liolib.c (22069B)
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 #include "llimits.h" 25 26 27 /* 28 ** Change this macro to accept other modes for 'fopen' besides 29 ** the standard ones. 30 */ 31 #if !defined(l_checkmode) 32 33 /* accepted extensions to 'mode' in 'fopen' */ 34 #if !defined(L_MODEEXT) 35 #define L_MODEEXT "b" 36 #endif 37 38 /* Check whether 'mode' matches '[rwa]%+?[L_MODEEXT]*' */ 39 static int l_checkmode (const char *mode) { 40 return (*mode != '\0' && strchr("rwa", *(mode++)) != NULL && 41 (*mode != '+' || ((void)(++mode), 1)) && /* skip if char is '+' */ 42 (strspn(mode, L_MODEEXT) == strlen(mode))); /* check extensions */ 43 } 44 45 #endif 46 47 /* 48 ** {====================================================== 49 ** l_popen spawns a new process connected to the current 50 ** one through the file streams. 51 ** ======================================================= 52 */ 53 54 #if !defined(l_popen) /* { */ 55 56 #if defined(LUA_USE_POSIX) /* { */ 57 58 #define l_popen(L,c,m) (fflush(NULL), popen(c,m)) 59 #define l_pclose(L,file) (pclose(file)) 60 61 #elif defined(LUA_USE_WINDOWS) /* }{ */ 62 63 #define l_popen(L,c,m) (_popen(c,m)) 64 #define l_pclose(L,file) (_pclose(file)) 65 66 #if !defined(l_checkmodep) 67 /* Windows accepts "[rw][bt]?" as valid modes */ 68 #define l_checkmodep(m) ((m[0] == 'r' || m[0] == 'w') && \ 69 (m[1] == '\0' || ((m[1] == 'b' || m[1] == 't') && m[2] == '\0'))) 70 #endif 71 72 #else /* }{ */ 73 74 /* ISO C definitions */ 75 #define l_popen(L,c,m) \ 76 ((void)c, (void)m, \ 77 luaL_error(L, "'popen' not supported"), \ 78 (FILE*)0) 79 #define l_pclose(L,file) ((void)L, (void)file, -1) 80 81 #endif /* } */ 82 83 #endif /* } */ 84 85 86 #if !defined(l_checkmodep) 87 /* By default, Lua accepts only "r" or "w" as valid modes */ 88 #define l_checkmodep(m) ((m[0] == 'r' || m[0] == 'w') && m[1] == '\0') 89 #endif 90 91 /* }====================================================== */ 92 93 94 #if !defined(l_getc) /* { */ 95 96 #if defined(LUA_USE_POSIX) 97 #define l_getc(f) getc_unlocked(f) 98 #define l_lockfile(f) flockfile(f) 99 #define l_unlockfile(f) funlockfile(f) 100 #else 101 #define l_getc(f) getc(f) 102 #define l_lockfile(f) ((void)0) 103 #define l_unlockfile(f) ((void)0) 104 #endif 105 106 #endif /* } */ 107 108 109 /* 110 ** {====================================================== 111 ** l_fseek: configuration for longer offsets 112 ** ======================================================= 113 */ 114 115 #if !defined(l_fseek) /* { */ 116 117 #if defined(LUA_USE_POSIX) /* { */ 118 119 #include <sys/types.h> 120 121 #define l_fseek(f,o,w) fseeko(f,o,w) 122 #define l_ftell(f) ftello(f) 123 #define l_seeknum off_t 124 125 #elif defined(LUA_USE_WINDOWS) && !defined(_CRTIMP_TYPEINFO) \ 126 && defined(_MSC_VER) && (_MSC_VER >= 1400) /* }{ */ 127 128 /* Windows (but not DDK) and Visual C++ 2005 or higher */ 129 #define l_fseek(f,o,w) _fseeki64(f,o,w) 130 #define l_ftell(f) _ftelli64(f) 131 #define l_seeknum __int64 132 133 #else /* }{ */ 134 135 /* ISO C definitions */ 136 #define l_fseek(f,o,w) fseek(f,o,w) 137 #define l_ftell(f) ftell(f) 138 #define l_seeknum long 139 140 #endif /* } */ 141 142 #endif /* } */ 143 144 /* }====================================================== */ 145 146 147 148 #define IO_PREFIX "_IO_" 149 #define IOPREF_LEN (sizeof(IO_PREFIX)/sizeof(char) - 1) 150 #define IO_INPUT (IO_PREFIX "input") 151 #define IO_OUTPUT (IO_PREFIX "output") 152 153 154 typedef luaL_Stream LStream; 155 156 157 #define tolstream(L) ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE)) 158 159 #define isclosed(p) ((p)->closef == NULL) 160 161 162 static int io_type (lua_State *L) { 163 LStream *p; 164 luaL_checkany(L, 1); 165 p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE); 166 if (p == NULL) 167 luaL_pushfail(L); /* not a file */ 168 else if (isclosed(p)) 169 lua_pushliteral(L, "closed file"); 170 else 171 lua_pushliteral(L, "file"); 172 return 1; 173 } 174 175 176 static int f_tostring (lua_State *L) { 177 LStream *p = tolstream(L); 178 if (isclosed(p)) 179 lua_pushliteral(L, "file (closed)"); 180 else 181 lua_pushfstring(L, "file (%p)", p->f); 182 return 1; 183 } 184 185 186 static FILE *tofile (lua_State *L) { 187 LStream *p = tolstream(L); 188 if (l_unlikely(isclosed(p))) 189 luaL_error(L, "attempt to use a closed file"); 190 lua_assert(p->f); 191 return p->f; 192 } 193 194 195 /* 196 ** When creating file handles, always creates a 'closed' file handle 197 ** before opening the actual file; so, if there is a memory error, the 198 ** handle is in a consistent state. 199 */ 200 static LStream *newprefile (lua_State *L) { 201 LStream *p = (LStream *)lua_newuserdatauv(L, sizeof(LStream), 0); 202 p->closef = NULL; /* mark file handle as 'closed' */ 203 luaL_setmetatable(L, LUA_FILEHANDLE); 204 return p; 205 } 206 207 208 /* 209 ** Calls the 'close' function from a file handle. The 'volatile' avoids 210 ** a bug in some versions of the Clang compiler (e.g., clang 3.0 for 211 ** 32 bits). 212 */ 213 static int aux_close (lua_State *L) { 214 LStream *p = tolstream(L); 215 volatile lua_CFunction cf = p->closef; 216 p->closef = NULL; /* mark stream as closed */ 217 return (*cf)(L); /* close it */ 218 } 219 220 221 static int f_close (lua_State *L) { 222 tofile(L); /* make sure argument is an open stream */ 223 return aux_close(L); 224 } 225 226 227 static int io_close (lua_State *L) { 228 if (lua_isnone(L, 1)) /* no argument? */ 229 lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT); /* use default output */ 230 return f_close(L); 231 } 232 233 234 static int f_gc (lua_State *L) { 235 LStream *p = tolstream(L); 236 if (!isclosed(p) && p->f != NULL) 237 aux_close(L); /* ignore closed and incompletely open files */ 238 return 0; 239 } 240 241 242 /* 243 ** function to close regular files 244 */ 245 static int io_fclose (lua_State *L) { 246 LStream *p = tolstream(L); 247 errno = 0; 248 return luaL_fileresult(L, (fclose(p->f) == 0), NULL); 249 } 250 251 252 static LStream *newfile (lua_State *L) { 253 LStream *p = newprefile(L); 254 p->f = NULL; 255 p->closef = &io_fclose; 256 return p; 257 } 258 259 260 static void opencheck (lua_State *L, const char *fname, const char *mode) { 261 LStream *p = newfile(L); 262 p->f = fopen(fname, mode); 263 if (l_unlikely(p->f == NULL)) 264 luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno)); 265 } 266 267 268 static int io_open (lua_State *L) { 269 const char *filename = luaL_checkstring(L, 1); 270 const char *mode = luaL_optstring(L, 2, "r"); 271 LStream *p = newfile(L); 272 const char *md = mode; /* to traverse/check mode */ 273 luaL_argcheck(L, l_checkmode(md), 2, "invalid mode"); 274 errno = 0; 275 p->f = fopen(filename, mode); 276 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 277 } 278 279 280 /* 281 ** function to close 'popen' files 282 */ 283 static int io_pclose (lua_State *L) { 284 LStream *p = tolstream(L); 285 errno = 0; 286 return luaL_execresult(L, l_pclose(L, p->f)); 287 } 288 289 290 static int io_popen (lua_State *L) { 291 const char *filename = luaL_checkstring(L, 1); 292 const char *mode = luaL_optstring(L, 2, "r"); 293 LStream *p = newprefile(L); 294 luaL_argcheck(L, l_checkmodep(mode), 2, "invalid mode"); 295 errno = 0; 296 p->f = l_popen(L, filename, mode); 297 p->closef = &io_pclose; 298 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 299 } 300 301 302 static int io_tmpfile (lua_State *L) { 303 LStream *p = newfile(L); 304 errno = 0; 305 p->f = tmpfile(); 306 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1; 307 } 308 309 310 static FILE *getiofile (lua_State *L, const char *findex) { 311 LStream *p; 312 lua_getfield(L, LUA_REGISTRYINDEX, findex); 313 p = (LStream *)lua_touserdata(L, -1); 314 if (l_unlikely(isclosed(p))) 315 luaL_error(L, "default %s file is closed", findex + IOPREF_LEN); 316 return p->f; 317 } 318 319 320 static int g_iofile (lua_State *L, const char *f, const char *mode) { 321 if (!lua_isnoneornil(L, 1)) { 322 const char *filename = lua_tostring(L, 1); 323 if (filename) 324 opencheck(L, filename, mode); 325 else { 326 tofile(L); /* check that it's a valid file handle */ 327 lua_pushvalue(L, 1); 328 } 329 lua_setfield(L, LUA_REGISTRYINDEX, f); 330 } 331 /* return current value */ 332 lua_getfield(L, LUA_REGISTRYINDEX, f); 333 return 1; 334 } 335 336 337 static int io_input (lua_State *L) { 338 return g_iofile(L, IO_INPUT, "r"); 339 } 340 341 342 static int io_output (lua_State *L) { 343 return g_iofile(L, IO_OUTPUT, "w"); 344 } 345 346 347 static int io_readline (lua_State *L); 348 349 350 /* 351 ** maximum number of arguments to 'f:lines'/'io.lines' (it + 3 must fit 352 ** in the limit for upvalues of a closure) 353 */ 354 #define MAXARGLINE 250 355 356 /* 357 ** Auxiliary function to create the iteration function for 'lines'. 358 ** The iteration function is a closure over 'io_readline', with 359 ** the following upvalues: 360 ** 1) The file being read (first value in the stack) 361 ** 2) the number of arguments to read 362 ** 3) a boolean, true iff file has to be closed when finished ('toclose') 363 ** *) a variable number of format arguments (rest of the stack) 364 */ 365 static void aux_lines (lua_State *L, int toclose) { 366 int n = lua_gettop(L) - 1; /* number of arguments to read */ 367 luaL_argcheck(L, n <= MAXARGLINE, MAXARGLINE + 2, "too many arguments"); 368 lua_pushvalue(L, 1); /* file */ 369 lua_pushinteger(L, n); /* number of arguments to read */ 370 lua_pushboolean(L, toclose); /* close/not close file when finished */ 371 lua_rotate(L, 2, 3); /* move the three values to their positions */ 372 lua_pushcclosure(L, io_readline, 3 + n); 373 } 374 375 376 static int f_lines (lua_State *L) { 377 tofile(L); /* check that it's a valid file handle */ 378 aux_lines(L, 0); 379 return 1; 380 } 381 382 383 /* 384 ** Return an iteration function for 'io.lines'. If file has to be 385 ** closed, also returns the file itself as a second result (to be 386 ** closed as the state at the exit of a generic for). 387 */ 388 static int io_lines (lua_State *L) { 389 int toclose; 390 if (lua_isnone(L, 1)) lua_pushnil(L); /* at least one argument */ 391 if (lua_isnil(L, 1)) { /* no file name? */ 392 lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT); /* get default input */ 393 lua_replace(L, 1); /* put it at index 1 */ 394 tofile(L); /* check that it's a valid file handle */ 395 toclose = 0; /* do not close it after iteration */ 396 } 397 else { /* open a new file */ 398 const char *filename = luaL_checkstring(L, 1); 399 opencheck(L, filename, "r"); 400 lua_replace(L, 1); /* put file at index 1 */ 401 toclose = 1; /* close it after iteration */ 402 } 403 aux_lines(L, toclose); /* push iteration function */ 404 if (toclose) { 405 lua_pushnil(L); /* state */ 406 lua_pushnil(L); /* control */ 407 lua_pushvalue(L, 1); /* file is the to-be-closed variable (4th result) */ 408 return 4; 409 } 410 else 411 return 1; 412 } 413 414 415 /* 416 ** {====================================================== 417 ** READ 418 ** ======================================================= 419 */ 420 421 422 /* maximum length of a numeral */ 423 #if !defined (L_MAXLENNUM) 424 #define L_MAXLENNUM 200 425 #endif 426 427 428 /* auxiliary structure used by 'read_number' */ 429 typedef struct { 430 FILE *f; /* file being read */ 431 int c; /* current character (look ahead) */ 432 int n; /* number of elements in buffer 'buff' */ 433 char buff[L_MAXLENNUM + 1]; /* +1 for ending '\0' */ 434 } RN; 435 436 437 /* 438 ** Add current char to buffer (if not out of space) and read next one 439 */ 440 static int nextc (RN *rn) { 441 if (l_unlikely(rn->n >= L_MAXLENNUM)) { /* buffer overflow? */ 442 rn->buff[0] = '\0'; /* invalidate result */ 443 return 0; /* fail */ 444 } 445 else { 446 rn->buff[rn->n++] = cast_char(rn->c); /* save current char */ 447 rn->c = l_getc(rn->f); /* read next one */ 448 return 1; 449 } 450 } 451 452 453 /* 454 ** Accept current char if it is in 'set' (of size 2) 455 */ 456 static int test2 (RN *rn, const char *set) { 457 if (rn->c == set[0] || rn->c == set[1]) 458 return nextc(rn); 459 else return 0; 460 } 461 462 463 /* 464 ** Read a sequence of (hex)digits 465 */ 466 static int readdigits (RN *rn, int hex) { 467 int count = 0; 468 while ((hex ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn)) 469 count++; 470 return count; 471 } 472 473 474 /* 475 ** Read a number: first reads a valid prefix of a numeral into a buffer. 476 ** Then it calls 'lua_stringtonumber' to check whether the format is 477 ** correct and to convert it to a Lua number. 478 */ 479 static int read_number (lua_State *L, FILE *f) { 480 RN rn; 481 int count = 0; 482 int hex = 0; 483 char decp[2]; 484 rn.f = f; rn.n = 0; 485 decp[0] = lua_getlocaledecpoint(); /* get decimal point from locale */ 486 decp[1] = '.'; /* always accept a dot */ 487 l_lockfile(rn.f); 488 do { rn.c = l_getc(rn.f); } while (isspace(rn.c)); /* skip spaces */ 489 test2(&rn, "-+"); /* optional sign */ 490 if (test2(&rn, "00")) { 491 if (test2(&rn, "xX")) hex = 1; /* numeral is hexadecimal */ 492 else count = 1; /* count initial '0' as a valid digit */ 493 } 494 count += readdigits(&rn, hex); /* integral part */ 495 if (test2(&rn, decp)) /* decimal point? */ 496 count += readdigits(&rn, hex); /* fractional part */ 497 if (count > 0 && test2(&rn, (hex ? "pP" : "eE"))) { /* exponent mark? */ 498 test2(&rn, "-+"); /* exponent sign */ 499 readdigits(&rn, 0); /* exponent digits */ 500 } 501 ungetc(rn.c, rn.f); /* unread look-ahead char */ 502 l_unlockfile(rn.f); 503 rn.buff[rn.n] = '\0'; /* finish string */ 504 if (l_likely(lua_stringtonumber(L, rn.buff))) 505 return 1; /* ok, it is a valid number */ 506 else { /* invalid format */ 507 lua_pushnil(L); /* "result" to be removed */ 508 return 0; /* read fails */ 509 } 510 } 511 512 513 static int test_eof (lua_State *L, FILE *f) { 514 int c = getc(f); 515 ungetc(c, f); /* no-op when c == EOF */ 516 lua_pushliteral(L, ""); 517 return (c != EOF); 518 } 519 520 521 static int read_line (lua_State *L, FILE *f, int chop) { 522 luaL_Buffer b; 523 int c; 524 luaL_buffinit(L, &b); 525 do { /* may need to read several chunks to get whole line */ 526 char *buff = luaL_prepbuffer(&b); /* preallocate buffer space */ 527 unsigned i = 0; 528 l_lockfile(f); /* no memory errors can happen inside the lock */ 529 while (i < LUAL_BUFFERSIZE && (c = l_getc(f)) != EOF && c != '\n') 530 buff[i++] = cast_char(c); /* read up to end of line or buffer limit */ 531 l_unlockfile(f); 532 luaL_addsize(&b, i); 533 } while (c != EOF && c != '\n'); /* repeat until end of line */ 534 if (!chop && c == '\n') /* want a newline and have one? */ 535 luaL_addchar(&b, '\n'); /* add ending newline to result */ 536 luaL_pushresult(&b); /* close buffer */ 537 /* return ok if read something (either a newline or something else) */ 538 return (c == '\n' || lua_rawlen(L, -1) > 0); 539 } 540 541 542 static void read_all (lua_State *L, FILE *f) { 543 size_t nr; 544 luaL_Buffer b; 545 luaL_buffinit(L, &b); 546 do { /* read file in chunks of LUAL_BUFFERSIZE bytes */ 547 char *p = luaL_prepbuffer(&b); 548 nr = fread(p, sizeof(char), LUAL_BUFFERSIZE, f); 549 luaL_addsize(&b, nr); 550 } while (nr == LUAL_BUFFERSIZE); 551 luaL_pushresult(&b); /* close buffer */ 552 } 553 554 555 static int read_chars (lua_State *L, FILE *f, size_t n) { 556 size_t nr; /* number of chars actually read */ 557 char *p; 558 luaL_Buffer b; 559 luaL_buffinit(L, &b); 560 p = luaL_prepbuffsize(&b, n); /* prepare buffer to read whole block */ 561 nr = fread(p, sizeof(char), n, f); /* try to read 'n' chars */ 562 luaL_addsize(&b, nr); 563 luaL_pushresult(&b); /* close buffer */ 564 return (nr > 0); /* true iff read something */ 565 } 566 567 568 static int g_read (lua_State *L, FILE *f, int first) { 569 int nargs = lua_gettop(L) - 1; 570 int n, success; 571 clearerr(f); 572 errno = 0; 573 if (nargs == 0) { /* no arguments? */ 574 success = read_line(L, f, 1); 575 n = first + 1; /* to return 1 result */ 576 } 577 else { 578 /* ensure stack space for all results and for auxlib's buffer */ 579 luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments"); 580 success = 1; 581 for (n = first; nargs-- && success; n++) { 582 if (lua_type(L, n) == LUA_TNUMBER) { 583 size_t l = (size_t)luaL_checkinteger(L, n); 584 success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l); 585 } 586 else { 587 const char *p = luaL_checkstring(L, n); 588 if (*p == '*') p++; /* skip optional '*' (for compatibility) */ 589 switch (*p) { 590 case 'n': /* number */ 591 success = read_number(L, f); 592 break; 593 case 'l': /* line */ 594 success = read_line(L, f, 1); 595 break; 596 case 'L': /* line with end-of-line */ 597 success = read_line(L, f, 0); 598 break; 599 case 'a': /* file */ 600 read_all(L, f); /* read entire file */ 601 success = 1; /* always success */ 602 break; 603 default: 604 return luaL_argerror(L, n, "invalid format"); 605 } 606 } 607 } 608 } 609 if (ferror(f)) 610 return luaL_fileresult(L, 0, NULL); 611 if (!success) { 612 lua_pop(L, 1); /* remove last result */ 613 luaL_pushfail(L); /* push nil instead */ 614 } 615 return n - first; 616 } 617 618 619 static int io_read (lua_State *L) { 620 return g_read(L, getiofile(L, IO_INPUT), 1); 621 } 622 623 624 static int f_read (lua_State *L) { 625 return g_read(L, tofile(L), 2); 626 } 627 628 629 /* 630 ** Iteration function for 'lines'. 631 */ 632 static int io_readline (lua_State *L) { 633 LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1)); 634 int i; 635 int n = (int)lua_tointeger(L, lua_upvalueindex(2)); 636 if (isclosed(p)) /* file is already closed? */ 637 return luaL_error(L, "file is already closed"); 638 lua_settop(L , 1); 639 luaL_checkstack(L, n, "too many arguments"); 640 for (i = 1; i <= n; i++) /* push arguments to 'g_read' */ 641 lua_pushvalue(L, lua_upvalueindex(3 + i)); 642 n = g_read(L, p->f, 2); /* 'n' is number of results */ 643 lua_assert(n > 0); /* should return at least a nil */ 644 if (lua_toboolean(L, -n)) /* read at least one value? */ 645 return n; /* return them */ 646 else { /* first result is false: EOF or error */ 647 if (n > 1) { /* is there error information? */ 648 /* 2nd result is error message */ 649 return luaL_error(L, "%s", lua_tostring(L, -n + 1)); 650 } 651 if (lua_toboolean(L, lua_upvalueindex(3))) { /* generator created file? */ 652 lua_settop(L, 0); /* clear stack */ 653 lua_pushvalue(L, lua_upvalueindex(1)); /* push file at index 1 */ 654 aux_close(L); /* close it */ 655 } 656 return 0; 657 } 658 } 659 660 /* }====================================================== */ 661 662 663 static int g_write (lua_State *L, FILE *f, int arg) { 664 int nargs = lua_gettop(L) - arg; 665 int status = 1; 666 errno = 0; 667 for (; nargs--; arg++) { 668 char buff[LUA_N2SBUFFSZ]; 669 const char *s; 670 size_t len = lua_numbertocstring(L, arg, buff); /* try as a number */ 671 if (len > 0) { /* did conversion work (value was a number)? */ 672 s = buff; 673 len--; 674 } 675 else /* must be a string */ 676 s = luaL_checklstring(L, arg, &len); 677 status = status && (fwrite(s, sizeof(char), len, f) == len); 678 } 679 if (l_likely(status)) 680 return 1; /* file handle already on stack top */ 681 else 682 return luaL_fileresult(L, status, NULL); 683 } 684 685 686 static int io_write (lua_State *L) { 687 return g_write(L, getiofile(L, IO_OUTPUT), 1); 688 } 689 690 691 static int f_write (lua_State *L) { 692 FILE *f = tofile(L); 693 lua_pushvalue(L, 1); /* push file at the stack top (to be returned) */ 694 return g_write(L, f, 2); 695 } 696 697 698 static int f_seek (lua_State *L) { 699 static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END}; 700 static const char *const modenames[] = {"set", "cur", "end", NULL}; 701 FILE *f = tofile(L); 702 int op = luaL_checkoption(L, 2, "cur", modenames); 703 lua_Integer p3 = luaL_optinteger(L, 3, 0); 704 l_seeknum offset = (l_seeknum)p3; 705 luaL_argcheck(L, (lua_Integer)offset == p3, 3, 706 "not an integer in proper range"); 707 errno = 0; 708 op = l_fseek(f, offset, mode[op]); 709 if (l_unlikely(op)) 710 return luaL_fileresult(L, 0, NULL); /* error */ 711 else { 712 lua_pushinteger(L, (lua_Integer)l_ftell(f)); 713 return 1; 714 } 715 } 716 717 718 static int f_setvbuf (lua_State *L) { 719 static const int mode[] = {_IONBF, _IOFBF, _IOLBF}; 720 static const char *const modenames[] = {"no", "full", "line", NULL}; 721 FILE *f = tofile(L); 722 int op = luaL_checkoption(L, 2, NULL, modenames); 723 lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE); 724 int res; 725 errno = 0; 726 res = setvbuf(f, NULL, mode[op], (size_t)sz); 727 return luaL_fileresult(L, res == 0, NULL); 728 } 729 730 731 732 static int io_flush (lua_State *L) { 733 FILE *f = getiofile(L, IO_OUTPUT); 734 errno = 0; 735 return luaL_fileresult(L, fflush(f) == 0, NULL); 736 } 737 738 739 static int f_flush (lua_State *L) { 740 FILE *f = tofile(L); 741 errno = 0; 742 return luaL_fileresult(L, fflush(f) == 0, NULL); 743 } 744 745 746 /* 747 ** functions for 'io' library 748 */ 749 static const luaL_Reg iolib[] = { 750 {"close", io_close}, 751 {"flush", io_flush}, 752 {"input", io_input}, 753 {"lines", io_lines}, 754 {"open", io_open}, 755 {"output", io_output}, 756 {"popen", io_popen}, 757 {"read", io_read}, 758 {"tmpfile", io_tmpfile}, 759 {"type", io_type}, 760 {"write", io_write}, 761 {NULL, NULL} 762 }; 763 764 765 /* 766 ** methods for file handles 767 */ 768 static const luaL_Reg meth[] = { 769 {"read", f_read}, 770 {"write", f_write}, 771 {"lines", f_lines}, 772 {"flush", f_flush}, 773 {"seek", f_seek}, 774 {"close", f_close}, 775 {"setvbuf", f_setvbuf}, 776 {NULL, NULL} 777 }; 778 779 780 /* 781 ** metamethods for file handles 782 */ 783 static const luaL_Reg metameth[] = { 784 {"__index", NULL}, /* placeholder */ 785 {"__gc", f_gc}, 786 {"__close", f_gc}, 787 {"__tostring", f_tostring}, 788 {NULL, NULL} 789 }; 790 791 792 static void createmeta (lua_State *L) { 793 luaL_newmetatable(L, LUA_FILEHANDLE); /* metatable for file handles */ 794 luaL_setfuncs(L, metameth, 0); /* add metamethods to new metatable */ 795 luaL_newlibtable(L, meth); /* create method table */ 796 luaL_setfuncs(L, meth, 0); /* add file methods to method table */ 797 lua_setfield(L, -2, "__index"); /* metatable.__index = method table */ 798 lua_pop(L, 1); /* pop metatable */ 799 } 800 801 802 /* 803 ** function to (not) close the standard files stdin, stdout, and stderr 804 */ 805 static int io_noclose (lua_State *L) { 806 LStream *p = tolstream(L); 807 p->closef = &io_noclose; /* keep file opened */ 808 luaL_pushfail(L); 809 lua_pushliteral(L, "cannot close standard file"); 810 return 2; 811 } 812 813 814 static void createstdfile (lua_State *L, FILE *f, const char *k, 815 const char *fname) { 816 LStream *p = newprefile(L); 817 p->f = f; 818 p->closef = &io_noclose; 819 if (k != NULL) { 820 lua_pushvalue(L, -1); 821 lua_setfield(L, LUA_REGISTRYINDEX, k); /* add file to registry */ 822 } 823 lua_setfield(L, -2, fname); /* add file to module */ 824 } 825 826 827 LUAMOD_API int luaopen_io (lua_State *L) { 828 luaL_newlib(L, iolib); /* new module */ 829 createmeta(L); 830 /* create (and set) default files */ 831 createstdfile(L, stdin, IO_INPUT, "stdin"); 832 createstdfile(L, stdout, IO_OUTPUT, "stdout"); 833 createstdfile(L, stderr, NULL, "stderr"); 834 return 1; 835 } 836