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