about summary refs log tree commit diff
path: root/libio/genops.c
blob: 71275da28c2511d3e2b04613b737418e22907354 (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
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
/* Copyright (C) 1993, 1995, 1997 Free Software Foundation, Inc.
   This file is part of the GNU IO Library.

   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.  */

/* Generic or default I/O operations. */

#include "libioP.h"
#ifdef __STDC__
#include <stdlib.h>
#endif
#include <string.h>

void
_IO_un_link (fp)
     _IO_FILE *fp;
{
  if (fp->_flags & _IO_LINKED)
    {
      _IO_FILE **f;
      for (f = &_IO_list_all; *f != NULL; f = &(*f)->_chain)
	{
	  if (*f == fp)
	    {
	      *f = fp->_chain;
	      break;
	    }
	}
      fp->_flags &= ~_IO_LINKED;
    }
}

void
_IO_link_in (fp)
     _IO_FILE *fp;
{
    if ((fp->_flags & _IO_LINKED) == 0)
      {
	fp->_flags |= _IO_LINKED;
	fp->_chain = _IO_list_all;
	_IO_list_all = fp;
      }
}

/* Return minimum _pos markers
   Assumes the current get area is the main get area. */
static _IO_size_t _IO_least_marker __P ((_IO_FILE *fp));

static _IO_size_t
_IO_least_marker (fp)
     _IO_FILE *fp;
{
  _IO_ssize_t least_so_far = fp->_IO_read_end - fp->_IO_read_base;
  struct _IO_marker *mark;
  for (mark = fp->_markers; mark != NULL; mark = mark->_next)
    if (mark->_pos < least_so_far)
      least_so_far = mark->_pos;
  return least_so_far;
}

/* Switch current get area from backup buffer to (start of) main get area. */

void
_IO_switch_to_main_get_area (fp)
     _IO_FILE *fp;
{
  char *tmp;
  fp->_flags &= ~_IO_IN_BACKUP;
  /* Swap _IO_read_end and _IO_save_end. */
  tmp = fp->_IO_read_end;
  fp->_IO_read_end = fp->_IO_save_end;
  fp->_IO_save_end= tmp;
  /* Swap _IO_read_base and _IO_save_base. */
  tmp = fp->_IO_read_base;
  fp->_IO_read_base = fp->_IO_save_base;
  fp->_IO_save_base = tmp;

  fp->_IO_read_ptr = fp->_IO_read_base;
}

/* Switch current get area from main get area to (end of) backup area. */

void
_IO_switch_to_backup_area (fp)
     _IO_FILE *fp;
{
  char *tmp;
  fp->_flags |= _IO_IN_BACKUP;
  /* Swap _IO_read_end and _IO_save_end. */
  tmp = fp->_IO_read_end;
  fp->_IO_read_end = fp->_IO_save_end;
  fp->_IO_save_end = tmp;
  /* Swap _gbase and _IO_save_base. */
  tmp = fp->_IO_read_base;
  fp->_IO_read_base = fp->_IO_save_base;
  fp->_IO_save_base = tmp;

  fp->_IO_read_ptr = fp->_IO_read_end;
}

int
_IO_switch_to_get_mode (fp)
     _IO_FILE *fp;
{
  if (fp->_IO_write_ptr > fp->_IO_write_base)
    if (_IO_OVERFLOW (fp, EOF) == EOF)
      return EOF;
  if (_IO_in_backup (fp))
    fp->_IO_read_base = fp->_IO_backup_base;
  else
    {
      fp->_IO_read_base = fp->_IO_buf_base;
      if (fp->_IO_write_ptr > fp->_IO_read_end)
	fp->_IO_read_end = fp->_IO_write_ptr;
    }
  fp->_IO_read_ptr = fp->_IO_write_ptr;

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

  fp->_flags &= ~_IO_CURRENTLY_PUTTING;
  return 0;
}

void
_IO_free_backup_area (fp)
     _IO_FILE *fp;
{
  if (_IO_in_backup (fp))
    _IO_switch_to_main_get_area (fp);  /* Just in case. */
  free (fp->_IO_save_base);
  fp->_IO_save_base = NULL;
  fp->_IO_save_end = NULL;
  fp->_IO_backup_base = NULL;
}

#if 0
int
_IO_switch_to_put_mode (fp)
     _IO_FILE *fp;
{
  fp->_IO_write_base = fp->_IO_read_ptr;
  fp->_IO_write_ptr = fp->_IO_read_ptr;
  /* Following is wrong if line- or un-buffered? */
  fp->_IO_write_end = (fp->_flags & _IO_IN_BACKUP
		       ? fp->_IO_read_end : fp->_IO_buf_end);

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

  fp->_flags |= _IO_CURRENTLY_PUTTING;
  return 0;
}
#endif

int
__overflow (f, ch)
     _IO_FILE *f;
     int ch;
{
  return _IO_OVERFLOW (f, ch);
}

static int save_for_backup __P ((_IO_FILE *fp))
#ifdef _LIBC
     internal_function
#endif
     ;

     static int
#ifdef _LIBC
     internal_function
#endif
save_for_backup (fp)
     _IO_FILE *fp;
{
  /* Append [_IO_read_base.._IO_read_end] to backup area. */
  int least_mark = _IO_least_marker (fp);
  /* needed_size is how much space we need in the backup area. */
  int needed_size = (fp->_IO_read_end - fp->_IO_read_base) - least_mark;
  int current_Bsize = fp->_IO_save_end - fp->_IO_save_base;
  int avail; /* Extra space available for future expansion. */
  int delta;
  struct _IO_marker *mark;
  if (needed_size > current_Bsize)
    {
      char *new_buffer;
      avail = 100;
      new_buffer = (char *) malloc (avail + needed_size);
      if (new_buffer == NULL)
	return EOF;		/* FIXME */
      if (least_mark < 0)
	{
	  memcpy (new_buffer + avail,
		  fp->_IO_save_end + least_mark,
		  -least_mark);
	  memcpy (new_buffer + avail - least_mark,
		  fp->_IO_read_base,
		  fp->_IO_read_end - fp->_IO_read_base);
	}
      else
	memcpy (new_buffer + avail,
		fp->_IO_read_base + least_mark,
		needed_size);
      if (fp->_IO_save_base)
	free (fp->_IO_save_base);
      fp->_IO_save_base = new_buffer;
      fp->_IO_save_end = new_buffer + avail + needed_size;
    }
  else
    {
      avail = current_Bsize - needed_size;
      if (least_mark < 0)
	{
	  memmove (fp->_IO_save_base + avail,
		   fp->_IO_save_end + least_mark,
		   -least_mark);
	  memcpy (fp->_IO_save_base + avail - least_mark,
		  fp->_IO_read_base,
		  fp->_IO_read_end - fp->_IO_read_base);
	}
      else if (needed_size > 0)
	memcpy (fp->_IO_save_base + avail,
		fp->_IO_read_base + least_mark,
		needed_size);
    }
  /* FIXME: Dubious arithmetic if pointers are NULL */
  fp->_IO_backup_base = fp->_IO_save_base + avail;
  /* Adjust all the streammarkers. */
  delta = fp->_IO_read_end - fp->_IO_read_base;
  for (mark = fp->_markers; mark != NULL; mark = mark->_next)
    mark->_pos -= delta;
  return 0;
}

int
__underflow (fp)
     _IO_FILE *fp;
{
  if (_IO_in_put_mode (fp))
    if (_IO_switch_to_get_mode (fp) == EOF)
      return EOF;
  if (fp->_IO_read_ptr < fp->_IO_read_end)
    return *(unsigned char *) fp->_IO_read_ptr;
  if (_IO_in_backup (fp))
    {
      _IO_switch_to_main_get_area (fp);
      if (fp->_IO_read_ptr < fp->_IO_read_end)
	return *fp->_IO_read_ptr;
    }
  if (_IO_have_markers (fp))
    {
      if (save_for_backup (fp))
	return EOF;
    }
  else if (_IO_have_backup (fp))
    _IO_free_backup_area (fp);
  return _IO_UNDERFLOW (fp);
}

int
__uflow (fp)
     _IO_FILE *fp;
{
  if (_IO_in_put_mode (fp))
    if (_IO_switch_to_get_mode (fp) == EOF)
      return EOF;
  if (fp->_IO_read_ptr < fp->_IO_read_end)
    return *(unsigned char *) fp->_IO_read_ptr++;
  if (_IO_in_backup (fp))
    {
      _IO_switch_to_main_get_area (fp);
      if (fp->_IO_read_ptr < fp->_IO_read_end)
	return *fp->_IO_read_ptr++;
    }
  if (_IO_have_markers (fp))
    {
      if (save_for_backup (fp))
	return EOF;
    }
  else if (_IO_have_backup (fp))
    _IO_free_backup_area (fp);
  return _IO_UFLOW (fp);
}

void
_IO_setb (f, b, eb, a)
     _IO_FILE *f;
      char *b;
     char *eb;
     int a;
{
  if (f->_IO_buf_base && !(f->_flags & _IO_USER_BUF))
    FREE_BUF (f->_IO_buf_base, _IO_blen (f));
  f->_IO_buf_base = b;
  f->_IO_buf_end = eb;
  if (a)
    f->_flags &= ~_IO_USER_BUF;
  else
    f->_flags |= _IO_USER_BUF;
}

void
_IO_doallocbuf (fp)
     _IO_FILE *fp;
{
  if (fp->_IO_buf_base)
    return;
  if (!(fp->_flags & _IO_UNBUFFERED))
    if (_IO_DOALLOCATE (fp) != EOF)
      return;
  _IO_setb (fp, fp->_shortbuf, fp->_shortbuf+1, 0);
}

int
_IO_default_underflow (fp)
     _IO_FILE *fp;
{
  return EOF;
}

int
_IO_default_uflow (fp)
     _IO_FILE *fp;
{
  int ch = _IO_UNDERFLOW (fp);
  if (ch == EOF)
    return EOF;
  return *(unsigned char *) fp->_IO_read_ptr++;
}

_IO_size_t
_IO_default_xsputn (f, data, n)
     _IO_FILE *f;
     const void *data;
     _IO_size_t n;
{
  const char *s = (char *) data;
  _IO_size_t more = n;
  if (more <= 0)
    return 0;
  for (;;)
    {
      /* Space available. */
      _IO_ssize_t count = f->_IO_write_end - f->_IO_write_ptr;
      if (count > 0)
	{
	  if ((_IO_size_t) count > more)
	    count = more;
	  if (count > 20)
	    {
	      memcpy (f->_IO_write_ptr, s, count);
	      s += count;
	      f->_IO_write_ptr += count;
            }
	  else if (count <= 0)
	    count = 0;
	  else
	    {
	      char *p = f->_IO_write_ptr;
	      _IO_ssize_t i;
	      for (i = count; --i >= 0; )
		*p++ = *s++;
	      f->_IO_write_ptr = p;
            }
	  more -= count;
        }
      if (more == 0 || __overflow (f, (unsigned char) *s++) == EOF)
	break;
      more--;
    }
  return n - more;
}

_IO_size_t
_IO_sgetn (fp, data, n)
     _IO_FILE *fp;
     void *data;
     _IO_size_t n;
{
  /* FIXME handle putback buffer here! */
  return _IO_XSGETN (fp, data, n);
}

_IO_size_t
_IO_default_xsgetn (fp, data, n)
     _IO_FILE *fp;
     void *data;
     _IO_size_t n;
{
  _IO_size_t more = n;
  char *s = (char*) data;
  for (;;)
    {
      /* Data available. */
      _IO_ssize_t count = fp->_IO_read_end - fp->_IO_read_ptr;
      if (count > 0)
	{
	  if ((_IO_size_t) count > more)
	    count = more;
	  if (count > 20)
	    {
	      memcpy (s, fp->_IO_read_ptr, count);
	      s += count;
	      fp->_IO_read_ptr += count;
	    }
	  else if (count <= 0)
	    count = 0;
	  else
	    {
	      char *p = fp->_IO_read_ptr;
	      int i = (int) count;
	      while (--i >= 0)
		*s++ = *p++;
	      fp->_IO_read_ptr = p;
            }
            more -= count;
        }
      if (more == 0 || __underflow (fp) == EOF)
	break;
    }
  return n - more;
}

#if 0
/* Seems not to be needed. --drepper */
int
_IO_sync (fp)
     _IO_FILE *fp;
{
  return 0;
}
#endif

_IO_FILE *
_IO_default_setbuf (fp, p, len)
     _IO_FILE *fp;
     char *p;
     _IO_ssize_t len;
{
    if (_IO_SYNC (fp) == EOF)
	return NULL;
    if (p == NULL || len == 0)
      {
	fp->_flags |= _IO_UNBUFFERED;
	_IO_setb (fp, fp->_shortbuf, fp->_shortbuf+1, 0);
      }
    else
      {
	fp->_flags &= ~_IO_UNBUFFERED;
	_IO_setb (fp, p, p+len, 0);
      }
    fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end = 0;
    fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_read_end = 0;
    return fp;
}

_IO_fpos64_t
_IO_default_seekpos (fp, pos, mode)
     _IO_FILE *fp;
     _IO_fpos64_t pos;
     int mode;
{
  return _IO_SEEKOFF (fp, _IO_pos_as_off (pos), 0, mode);
}

int
_IO_default_doallocate (fp)
     _IO_FILE *fp;
{
  char *buf;

  ALLOC_BUF (buf, _IO_BUFSIZ, EOF);
  _IO_setb (fp, buf, buf+_IO_BUFSIZ, 1);
  return 1;
}

void
_IO_init (fp, flags)
     _IO_FILE *fp;
     int flags;
{
  fp->_flags = _IO_MAGIC|flags;
  fp->_IO_buf_base = NULL;
  fp->_IO_buf_end = NULL;
  fp->_IO_read_base = NULL;
  fp->_IO_read_ptr = NULL;
  fp->_IO_read_end = NULL;
  fp->_IO_write_base = NULL;
  fp->_IO_write_ptr = NULL;
  fp->_IO_write_end = NULL;
  fp->_chain = NULL; /* Not necessary. */

  fp->_IO_save_base = NULL;
  fp->_IO_backup_base = NULL;
  fp->_IO_save_end = NULL;
  fp->_markers = NULL;
  fp->_cur_column = 0;
#ifdef _IO_MTSAFE_IO
  _IO_lock_init (*fp->_lock);
#endif
}

int
_IO_default_sync (fp)
     _IO_FILE *fp;
{
  return 0;
}

/* The way the C++ classes are mapped into the C functions in the
   current implementation, this function can get called twice! */

void
_IO_default_finish (fp, dummy)
     _IO_FILE *fp;
     int dummy;
{
  struct _IO_marker *mark;
  if (fp->_IO_buf_base && !(fp->_flags & _IO_USER_BUF))
    {
      FREE_BUF (fp->_IO_buf_base, _IO_blen (fp));
      fp->_IO_buf_base = fp->_IO_buf_end = NULL;
    }

  for (mark = fp->_markers; mark != NULL; mark = mark->_next)
    mark->_sbuf = NULL;

  if (fp->_IO_save_base)
    {
      free (fp->_IO_save_base);
      fp->_IO_save_base = NULL;
    }

#ifdef _IO_MTSAFE_IO
  _IO_lock_fini (*fp->_lock);
#endif

  _IO_un_link (fp);
}

_IO_fpos64_t
_IO_default_seekoff (fp, offset, dir, mode)
     _IO_FILE *fp;
     _IO_off64_t offset;
     int dir;
     int mode;
{
    return _IO_pos_BAD;
}

int
_IO_sputbackc (fp, c)
     _IO_FILE *fp;
     int c;
{
  int result;

  if (fp->_IO_read_ptr > fp->_IO_read_base
      && (unsigned char)fp->_IO_read_ptr[-1] == (unsigned char)c)
    {
      fp->_IO_read_ptr--;
      result = (unsigned char) c;
    }
  else
    result = _IO_PBACKFAIL (fp, c);

  if (result != EOF)
    fp->_flags &= ~_IO_EOF_SEEN;

  return result;
}

int
_IO_sungetc (fp)
     _IO_FILE *fp;
{
  int result;

  if (fp->_IO_read_ptr > fp->_IO_read_base)
    {
      fp->_IO_read_ptr--;
      result = (unsigned char) *fp->_IO_read_ptr;
    }
  else
    result = _IO_PBACKFAIL (fp, EOF);

  if (result != EOF)
    fp->_flags &= ~_IO_EOF_SEEN;

  return result;
}

#if 0 /* Work in progress */
/* Seems not to be needed.  */
#if 0
void
_IO_set_column (fp, c)
     _IO_FILE *fp;
     int c;
{
  if (c == -1)
    fp->_column = -1;
  else
    fp->_column = c - (fp->_IO_write_ptr - fp->_IO_write_base);
}
#else
int
_IO_set_column (fp, i)
     _IO_FILE *fp;
     int i;
{
  fp->_cur_column = i + 1;
  return 0;
}
#endif
#endif


unsigned
_IO_adjust_column (start, line, count)
     unsigned start;
     const char *line;
     int count;
{
  const char *ptr = line + count;
  while (ptr > line)
    if (*--ptr == '\n')
      return line + count - ptr - 1;
  return start + count;
}

#if 0
/* Seems not to be needed. --drepper */
int
_IO_get_column (fp)
     _IO_FILE *fp;
{
  if (fp->_cur_column)
    return _IO_adjust_column (fp->_cur_column - 1,
			      fp->_IO_write_base,
			      fp->_IO_write_ptr - fp->_IO_write_base);
  return -1;
}
#endif

int
_IO_flush_all ()
{
  int result = 0;
  _IO_FILE *fp;
  for (fp = _IO_list_all; fp != NULL; fp = fp->_chain)
    if (fp->_IO_write_ptr > fp->_IO_write_base
	&& _IO_OVERFLOW (fp, EOF) == EOF)
      result = EOF;
  return result;
}

void
_IO_flush_all_linebuffered ()
{
  _IO_FILE *fp;
  for (fp = _IO_list_all; fp != NULL; fp = fp->_chain)
    if ((fp->_flags & _IO_NO_WRITES) == 0 && fp->_flags & _IO_LINE_BUF)
      _IO_OVERFLOW (fp, EOF);
}

static void _IO_unbuffer_all __P ((void));

static void
_IO_unbuffer_all ()
{
  _IO_FILE *fp;
  for (fp = _IO_list_all; fp != NULL; fp = fp->_chain)
    if (! (fp->_flags & _IO_UNBUFFERED))
      _IO_SETBUF (fp, NULL, 0);
}

void
_IO_cleanup ()
{
  _IO_flush_all ();

  /* We currently don't have a reliable mechanism for making sure that
     C++ static destructors are executed in the correct order.
     So it is possible that other static destructors might want to
     write to cout - and they're supposed to be able to do so.

     The following will make the standard streambufs be unbuffered,
     which forces any output from late destructors to be written out. */
  _IO_unbuffer_all ();
}

void
_IO_init_marker (marker, fp)
     struct _IO_marker *marker;
     _IO_FILE *fp;
{
  marker->_sbuf = fp;
  if (_IO_in_put_mode (fp))
    _IO_switch_to_get_mode (fp);
  if (_IO_in_backup (fp))
    marker->_pos = fp->_IO_read_ptr - fp->_IO_read_end;
  else
    marker->_pos = fp->_IO_read_ptr - fp->_IO_read_base;

  /* Should perhaps sort the chain? */
  marker->_next = fp->_markers;
  fp->_markers = marker;
}

void
_IO_remove_marker (marker)
     struct _IO_marker *marker;
{
  /* Unlink from sb's chain. */
  struct _IO_marker **ptr = &marker->_sbuf->_markers;
  for (; ; ptr = &(*ptr)->_next)
    {
      if (*ptr == NULL)
	break;
      else if (*ptr == marker)
	{
	  *ptr = marker->_next;
	  return;
	}
    }
#if 0
    if _sbuf has a backup area that is no longer needed, should we delete
    it now, or wait until the next underflow?
#endif
}

#define BAD_DELTA EOF

int
_IO_marker_difference (mark1, mark2)
     struct _IO_marker *mark1;
     struct _IO_marker *mark2;
{
  return mark1->_pos - mark2->_pos;
}

/* Return difference between MARK and current position of MARK's stream. */
int
_IO_marker_delta (mark)
     struct _IO_marker *mark;
{
  int cur_pos;
  if (mark->_sbuf == NULL)
    return BAD_DELTA;
  if (_IO_in_backup (mark->_sbuf))
    cur_pos = mark->_sbuf->_IO_read_ptr - mark->_sbuf->_IO_read_end;
  else
    cur_pos = mark->_sbuf->_IO_read_ptr - mark->_sbuf->_IO_read_base;
  return mark->_pos - cur_pos;
}

int
_IO_seekmark (fp, mark, delta)
     _IO_FILE *fp;
     struct _IO_marker *mark;
     int delta;
{
  if (mark->_sbuf != fp)
    return EOF;
 if (mark->_pos >= 0)
    {
      if (_IO_in_backup (fp))
	_IO_switch_to_main_get_area (fp);
      fp->_IO_read_ptr = fp->_IO_read_base + mark->_pos;
    }
  else
    {
      if (!_IO_in_backup (fp))
	_IO_switch_to_backup_area (fp);
      fp->_IO_read_ptr = fp->_IO_read_end + mark->_pos;
    }
  return 0;
}

void
_IO_unsave_markers (fp)
     _IO_FILE *fp;
{
  struct _IO_marker *mark = fp->_markers;
  if (mark)
    {
#ifdef TODO
      streampos offset = seekoff (0, ios::cur, ios::in);
      if (offset != EOF)
	{
	  offset += eGptr () - Gbase ();
	  for ( ; mark != NULL; mark = mark->_next)
	    mark->set_streampos (mark->_pos + offset);
	}
    else
      {
	for ( ; mark != NULL; mark = mark->_next)
	  mark->set_streampos (EOF);
      }
#endif
      fp->_markers = 0;
    }

  if (_IO_have_backup (fp))
    _IO_free_backup_area (fp);
}

#if 0
/* Seems not to be needed. --drepper */
int
_IO_nobackup_pbackfail (fp, c)
     _IO_FILE *fp;
     int c;
{
  if (fp->_IO_read_ptr > fp->_IO_read_base)
	fp->_IO_read_ptr--;
  if (c != EOF && *fp->_IO_read_ptr != c)
      *fp->_IO_read_ptr = c;
  return (unsigned char) c;
}
#endif

int
_IO_default_pbackfail (fp, c)
     _IO_FILE *fp;
     int c;
{
  if (fp->_IO_read_ptr <= fp->_IO_read_base)
    {
      /* Need to handle a filebuf in write mode (switch to read mode). FIXME!*/
      if (_IO_have_backup (fp) && !_IO_in_backup (fp))
	_IO_switch_to_backup_area (fp);

      if (!_IO_have_backup (fp))
	{
	  /* No backup buffer: allocate one. */
	  /* Use nshort buffer, if unused? (probably not)  FIXME */
	  int backup_size = 128;
	  char *bbuf = (char *) malloc (backup_size);
	  if (bbuf == NULL)
	    return EOF;
	  fp->_IO_save_base = bbuf;
	  fp->_IO_save_end = fp->_IO_save_base + backup_size;
	  fp->_IO_backup_base = fp->_IO_save_end;
	  _IO_switch_to_backup_area (fp);
	}
      else if (fp->_IO_read_ptr <= fp->_IO_read_base)
	{
	  /* Increase size of existing backup buffer. */
	  _IO_size_t new_size;
	  _IO_size_t old_size = fp->_IO_read_end - fp->_IO_read_base;
	  char *new_buf;
	  new_size = 2 * old_size;
	  new_buf = (char *) malloc (new_size);
	  if (new_buf == NULL)
	    return EOF;
	  memcpy (new_buf + (new_size - old_size), fp->_IO_read_base,
		  old_size);
	  free (fp->_IO_read_base);
	  _IO_setg (fp, new_buf, new_buf + (new_size - old_size),
		    new_buf + new_size);
	  fp->_IO_backup_base = fp->_IO_read_ptr;
	}
    }
  --fp->_IO_read_ptr;
  if (c != EOF && *fp->_IO_read_ptr != c)
    *fp->_IO_read_ptr = c;
  return (unsigned char) *fp->_IO_read_ptr;
}

_IO_fpos64_t
_IO_default_seek (fp, offset, dir)
     _IO_FILE *fp;
     _IO_off64_t offset;
     int dir;
{
  return _IO_pos_BAD;
}

int
_IO_default_stat (fp, st)
     _IO_FILE *fp;
     void* st;
{
  return EOF;
}

_IO_ssize_t
_IO_default_read (fp, data, n)
     _IO_FILE* fp;
     void *data;
     _IO_ssize_t n;
{
  return -1;
}

_IO_ssize_t
_IO_default_write (fp, data, n)
     _IO_FILE *fp;
     const void *data;
     _IO_ssize_t n;
{
  return 0;
}

int
_IO_default_showmanyc (fp)
     _IO_FILE *fp;
{
  return -1;
}

void
_IO_default_imbue (fp, locale)
     _IO_FILE *fp;
     void *locale;
{
}


#ifdef TODO
#if defined(linux)
#define IO_CLEANUP ;
#endif

#ifdef IO_CLEANUP
  IO_CLEANUP
#else
struct __io_defs {
    __io_defs() { }
    ~__io_defs() { _IO_cleanup (); }
};
__io_defs io_defs__;
#endif

#endif /* TODO */

#ifdef weak_alias
weak_alias (_IO_cleanup, _cleanup)
#endif

#ifdef text_set_element
text_set_element(__libc_atexit, _cleanup);
#endif