1 /* 2 ** $Id: liolib.c $ 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 != '+' || ((void)(++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_checkmodep) 56 /* By default, Lua accepts only "r" or "w" as mode */ 57 #define l_checkmodep(m) ((m[0] == 'r' || m[0] == 'w') && m[1] == '\0') 58 #endif 59 60 61 #if !defined(l_popen) /* { */ 62 63 #if defined(LUA_USE_POSIX) /* { */ 64 65 #define l_popen(L,c,m) (fflush(NULL), popen(c,m)) 66 #define l_pclose(L,file) (pclose(file)) 67 68 #elif defined(LUA_USE_WINDOWS) /* }{ */ 69 70 #define l_popen(L,c,m) (_popen(c,m)) 71 #define l_pclose(L,file) (_pclose(file)) 72 73 #else /* }{ */ 74 75 /* ISO C definitions */ 76 #define l_popen(L,c,m) \ 77 ((void)c, (void)m, \ 78 luaL_error(L, "'popen' not supported"), \ 79 (FILE*)0) 80 #define l_pclose(L,file) ((void)L, (void)file, -1) 81 82 #endif /* } */ 83 84 #endif /* } */ 85 86 /* }====================================================== */ 87 88 89 #if !defined(l_getc) /* { */ 90 91 #if defined(LUA_USE_POSIX) 92 #define l_getc(f) getc_unlocked(f) 93 #define l_lockfile(f) flockfile(f) 94 #define l_unlockfile(f) funlockfile(f) 95 #else 96 #define l_getc(f) getc(f) 97 #define l_lockfile(f) ((void)0) 98 #define l_unlockfile(f) ((void)0) 99 #endif 100 101 #endif /* } */ 102 103 104 /* 105 ** {====================================================== 106 ** l_fseek: configuration for longer offsets 107 ** ======================================================= 108 */ 109 110 #if !defined(l_fseek) /* { */ 111 112 #if defined(LUA_USE_POSIX) /* { */ 113 114 #include <sys/types.h> 115 116 #define l_fseek(f,o,w) fseeko(f,o,w) 117 #define l_ftell(f) ftello(f) 118 #define l_seeknum off_t 119 120 #elif defined(LUA_USE_WINDOWS) && !defined(_CRTIMP_TYPEINFO) \ 121 && defined(_MSC_VER) && (_MSC_VER >= 1400) /* }{ */ 122 123 /* Windows (but not DDK) and Visual C++ 2005 or higher */ 124 #define l_fseek(f,o,w) _fseeki64(f,o,w) 125 #define l_ftell(f) _ftelli64(f) 126 #define l_seeknum __int64 127 128 #else /* }{ */ 129 130 /* ISO C definitions */ 131 #define l_fseek(f,o,w) fseek(f,o,w) 132 #define l_ftell(f) ftell(f) 133 #define l_seeknum long 134 135 #endif /* } */ 136 137 #endif /* } */ 138 139 /* }====================================================== */ 140 141 142 143 #define IO_PREFIX "_IO_" 144 #define IOPREF_LEN (sizeof(IO_PREFIX)/sizeof(char) - 1) 145 #define IO_INPUT (IO_PREFIX "input") 146 #define IO_OUTPUT (IO_PREFIX "output") 147 148 149 typedef luaL_Stream LStream; 150 151 152 #define tolstream(L) ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE)) 153 154 #define isclosed(p) ((p)->closef == NULL) 155 156 157 static int io_type (lua_State *L) { 158 LStream *p; 159 luaL_checkany(L, 1); 160 p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE); 161 if (p == NULL) 162 luaL_pushfail(L); /* not a file */ 163 else if (isclosed(p)) 164 lua_pushliteral(L, "closed file"); 165 else 166 lua_pushliteral(L, "file"); 167 return 1; 168 } 169 170 171 static int f_tostring (lua_State *L) { 172 LStream *p = tolstream(L); 173 if (isclosed(p)) 174 lua_pushliteral(L, "file (closed)"); 175 else 176 lua_pushfstring(L, "file (%p)", p->f); 177 return 1; 178 } 179 180 181 static FILE *tofile (lua_State *L) { 182 LStream *p = tolstream(L); 183 if (isclosed(p)) 184 luaL_error(L, "attempt to use a closed file"); 185 lua_assert(p->f); 186 return p->f; 187 } 188 189 190 /* 191 ** When creating file handles, always creates a 'closed' file handle 192 ** before opening the actual file; so, if there is a memory error, the 193 ** handle is in a consistent state. 194 */ 195 static LStream *newprefile (lua_State *L) { 196 LStream *p = (LStream *)lua_newuserdatauv(L, sizeof(LStream), 0); 197 p->closef = NULL; /* mark file handle as 'closed' */ 198 luaL_setmetatable(L, LUA_FILEHANDLE); 199 return p; 200 } 201 202 203 /* 204 ** Calls the 'close' function from a file handle. The 'volatile' avoids 205 ** a bug in some versions of the Clang compiler (e.g., clang 3.0 for 206 ** 32 bits). 207 */ 208 static int aux_close (lua_State *L) { 209 LStream *p = tolstream(L); 210 volatile lua_CFunction cf = p->closef; 211 p->closef = NULL; /* mark stream as closed */ 212 return (*cf)(L); /* close it */ 213 } 214 215 216 static int f_close (lua_State *L) { 217 tofile(L); /* make sure argument is an open stream */ 218 return aux_close(L); 219 } 220 221 222 static int io_close (lua_State *L) { 223 if (lua_isnone(L, 1)) /* no argument? */ 224 lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT); /* use default output */ 225 return f_close(L); 226 } 227 228 229 static int f_gc (lua_State *L) { 230 LStream *p = tolstream(L); 231 if (!isclosed(p) && p->f != NULL) 232 aux_close(L); /* ignore closed and incompletely open files */ 233 return 0; 234 } 235 236 237 /* 238 ** function to close regular files 239 */ 240 static int io_fclose (lua_State *L) { 241 LStream *p = tolstream(L); 242 int res = fclose(p->f); 243 return luaL_fileresult(L, (res == 0), NULL); 244 } 245 246 247 static LStream *newfile (lua_State *L) { 248 LStream *p = newprefile(L); 249 p->f = NULL; 250 p->closef = &io_fclose; 251 return p; 252 } 253 254 255 static void opencheck (lua_State *L, const char *fname, const char *mode) { 256 LStream *p = newfile(L); 257 p->f = fopen(fname, mode); 258 if (p->f == NULL) 259 luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno)); 260 } 261 262 263 static int io_open (lua_State *L) { 264 const char *filename = luaL_checkstring(L, 1); 265 const char *mode = luaL_optstring(L, 2, "r"); 266 LStream *p = newfile(L); 267 const char *md = mode; /* to traverse/check mode */ 268 luaL_argcheck(L, l_checkmode(md), 2, "invalid mode"); 269 p->f = fopen(filename, mode); 270 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 271 } 272 273 274 /* 275 ** function to close 'popen' files 276 */ 277 static int io_pclose (lua_State *L) { 278 LStream *p = tolstream(L); 279 errno = 0; 280 return luaL_execresult(L, l_pclose(L, p->f)); 281 } 282 283 284 static int io_popen (lua_State *L) { 285 const char *filename = luaL_checkstring(L, 1); 286 const char *mode = luaL_optstring(L, 2, "r"); 287 LStream *p = newprefile(L); 288 luaL_argcheck(L, l_checkmodep(mode), 2, "invalid mode"); 289 p->f = l_popen(L, filename, mode); 290 p->closef = &io_pclose; 291 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 292 } 293 294 295 static int io_tmpfile (lua_State *L) { 296 LStream *p = newfile(L); 297 p->f = tmpfile(); 298 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1; 299 } 300 301 302 static FILE *getiofile (lua_State *L, const char *findex) { 303 LStream *p; 304 lua_getfield(L, LUA_REGISTRYINDEX, findex); 305 p = (LStream *)lua_touserdata(L, -1); 306 if (isclosed(p)) 307 luaL_error(L, "default %s file is closed", findex + IOPREF_LEN); 308 return p->f; 309 } 310 311 312 static int g_iofile (lua_State *L, const char *f, const char *mode) { 313 if (!lua_isnoneornil(L, 1)) { 314 const char *filename = lua_tostring(L, 1); 315 if (filename) 316 opencheck(L, filename, mode); 317 else { 318 tofile(L); /* check that it's a valid file handle */ 319 lua_pushvalue(L, 1); 320 } 321 lua_setfield(L, LUA_REGISTRYINDEX, f); 322 } 323 /* return current value */ 324 lua_getfield(L, LUA_REGISTRYINDEX, f); 325 return 1; 326 } 327 328 329 static int io_input (lua_State *L) { 330 return g_iofile(L, IO_INPUT, "r"); 331 } 332 333 334 static int io_output (lua_State *L) { 335 return g_iofile(L, IO_OUTPUT, "w"); 336 } 337 338 339 static int io_readline (lua_State *L); 340 341 342 /* 343 ** maximum number of arguments to 'f:lines'/'io.lines' (it + 3 must fit 344 ** in the limit for upvalues of a closure) 345 */ 346 #define MAXARGLINE 250 347 348 /* 349 ** Auxiliary function to create the iteration function for 'lines'. 350 ** The iteration function is a closure over 'io_readline', with 351 ** the following upvalues: 352 ** 1) The file being read (first value in the stack) 353 ** 2) the number of arguments to read 354 ** 3) a boolean, true iff file has to be closed when finished ('toclose') 355 ** *) a variable number of format arguments (rest of the stack) 356 */ 357 static void aux_lines (lua_State *L, int toclose) { 358 int n = lua_gettop(L) - 1; /* number of arguments to read */ 359 luaL_argcheck(L, n <= MAXARGLINE, MAXARGLINE + 2, "too many arguments"); 360 lua_pushvalue(L, 1); /* file */ 361 lua_pushinteger(L, n); /* number of arguments to read */ 362 lua_pushboolean(L, toclose); /* close/not close file when finished */ 363 lua_rotate(L, 2, 3); /* move the three values to their positions */ 364 lua_pushcclosure(L, io_readline, 3 + n); 365 } 366 367 368 static int f_lines (lua_State *L) { 369 tofile(L); /* check that it's a valid file handle */ 370 aux_lines(L, 0); 371 return 1; 372 } 373 374 375 /* 376 ** Return an iteration function for 'io.lines'. If file has to be 377 ** closed, also returns the file itself as a second result (to be 378 ** closed as the state at the exit of a generic for). 379 */ 380 static int io_lines (lua_State *L) { 381 int toclose; 382 if (lua_isnone(L, 1)) lua_pushnil(L); /* at least one argument */ 383 if (lua_isnil(L, 1)) { /* no file name? */ 384 lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT); /* get default input */ 385 lua_replace(L, 1); /* put it at index 1 */ 386 tofile(L); /* check that it's a valid file handle */ 387 toclose = 0; /* do not close it after iteration */ 388 } 389 else { /* open a new file */ 390 const char *filename = luaL_checkstring(L, 1); 391 opencheck(L, filename, "r"); 392 lua_replace(L, 1); /* put file at index 1 */ 393 toclose = 1; /* close it after iteration */ 394 } 395 aux_lines(L, toclose); /* push iteration function */ 396 if (toclose) { 397 lua_pushnil(L); /* state */ 398 lua_pushnil(L); /* control */ 399 lua_pushvalue(L, 1); /* file is the to-be-closed variable (4th result) */ 400 return 4; 401 } 402 else 403 return 1; 404 } 405 406 407 /* 408 ** {====================================================== 409 ** READ 410 ** ======================================================= 411 */ 412 413 414 /* maximum length of a numeral */ 415 #if !defined (L_MAXLENNUM) 416 #define L_MAXLENNUM 200 417 #endif 418 419 420 /* auxiliary structure used by 'read_number' */ 421 typedef struct { 422 FILE *f; /* file being read */ 423 int c; /* current character (look ahead) */ 424 int n; /* number of elements in buffer 'buff' */ 425 char buff[L_MAXLENNUM + 1]; /* +1 for ending '\0' */ 426 } RN; 427 428 429 /* 430 ** Add current char to buffer (if not out of space) and read next one 431 */ 432 static int nextc (RN *rn) { 433 if (rn->n >= L_MAXLENNUM) { /* buffer overflow? */ 434 rn->buff[0] = '\0'; /* invalidate result */ 435 return 0; /* fail */ 436 } 437 else { 438 rn->buff[rn->n++] = rn->c; /* save current char */ 439 rn->c = l_getc(rn->f); /* read next one */ 440 return 1; 441 } 442 } 443 444 445 /* 446 ** Accept current char if it is in 'set' (of size 2) 447 */ 448 static int test2 (RN *rn, const char *set) { 449 if (rn->c == set[0] || rn->c == set[1]) 450 return nextc(rn); 451 else return 0; 452 } 453 454 455 /* 456 ** Read a sequence of (hex)digits 457 */ 458 static int readdigits (RN *rn, int hex) { 459 int count = 0; 460 while ((hex ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn)) 461 count++; 462 return count; 463 } 464 465 466 /* 467 ** Read a number: first reads a valid prefix of a numeral into a buffer. 468 ** Then it calls 'lua_stringtonumber' to check whether the format is 469 ** correct and to convert it to a Lua number. 470 */ 471 static int read_number (lua_State *L, FILE *f) { 472 RN rn; 473 int count = 0; 474 int hex = 0; 475 char decp[2]; 476 rn.f = f; rn.n = 0; 477 decp[0] = lua_getlocaledecpoint(); /* get decimal point from locale */ 478 decp[1] = '.'; /* always accept a dot */ 479 l_lockfile(rn.f); 480 do { rn.c = l_getc(rn.f); } while (isspace(rn.c)); /* skip spaces */ 481 test2(&rn, "-+"); /* optional sign */ 482 if (test2(&rn, "00")) { 483 if (test2(&rn, "xX")) hex = 1; /* numeral is hexadecimal */ 484 else count = 1; /* count initial '0' as a valid digit */ 485 } 486 count += readdigits(&rn, hex); /* integral part */ 487 if (test2(&rn, decp)) /* decimal point? */ 488 count += readdigits(&rn, hex); /* fractional part */ 489 if (count > 0 && test2(&rn, (hex ? "pP" : "eE"))) { /* exponent mark? */ 490 test2(&rn, "-+"); /* exponent sign */ 491 readdigits(&rn, 0); /* exponent digits */ 492 } 493 ungetc(rn.c, rn.f); /* unread look-ahead char */ 494 l_unlockfile(rn.f); 495 rn.buff[rn.n] = '\0'; /* finish string */ 496 if (lua_stringtonumber(L, rn.buff)) /* is this a valid number? */ 497 return 1; /* ok */ 498 else { /* invalid format */ 499 lua_pushnil(L); /* "result" to be removed */ 500 return 0; /* read fails */ 501 } 502 } 503 504 505 static int test_eof (lua_State *L, FILE *f) { 506 int c = getc(f); 507 ungetc(c, f); /* no-op when c == EOF */ 508 lua_pushliteral(L, ""); 509 return (c != EOF); 510 } 511 512 513 static int read_line (lua_State *L, FILE *f, int chop) { 514 luaL_Buffer b; 515 int c; 516 luaL_buffinit(L, &b); 517 do { /* may need to read several chunks to get whole line */ 518 char *buff = luaL_prepbuffer(&b); /* preallocate buffer space */ 519 int i = 0; 520 l_lockfile(f); /* no memory errors can happen inside the lock */ 521 while (i < LUAL_BUFFERSIZE && (c = l_getc(f)) != EOF && c != '\n') 522 buff[i++] = c; /* read up to end of line or buffer limit */ 523 l_unlockfile(f); 524 luaL_addsize(&b, i); 525 } while (c != EOF && c != '\n'); /* repeat until end of line */ 526 if (!chop && c == '\n') /* want a newline and have one? */ 527 luaL_addchar(&b, c); /* add ending newline to result */ 528 luaL_pushresult(&b); /* close buffer */ 529 /* return ok if read something (either a newline or something else) */ 530 return (c == '\n' || lua_rawlen(L, -1) > 0); 531 } 532 533 534 static void read_all (lua_State *L, FILE *f) { 535 size_t nr; 536 luaL_Buffer b; 537 luaL_buffinit(L, &b); 538 do { /* read file in chunks of LUAL_BUFFERSIZE bytes */ 539 char *p = luaL_prepbuffer(&b); 540 nr = fread(p, sizeof(char), LUAL_BUFFERSIZE, f); 541 luaL_addsize(&b, nr); 542 } while (nr == LUAL_BUFFERSIZE); 543 luaL_pushresult(&b); /* close buffer */ 544 } 545 546 547 static int read_chars (lua_State *L, FILE *f, size_t n) { 548 size_t nr; /* number of chars actually read */ 549 char *p; 550 luaL_Buffer b; 551 luaL_buffinit(L, &b); 552 p = luaL_prepbuffsize(&b, n); /* prepare buffer to read whole block */ 553 nr = fread(p, sizeof(char), n, f); /* try to read 'n' chars */ 554 luaL_addsize(&b, nr); 555 luaL_pushresult(&b); /* close buffer */ 556 return (nr > 0); /* true iff read something */ 557 } 558 559 560 static int g_read (lua_State *L, FILE *f, int first) { 561 int nargs = lua_gettop(L) - 1; 562 int n, success; 563 clearerr(f); 564 if (nargs == 0) { /* no arguments? */ 565 success = read_line(L, f, 1); 566 n = first + 1; /* to return 1 result */ 567 } 568 else { 569 /* ensure stack space for all results and for auxlib's buffer */ 570 luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments"); 571 success = 1; 572 for (n = first; nargs-- && success; n++) { 573 if (lua_type(L, n) == LUA_TNUMBER) { 574 size_t l = (size_t)luaL_checkinteger(L, n); 575 success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l); 576 } 577 else { 578 const char *p = luaL_checkstring(L, n); 579 if (*p == '*') p++; /* skip optional '*' (for compatibility) */ 580 switch (*p) { 581 case 'n': /* number */ 582 success = read_number(L, f); 583 break; 584 case 'l': /* line */ 585 success = read_line(L, f, 1); 586 break; 587 case 'L': /* line with end-of-line */ 588 success = read_line(L, f, 0); 589 break; 590 case 'a': /* file */ 591 read_all(L, f); /* read entire file */ 592 success = 1; /* always success */ 593 break; 594 default: 595 return luaL_argerror(L, n, "invalid format"); 596 } 597 } 598 } 599 } 600 if (ferror(f)) 601 return luaL_fileresult(L, 0, NULL); 602 if (!success) { 603 lua_pop(L, 1); /* remove last result */ 604 luaL_pushfail(L); /* push nil instead */ 605 } 606 return n - first; 607 } 608 609 610 static int io_read (lua_State *L) { 611 return g_read(L, getiofile(L, IO_INPUT), 1); 612 } 613 614 615 static int f_read (lua_State *L) { 616 return g_read(L, tofile(L), 2); 617 } 618 619 620 /* 621 ** Iteration function for 'lines'. 622 */ 623 static int io_readline (lua_State *L) { 624 LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1)); 625 int i; 626 int n = (int)lua_tointeger(L, lua_upvalueindex(2)); 627 if (isclosed(p)) /* file is already closed? */ 628 return luaL_error(L, "file is already closed"); 629 lua_settop(L , 1); 630 luaL_checkstack(L, n, "too many arguments"); 631 for (i = 1; i <= n; i++) /* push arguments to 'g_read' */ 632 lua_pushvalue(L, lua_upvalueindex(3 + i)); 633 n = g_read(L, p->f, 2); /* 'n' is number of results */ 634 lua_assert(n > 0); /* should return at least a nil */ 635 if (lua_toboolean(L, -n)) /* read at least one value? */ 636 return n; /* return them */ 637 else { /* first result is false: EOF or error */ 638 if (n > 1) { /* is there error information? */ 639 /* 2nd result is error message */ 640 return luaL_error(L, "%s", lua_tostring(L, -n + 1)); 641 } 642 if (lua_toboolean(L, lua_upvalueindex(3))) { /* generator created file? */ 643 lua_settop(L, 0); /* clear stack */ 644 lua_pushvalue(L, lua_upvalueindex(1)); /* push file at index 1 */ 645 aux_close(L); /* close it */ 646 } 647 return 0; 648 } 649 } 650 651 /* }====================================================== */ 652 653 654 static int g_write (lua_State *L, FILE *f, int arg) { 655 int nargs = lua_gettop(L) - arg; 656 int status = 1; 657 for (; nargs--; arg++) { 658 if (lua_type(L, arg) == LUA_TNUMBER) { 659 /* optimization: could be done exactly as for strings */ 660 int len = lua_isinteger(L, arg) 661 ? fprintf(f, LUA_INTEGER_FMT, 662 (LUAI_UACINT)lua_tointeger(L, arg)) 663 : fprintf(f, LUA_NUMBER_FMT, 664 (LUAI_UACNUMBER)lua_tonumber(L, arg)); 665 status = status && (len > 0); 666 } 667 else { 668 size_t l; 669 const char *s = luaL_checklstring(L, arg, &l); 670 status = status && (fwrite(s, sizeof(char), l, f) == l); 671 } 672 } 673 if (status) return 1; /* file handle already on stack top */ 674 else return luaL_fileresult(L, status, NULL); 675 } 676 677 678 static int io_write (lua_State *L) { 679 return g_write(L, getiofile(L, IO_OUTPUT), 1); 680 } 681 682 683 static int f_write (lua_State *L) { 684 FILE *f = tofile(L); 685 lua_pushvalue(L, 1); /* push file at the stack top (to be returned) */ 686 return g_write(L, f, 2); 687 } 688 689 690 static int f_seek (lua_State *L) { 691 static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END}; 692 static const char *const modenames[] = {"set", "cur", "end", NULL}; 693 FILE *f = tofile(L); 694 int op = luaL_checkoption(L, 2, "cur", modenames); 695 lua_Integer p3 = luaL_optinteger(L, 3, 0); 696 l_seeknum offset = (l_seeknum)p3; 697 luaL_argcheck(L, (lua_Integer)offset == p3, 3, 698 "not an integer in proper range"); 699 op = l_fseek(f, offset, mode[op]); 700 if (op) 701 return luaL_fileresult(L, 0, NULL); /* error */ 702 else { 703 lua_pushinteger(L, (lua_Integer)l_ftell(f)); 704 return 1; 705 } 706 } 707 708 709 static int f_setvbuf (lua_State *L) { 710 static const int mode[] = {_IONBF, _IOFBF, _IOLBF}; 711 static const char *const modenames[] = {"no", "full", "line", NULL}; 712 FILE *f = tofile(L); 713 int op = luaL_checkoption(L, 2, NULL, modenames); 714 lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE); 715 int res = setvbuf(f, NULL, mode[op], (size_t)sz); 716 return luaL_fileresult(L, res == 0, NULL); 717 } 718 719 720 721 static int io_flush (lua_State *L) { 722 return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL); 723 } 724 725 726 static int f_flush (lua_State *L) { 727 return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL); 728 } 729 730 731 /* 732 ** functions for 'io' library 733 */ 734 static const luaL_Reg iolib[] = { 735 {"close", io_close}, 736 {"flush", io_flush}, 737 {"input", io_input}, 738 {"lines", io_lines}, 739 {"open", io_open}, 740 {"output", io_output}, 741 {"popen", io_popen}, 742 {"read", io_read}, 743 {"tmpfile", io_tmpfile}, 744 {"type", io_type}, 745 {"write", io_write}, 746 {NULL, NULL} 747 }; 748 749 750 /* 751 ** methods for file handles 752 */ 753 static const luaL_Reg meth[] = { 754 {"read", f_read}, 755 {"write", f_write}, 756 {"lines", f_lines}, 757 {"flush", f_flush}, 758 {"seek", f_seek}, 759 {"close", f_close}, 760 {"setvbuf", f_setvbuf}, 761 {NULL, NULL} 762 }; 763 764 765 /* 766 ** metamethods for file handles 767 */ 768 static const luaL_Reg metameth[] = { 769 {"__index", NULL}, /* place holder */ 770 {"__gc", f_gc}, 771 {"__close", f_gc}, 772 {"__tostring", f_tostring}, 773 {NULL, NULL} 774 }; 775 776 777 static void createmeta (lua_State *L) { 778 luaL_newmetatable(L, LUA_FILEHANDLE); /* metatable for file handles */ 779 luaL_setfuncs(L, metameth, 0); /* add metamethods to new metatable */ 780 luaL_newlibtable(L, meth); /* create method table */ 781 luaL_setfuncs(L, meth, 0); /* add file methods to method table */ 782 lua_setfield(L, -2, "__index"); /* metatable.__index = method table */ 783 lua_pop(L, 1); /* pop metatable */ 784 } 785 786 787 /* 788 ** function to (not) close the standard files stdin, stdout, and stderr 789 */ 790 static int io_noclose (lua_State *L) { 791 LStream *p = tolstream(L); 792 p->closef = &io_noclose; /* keep file opened */ 793 luaL_pushfail(L); 794 lua_pushliteral(L, "cannot close standard file"); 795 return 2; 796 } 797 798 799 static void createstdfile (lua_State *L, FILE *f, const char *k, 800 const char *fname) { 801 LStream *p = newprefile(L); 802 p->f = f; 803 p->closef = &io_noclose; 804 if (k != NULL) { 805 lua_pushvalue(L, -1); 806 lua_setfield(L, LUA_REGISTRYINDEX, k); /* add file to registry */ 807 } 808 lua_setfield(L, -2, fname); /* add file to module */ 809 } 810 811 812 LUAMOD_API int luaopen_io (lua_State *L) { 813 luaL_newlib(L, iolib); /* new module */ 814 createmeta(L); 815 /* create (and set) default files */ 816 createstdfile(L, stdin, IO_INPUT, "stdin"); 817 createstdfile(L, stdout, IO_OUTPUT, "stdout"); 818 createstdfile(L, stderr, NULL, "stderr"); 819 return 1; 820 } 821 822