1 /*
2 ** $Id: liolib.c,v 2.151.1.1 2017/04/19 17:29:57 roberto Exp $
3 ** Standard I/O (and system) library
4 ** See Copyright Notice in lua.h
5 */
6
7 #define liolib_c
8 #define LUA_LIB
9
10 #include "lprefix.h"
11
12
13 #include <ctype.h>
14 #include <errno.h>
15 #include <locale.h>
16 #include <stdio.h>
17 #include <stdlib.h>
18 #include <string.h>
19
20 #include "lua.h"
21
22 #include "lauxlib.h"
23 #include "lualib.h"
24
25
26
27
28 /*
29 ** Change this macro to accept other modes for 'fopen' besides
30 ** the standard ones.
31 */
32 #if !defined(l_checkmode)
33
34 /* accepted extensions to 'mode' in 'fopen' */
35 #if !defined(L_MODEEXT)
36 #define L_MODEEXT "b"
37 #endif
38
39 /* Check whether 'mode' matches '[rwa]%+?[L_MODEEXT]*' */
l_checkmode(const char * mode)40 static int l_checkmode (const char *mode) {
41 return (*mode != '\0' && strchr("rwa", *(mode++)) != NULL &&
42 (*mode != '+' || (++mode, 1)) && /* skip if char is '+' */
43 (strspn(mode, L_MODEEXT) == strlen(mode))); /* check extensions */
44 }
45
46 #endif
47
48 /*
49 ** {======================================================
50 ** l_popen spawns a new process connected to the current
51 ** one through the file streams.
52 ** =======================================================
53 */
54
55 #if !defined(l_popen) /* { */
56
57 #if defined(LUA_USE_POSIX) /* { */
58
59 #define l_popen(L,c,m) (fflush(NULL), popen(c,m))
60 #define l_pclose(L,file) (pclose(file))
61
62 #elif defined(LUA_USE_WINDOWS) /* }{ */
63
64 #define l_popen(L,c,m) (_popen(c,m))
65 #define l_pclose(L,file) (_pclose(file))
66
67 #else /* }{ */
68
69 /* ISO C definitions */
70 #define l_popen(L,c,m) \
71 ((void)((void)c, m), \
72 luaL_error(L, "'popen' not supported"), \
73 (FILE*)0)
74 #define l_pclose(L,file) ((void)L, (void)file, -1)
75
76 #endif /* } */
77
78 #endif /* } */
79
80 /* }====================================================== */
81
82
83 #if !defined(l_getc) /* { */
84
85 #if defined(LUA_USE_POSIX)
86 #define l_getc(f) getc_unlocked(f)
87 #define l_lockfile(f) flockfile(f)
88 #define l_unlockfile(f) funlockfile(f)
89 #else
90 #define l_getc(f) getc(f)
91 #define l_lockfile(f) ((void)0)
92 #define l_unlockfile(f) ((void)0)
93 #endif
94
95 #endif /* } */
96
97
98 /*
99 ** {======================================================
100 ** l_fseek: configuration for longer offsets
101 ** =======================================================
102 */
103
104 #if !defined(l_fseek) /* { */
105
106 #if defined(LUA_USE_POSIX) /* { */
107
108 #include <sys/types.h>
109
110 #define l_fseek(f,o,w) fseeko(f,o,w)
111 #define l_ftell(f) ftello(f)
112 #define l_seeknum off_t
113
114 #elif defined(LUA_USE_WINDOWS) && !defined(_CRTIMP_TYPEINFO) \
115 && defined(_MSC_VER) && (_MSC_VER >= 1400) /* }{ */
116
117 /* Windows (but not DDK) and Visual C++ 2005 or higher */
118 #define l_fseek(f,o,w) _fseeki64(f,o,w)
119 #define l_ftell(f) _ftelli64(f)
120 #define l_seeknum __int64
121
122 #else /* }{ */
123
124 /* ISO C definitions */
125 #define l_fseek(f,o,w) fseek(f,o,w)
126 #define l_ftell(f) ftell(f)
127 #define l_seeknum long
128
129 #endif /* } */
130
131 #endif /* } */
132
133 /* }====================================================== */
134
135
136 #define IO_PREFIX "_IO_"
137 #define IOPREF_LEN (sizeof(IO_PREFIX)/sizeof(char) - 1)
138 #define IO_INPUT (IO_PREFIX "input")
139 #define IO_OUTPUT (IO_PREFIX "output")
140
141
142 typedef luaL_Stream LStream;
143
144
145 #define tolstream(L) ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))
146
147 #define isclosed(p) ((p)->closef == NULL)
148
149
io_type(lua_State * L)150 static int io_type (lua_State *L) {
151 LStream *p;
152 luaL_checkany(L, 1);
153 p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE);
154 if (p == NULL)
155 lua_pushnil(L); /* not a file */
156 else if (isclosed(p))
157 lua_pushliteral(L, "closed file");
158 else
159 lua_pushliteral(L, "file");
160 return 1;
161 }
162
163
f_tostring(lua_State * L)164 static int f_tostring (lua_State *L) {
165 LStream *p = tolstream(L);
166 if (isclosed(p))
167 lua_pushliteral(L, "file (closed)");
168 else
169 lua_pushfstring(L, "file (%p)", p->f);
170 return 1;
171 }
172
173
tofile(lua_State * L)174 static FILE *tofile (lua_State *L) {
175 LStream *p = tolstream(L);
176 if (isclosed(p))
177 luaL_error(L, "attempt to use a closed file");
178 lua_assert(p->f);
179 return p->f;
180 }
181
182
183 /*
184 ** When creating file handles, always creates a 'closed' file handle
185 ** before opening the actual file; so, if there is a memory error, the
186 ** handle is in a consistent state.
187 */
newprefile(lua_State * L)188 static LStream *newprefile (lua_State *L) {
189 LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream));
190 p->closef = NULL; /* mark file handle as 'closed' */
191 luaL_setmetatable(L, LUA_FILEHANDLE);
192 return p;
193 }
194
195
196 /*
197 ** Calls the 'close' function from a file handle. The 'volatile' avoids
198 ** a bug in some versions of the Clang compiler (e.g., clang 3.0 for
199 ** 32 bits).
200 */
aux_close(lua_State * L)201 static int aux_close (lua_State *L) {
202 LStream *p = tolstream(L);
203 volatile lua_CFunction cf = p->closef;
204 p->closef = NULL; /* mark stream as closed */
205 return (*cf)(L); /* close it */
206 }
207
208
f_close(lua_State * L)209 static int f_close (lua_State *L) {
210 tofile(L); /* make sure argument is an open stream */
211 return aux_close(L);
212 }
213
214
io_close(lua_State * L)215 static int io_close (lua_State *L) {
216 if (lua_isnone(L, 1)) /* no argument? */
217 lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT); /* use standard output */
218 return f_close(L);
219 }
220
221
f_gc(lua_State * L)222 static int f_gc (lua_State *L) {
223 LStream *p = tolstream(L);
224 if (!isclosed(p) && p->f != NULL)
225 aux_close(L); /* ignore closed and incompletely open files */
226 return 0;
227 }
228
229
230 /*
231 ** function to close regular files
232 */
io_fclose(lua_State * L)233 static int io_fclose (lua_State *L) {
234 LStream *p = tolstream(L);
235 int res = fclose(p->f);
236 return luaL_fileresult(L, (res == 0), NULL);
237 }
238
239
newfile(lua_State * L)240 static LStream *newfile (lua_State *L) {
241 LStream *p = newprefile(L);
242 p->f = NULL;
243 p->closef = &io_fclose;
244 return p;
245 }
246
247
opencheck(lua_State * L,const char * fname,const char * mode)248 static void opencheck (lua_State *L, const char *fname, const char *mode) {
249 LStream *p = newfile(L);
250 p->f = fopen(fname, mode);
251 if (p->f == NULL)
252 luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno));
253 }
254
255
io_open(lua_State * L)256 static int io_open (lua_State *L) {
257 const char *filename = luaL_checkstring(L, 1);
258 const char *mode = luaL_optstring(L, 2, "r");
259 LStream *p = newfile(L);
260 const char *md = mode; /* to traverse/check mode */
261 luaL_argcheck(L, l_checkmode(md), 2, "invalid mode");
262 p->f = fopen(filename, mode);
263 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
264 }
265
266
267 /*
268 ** function to close 'popen' files
269 */
io_pclose(lua_State * L)270 static int io_pclose (lua_State *L) {
271 LStream *p = tolstream(L);
272 return luaL_execresult(L, l_pclose(L, p->f));
273 }
274
275
io_popen(lua_State * L)276 static int io_popen (lua_State *L) {
277 const char *filename = luaL_checkstring(L, 1);
278 const char *mode = luaL_optstring(L, 2, "r");
279 LStream *p = newprefile(L);
280 luaL_argcheck(L, ((mode[0] == 'r' || mode[0] == 'w') && mode[1] == '\0'),
281 2, "invalid mode");
282 p->f = l_popen(L, filename, mode);
283 p->closef = &io_pclose;
284 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
285 }
286
287
io_tmpfile(lua_State * L)288 static int io_tmpfile (lua_State *L) {
289 LStream *p = newfile(L);
290 p->f = tmpfile();
291 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1;
292 }
293
294
getiofile(lua_State * L,const char * findex)295 static FILE *getiofile (lua_State *L, const char *findex) {
296 LStream *p;
297 lua_getfield(L, LUA_REGISTRYINDEX, findex);
298 p = (LStream *)lua_touserdata(L, -1);
299 if (isclosed(p))
300 luaL_error(L, "standard %s file is closed", findex + IOPREF_LEN);
301 return p->f;
302 }
303
304
g_iofile(lua_State * L,const char * f,const char * mode)305 static int g_iofile (lua_State *L, const char *f, const char *mode) {
306 if (!lua_isnoneornil(L, 1)) {
307 const char *filename = lua_tostring(L, 1);
308 if (filename)
309 opencheck(L, filename, mode);
310 else {
311 tofile(L); /* check that it's a valid file handle */
312 lua_pushvalue(L, 1);
313 }
314 lua_setfield(L, LUA_REGISTRYINDEX, f);
315 }
316 /* return current value */
317 lua_getfield(L, LUA_REGISTRYINDEX, f);
318 return 1;
319 }
320
321
io_input(lua_State * L)322 static int io_input (lua_State *L) {
323 return g_iofile(L, IO_INPUT, "r");
324 }
325
326
io_output(lua_State * L)327 static int io_output (lua_State *L) {
328 return g_iofile(L, IO_OUTPUT, "w");
329 }
330
331
332 static int io_readline (lua_State *L);
333
334
335 /*
336 ** maximum number of arguments to 'f:lines'/'io.lines' (it + 3 must fit
337 ** in the limit for upvalues of a closure)
338 */
339 #define MAXARGLINE 250
340
aux_lines(lua_State * L,int toclose)341 static void aux_lines (lua_State *L, int toclose) {
342 int n = lua_gettop(L) - 1; /* number of arguments to read */
343 luaL_argcheck(L, n <= MAXARGLINE, MAXARGLINE + 2, "too many arguments");
344 lua_pushinteger(L, n); /* number of arguments to read */
345 lua_pushboolean(L, toclose); /* close/not close file when finished */
346 lua_rotate(L, 2, 2); /* move 'n' and 'toclose' to their positions */
347 lua_pushcclosure(L, io_readline, 3 + n);
348 }
349
350
f_lines(lua_State * L)351 static int f_lines (lua_State *L) {
352 tofile(L); /* check that it's a valid file handle */
353 aux_lines(L, 0);
354 return 1;
355 }
356
357
io_lines(lua_State * L)358 static int io_lines (lua_State *L) {
359 int toclose;
360 if (lua_isnone(L, 1)) lua_pushnil(L); /* at least one argument */
361 if (lua_isnil(L, 1)) { /* no file name? */
362 lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT); /* get default input */
363 lua_replace(L, 1); /* put it at index 1 */
364 tofile(L); /* check that it's a valid file handle */
365 toclose = 0; /* do not close it after iteration */
366 }
367 else { /* open a new file */
368 const char *filename = luaL_checkstring(L, 1);
369 opencheck(L, filename, "r");
370 lua_replace(L, 1); /* put file at index 1 */
371 toclose = 1; /* close it after iteration */
372 }
373 aux_lines(L, toclose);
374 return 1;
375 }
376
377
378 /*
379 ** {======================================================
380 ** READ
381 ** =======================================================
382 */
383
384
385 /* maximum length of a numeral */
386 #if !defined (L_MAXLENNUM)
387 #define L_MAXLENNUM 200
388 #endif
389
390
391 /* auxiliary structure used by 'read_number' */
392 typedef struct {
393 FILE *f; /* file being read */
394 int c; /* current character (look ahead) */
395 int n; /* number of elements in buffer 'buff' */
396 char buff[L_MAXLENNUM + 1]; /* +1 for ending '\0' */
397 } RN;
398
399
400 /*
401 ** Add current char to buffer (if not out of space) and read next one
402 */
nextc(RN * rn)403 static int nextc (RN *rn) {
404 if (rn->n >= L_MAXLENNUM) { /* buffer overflow? */
405 rn->buff[0] = '\0'; /* invalidate result */
406 return 0; /* fail */
407 }
408 else {
409 rn->buff[rn->n++] = rn->c; /* save current char */
410 rn->c = l_getc(rn->f); /* read next one */
411 return 1;
412 }
413 }
414
415
416 /*
417 ** Accept current char if it is in 'set' (of size 2)
418 */
test2(RN * rn,const char * set)419 static int test2 (RN *rn, const char *set) {
420 if (rn->c == set[0] || rn->c == set[1])
421 return nextc(rn);
422 else return 0;
423 }
424
425
426 /*
427 ** Read a sequence of (hex)digits
428 */
readdigits(RN * rn,int hex)429 static int readdigits (RN *rn, int hex) {
430 int count = 0;
431 while ((hex ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn))
432 count++;
433 return count;
434 }
435
436
437 /*
438 ** Read a number: first reads a valid prefix of a numeral into a buffer.
439 ** Then it calls 'lua_stringtonumber' to check whether the format is
440 ** correct and to convert it to a Lua number
441 */
read_number(lua_State * L,FILE * f)442 static int read_number (lua_State *L, FILE *f) {
443 RN rn;
444 int count = 0;
445 int hex = 0;
446 char decp[2];
447 rn.f = f; rn.n = 0;
448 decp[0] = lua_getlocaledecpoint(); /* get decimal point from locale */
449 decp[1] = '.'; /* always accept a dot */
450 l_lockfile(rn.f);
451 do { rn.c = l_getc(rn.f); } while (isspace(rn.c)); /* skip spaces */
452 test2(&rn, "-+"); /* optional signal */
453 if (test2(&rn, "00")) {
454 if (test2(&rn, "xX")) hex = 1; /* numeral is hexadecimal */
455 else count = 1; /* count initial '0' as a valid digit */
456 }
457 count += readdigits(&rn, hex); /* integral part */
458 if (test2(&rn, decp)) /* decimal point? */
459 count += readdigits(&rn, hex); /* fractional part */
460 if (count > 0 && test2(&rn, (hex ? "pP" : "eE"))) { /* exponent mark? */
461 test2(&rn, "-+"); /* exponent signal */
462 readdigits(&rn, 0); /* exponent digits */
463 }
464 ungetc(rn.c, rn.f); /* unread look-ahead char */
465 l_unlockfile(rn.f);
466 rn.buff[rn.n] = '\0'; /* finish string */
467 if (lua_stringtonumber(L, rn.buff)) /* is this a valid number? */
468 return 1; /* ok */
469 else { /* invalid format */
470 lua_pushnil(L); /* "result" to be removed */
471 return 0; /* read fails */
472 }
473 }
474
475
test_eof(lua_State * L,FILE * f)476 static int test_eof (lua_State *L, FILE *f) {
477 int c = getc(f);
478 ungetc(c, f); /* no-op when c == EOF */
479 lua_pushliteral(L, "");
480 return (c != EOF);
481 }
482
483
read_line(lua_State * L,FILE * f,int chop)484 static int read_line (lua_State *L, FILE *f, int chop) {
485 luaL_Buffer b;
486 int c = '\0';
487 luaL_buffinit(L, &b);
488 while (c != EOF && c != '\n') { /* repeat until end of line */
489 char *buff = luaL_prepbuffer(&b); /* preallocate buffer */
490 int i = 0;
491 l_lockfile(f); /* no memory errors can happen inside the lock */
492 while (i < LUAL_BUFFERSIZE && (c = l_getc(f)) != EOF && c != '\n')
493 buff[i++] = c;
494 l_unlockfile(f);
495 luaL_addsize(&b, i);
496 }
497 if (!chop && c == '\n') /* want a newline and have one? */
498 luaL_addchar(&b, c); /* add ending newline to result */
499 luaL_pushresult(&b); /* close buffer */
500 /* return ok if read something (either a newline or something else) */
501 return (c == '\n' || lua_rawlen(L, -1) > 0);
502 }
503
504
read_all(lua_State * L,FILE * f)505 static void read_all (lua_State *L, FILE *f) {
506 size_t nr;
507 luaL_Buffer b;
508 luaL_buffinit(L, &b);
509 do { /* read file in chunks of LUAL_BUFFERSIZE bytes */
510 char *p = luaL_prepbuffer(&b);
511 nr = fread(p, sizeof(char), LUAL_BUFFERSIZE, f);
512 luaL_addsize(&b, nr);
513 } while (nr == LUAL_BUFFERSIZE);
514 luaL_pushresult(&b); /* close buffer */
515 }
516
517
read_chars(lua_State * L,FILE * f,size_t n)518 static int read_chars (lua_State *L, FILE *f, size_t n) {
519 size_t nr; /* number of chars actually read */
520 char *p;
521 luaL_Buffer b;
522 luaL_buffinit(L, &b);
523 p = luaL_prepbuffsize(&b, n); /* prepare buffer to read whole block */
524 nr = fread(p, sizeof(char), n, f); /* try to read 'n' chars */
525 luaL_addsize(&b, nr);
526 luaL_pushresult(&b); /* close buffer */
527 return (nr > 0); /* true iff read something */
528 }
529
530
g_read(lua_State * L,FILE * f,int first)531 static int g_read (lua_State *L, FILE *f, int first) {
532 int nargs = lua_gettop(L) - 1;
533 int success;
534 int n;
535 clearerr(f);
536 if (nargs == 0) { /* no arguments? */
537 success = read_line(L, f, 1);
538 n = first+1; /* to return 1 result */
539 }
540 else { /* ensure stack space for all results and for auxlib's buffer */
541 luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");
542 success = 1;
543 for (n = first; nargs-- && success; n++) {
544 if (lua_type(L, n) == LUA_TNUMBER) {
545 size_t l = (size_t)luaL_checkinteger(L, n);
546 success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
547 }
548 else {
549 const char *p = luaL_checkstring(L, n);
550 if (*p == '*') p++; /* skip optional '*' (for compatibility) */
551 switch (*p) {
552 case 'n': /* number */
553 success = read_number(L, f);
554 break;
555 case 'l': /* line */
556 success = read_line(L, f, 1);
557 break;
558 case 'L': /* line with end-of-line */
559 success = read_line(L, f, 0);
560 break;
561 case 'a': /* file */
562 read_all(L, f); /* read entire file */
563 success = 1; /* always success */
564 break;
565 default:
566 return luaL_argerror(L, n, "invalid format");
567 }
568 }
569 }
570 }
571 if (ferror(f))
572 return luaL_fileresult(L, 0, NULL);
573 if (!success) {
574 lua_pop(L, 1); /* remove last result */
575 lua_pushnil(L); /* push nil instead */
576 }
577 return n - first;
578 }
579
580
io_read(lua_State * L)581 static int io_read (lua_State *L) {
582 return g_read(L, getiofile(L, IO_INPUT), 1);
583 }
584
585
f_read(lua_State * L)586 static int f_read (lua_State *L) {
587 return g_read(L, tofile(L), 2);
588 }
589
590
io_readline(lua_State * L)591 static int io_readline (lua_State *L) {
592 LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1));
593 int i;
594 int n = (int)lua_tointeger(L, lua_upvalueindex(2));
595 if (isclosed(p)) /* file is already closed? */
596 return luaL_error(L, "file is already closed");
597 lua_settop(L , 1);
598 luaL_checkstack(L, n, "too many arguments");
599 for (i = 1; i <= n; i++) /* push arguments to 'g_read' */
600 lua_pushvalue(L, lua_upvalueindex(3 + i));
601 n = g_read(L, p->f, 2); /* 'n' is number of results */
602 lua_assert(n > 0); /* should return at least a nil */
603 if (lua_toboolean(L, -n)) /* read at least one value? */
604 return n; /* return them */
605 else { /* first result is nil: EOF or error */
606 if (n > 1) { /* is there error information? */
607 /* 2nd result is error message */
608 return luaL_error(L, "%s", lua_tostring(L, -n + 1));
609 }
610 if (lua_toboolean(L, lua_upvalueindex(3))) { /* generator created file? */
611 lua_settop(L, 0);
612 lua_pushvalue(L, lua_upvalueindex(1));
613 aux_close(L); /* close it */
614 }
615 return 0;
616 }
617 }
618
619 /* }====================================================== */
620
621
g_write(lua_State * L,FILE * f,int arg)622 static int g_write (lua_State *L, FILE *f, int arg) {
623 int nargs = lua_gettop(L) - arg;
624 int status = 1;
625 for (; nargs--; arg++) {
626 if (lua_type(L, arg) == LUA_TNUMBER) {
627 /* optimization: could be done exactly as for strings */
628 int len = lua_isinteger(L, arg)
629 ? fprintf(f, LUA_INTEGER_FMT,
630 (LUAI_UACINT)lua_tointeger(L, arg))
631 : fprintf(f, LUA_NUMBER_FMT,
632 (LUAI_UACNUMBER)lua_tonumber(L, arg));
633 status = status && (len > 0);
634 }
635 else {
636 size_t l;
637 const char *s = luaL_checklstring(L, arg, &l);
638 status = status && (fwrite(s, sizeof(char), l, f) == l);
639 }
640 }
641 if (status) return 1; /* file handle already on stack top */
642 else return luaL_fileresult(L, status, NULL);
643 }
644
645
io_write(lua_State * L)646 static int io_write (lua_State *L) {
647 return g_write(L, getiofile(L, IO_OUTPUT), 1);
648 }
649
650
f_write(lua_State * L)651 static int f_write (lua_State *L) {
652 FILE *f = tofile(L);
653 lua_pushvalue(L, 1); /* push file at the stack top (to be returned) */
654 return g_write(L, f, 2);
655 }
656
657
f_seek(lua_State * L)658 static int f_seek (lua_State *L) {
659 static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
660 static const char *const modenames[] = {"set", "cur", "end", NULL};
661 FILE *f = tofile(L);
662 int op = luaL_checkoption(L, 2, "cur", modenames);
663 lua_Integer p3 = luaL_optinteger(L, 3, 0);
664 l_seeknum offset = (l_seeknum)p3;
665 luaL_argcheck(L, (lua_Integer)offset == p3, 3,
666 "not an integer in proper range");
667 op = l_fseek(f, offset, mode[op]);
668 if (op)
669 return luaL_fileresult(L, 0, NULL); /* error */
670 else {
671 lua_pushinteger(L, (lua_Integer)l_ftell(f));
672 return 1;
673 }
674 }
675
676
f_setvbuf(lua_State * L)677 static int f_setvbuf (lua_State *L) {
678 static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
679 static const char *const modenames[] = {"no", "full", "line", NULL};
680 FILE *f = tofile(L);
681 int op = luaL_checkoption(L, 2, NULL, modenames);
682 lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
683 int res = setvbuf(f, NULL, mode[op], (size_t)sz);
684 return luaL_fileresult(L, res == 0, NULL);
685 }
686
687
688
io_flush(lua_State * L)689 static int io_flush (lua_State *L) {
690 return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
691 }
692
693
f_flush(lua_State * L)694 static int f_flush (lua_State *L) {
695 return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL);
696 }
697
698
699 /*
700 ** functions for 'io' library
701 */
702 static const luaL_Reg iolib[] = {
703 {"close", io_close},
704 {"flush", io_flush},
705 {"input", io_input},
706 {"lines", io_lines},
707 {"open", io_open},
708 {"output", io_output},
709 {"popen", io_popen},
710 {"read", io_read},
711 {"tmpfile", io_tmpfile},
712 {"type", io_type},
713 {"write", io_write},
714 {NULL, NULL}
715 };
716
717
718 /*
719 ** methods for file handles
720 */
721 static const luaL_Reg flib[] = {
722 {"close", f_close},
723 {"flush", f_flush},
724 {"lines", f_lines},
725 {"read", f_read},
726 {"seek", f_seek},
727 {"setvbuf", f_setvbuf},
728 {"write", f_write},
729 {"__gc", f_gc},
730 {"__tostring", f_tostring},
731 {NULL, NULL}
732 };
733
734
createmeta(lua_State * L)735 static void createmeta (lua_State *L) {
736 luaL_newmetatable(L, LUA_FILEHANDLE); /* create metatable for file handles */
737 lua_pushvalue(L, -1); /* push metatable */
738 lua_setfield(L, -2, "__index"); /* metatable.__index = metatable */
739 luaL_setfuncs(L, flib, 0); /* add file methods to new metatable */
740 lua_pop(L, 1); /* pop new metatable */
741 }
742
743
744 /*
745 ** function to (not) close the standard files stdin, stdout, and stderr
746 */
io_noclose(lua_State * L)747 static int io_noclose (lua_State *L) {
748 LStream *p = tolstream(L);
749 p->closef = &io_noclose; /* keep file opened */
750 lua_pushnil(L);
751 lua_pushliteral(L, "cannot close standard file");
752 return 2;
753 }
754
755
createstdfile(lua_State * L,FILE * f,const char * k,const char * fname)756 static void createstdfile (lua_State *L, FILE *f, const char *k,
757 const char *fname) {
758 LStream *p = newprefile(L);
759 p->f = f;
760 p->closef = &io_noclose;
761 if (k != NULL) {
762 lua_pushvalue(L, -1);
763 lua_setfield(L, LUA_REGISTRYINDEX, k); /* add file to registry */
764 }
765 lua_setfield(L, -2, fname); /* add file to module */
766 }
767
768
luaopen_io(lua_State * L)769 LUAMOD_API int luaopen_io (lua_State *L) {
770 luaL_newlib(L, iolib); /* new module */
771 createmeta(L);
772 /* create (and set) default files */
773 createstdfile(L, stdin, IO_INPUT, "stdin");
774 createstdfile(L, stdout, IO_OUTPUT, "stdout");
775 createstdfile(L, stderr, NULL, "stderr");
776 return 1;
777 }
778
779