1/* $NetBSD: liolib.c,v 1.10 2023/04/16 20:46:17 nikita Exp $ */ 2 3/* 4** Id: liolib.c 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]*' */ 42static int l_checkmode (const char *mode) { 43 return (*mode != '\0' && strchr("rwa", *(mode++)) != NULL && 44 (*mode != '+' || ((void)(++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#if !defined(l_checkmodep) 70/* Windows accepts "[rw][bt]?" as valid modes */ 71#define l_checkmodep(m) ((m[0] == 'r' || m[0] == 'w') && \ 72 (m[1] == '\0' || ((m[1] == 'b' || m[1] == 't') && m[2] == '\0'))) 73#endif 74 75#else /* }{ */ 76 77/* ISO C definitions */ 78#define l_popen(L,c,m) \ 79 ((void)c, (void)m, \ 80 luaL_error(L, "'popen' not supported"), \ 81 (FILE*)0) 82#define l_pclose(L,file) ((void)L, (void)file, -1) 83 84#endif /* } */ 85 86#endif /* } */ 87 88 89#if !defined(l_checkmodep) 90/* By default, Lua accepts only "r" or "w" as valid modes */ 91#define l_checkmodep(m) ((m[0] == 'r' || m[0] == 'w') && m[1] == '\0') 92#endif 93 94/* }====================================================== */ 95 96 97#if !defined(l_getc) /* { */ 98 99#if defined(LUA_USE_POSIX) 100#define l_getc(f) getc_unlocked(f) 101#define l_lockfile(f) flockfile(f) 102#define l_unlockfile(f) funlockfile(f) 103#else 104#define l_getc(f) getc(f) 105#define l_lockfile(f) ((void)0) 106#define l_unlockfile(f) ((void)0) 107#endif 108 109#endif /* } */ 110 111 112/* 113** {====================================================== 114** l_fseek: configuration for longer offsets 115** ======================================================= 116*/ 117 118#if !defined(l_fseek) /* { */ 119 120#if defined(LUA_USE_POSIX) /* { */ 121 122#include <sys/types.h> 123 124#define l_fseek(f,o,w) fseeko(f,o,w) 125#define l_ftell(f) ftello(f) 126#define l_seeknum off_t 127 128#elif defined(LUA_USE_WINDOWS) && !defined(_CRTIMP_TYPEINFO) \ 129 && defined(_MSC_VER) && (_MSC_VER >= 1400) /* }{ */ 130 131/* Windows (but not DDK) and Visual C++ 2005 or higher */ 132#define l_fseek(f,o,w) _fseeki64(f,o,w) 133#define l_ftell(f) _ftelli64(f) 134#define l_seeknum __int64 135 136#else /* }{ */ 137 138/* ISO C definitions */ 139#define l_fseek(f,o,w) fseek(f,o,w) 140#define l_ftell(f) ftell(f) 141#define l_seeknum long 142 143#endif /* } */ 144 145#endif /* } */ 146 147/* }====================================================== */ 148 149 150 151#define IO_PREFIX "_IO_" 152#define IOPREF_LEN (sizeof(IO_PREFIX)/sizeof(char) - 1) 153#define IO_INPUT (IO_PREFIX "input") 154#define IO_OUTPUT (IO_PREFIX "output") 155 156 157typedef luaL_Stream LStream; 158 159 160#define tolstream(L) ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE)) 161 162#define isclosed(p) ((p)->closef == NULL) 163 164 165static int io_type (lua_State *L) { 166 LStream *p; 167 luaL_checkany(L, 1); 168 p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE); 169 if (p == NULL) 170 luaL_pushfail(L); /* not a file */ 171 else if (isclosed(p)) 172 lua_pushliteral(L, "closed file"); 173 else 174 lua_pushliteral(L, "file"); 175 return 1; 176} 177 178 179static int f_tostring (lua_State *L) { 180 LStream *p = tolstream(L); 181 if (isclosed(p)) 182 lua_pushliteral(L, "file (closed)"); 183 else 184 lua_pushfstring(L, "file (%p)", p->f); 185 return 1; 186} 187 188 189static FILE *tofile (lua_State *L) { 190 LStream *p = tolstream(L); 191 if (l_unlikely(isclosed(p))) 192 luaL_error(L, "attempt to use a closed file"); 193 lua_assert(p->f); 194 return p->f; 195} 196 197 198/* 199** When creating file handles, always creates a 'closed' file handle 200** before opening the actual file; so, if there is a memory error, the 201** handle is in a consistent state. 202*/ 203static LStream *newprefile (lua_State *L) { 204 LStream *p = (LStream *)lua_newuserdatauv(L, sizeof(LStream), 0); 205 p->closef = NULL; /* mark file handle as 'closed' */ 206 luaL_setmetatable(L, LUA_FILEHANDLE); 207 return p; 208} 209 210 211/* 212** Calls the 'close' function from a file handle. The 'volatile' avoids 213** a bug in some versions of the Clang compiler (e.g., clang 3.0 for 214** 32 bits). 215*/ 216static int aux_close (lua_State *L) { 217 LStream *p = tolstream(L); 218 volatile lua_CFunction cf = p->closef; 219 p->closef = NULL; /* mark stream as closed */ 220 return (*cf)(L); /* close it */ 221} 222 223 224static int f_close (lua_State *L) { 225 tofile(L); /* make sure argument is an open stream */ 226 return aux_close(L); 227} 228 229 230static int io_close (lua_State *L) { 231 if (lua_isnone(L, 1)) /* no argument? */ 232 lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT); /* use default output */ 233 return f_close(L); 234} 235 236 237static int f_gc (lua_State *L) { 238 LStream *p = tolstream(L); 239 if (!isclosed(p) && p->f != NULL) 240 aux_close(L); /* ignore closed and incompletely open files */ 241 return 0; 242} 243 244 245/* 246** function to close regular files 247*/ 248static int io_fclose (lua_State *L) { 249 LStream *p = tolstream(L); 250 int res = fclose(p->f); 251 return luaL_fileresult(L, (res == 0), NULL); 252} 253 254 255static LStream *newfile (lua_State *L) { 256 LStream *p = newprefile(L); 257 p->f = NULL; 258 p->closef = &io_fclose; 259 return p; 260} 261 262 263static void opencheck (lua_State *L, const char *fname, const char *mode) { 264 LStream *p = newfile(L); 265 p->f = fopen(fname, mode); 266 if (l_unlikely(p->f == NULL)) 267 luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno)); 268} 269 270 271static int io_open (lua_State *L) { 272 const char *filename = luaL_checkstring(L, 1); 273 const char *mode = luaL_optstring(L, 2, "r"); 274 LStream *p = newfile(L); 275 const char *md = mode; /* to traverse/check mode */ 276 luaL_argcheck(L, l_checkmode(md), 2, "invalid mode"); 277 p->f = fopen(filename, mode); 278 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 279} 280 281 282/* 283** function to close 'popen' files 284*/ 285static int io_pclose (lua_State *L) { 286 LStream *p = tolstream(L); 287 errno = 0; 288 return luaL_execresult(L, l_pclose(L, p->f)); 289} 290 291 292static int io_popen (lua_State *L) { 293 const char *filename = luaL_checkstring(L, 1); 294 const char *mode = luaL_optstring(L, 2, "r"); 295 LStream *p = newprefile(L); 296 luaL_argcheck(L, l_checkmodep(mode), 2, "invalid mode"); 297 p->f = l_popen(L, filename, mode); 298 p->closef = &io_pclose; 299 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 300} 301 302 303static int io_tmpfile (lua_State *L) { 304 LStream *p = newfile(L); 305 p->f = tmpfile(); 306 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1; 307} 308 309 310static 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 320static 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 337static int io_input (lua_State *L) { 338 return g_iofile(L, IO_INPUT, "r"); 339} 340 341 342static int io_output (lua_State *L) { 343 return g_iofile(L, IO_OUTPUT, "w"); 344} 345 346 347static 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*/ 365static 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 376static 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*/ 388static 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' */ 429typedef 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*/ 440static 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++] = 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*/ 456static 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*/ 466static 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*/ 479static 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 513static 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 521static 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 int 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++] = 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, c); /* 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 542static 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 555static 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 568static 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 if (nargs == 0) { /* no arguments? */ 573 success = read_line(L, f, 1); 574 n = first + 1; /* to return 1 result */ 575 } 576 else { 577 /* ensure stack space for all results and for auxlib's buffer */ 578 luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments"); 579 success = 1; 580 for (n = first; nargs-- && success; n++) { 581 if (lua_type(L, n) == LUA_TNUMBER) { 582 size_t l = (size_t)luaL_checkinteger(L, n); 583 success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l); 584 } 585 else { 586 const char *p = luaL_checkstring(L, n); 587 if (*p == '*') p++; /* skip optional '*' (for compatibility) */ 588 switch (*p) { 589 case 'n': /* number */ 590 success = read_number(L, f); 591 break; 592 case 'l': /* line */ 593 success = read_line(L, f, 1); 594 break; 595 case 'L': /* line with end-of-line */ 596 success = read_line(L, f, 0); 597 break; 598 case 'a': /* file */ 599 read_all(L, f); /* read entire file */ 600 success = 1; /* always success */ 601 break; 602 default: 603 return luaL_argerror(L, n, "invalid format"); 604 } 605 } 606 } 607 } 608 if (ferror(f)) 609 return luaL_fileresult(L, 0, NULL); 610 if (!success) { 611 lua_pop(L, 1); /* remove last result */ 612 luaL_pushfail(L); /* push nil instead */ 613 } 614 return n - first; 615} 616 617 618static int io_read (lua_State *L) { 619 return g_read(L, getiofile(L, IO_INPUT), 1); 620} 621 622 623static int f_read (lua_State *L) { 624 return g_read(L, tofile(L), 2); 625} 626 627 628/* 629** Iteration function for 'lines'. 630*/ 631static int io_readline (lua_State *L) { 632 LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1)); 633 int i; 634 int n = (int)lua_tointeger(L, lua_upvalueindex(2)); 635 if (isclosed(p)) /* file is already closed? */ 636 return luaL_error(L, "file is already closed"); 637 lua_settop(L , 1); 638 luaL_checkstack(L, n, "too many arguments"); 639 for (i = 1; i <= n; i++) /* push arguments to 'g_read' */ 640 lua_pushvalue(L, lua_upvalueindex(3 + i)); 641 n = g_read(L, p->f, 2); /* 'n' is number of results */ 642 lua_assert(n > 0); /* should return at least a nil */ 643 if (lua_toboolean(L, -n)) /* read at least one value? */ 644 return n; /* return them */ 645 else { /* first result is false: EOF or error */ 646 if (n > 1) { /* is there error information? */ 647 /* 2nd result is error message */ 648 return luaL_error(L, "%s", lua_tostring(L, -n + 1)); 649 } 650 if (lua_toboolean(L, lua_upvalueindex(3))) { /* generator created file? */ 651 lua_settop(L, 0); /* clear stack */ 652 lua_pushvalue(L, lua_upvalueindex(1)); /* push file at index 1 */ 653 aux_close(L); /* close it */ 654 } 655 return 0; 656 } 657} 658 659/* }====================================================== */ 660 661 662static int g_write (lua_State *L, FILE *f, int arg) { 663 int nargs = lua_gettop(L) - arg; 664 int status = 1; 665 for (; nargs--; arg++) { 666 if (lua_type(L, arg) == LUA_TNUMBER) { 667 /* optimization: could be done exactly as for strings */ 668 int len = lua_isinteger(L, arg) 669 ? fprintf(f, LUA_INTEGER_FMT, 670 (LUAI_UACINT)lua_tointeger(L, arg)) 671 : fprintf(f, LUA_NUMBER_FMT, 672 (LUAI_UACNUMBER)lua_tonumber(L, arg)); 673 status = status && (len > 0); 674 } 675 else { 676 size_t l; 677 const char *s = luaL_checklstring(L, arg, &l); 678 status = status && (fwrite(s, sizeof(char), l, f) == l); 679 } 680 } 681 if (l_likely(status)) 682 return 1; /* file handle already on stack top */ 683 else return luaL_fileresult(L, status, NULL); 684} 685 686 687static int io_write (lua_State *L) { 688 return g_write(L, getiofile(L, IO_OUTPUT), 1); 689} 690 691 692static int f_write (lua_State *L) { 693 FILE *f = tofile(L); 694 lua_pushvalue(L, 1); /* push file at the stack top (to be returned) */ 695 return g_write(L, f, 2); 696} 697 698 699static int f_seek (lua_State *L) { 700 static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END}; 701 static const char *const modenames[] = {"set", "cur", "end", NULL}; 702 FILE *f = tofile(L); 703 int op = luaL_checkoption(L, 2, "cur", modenames); 704 lua_Integer p3 = luaL_optinteger(L, 3, 0); 705 l_seeknum offset = (l_seeknum)p3; 706 luaL_argcheck(L, (lua_Integer)offset == p3, 3, 707 "not an integer in proper range"); 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 718static 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 = setvbuf(f, NULL, mode[op], (size_t)sz); 725 return luaL_fileresult(L, res == 0, NULL); 726} 727 728 729 730static int io_flush (lua_State *L) { 731 return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL); 732} 733 734 735static int f_flush (lua_State *L) { 736 return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL); 737} 738 739 740/* 741** functions for 'io' library 742*/ 743static const luaL_Reg iolib[] = { 744 {"close", io_close}, 745 {"flush", io_flush}, 746 {"input", io_input}, 747 {"lines", io_lines}, 748 {"open", io_open}, 749 {"output", io_output}, 750 {"popen", io_popen}, 751 {"read", io_read}, 752 {"tmpfile", io_tmpfile}, 753 {"type", io_type}, 754 {"write", io_write}, 755 {NULL, NULL} 756}; 757 758 759/* 760** methods for file handles 761*/ 762static const luaL_Reg meth[] = { 763 {"read", f_read}, 764 {"write", f_write}, 765 {"lines", f_lines}, 766 {"flush", f_flush}, 767 {"seek", f_seek}, 768 {"close", f_close}, 769 {"setvbuf", f_setvbuf}, 770 {NULL, NULL} 771}; 772 773 774/* 775** metamethods for file handles 776*/ 777static const luaL_Reg metameth[] = { 778 {"__index", NULL}, /* place holder */ 779 {"__gc", f_gc}, 780 {"__close", f_gc}, 781 {"__tostring", f_tostring}, 782 {NULL, NULL} 783}; 784 785 786static void createmeta (lua_State *L) { 787 luaL_newmetatable(L, LUA_FILEHANDLE); /* metatable for file handles */ 788 luaL_setfuncs(L, metameth, 0); /* add metamethods to new metatable */ 789 luaL_newlibtable(L, meth); /* create method table */ 790 luaL_setfuncs(L, meth, 0); /* add file methods to method table */ 791 lua_setfield(L, -2, "__index"); /* metatable.__index = method table */ 792 lua_pop(L, 1); /* pop metatable */ 793} 794 795 796/* 797** function to (not) close the standard files stdin, stdout, and stderr 798*/ 799static int io_noclose (lua_State *L) { 800 LStream *p = tolstream(L); 801 p->closef = &io_noclose; /* keep file opened */ 802 luaL_pushfail(L); 803 lua_pushliteral(L, "cannot close standard file"); 804 return 2; 805} 806 807 808static void createstdfile (lua_State *L, FILE *f, const char *k, 809 const char *fname) { 810 LStream *p = newprefile(L); 811 p->f = f; 812 p->closef = &io_noclose; 813 if (k != NULL) { 814 lua_pushvalue(L, -1); 815 lua_setfield(L, LUA_REGISTRYINDEX, k); /* add file to registry */ 816 } 817 lua_setfield(L, -2, fname); /* add file to module */ 818} 819 820 821LUAMOD_API int luaopen_io (lua_State *L) { 822 luaL_newlib(L, iolib); /* new module */ 823 createmeta(L); 824 /* create (and set) default files */ 825 createstdfile(L, stdin, IO_INPUT, "stdin"); 826 createstdfile(L, stdout, IO_OUTPUT, "stdout"); 827 createstdfile(L, stderr, NULL, "stderr"); 828 return 1; 829} 830 831