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]*' */
l_checkmode(const char * mode)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
io_type(lua_State * L)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
f_tostring(lua_State * L)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
tofile(lua_State * L)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 */
newprefile(lua_State * L)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 */
aux_close(lua_State * L)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
f_close(lua_State * L)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
io_close(lua_State * L)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
f_gc(lua_State * L)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 */
io_fclose(lua_State * L)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
newfile(lua_State * L)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
opencheck(lua_State * L,const char * fname,const char * mode)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
io_open(lua_State * L)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 */
io_pclose(lua_State * L)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
io_popen(lua_State * L)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
io_tmpfile(lua_State * L)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
getiofile(lua_State * L,const char * findex)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
g_iofile(lua_State * L,const char * f,const char * mode)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
io_input(lua_State * L)329 static int io_input (lua_State *L) {
330 return g_iofile(L, IO_INPUT, "r");
331 }
332
333
io_output(lua_State * L)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 */
aux_lines(lua_State * L,int toclose)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
f_lines(lua_State * L)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 */
io_lines(lua_State * L)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 */
nextc(RN * rn)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 */
test2(RN * rn,const char * set)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 */
readdigits(RN * rn,int hex)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 */
read_number(lua_State * L,FILE * f)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
test_eof(lua_State * L,FILE * f)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
read_line(lua_State * L,FILE * f,int chop)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
read_all(lua_State * L,FILE * f)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
read_chars(lua_State * L,FILE * f,size_t n)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
g_read(lua_State * L,FILE * f,int first)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
io_read(lua_State * L)610 static int io_read (lua_State *L) {
611 return g_read(L, getiofile(L, IO_INPUT), 1);
612 }
613
614
f_read(lua_State * L)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 */
io_readline(lua_State * L)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
g_write(lua_State * L,FILE * f,int arg)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
io_write(lua_State * L)678 static int io_write (lua_State *L) {
679 return g_write(L, getiofile(L, IO_OUTPUT), 1);
680 }
681
682
f_write(lua_State * L)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
f_seek(lua_State * L)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
f_setvbuf(lua_State * L)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
io_flush(lua_State * L)721 static int io_flush (lua_State *L) {
722 return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
723 }
724
725
f_flush(lua_State * L)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
createmeta(lua_State * L)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 */
io_noclose(lua_State * L)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
createstdfile(lua_State * L,FILE * f,const char * k,const char * fname)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
luaopen_io(lua_State * L)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