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_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
149typedef 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
157static 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
171static 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
181static 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*/
195static 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*/
208static 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
216static int f_close (lua_State *L) {
217  tofile(L);  /* make sure argument is an open stream */
218  return aux_close(L);
219}
220
221
222static 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
229static 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*/
240static 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
247static 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
255static 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
263static 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*/
277static 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
284static 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
295static 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
302static 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
312static 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
329static int io_input (lua_State *L) {
330  return g_iofile(L, IO_INPUT, "r");
331}
332
333
334static int io_output (lua_State *L) {
335  return g_iofile(L, IO_OUTPUT, "w");
336}
337
338
339static 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*/
357static 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
368static 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*/
380static 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' */
421typedef 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*/
432static 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*/
448static 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*/
458static 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*/
471static 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
505static 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
513static 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
534static 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
547static 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
560static 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
610static int io_read (lua_State *L) {
611  return g_read(L, getiofile(L, IO_INPUT), 1);
612}
613
614
615static int f_read (lua_State *L) {
616  return g_read(L, tofile(L), 2);
617}
618
619
620/*
621** Iteration function for 'lines'.
622*/
623static 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
654static 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
678static int io_write (lua_State *L) {
679  return g_write(L, getiofile(L, IO_OUTPUT), 1);
680}
681
682
683static 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
690static 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
709static 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
721static int io_flush (lua_State *L) {
722  return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
723}
724
725
726static 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*/
734static 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*/
753static 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*/
768static 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
777static 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*/
790static 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
799static 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
812LUAMOD_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