about summary refs log tree commit diff
path: root/libio/wfileops.c
blob: 9fa91f03998e2ec3391b35be3ccf54da65e0ece1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
/* Copyright (C) 1993, 95, 97, 98, 99, 2000 Free Software Foundation, Inc.
   This file is part of the GNU IO Library.
   Written by Ulrich Drepper <drepper@cygnus.com>.
   Based on the single byte version by Per Bothner <bothner@cygnus.com>.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This library is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this library; see the file COPYING.  If not, write to
   the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
   MA 02111-1307, USA.

   As a special exception, if you link this library with files
   compiled with a GNU compiler to produce an executable, this does
   not cause the resulting executable to be covered by the GNU General
   Public License.  This exception does not however invalidate any
   other reasons why the executable file might be covered by the GNU
   General Public License.  */

#include <assert.h>
#include <libioP.h>
#include <wchar.h>
#include <gconv.h>
#include <stdlib.h>
#include <string.h>


_IO_FILE *
_IO_wfile_setbuf (fp, p, len)
     _IO_FILE *fp;
     wchar_t *p;
     _IO_ssize_t len;
{
  if (_IO_wdefault_setbuf (fp, p, len) == NULL)
    return NULL;

  fp->_wide_data->_IO_write_base = fp->_wide_data->_IO_write_ptr =
    fp->_wide_data->_IO_write_end = fp->_wide_data->_IO_buf_base;
  _IO_wsetg (fp, fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base,
	     fp->_wide_data->_IO_buf_base);

  return fp;
}


/* Convert TO_DO wide character from DATA to FP.
   Then mark FP as having empty buffers. */
int
_IO_wdo_write (fp, data, to_do)
     _IO_FILE *fp;
     const wchar_t *data;
     _IO_size_t to_do;
{
  struct _IO_codecvt *cc = &fp->_codecvt;

  if (to_do > 0)
    {
      if (fp->_IO_write_end == fp->_IO_write_ptr
	  && fp->_IO_write_end != fp->_IO_write_base)
	{
	  if (_IO_new_do_write (fp, fp->_IO_write_base,
				fp->_IO_write_ptr - fp->_IO_write_base) == EOF)
	    return EOF;
	}

      do
	{
	  enum __codecvt_result result;
	  const wchar_t *new_data;

	  /* Now convert from the internal format into the external buffer.  */
	  result = (*cc->__codecvt_do_out) (cc, &fp->_wide_data->_IO_state,
					    data, data + to_do, &new_data,
					    fp->_IO_write_ptr,
					    fp->_IO_buf_end,
					    &fp->_IO_write_ptr);

	  /* Write out what we produced so far.  */
	  if (_IO_new_do_write (fp, fp->_IO_write_base,
				fp->_IO_write_ptr - fp->_IO_write_base) == EOF)
	    /* Something went wrong.  */
	    return EOF;

	  to_do -= new_data - data;

	  /* Next see whether we had problems during the conversion.  If yes,
	     we cannot go on.  */
	  if (result != __codecvt_ok
	      && (result != __codecvt_partial || new_data - data == 0))
	    break;

	  data = new_data;
	}
      while (to_do > 0);
    }

  _IO_wsetg (fp, fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base,
	     fp->_wide_data->_IO_buf_base);
  fp->_wide_data->_IO_write_base = fp->_wide_data->_IO_write_ptr
    = fp->_wide_data->_IO_buf_base;
  fp->_wide_data->_IO_write_end = ((fp->_flags & (_IO_LINE_BUF+_IO_UNBUFFERED))
				   ? fp->_wide_data->_IO_buf_base
				   : fp->_wide_data->_IO_buf_end);

  return to_do == 0 ? 0 : WEOF;
}


wint_t
_IO_wfile_underflow (fp)
     _IO_FILE *fp;
{
  struct _IO_codecvt *cd;
  enum __codecvt_result status;
  _IO_ssize_t count;
  int tries;
  const char *read_ptr_copy;

  if (fp->_flags & _IO_NO_READS)
    {
      fp->_flags |= _IO_ERR_SEEN;
      __set_errno (EBADF);
      return WEOF;
    }
  if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
    return *fp->_wide_data->_IO_read_ptr;

  cd = &fp->_codecvt;

  /* Maybe there is something left in the external buffer.  */
  if (fp->_IO_read_ptr < fp->_IO_read_end)
    {
      /* Convert it.  */
      size_t avail_bytes = fp->_IO_read_end - fp->_IO_read_ptr;

      if (avail_bytes >= (*cd->__codecvt_do_max_length) (cd))
	{
	  /* There is more in the external.  */
	  const char *read_stop = (const char *) fp->_IO_read_ptr;

	  fp->_wide_data->_IO_last_state = fp->_wide_data->_IO_state;
	  status = (*cd->__codecvt_do_in) (cd, &fp->_wide_data->_IO_state,
					   fp->_IO_read_ptr, fp->_IO_read_end,
					   &read_stop,
					   fp->_wide_data->_IO_read_end,
					   fp->_wide_data->_IO_buf_end,
					   &fp->_wide_data->_IO_read_end);

	  fp->_IO_read_ptr = (char *) read_stop;

	  /* If we managed to generate some text return the next character.  */
	  if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
	    return *fp->_wide_data->_IO_read_ptr;

	  if (status == __codecvt_error)
	    {
	      __set_errno (EILSEQ);
	      fp->_flags |= _IO_ERR_SEEN;
	      return WEOF;
	    }
	}

      /* Move the remaining content of the read buffer to the beginning.  */
      memmove (fp->_IO_buf_base, fp->_IO_read_ptr,
	       fp->_IO_read_end - fp->_IO_read_ptr);
      fp->_IO_read_end = (fp->_IO_buf_base
			  + (fp->_IO_read_end - fp->_IO_read_ptr));
      fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_buf_base;
    }
  else
    fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_read_end =
      fp->_IO_buf_base;

  if (fp->_IO_buf_base == NULL)
    {
      /* Maybe we already have a push back pointer.  */
      if (fp->_IO_save_base != NULL)
	{
	  free (fp->_IO_save_base);
	  fp->_flags &= ~_IO_IN_BACKUP;
	}
      _IO_doallocbuf (fp);

      fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_read_end =
	fp->_IO_buf_base;
    }

  fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end =
    fp->_IO_buf_base;

  if (fp->_wide_data->_IO_buf_base == NULL)
    {
      /* Maybe we already have a push back pointer.  */
      if (fp->_wide_data->_IO_save_base != NULL)
	{
	  free (fp->_wide_data->_IO_save_base);
	  fp->_flags &= ~_IO_IN_BACKUP;
	}
      _IO_wdoallocbuf (fp);
    }

  /* Flush all line buffered files before reading. */
  /* FIXME This can/should be moved to genops ?? */
  if (fp->_flags & (_IO_LINE_BUF|_IO_UNBUFFERED))
    _IO_flush_all_linebuffered ();

  _IO_switch_to_get_mode (fp);

  fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_read_ptr =
    fp->_wide_data->_IO_buf_base;
  fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_buf_base;
  fp->_wide_data->_IO_write_base = fp->_wide_data->_IO_write_ptr =
    fp->_wide_data->_IO_write_end = fp->_wide_data->_IO_buf_base;

  tries = 0;
 again:
  count = _IO_SYSREAD (fp, fp->_IO_read_end,
		       fp->_IO_buf_end - fp->_IO_read_end);
  if (count <= 0)
    {
      if (count == 0 && tries == 0)
	fp->_flags |= _IO_EOF_SEEN;
      else
	fp->_flags |= _IO_ERR_SEEN, count = 0;
    }
  fp->_IO_read_end += count;
  if (count == 0)
    {
      if (tries != 0)
	/* There are some bytes in the external buffer but they don't
           convert to anything.  */
	__set_errno (EILSEQ);
      return WEOF;
    }
  if (fp->_offset != _IO_pos_BAD)
    _IO_pos_adjust (fp->_offset, count);

  /* Now convert the read input.  */
  fp->_wide_data->_IO_last_state = fp->_wide_data->_IO_state;
  fp->_IO_read_base = fp->_IO_read_ptr;
  status = (*cd->__codecvt_do_in) (cd, &fp->_wide_data->_IO_state,
				   fp->_IO_read_ptr, fp->_IO_read_end,
				   &read_ptr_copy,
				   fp->_wide_data->_IO_read_end,
				   fp->_wide_data->_IO_buf_end,
				   &fp->_wide_data->_IO_read_end);

  fp->_IO_read_ptr = (char *) read_ptr_copy;
  if (fp->_wide_data->_IO_read_end == fp->_wide_data->_IO_buf_base)
    {
      if (status == __codecvt_error || fp->_IO_read_end == fp->_IO_buf_end)
	{
	  __set_errno (EILSEQ);
	  fp->_flags |= _IO_ERR_SEEN;
	  return WEOF;
	}

      /* The read bytes make no complete character.  Try reading again.  */
      assert (status == __codecvt_partial);
      ++tries;
      goto again;
    }

  return *fp->_wide_data->_IO_read_ptr;
}


wint_t
_IO_wfile_overflow (f, wch)
     _IO_FILE *f;
     wint_t wch;
{
  if (f->_flags & _IO_NO_WRITES) /* SET ERROR */
    {
      f->_flags |= _IO_ERR_SEEN;
      __set_errno (EBADF);
      return WEOF;
    }
  /* If currently reading or no buffer allocated. */
  if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0)
    {
      /* Allocate a buffer if needed. */
      if (f->_wide_data->_IO_write_base == 0)
	{
	  _IO_wdoallocbuf (f);
	  _IO_wsetg (f, f->_wide_data->_IO_buf_base,
		     f->_wide_data->_IO_buf_base, f->_wide_data->_IO_buf_base);

	  if (f->_IO_write_base == NULL)
	    {
	      _IO_doallocbuf (f);
	      _IO_setg (f, f->_IO_buf_base, f->_IO_buf_base, f->_IO_buf_base);
	    }
	}
      else
	{
	  /* Otherwise must be currently reading.  If _IO_read_ptr
	     (and hence also _IO_read_end) is at the buffer end,
	     logically slide the buffer forwards one block (by setting
	     the read pointers to all point at the beginning of the
	     block).  This makes room for subsequent output.
	     Otherwise, set the read pointers to _IO_read_end (leaving
	     that alone, so it can continue to correspond to the
	     external position). */
	  if (f->_wide_data->_IO_read_ptr == f->_wide_data->_IO_buf_end)
	    {
	      f->_IO_read_end = f->_IO_read_ptr = f->_IO_buf_base;
	      f->_wide_data->_IO_read_end = f->_wide_data->_IO_read_ptr =
		f->_wide_data->_IO_buf_base;
	    }
	}
      f->_wide_data->_IO_write_ptr = f->_wide_data->_IO_read_ptr;
      f->_wide_data->_IO_write_base = f->_wide_data->_IO_write_ptr;
      f->_wide_data->_IO_write_end = f->_wide_data->_IO_buf_end;
      f->_wide_data->_IO_read_base = f->_wide_data->_IO_read_ptr =
	f->_wide_data->_IO_read_end;

      f->_IO_write_ptr = f->_IO_read_ptr;
      f->_IO_write_base = f->_IO_write_ptr;
      f->_IO_write_end = f->_IO_buf_end;
      f->_IO_read_base = f->_IO_read_ptr = f->_IO_read_end;

      f->_flags |= _IO_CURRENTLY_PUTTING;
      if (f->_flags & (_IO_LINE_BUF+_IO_UNBUFFERED))
	f->_wide_data->_IO_write_end = f->_wide_data->_IO_write_ptr;
    }
  if (wch == WEOF)
    return _IO_do_flush (f);
  if (f->_wide_data->_IO_write_ptr == f->_wide_data->_IO_buf_end)
    /* Buffer is really full */
    if (_IO_do_flush (f) == WEOF)
      return WEOF;
  *f->_wide_data->_IO_write_ptr++ = wch;
  if ((f->_flags & _IO_UNBUFFERED)
      || ((f->_flags & _IO_LINE_BUF) && wch == L'\n'))
    if (_IO_do_flush (f) == WEOF)
      return WEOF;
  return wch;
}

wint_t
_IO_wfile_sync (fp)
     _IO_FILE *fp;
{
  _IO_ssize_t delta;
  wint_t retval = 0;

  /*    char* ptr = cur_ptr(); */
  if (fp->_wide_data->_IO_write_ptr > fp->_wide_data->_IO_write_base)
    if (_IO_do_flush (fp))
      return WEOF;
  delta = fp->_wide_data->_IO_read_ptr - fp->_wide_data->_IO_read_end;
  if (delta != 0)
    {
      /* We have to find out how many bytes we have to go back in the
	 external buffer.  */
      struct _IO_codecvt *cv = &fp->_codecvt;
      _IO_off64_t new_pos;

      int clen = (*cv->__codecvt_do_encoding) (cv);

      if (clen > 0)
	/* It is easy, a fixed number of input bytes are used for each
	   wide character.  */
	delta *= clen;
      else
	{
	  /* We have to find out the hard way how much to back off.
             To do this we determine how much input we needed to
             generate the wide characters up to the current reading
             position.  */
	  int nread;

	  fp->_wide_data->_IO_state = fp->_wide_data->_IO_last_state;
	  nread = (*cv->__codecvt_do_length) (cv, &fp->_wide_data->_IO_state,
					      fp->_IO_read_base,
					      fp->_IO_read_end, delta);
	  fp->_IO_read_ptr = fp->_IO_read_base + nread;
	  delta = -(fp->_IO_read_end - fp->_IO_read_base - nread);
	}

      new_pos = _IO_SYSSEEK (fp, delta, 1);
      if (new_pos != (_IO_off64_t) EOF)
	{
	  fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_read_ptr;
	  fp->_IO_read_end = fp->_IO_read_ptr;
	}
#ifdef ESPIPE
      else if (errno == ESPIPE)
	; /* Ignore error from unseekable devices. */
#endif
      else
	retval = WEOF;
    }
  if (retval != WEOF)
    fp->_offset = _IO_pos_BAD;
  /* FIXME: Cleanup - can this be shared? */
  /*    setg(base(), ptr, ptr); */
  return retval;
}

_IO_off64_t
_IO_wfile_seekoff (fp, offset, dir, mode)
     _IO_FILE *fp;
     _IO_off64_t offset;
     int dir;
     int mode;
{
  _IO_off64_t result;
  _IO_off64_t delta, new_offset;
  long int count;
  /* POSIX.1 8.2.3.7 says that after a call the fflush() the file
     offset of the underlying file must be exact.  */
  int must_be_exact = ((fp->_wide_data->_IO_read_base
			== fp->_wide_data->_IO_read_end)
		       && (fp->_wide_data->_IO_write_base
			   == fp->_wide_data->_IO_write_ptr));

  if (mode == 0)
    dir = _IO_seek_cur, offset = 0; /* Don't move any pointers. */

  /* Flush unwritten characters.
     (This may do an unneeded write if we seek within the buffer.
     But to be able to switch to reading, we would need to set
     egptr to ptr.  That can't be done in the current design,
     which assumes file_ptr() is eGptr.  Anyway, since we probably
     end up flushing when we close(), it doesn't make much difference.)
     FIXME: simulate mem-papped files. */

  if (fp->_wide_data->_IO_write_ptr > fp->_wide_data->_IO_write_base
      || _IO_in_put_mode (fp))
    if (_IO_switch_to_wget_mode (fp))
      return WEOF;

  if (fp->_wide_data->_IO_buf_base == NULL)
    {
      /* It could be that we already have a pushback buffer.  */
      if (fp->_wide_data->_IO_read_base != NULL)
	{
	  free (fp->_wide_data->_IO_read_base);
	  fp->_flags &= ~_IO_IN_BACKUP;
	}
      _IO_doallocbuf (fp);
      _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
      _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
      _IO_wsetp (fp, fp->_wide_data->_IO_buf_base,
		 fp->_wide_data->_IO_buf_base);
      _IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
		 fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
    }

  switch (dir)
    {
      struct _IO_codecvt *cv;
      int clen;

    case _IO_seek_cur:
      /* Adjust for read-ahead (bytes is buffer).  To do this we must
         find out which position in the external buffer corresponds to
         the current position in the internal buffer.  */
      cv = &fp->_codecvt;
      clen = (*cv->__codecvt_do_encoding) (cv);

      if (clen > 0)
	offset -= (fp->_wide_data->_IO_read_end
		   - fp->_wide_data->_IO_read_ptr) * clen;
      else
	{
	  int nread;

	  delta = fp->_wide_data->_IO_read_ptr - fp->_wide_data->_IO_read_end;
	  fp->_wide_data->_IO_state = fp->_wide_data->_IO_last_state;
	  nread = (*cv->__codecvt_do_length) (cv, &fp->_wide_data->_IO_state,
					      fp->_IO_read_base,
					      fp->_IO_read_end, delta);
	  fp->_IO_read_ptr = fp->_IO_read_base + nread;
	  offset -= fp->_IO_read_end - fp->_IO_read_base - nread;
	}

      if (fp->_offset == _IO_pos_BAD)
	goto dumb;
      /* Make offset absolute, assuming current pointer is file_ptr(). */
      offset += fp->_offset;

      dir = _IO_seek_set;
      break;
    case _IO_seek_set:
      break;
    case _IO_seek_end:
      {
	struct _G_stat64 st;
	if (_IO_SYSSTAT (fp, &st) == 0 && S_ISREG (st.st_mode))
	  {
	    offset += st.st_size;
	    dir = _IO_seek_set;
	  }
	else
	  goto dumb;
      }
    }
  /* At this point, dir==_IO_seek_set. */

  /* If we are only interested in the current position we've found it now.  */
  if (mode == 0)
    return offset;

  /* If destination is within current buffer, optimize: */
  if (fp->_offset != _IO_pos_BAD && fp->_IO_read_base != NULL
      && !_IO_in_backup (fp))
    {
      /* Offset relative to start of main get area. */
      _IO_off64_t rel_offset = (offset - fp->_offset
				+ (fp->_IO_read_end - fp->_IO_read_base));
      if (rel_offset >= 0)
	{
#if 0
	  if (_IO_in_backup (fp))
	    _IO_switch_to_main_get_area (fp);
#endif
	  if (rel_offset <= fp->_IO_read_end - fp->_IO_read_base)
	    {
	      fp->_IO_read_ptr = fp->_IO_read_base + rel_offset;
	      _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);

	      /* Now set the pointer for the internal buffer.  This
                 might be an iterative process.  Though the read
                 pointer is somewhere in the current external buffer
                 this does not mean we can convert this whole buffer
                 at once fitting in the internal buffer.  */
	      do
		{

		}
	      while (0);

	      _IO_mask_flags (fp, 0, _IO_EOF_SEEN);
	      goto resync;
	    }
#ifdef TODO
	    /* If we have streammarkers, seek forward by reading ahead. */
	    if (_IO_have_markers (fp))
	      {
		int to_skip = rel_offset
		  - (fp->_IO_read_ptr - fp->_IO_read_base);
		if (ignore (to_skip) != to_skip)
		  goto dumb;
		_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
		goto resync;
	      }
#endif
	}
#ifdef TODO
      if (rel_offset < 0 && rel_offset >= Bbase () - Bptr ())
	{
	  if (!_IO_in_backup (fp))
	    _IO_switch_to_backup_area (fp);
	  gbump (fp->_IO_read_end + rel_offset - fp->_IO_read_ptr);
	  _IO_mask_flags (fp, 0, _IO_EOF_SEEN);
	  goto resync;
	}
#endif
    }

#ifdef TODO
  _IO_unsave_markers (fp);
#endif

  if (fp->_flags & _IO_NO_READS)
    goto dumb;

  /* Try to seek to a block boundary, to improve kernel page management. */
  new_offset = offset & ~(fp->_IO_buf_end - fp->_IO_buf_base - 1);
  delta = offset - new_offset;
  if (delta > fp->_IO_buf_end - fp->_IO_buf_base)
    {
      new_offset = offset;
      delta = 0;
    }
  result = _IO_SYSSEEK (fp, new_offset, 0);
  if (result < 0)
    return EOF;
  if (delta == 0)
    count = 0;
  else
    {
      count = _IO_SYSREAD (fp, fp->_IO_buf_base,
			   (must_be_exact
			    ? delta : fp->_IO_buf_end - fp->_IO_buf_base));
      if (count < delta)
	{
	  /* We weren't allowed to read, but try to seek the remainder. */
	  offset = count == EOF ? delta : delta-count;
	  dir = _IO_seek_cur;
	  goto dumb;
	}
    }
  _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base + delta,
	    fp->_IO_buf_base + count);
  _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
  fp->_offset = result + count;
  _IO_mask_flags (fp, 0, _IO_EOF_SEEN);
  return offset;
 dumb:

  _IO_unsave_markers (fp);
  result = _IO_SYSSEEK (fp, offset, dir);
  if (result != EOF)
    {
      _IO_mask_flags (fp, 0, _IO_EOF_SEEN);
      fp->_offset = result;
      _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
      _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
    }
  return result;

resync:
  /* We need to do it since it is possible that the file offset in
     the kernel may be changed behind our back. It may happen when
     we fopen a file and then do a fork. One process may access the
     the file and the kernel file offset will be changed. */
  if (fp->_offset >= 0)
    _IO_SYSSEEK (fp, fp->_offset, 0);

  return offset;
}


_IO_size_t
_IO_wfile_xsputn (f, data, n)
     _IO_FILE *f;
     const void *data;
     _IO_size_t n;
{
  register const wchar_t *s = (const wchar_t *) data;
  _IO_size_t to_do = n;
  int must_flush = 0;
  _IO_size_t count;

  if (n <= 0)
    return 0;
  /* This is an optimized implementation.
     If the amount to be written straddles a block boundary
     (or the filebuf is unbuffered), use sys_write directly. */

  /* First figure out how much space is available in the buffer. */
  count = f->_wide_data->_IO_write_end - f->_wide_data->_IO_write_ptr;
  if ((f->_flags & _IO_LINE_BUF) && (f->_flags & _IO_CURRENTLY_PUTTING))
    {
      count = f->_wide_data->_IO_buf_end - f->_wide_data->_IO_write_ptr;
      if (count >= n)
	{
	  register const wchar_t *p;
	  for (p = s + n; p > s; )
	    {
	      if (*--p == L'\n')
		{
		  count = p - s + 1;
		  must_flush = 1;
		  break;
		}
	    }
	}
    }
  /* Then fill the buffer. */
  if (count > 0)
    {
      if (count > to_do)
	count = to_do;
      if (count > 20)
	{
#ifdef _LIBC
	  f->_wide_data->_IO_write_ptr =
	    __wmempcpy (f->_wide_data->_IO_write_ptr, s, count);
#else
	  wmemcpy (f->_wide_data->_IO_write_ptr, s, count);
	  f->_wide_data->_IO_write_ptr += count;
#endif
	  s += count;
	}
      else
	{
	  register wchar_t *p = f->_wide_data->_IO_write_ptr;
	  register int i = (int) count;
	  while (--i >= 0)
	    *p++ = *s++;
	  f->_wide_data->_IO_write_ptr = p;
	}
      to_do -= count;
    }
  if (to_do > 0)
    to_do -= _IO_wdefault_xsputn (f, s, to_do);
  if (must_flush
      && f->_wide_data->_IO_write_ptr != f->_wide_data->_IO_write_base)
    _IO_wdo_write (f, f->_wide_data->_IO_write_base,
		   f->_wide_data->_IO_write_ptr
		   - f->_wide_data->_IO_write_base);

  return n - to_do;
}


struct _IO_jump_t _IO_wfile_jumps =
{
  JUMP_INIT_DUMMY,
  JUMP_INIT(finish, _IO_new_file_finish),
  JUMP_INIT(overflow, (_IO_overflow_t) _IO_wfile_overflow),
  JUMP_INIT(underflow, (_IO_underflow_t) _IO_wfile_underflow),
  JUMP_INIT(uflow, (_IO_underflow_t) _IO_wdefault_uflow),
  JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wdefault_pbackfail),
  JUMP_INIT(xsputn, _IO_wfile_xsputn),
  JUMP_INIT(xsgetn, _IO_file_xsgetn),
  JUMP_INIT(seekoff, _IO_wfile_seekoff),
  JUMP_INIT(seekpos, _IO_default_seekpos),
  JUMP_INIT(setbuf, _IO_new_file_setbuf),
  JUMP_INIT(sync, (_IO_sync_t) _IO_wfile_sync),
  JUMP_INIT(doallocate, _IO_wfile_doallocate),
  JUMP_INIT(read, _IO_file_read),
  JUMP_INIT(write, _IO_new_file_write),
  JUMP_INIT(seek, _IO_file_seek),
  JUMP_INIT(close, _IO_file_close),
  JUMP_INIT(stat, _IO_file_stat),
  JUMP_INIT(showmanyc, _IO_default_showmanyc),
  JUMP_INIT(imbue, _IO_default_imbue)
};