liolib.c (20403B)
1 /* 2 ** $Id: liolib.c,v 2.151.1.1 2017/04/19 17:29:57 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 f_close (lua_State *L) { 210 tofile(L); /* make sure argument is an open stream */ 211 return aux_close(L); 212 } 213 214 215 static int io_close (lua_State *L) { 216 if (lua_isnone(L, 1)) /* no argument? */ 217 lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT); /* use standard output */ 218 return f_close(L); 219 } 220 221 222 static int f_gc (lua_State *L) { 223 LStream *p = tolstream(L); 224 if (!isclosed(p) && p->f != NULL) 225 aux_close(L); /* ignore closed and incompletely open files */ 226 return 0; 227 } 228 229 230 /* 231 ** function to close regular files 232 */ 233 static int io_fclose (lua_State *L) { 234 LStream *p = tolstream(L); 235 int res = fclose(p->f); 236 return luaL_fileresult(L, (res == 0), NULL); 237 } 238 239 240 static LStream *newfile (lua_State *L) { 241 LStream *p = newprefile(L); 242 p->f = NULL; 243 p->closef = &io_fclose; 244 return p; 245 } 246 247 248 static void opencheck (lua_State *L, const char *fname, const char *mode) { 249 LStream *p = newfile(L); 250 p->f = fopen(fname, mode); 251 if (p->f == NULL) 252 luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno)); 253 } 254 255 256 static int io_open (lua_State *L) { 257 const char *filename = luaL_checkstring(L, 1); 258 const char *mode = luaL_optstring(L, 2, "r"); 259 LStream *p = newfile(L); 260 const char *md = mode; /* to traverse/check mode */ 261 luaL_argcheck(L, l_checkmode(md), 2, "invalid mode"); 262 p->f = fopen(filename, mode); 263 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 264 } 265 266 267 /* 268 ** function to close 'popen' files 269 */ 270 static int io_pclose (lua_State *L) { 271 LStream *p = tolstream(L); 272 return luaL_execresult(L, l_pclose(L, p->f)); 273 } 274 275 276 static int io_popen (lua_State *L) { 277 const char *filename = luaL_checkstring(L, 1); 278 const char *mode = luaL_optstring(L, 2, "r"); 279 LStream *p = newprefile(L); 280 luaL_argcheck(L, ((mode[0] == 'r' || mode[0] == 'w') && mode[1] == '\0'), 281 2, "invalid mode"); 282 p->f = l_popen(L, filename, mode); 283 p->closef = &io_pclose; 284 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 285 } 286 287 288 static int io_tmpfile (lua_State *L) { 289 LStream *p = newfile(L); 290 p->f = tmpfile(); 291 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1; 292 } 293 294 295 static FILE *getiofile (lua_State *L, const char *findex) { 296 LStream *p; 297 lua_getfield(L, LUA_REGISTRYINDEX, findex); 298 p = (LStream *)lua_touserdata(L, -1); 299 if (isclosed(p)) 300 luaL_error(L, "standard %s file is closed", findex + IOPREF_LEN); 301 return p->f; 302 } 303 304 305 static int g_iofile (lua_State *L, const char *f, const char *mode) { 306 if (!lua_isnoneornil(L, 1)) { 307 const char *filename = lua_tostring(L, 1); 308 if (filename) 309 opencheck(L, filename, mode); 310 else { 311 tofile(L); /* check that it's a valid file handle */ 312 lua_pushvalue(L, 1); 313 } 314 lua_setfield(L, LUA_REGISTRYINDEX, f); 315 } 316 /* return current value */ 317 lua_getfield(L, LUA_REGISTRYINDEX, f); 318 return 1; 319 } 320 321 322 static int io_input (lua_State *L) { 323 return g_iofile(L, IO_INPUT, "r"); 324 } 325 326 327 static int io_output (lua_State *L) { 328 return g_iofile(L, IO_OUTPUT, "w"); 329 } 330 331 332 static int io_readline (lua_State *L); 333 334 335 /* 336 ** maximum number of arguments to 'f:lines'/'io.lines' (it + 3 must fit 337 ** in the limit for upvalues of a closure) 338 */ 339 #define MAXARGLINE 250 340 341 static void aux_lines (lua_State *L, int toclose) { 342 int n = lua_gettop(L) - 1; /* number of arguments to read */ 343 luaL_argcheck(L, n <= MAXARGLINE, MAXARGLINE + 2, "too many arguments"); 344 lua_pushinteger(L, n); /* number of arguments to read */ 345 lua_pushboolean(L, toclose); /* close/not close file when finished */ 346 lua_rotate(L, 2, 2); /* move 'n' and 'toclose' to their positions */ 347 lua_pushcclosure(L, io_readline, 3 + n); 348 } 349 350 351 static int f_lines (lua_State *L) { 352 tofile(L); /* check that it's a valid file handle */ 353 aux_lines(L, 0); 354 return 1; 355 } 356 357 358 static int io_lines (lua_State *L) { 359 int toclose; 360 if (lua_isnone(L, 1)) lua_pushnil(L); /* at least one argument */ 361 if (lua_isnil(L, 1)) { /* no file name? */ 362 lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT); /* get default input */ 363 lua_replace(L, 1); /* put it at index 1 */ 364 tofile(L); /* check that it's a valid file handle */ 365 toclose = 0; /* do not close it after iteration */ 366 } 367 else { /* open a new file */ 368 const char *filename = luaL_checkstring(L, 1); 369 opencheck(L, filename, "r"); 370 lua_replace(L, 1); /* put file at index 1 */ 371 toclose = 1; /* close it after iteration */ 372 } 373 aux_lines(L, toclose); 374 return 1; 375 } 376 377 378 /* 379 ** {====================================================== 380 ** READ 381 ** ======================================================= 382 */ 383 384 385 /* maximum length of a numeral */ 386 #if !defined (L_MAXLENNUM) 387 #define L_MAXLENNUM 200 388 #endif 389 390 391 /* auxiliary structure used by 'read_number' */ 392 typedef struct { 393 FILE *f; /* file being read */ 394 int c; /* current character (look ahead) */ 395 int n; /* number of elements in buffer 'buff' */ 396 char buff[L_MAXLENNUM + 1]; /* +1 for ending '\0' */ 397 } RN; 398 399 400 /* 401 ** Add current char to buffer (if not out of space) and read next one 402 */ 403 static int nextc (RN *rn) { 404 if (rn->n >= L_MAXLENNUM) { /* buffer overflow? */ 405 rn->buff[0] = '\0'; /* invalidate result */ 406 return 0; /* fail */ 407 } 408 else { 409 rn->buff[rn->n++] = rn->c; /* save current char */ 410 rn->c = l_getc(rn->f); /* read next one */ 411 return 1; 412 } 413 } 414 415 416 /* 417 ** Accept current char if it is in 'set' (of size 2) 418 */ 419 static int test2 (RN *rn, const char *set) { 420 if (rn->c == set[0] || rn->c == set[1]) 421 return nextc(rn); 422 else return 0; 423 } 424 425 426 /* 427 ** Read a sequence of (hex)digits 428 */ 429 static int readdigits (RN *rn, int hex) { 430 int count = 0; 431 while ((hex ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn)) 432 count++; 433 return count; 434 } 435 436 437 /* 438 ** Read a number: first reads a valid prefix of a numeral into a buffer. 439 ** Then it calls 'lua_stringtonumber' to check whether the format is 440 ** correct and to convert it to a Lua number 441 */ 442 static int read_number (lua_State *L, FILE *f) { 443 RN rn; 444 int count = 0; 445 int hex = 0; 446 char decp[2]; 447 rn.f = f; rn.n = 0; 448 decp[0] = lua_getlocaledecpoint(); /* get decimal point from locale */ 449 decp[1] = '.'; /* always accept a dot */ 450 l_lockfile(rn.f); 451 do { rn.c = l_getc(rn.f); } while (isspace(rn.c)); /* skip spaces */ 452 test2(&rn, "-+"); /* optional signal */ 453 if (test2(&rn, "00")) { 454 if (test2(&rn, "xX")) hex = 1; /* numeral is hexadecimal */ 455 else count = 1; /* count initial '0' as a valid digit */ 456 } 457 count += readdigits(&rn, hex); /* integral part */ 458 if (test2(&rn, decp)) /* decimal point? */ 459 count += readdigits(&rn, hex); /* fractional part */ 460 if (count > 0 && test2(&rn, (hex ? "pP" : "eE"))) { /* exponent mark? */ 461 test2(&rn, "-+"); /* exponent signal */ 462 readdigits(&rn, 0); /* exponent digits */ 463 } 464 ungetc(rn.c, rn.f); /* unread look-ahead char */ 465 l_unlockfile(rn.f); 466 rn.buff[rn.n] = '\0'; /* finish string */ 467 if (lua_stringtonumber(L, rn.buff)) /* is this a valid number? */ 468 return 1; /* ok */ 469 else { /* invalid format */ 470 lua_pushnil(L); /* "result" to be removed */ 471 return 0; /* read fails */ 472 } 473 } 474 475 476 static int test_eof (lua_State *L, FILE *f) { 477 int c = getc(f); 478 ungetc(c, f); /* no-op when c == EOF */ 479 lua_pushliteral(L, ""); 480 return (c != EOF); 481 } 482 483 484 static int read_line (lua_State *L, FILE *f, int chop) { 485 luaL_Buffer b; 486 int c = '\0'; 487 luaL_buffinit(L, &b); 488 while (c != EOF && c != '\n') { /* repeat until end of line */ 489 char *buff = luaL_prepbuffer(&b); /* preallocate buffer */ 490 int i = 0; 491 l_lockfile(f); /* no memory errors can happen inside the lock */ 492 while (i < LUAL_BUFFERSIZE && (c = l_getc(f)) != EOF && c != '\n') 493 buff[i++] = c; 494 l_unlockfile(f); 495 luaL_addsize(&b, i); 496 } 497 if (!chop && c == '\n') /* want a newline and have one? */ 498 luaL_addchar(&b, c); /* add ending newline to result */ 499 luaL_pushresult(&b); /* close buffer */ 500 /* return ok if read something (either a newline or something else) */ 501 return (c == '\n' || lua_rawlen(L, -1) > 0); 502 } 503 504 505 static void read_all (lua_State *L, FILE *f) { 506 size_t nr; 507 luaL_Buffer b; 508 luaL_buffinit(L, &b); 509 do { /* read file in chunks of LUAL_BUFFERSIZE bytes */ 510 char *p = luaL_prepbuffer(&b); 511 nr = fread(p, sizeof(char), LUAL_BUFFERSIZE, f); 512 luaL_addsize(&b, nr); 513 } while (nr == LUAL_BUFFERSIZE); 514 luaL_pushresult(&b); /* close buffer */ 515 } 516 517 518 static int read_chars (lua_State *L, FILE *f, size_t n) { 519 size_t nr; /* number of chars actually read */ 520 char *p; 521 luaL_Buffer b; 522 luaL_buffinit(L, &b); 523 p = luaL_prepbuffsize(&b, n); /* prepare buffer to read whole block */ 524 nr = fread(p, sizeof(char), n, f); /* try to read 'n' chars */ 525 luaL_addsize(&b, nr); 526 luaL_pushresult(&b); /* close buffer */ 527 return (nr > 0); /* true iff read something */ 528 } 529 530 531 static int g_read (lua_State *L, FILE *f, int first) { 532 int nargs = lua_gettop(L) - 1; 533 int success; 534 int n; 535 clearerr(f); 536 if (nargs == 0) { /* no arguments? */ 537 success = read_line(L, f, 1); 538 n = first+1; /* to return 1 result */ 539 } 540 else { /* ensure stack space for all results and for auxlib's buffer */ 541 luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments"); 542 success = 1; 543 for (n = first; nargs-- && success; n++) { 544 if (lua_type(L, n) == LUA_TNUMBER) { 545 size_t l = (size_t)luaL_checkinteger(L, n); 546 success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l); 547 } 548 else { 549 const char *p = luaL_checkstring(L, n); 550 if (*p == '*') p++; /* skip optional '*' (for compatibility) */ 551 switch (*p) { 552 case 'n': /* number */ 553 success = read_number(L, f); 554 break; 555 case 'l': /* line */ 556 success = read_line(L, f, 1); 557 break; 558 case 'L': /* line with end-of-line */ 559 success = read_line(L, f, 0); 560 break; 561 case 'a': /* file */ 562 read_all(L, f); /* read entire file */ 563 success = 1; /* always success */ 564 break; 565 default: 566 return luaL_argerror(L, n, "invalid format"); 567 } 568 } 569 } 570 } 571 if (ferror(f)) 572 return luaL_fileresult(L, 0, NULL); 573 if (!success) { 574 lua_pop(L, 1); /* remove last result */ 575 lua_pushnil(L); /* push nil instead */ 576 } 577 return n - first; 578 } 579 580 581 static int io_read (lua_State *L) { 582 return g_read(L, getiofile(L, IO_INPUT), 1); 583 } 584 585 586 static int f_read (lua_State *L) { 587 return g_read(L, tofile(L), 2); 588 } 589 590 591 static int io_readline (lua_State *L) { 592 LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1)); 593 int i; 594 int n = (int)lua_tointeger(L, lua_upvalueindex(2)); 595 if (isclosed(p)) /* file is already closed? */ 596 return luaL_error(L, "file is already closed"); 597 lua_settop(L , 1); 598 luaL_checkstack(L, n, "too many arguments"); 599 for (i = 1; i <= n; i++) /* push arguments to 'g_read' */ 600 lua_pushvalue(L, lua_upvalueindex(3 + i)); 601 n = g_read(L, p->f, 2); /* 'n' is number of results */ 602 lua_assert(n > 0); /* should return at least a nil */ 603 if (lua_toboolean(L, -n)) /* read at least one value? */ 604 return n; /* return them */ 605 else { /* first result is nil: EOF or error */ 606 if (n > 1) { /* is there error information? */ 607 /* 2nd result is error message */ 608 return luaL_error(L, "%s", lua_tostring(L, -n + 1)); 609 } 610 if (lua_toboolean(L, lua_upvalueindex(3))) { /* generator created file? */ 611 lua_settop(L, 0); 612 lua_pushvalue(L, lua_upvalueindex(1)); 613 aux_close(L); /* close it */ 614 } 615 return 0; 616 } 617 } 618 619 /* }====================================================== */ 620 621 622 static int g_write (lua_State *L, FILE *f, int arg) { 623 int nargs = lua_gettop(L) - arg; 624 int status = 1; 625 for (; nargs--; arg++) { 626 if (lua_type(L, arg) == LUA_TNUMBER) { 627 /* optimization: could be done exactly as for strings */ 628 int len = lua_isinteger(L, arg) 629 ? fprintf(f, LUA_INTEGER_FMT, 630 (LUAI_UACINT)lua_tointeger(L, arg)) 631 : fprintf(f, LUA_NUMBER_FMT, 632 (LUAI_UACNUMBER)lua_tonumber(L, arg)); 633 status = status && (len > 0); 634 } 635 else { 636 size_t l; 637 const char *s = luaL_checklstring(L, arg, &l); 638 status = status && (fwrite(s, sizeof(char), l, f) == l); 639 } 640 } 641 if (status) return 1; /* file handle already on stack top */ 642 else return luaL_fileresult(L, status, NULL); 643 } 644 645 646 static int io_write (lua_State *L) { 647 return g_write(L, getiofile(L, IO_OUTPUT), 1); 648 } 649 650 651 static int f_write (lua_State *L) { 652 FILE *f = tofile(L); 653 lua_pushvalue(L, 1); /* push file at the stack top (to be returned) */ 654 return g_write(L, f, 2); 655 } 656 657 658 static int f_seek (lua_State *L) { 659 static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END}; 660 static const char *const modenames[] = {"set", "cur", "end", NULL}; 661 FILE *f = tofile(L); 662 int op = luaL_checkoption(L, 2, "cur", modenames); 663 lua_Integer p3 = luaL_optinteger(L, 3, 0); 664 l_seeknum offset = (l_seeknum)p3; 665 luaL_argcheck(L, (lua_Integer)offset == p3, 3, 666 "not an integer in proper range"); 667 op = l_fseek(f, offset, mode[op]); 668 if (op) 669 return luaL_fileresult(L, 0, NULL); /* error */ 670 else { 671 lua_pushinteger(L, (lua_Integer)l_ftell(f)); 672 return 1; 673 } 674 } 675 676 677 static int f_setvbuf (lua_State *L) { 678 static const int mode[] = {_IONBF, _IOFBF, _IOLBF}; 679 static const char *const modenames[] = {"no", "full", "line", NULL}; 680 FILE *f = tofile(L); 681 int op = luaL_checkoption(L, 2, NULL, modenames); 682 lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE); 683 int res = setvbuf(f, NULL, mode[op], (size_t)sz); 684 return luaL_fileresult(L, res == 0, NULL); 685 } 686 687 688 689 static int io_flush (lua_State *L) { 690 return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL); 691 } 692 693 694 static int f_flush (lua_State *L) { 695 return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL); 696 } 697 698 699 /* 700 ** functions for 'io' library 701 */ 702 static const luaL_Reg iolib[] = { 703 {"close", io_close}, 704 {"flush", io_flush}, 705 {"input", io_input}, 706 {"lines", io_lines}, 707 {"open", io_open}, 708 {"output", io_output}, 709 {"popen", io_popen}, 710 {"read", io_read}, 711 {"tmpfile", io_tmpfile}, 712 {"type", io_type}, 713 {"write", io_write}, 714 {NULL, NULL} 715 }; 716 717 718 /* 719 ** methods for file handles 720 */ 721 static const luaL_Reg flib[] = { 722 {"close", f_close}, 723 {"flush", f_flush}, 724 {"lines", f_lines}, 725 {"read", f_read}, 726 {"seek", f_seek}, 727 {"setvbuf", f_setvbuf}, 728 {"write", f_write}, 729 {"__gc", f_gc}, 730 {"__tostring", f_tostring}, 731 {NULL, NULL} 732 }; 733 734 735 static void createmeta (lua_State *L) { 736 luaL_newmetatable(L, LUA_FILEHANDLE); /* create metatable for file handles */ 737 lua_pushvalue(L, -1); /* push metatable */ 738 lua_setfield(L, -2, "__index"); /* metatable.__index = metatable */ 739 luaL_setfuncs(L, flib, 0); /* add file methods to new metatable */ 740 lua_pop(L, 1); /* pop new metatable */ 741 } 742 743 744 /* 745 ** function to (not) close the standard files stdin, stdout, and stderr 746 */ 747 static int io_noclose (lua_State *L) { 748 LStream *p = tolstream(L); 749 p->closef = &io_noclose; /* keep file opened */ 750 lua_pushnil(L); 751 lua_pushliteral(L, "cannot close standard file"); 752 return 2; 753 } 754 755 756 static void createstdfile (lua_State *L, FILE *f, const char *k, 757 const char *fname) { 758 LStream *p = newprefile(L); 759 p->f = f; 760 p->closef = &io_noclose; 761 if (k != NULL) { 762 lua_pushvalue(L, -1); 763 lua_setfield(L, LUA_REGISTRYINDEX, k); /* add file to registry */ 764 } 765 lua_setfield(L, -2, fname); /* add file to module */ 766 } 767 768 769 LUAMOD_API int luaopen_io (lua_State *L) { 770 luaL_newlib(L, iolib); /* new module */ 771 createmeta(L); 772 /* create (and set) default files */ 773 createstdfile(L, stdin, IO_INPUT, "stdin"); 774 createstdfile(L, stdout, IO_OUTPUT, "stdout"); 775 createstdfile(L, stderr, NULL, "stderr"); 776 return 1; 777 } 778