = 0; 441 char decp[2]; 442 rn.f = f; rn.n = 0; 443 decp[0] = lua_getlocaledecpoint(); /* get decimal point from locale */ 444 decp[1] = '.'; /* always accept a dot */ 445 l_lockfile(rn.f); 446 do { rn.c = l_getc(rn.f); } while (isspace(rn.c)); /* skip spaces */ 447 test2(&rn, "-+"); /* optional signal */ 448 if (test2(&rn, "00")) { 449 if (test2(&rn, "xX")) hex = 1; /* numeral is hexadecimal */ 450 else count = 1; /* count initial '0' as a valid digit */ 451 } 452 count += readdigits(&rn, hex); /* integral part */ 453 if (test2(&rn, decp)) /* decimal point? */ 454 count += readdigits(&rn, hex); /* fractional part */ 455 if (count > 0 && test2(&rn, (hex ? "pP" : "eE"))) { /* exponent mark? */ 456 test2(&rn, "-+"); /* exponent signal */ 457 readdigits(&rn, 0); /* exponent digits */ 458 } 459 ungetc(rn.c, rn.f); /* unread look-ahead char */ 460 l_unlockfile(rn.f); 461 rn.buff[rn.n] = '\0'; /* finish string */ 462 if (lua_stringtonumber(L, rn.buff)) /* is this a valid number? */ 463 return 1; /* ok */ 464 else { /* invalid format */ 465 lua_pushnil(L); /* "result" to be removed */ 466 return 0; /* read fails */ 467 } 468 } 469 470 471 static int test_eof (lua_State *L, FILE *f) { 472 int c = getc(f); 473 ungetc(c, f); /* no-op when c == EOF */ 474 lua_pushliteral(L, ""); 475 return (c != EOF); 476 } 477 478 479 static int read_line (lua_State *L, FILE *f, int chop) { 480 luaL_Buffer b; 481 int c = '\0'; 482 luaL_buffinit(L, &b); 483 while (c != EOF && c != '\n') { /* repeat until end of line */ 484 char *buff = luaL_prepbuffer(&b); /* preallocate buffer */ 485 int i = 0; 486 l_lockfile(f); /* no memory errors can happen inside the lock */ 487 while (i < LUAL_BUFFERSIZE && (c = l_getc(f)) != EOF && c != '\n') 488 buff[i++] = c; 489 l_unlockfile(f); 490 luaL_addsize(&b, i); 491 } 492 if (!chop && c == '\n') /* want a newline and have one? */ 493 luaL_addchar(&b, c); /* add ending newline to result */ 494 luaL_pushresult(&b); /* close buffer */ 495 /* return ok if read something (either a newline or something else) */ 496 return (c == '\n' || lua_rawlen(L, -1) > 0); 497 } 498 499 500 static void read_all (lua_State *L, FILE *f) { 501 size_t nr; 502 luaL_Buffer b; 503 luaL_buffinit(L, &b); 504 do { /* read file in chunks of LUAL_BUFFERSIZE bytes */ 505 char *p = luaL_prepbuffer(&b); 506 nr = fread(p, sizeof(char), LUAL_BUFFERSIZE, f); 507 luaL_addsize(&b, nr); 508 } while (nr == LUAL_BUFFERSIZE); 509 luaL_pushresult(&b); /* close buffer */ 510 } 511 512 513 static int read_chars (lua_State *L, FILE *f, size_t n) { 514 size_t nr; /* number of chars actually read */ 515 char *p; 516 luaL_Buffer b; 517 luaL_buffinit(L, &b); 518 p = luaL_prepbuffsize(&b, n); /* prepare buffer to read whole block */ 519 nr = fread(p, sizeof(char), n, f); /* try to read 'n' chars */ 520 luaL_addsize(&b, nr); 521 luaL_pushresult(&b); /* close buffer */ 522 return (nr > 0); /* true iff read something */ 523 } 524 525 526 static int g_read (lua_State *L, FILE *f, int first) { 527 int nargs = lua_gettop(L) - 1; 528 int success; 529 int n; 530 clearerr(f); 531 if (nargs == 0) { /* no arguments? */ 532 success = read_line(L, f, 1); 533 n = first+1; /* to return 1 result */ 534 } 535 else { /* ensure stack space for all results and for auxlib's buffer */ 536 luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments"); 537 success = 1; 538 for (n = first; nargs-- && success; n++) { 539 if (lua_type(L, n) == LUA_TNUMBER) { 540 size_t l = (size_t)luaL_checkinteger(L, n); 541 success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l); 542 } 543 else { 544 const char *p = luaL_checkstring(L, n); 545 if (*p == '*') p++; /* skip optional '*' (for compatibility) */ 546 switch (*p) { 547 case 'n': /* number */ 548 success = read_number(L, f); 549 break; 550 case 'l': /* line */ 551 success = read_line(L, f, 1); 552 break; 553 case 'L': /* line with end-of-line */ 554 success = read_line(L, f, 0); 555 break; 556 case 'a': /* file */ 557 read_all(L, f); /* read entire file */ 558 success = 1; /* always success */ 559 break; 560 default: 561 return luaL_argerror(L, n, "invalid format"); 562 } 563 } 564 } 565 } 566 if (ferror(f)) 567 return luaL_fileresult(L, 0, NULL); 568 if (!success) { 569 lua_pop(L, 1); /* remove last result */ 570 lua_pushnil(L); /* push nil instead */ 571 } 572 return n - first; 573 } 574 575 576 static int io_read (lua_State *L) { 577 return g_read(L, getiofile(L, IO_INPUT), 1); 578 } 579 580 581 static int f_read (lua_State *L) { 582 return g_read(L, tofile(L), 2); 583 } 584 585 586 static int io_readline (lua_State *L) { 587 LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1)); 588 int i; 589 int n = (int)lua_tointeger(L, lua_upvalueindex(2)); 590 if (isclosed(p)) /* file is already closed? */ 591 return luaL_error(L, "file is already closed"); 592 lua_settop(L , 1); 593 luaL_checkstack(L, n, "too many arguments"); 594 for (i = 1; i <= n; i++) /* push arguments to 'g_read' */ 595 lua_pushvalue(L, lua_upvalueindex(3 + i)); 596 n = g_read(L, p->f, 2); /* 'n' is number of results */ 597 lua_assert(n > 0); /* should return at least a nil */ 598 if (lua_toboolean(L, -n)) /* read at least one value? */ 599 return n; /* return them */ 600 else { /* first result is nil: EOF or error */ 601 if (n > 1) { /* is there error information? */ 602 /* 2nd result is error message */ 603 return luaL_error(L, "%s", lua_tostring(L, -n + 1)); 604 } 605 if (lua_toboolean(L, lua_upvalueindex(3))) { /* generator created file? */ 606 lua_settop(L, 0); 607 lua_pushvalue(L, lua_upvalueindex(1)); 608 aux_close(L); /* close it */ 609 } 610 return 0; 611 } 612 } 613 614 /* }====================================================== */ 615 616 617 static int g_write (lua_State *L, FILE *f, int arg) { 618 int nargs = lua_gettop(L) - arg; 619 int status = 1; 620 for (; nargs--; arg++) { 621 if (lua_type(L, arg) == LUA_TNUMBER) { 622 /* optimization: could be done exactly as for strings */ 623 int len = lua_isinteger(L, arg) 624 ? fprintf(f, LUA_INTEGER_FMT, 625 (LUAI_UACINT)lua_tointeger(L, arg)) 626 : fprintf(f, LUA_NUMBER_FMT, 627 (LUAI_UACNUMBER)lua_tonumber(L, arg)); 628 status = status && (len > 0); 629 } 630 else { 631 size_t l; 632 const char *s = luaL_checklstring(L, arg, &l); 633 status = status && (fwrite(s, sizeof(char), l, f) == l); 634 } 635 } 636 if (status) return 1; /* file handle already on stack top */ 637 else return luaL_fileresult(L, status, NULL); 638 } 639 640 641 static int io_write (lua_State *L) { 642 return g_write(L, getiofile(L, IO_OUTPUT), 1); 643 } 644 645 646 static int f_write (lua_State *L) { 647 FILE *f = tofile(L); 648 lua_pushvalue(L, 1); /* push file at the stack top (to be returned) */ 649 return g_write(L, f, 2); 650 } 651 652 653 static int f_seek (lua_State *L) { 654 static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END}; 655 static const char *const modenames[] = {"set", "cur", "end", NULL}; 656 FILE *f = tofile(L); 657 int op = luaL_checkoption(L, 2, "cur", modenames); 658 lua_Integer p3 = luaL_optinteger(L, 3, 0); 659 l_seeknum offset = (l_seeknum)p3; 660 luaL_argcheck(L, (lua_Integer)offset == p3, 3, 661 "not an integer in proper range"); 662 op = l_fseek(f, offset, mode[op]); 663 if (op) 664 return luaL_fileresult(L, 0, NULL); /* error */ 665 else { 666 lua_pushinteger(L, (lua_Integer)l_ftell(f)); 667 return 1; 668 } 669 } 670 671 672 static int f_setvbuf (lua_State *L) { 673 static const int mode[] = {_IONBF, _IOFBF, _IOLBF}; 674 static const char *const modenames[] = {"no", "full", "line", NULL}; 675 FILE *f = tofile(L); 676 int op = luaL_checkoption(L, 2, NULL, modenames); 677 lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE); 678 int res = setvbuf(f, NULL, mode[op], (size_t)sz); 679 return luaL_fileresult(L, res == 0, NULL); 680 } 681 682 683 684 static int io_flush (lua_State *L) { 685 return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL); 686 } 687 688 689 static int f_flush (lua_State *L) { 690 return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL); 691 } 692 693 694 /* 695 ** functions for 'io' library 696 */ 697 static const luaL_Reg iolib[] = { 698 {"close", io_close}, 699 {"flush", io_flush}, 700 {"input", io_input}, 701 {"lines", io_lines}, 702 {"open", io_open}, 703 {"output", io_output}, 704 {"popen", io_popen}, 705 {"read", io_read}, 706 {"tmpfile", io_tmpfile}, 707 {"type", io_type}, 708 {"write", io_write}, 709 {NULL, NULL} 710 }; 711 712 713 /* 714 ** methods for file handles 715 */ 716 static const luaL_Reg flib[] = { 717 {"close", io_close}, 718 {"flush", f_flush}, 719 {"lines", f_lines}, 720 {"read", f_read}, 721 {"seek", f_seek}, 722 {"setvbuf", f_setvbuf}, 723 {"write", f_write}, 724 {"__gc", f_gc}, 725 {"__tostring", f_tostring}, 726 {NULL, NULL} 727 }; 728 729 730 static void createmeta (lua_State *L) { 731 luaL_newmetatable(L, LUA_FILEHANDLE); /* create metatable for file handles */ 732 lua_pushvalue(L, -1); /* push metatable */ 733 lua_setfield(L, -2, "__index"); /* metatable.__index = metatable */ 734 luaL_setfuncs(L, flib, 0); /* add file methods to new metatable */ 735 lua_pop(L, 1); /* pop new metatable */ 736 } 737 738 739 /* 740 ** function to (not) close the standard files stdin, stdout, and stderr 741 */ 742 static int io_noclose (lua_State *L) { 743 LStream *p = tolstream(L); 744 p->closef = &io_noclose; /* keep file opened */ 745 lua_pushnil(L); 746 lua_pushliteral(L, "cannot close standard file"); 747 return 2; 748 } 749 750 751 static void createstdfile (lua_State *L, FILE *f, const char *k, 752 const char *fname) { 753 LStream *p = newprefile(L); 754 p->f = f; 755 p->closef = &io_noclose; 756 if (k != NULL) { 757 lua_pushvalue(L, -1); 758 lua_setfield(L, LUA_REGISTRYINDEX, k); /* add file to registry */ 759 } 760 lua_setfield(L, -2, fname); /* add file to module */ 761 } 762 763 764 LUAMOD_API int luaopen_io (lua_State *L) { 765 luaL_newlib(L, iolib); /* new module */ 766 createmeta(L); 767 /* create (and set) default files */ 768 createstdfile(L, stdin, IO_INPUT, "stdin"); 769 createstdfile(L, stdout, IO_OUTPUT, "stdout"); 770 createstdfile(L, stderr, NULL, "stderr"); 771 return 1; 772 } 773 774