about summary refs log tree commit diff
path: root/stdio/vfprintf.c
blob: 63a51484639678183d3a07fea4339becff65b6e7 (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
/* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.

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

The GNU C 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <ctype.h>
#include <errno.h>
#include <float.h>
#include <limits.h>
#include <math.h>
#include <printf.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <printf.h>
#include <stddef.h>
#include "_itoa.h"
#include "../locale/localeinfo.h"

/* Include the shared code for parsing the format string.  */
#include "printf-parse.h"


/* This function from the GNU C library is also used in libio.
   To compile for use in libio, compile with -DUSE_IN_LIBIO.  */

#ifdef USE_IN_LIBIO
/* This code is for use in libio.  */
#include <libioP.h>
#define PUT(f, s, n)	_IO_sputn (f, s, n)
#define PAD(padchar)							      \
  if (specs[cnt].info.width > 0)					      \
    done += _IO_padn (s, padchar, specs[cnt].info.width)
#define PUTC(c, f)	_IO_putc (c, f)
#define vfprintf	_IO_vfprintf
#define size_t		_IO_size_t
#define FILE		_IO_FILE
#define va_list		_IO_va_list
#undef	BUFSIZ
#define BUFSIZ		_IO_BUFSIZ
#define ARGCHECK(s, format)						      \
  do									      \
    {									      \
      /* Check file argument for consistence.  */			      \
      CHECK_FILE (s, -1);						      \
      if (s->_flags & _IO_NO_WRITES || format == NULL)			      \
	{								      \
	  MAYBE_SET_EINVAL;						      \
	  return -1;							      \
	}								      \
    } while (0)
#define UNBUFFERED_P(s)	((s)->_IO_file_flags & _IO_UNBUFFERED)
#else /* ! USE_IN_LIBIO */
/* This code is for use in the GNU C library.  */
#include <stdio.h>
#define PUTC(c, f)	putc (c, f)
#define PUT(f, s, n)	fwrite (s, 1, n, f)
ssize_t __printf_pad __P ((FILE *, char pad, size_t n));
#define PAD(padchar)							      \
  if (specs[cnt].info.width > 0)					      \
    { if (__printf_pad (s, padchar, specs[cnt].info.width) == -1)	      \
	return -1; else done += specs[cnt].info.width; }
#define ARGCHECK(s, format) \
  do									      \
    {									      \
      /* Check file argument for consistence.  */			      \
      if (!__validfp(s) || !s->__mode.__write || format == NULL)	      \
	{								      \
	  errno = EINVAL;						      \
	  return -1;							      \
	}								      \
      if (!s->__seen)							      \
	{								      \
	  if (__flshfp (s, EOF) == EOF)					      \
	    return -1;							      \
	}								      \
    } while (0)
#define UNBUFFERED_P(s)	((s)->__buffer == NULL)
#endif /* USE_IN_LIBIO */


#define	outchar(x)							      \
  do									      \
    {									      \
      register const int outc = (x);					      \
      if (putc (outc, s) == EOF)					      \
	return -1;							      \
      else								      \
	++done;								      \
    } while (0)

#define outstring(string, len)						      \
  do									      \
    {									      \
      if (len > 20)							      \
	{								      \
	  if (PUT (s, string, len) != len)				      \
	    return -1;							      \
	  done += len;							      \
	}								      \
      else								      \
	{								      \
	  register const char *cp = string;				      \
	  register int l = len;						      \
	  while (l-- > 0)						      \
	    outchar (*cp++);						      \
	}								      \
    } while (0)

/* Helper function to provide temporary buffering for unbuffered streams.  */
static int buffered_vfprintf __P ((FILE *stream, const char *fmt, va_list));

static printf_function printf_unknown;

extern printf_function **__printf_function_table;

static char *group_number __P ((char *, char *, const char *, wchar_t));


int
vfprintf (s, format, ap)
    register FILE *s;
    const char *format;
    va_list ap;
{
  /* The character used as thousands separator.  */
  wchar_t thousands_sep;

  /* The string describing the size of groups of digits.  */
  const char *grouping;

  /* Array with information about the needed arguments.  This has to be
     dynamically extendable.  */
  size_t nspecs;
  size_t nspecs_max;
  struct printf_spec *specs;

  /* The number of arguments the format string requests.  This will
     determine the size of the array needed to store the argument
     attributes.  */
  size_t nargs;
  int *args_type;
  union printf_arg *args_value;

  /* Positional parameters refer to arguments directly.  This could also
     determine the maximum number of arguments.  Track the maximum number.  */
  size_t max_ref_arg;

  /* End of leading constant string.  */
  const char *lead_str_end;

  /* Number of characters written.  */
  register size_t done = 0;

  /* Running pointer through format string.  */
  const char *f;

  /* Just a counter.  */
  int cnt;

  ARGCHECK (s, format);

  if (UNBUFFERED_P (s))
    /* Use a helper function which will allocate a local temporary buffer
       for the stream and then call us again.  */
    return buffered_vfprintf (s, format, ap);

  /* Reset multibyte characters to their initial state.  */
  (void) mblen ((char *) NULL, 0);

  /* Figure out the thousands separator character.  */
  if (mbtowc (&thousands_sep, _NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP),
              strlen (_NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP))) <= 0)
    thousands_sep = (wchar_t) *_NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP);
  grouping = _NL_CURRENT (LC_NUMERIC, GROUPING);
  if (*grouping == '\0' || *grouping == CHAR_MAX || thousands_sep == L'\0')
    grouping = NULL;

  nspecs_max = 32;		/* A more or less arbitrary start value.  */
  specs = alloca (nspecs_max * sizeof (struct printf_spec));
  nspecs = 0;
  nargs = 0;
  max_ref_arg = 0;

  /* Find the first format specifier.  */
  lead_str_end = find_spec (format);

  for (f = lead_str_end; *f != '\0'; f = specs[nspecs++].next_fmt)
    {
      if (nspecs >= nspecs_max)
	{
	  /* Extend the array of format specifiers.  */
	  struct printf_spec *old = specs;

	  nspecs_max *= 2;
	  specs = alloca (nspecs_max * sizeof (struct printf_spec));
	  if (specs == &old[nspecs])
	    /* Stack grows up, OLD was the last thing allocated; extend it.  */
	    nspecs_max += nspecs_max / 2;
	  else
	    {
	      /* Copy the old array's elements to the new space.  */
	      memcpy (specs, old, nspecs * sizeof (struct printf_spec));
	      if (old == &specs[nspecs])
		/* Stack grows down, OLD was just below the new SPECS.
		   We can use that space when the new space runs out.  */
		nspecs_max += nspecs_max / 2;
	    }
	}

      /* Parse the format specifier.  */
      nargs += parse_one_spec (f, nargs, &specs[nspecs], &max_ref_arg);
    }

  /* Determine the number of arguments the format string consumes.  */
  nargs = MAX (nargs, max_ref_arg);

  /* Allocate memory for the argument descriptions.  */
  args_type = alloca (nargs * sizeof (int));
  args_value = alloca (nargs * sizeof (union printf_arg));

  /* XXX Could do sanity check here:
     Initialize args_type elts to zero.
     If any is still zero after this loop, format is invalid.  */

  /* Fill in the types of all the arguments.  */
  for (cnt = 0; cnt < nspecs; ++cnt)
    {
      /* If the width is determined by an argument this is an int.  */ 
      if (specs[cnt].width_arg != -1)
	args_type[specs[cnt].width_arg] = PA_INT;

      /* If the precision is determined by an argument this is an int.  */ 
      if (specs[cnt].prec_arg != -1)
	args_type[specs[cnt].prec_arg] = PA_INT;

      switch (specs[cnt].ndata_args)
	{
	case 0:			/* No arguments.  */
	  break;
	case 1:			/* One argument; we already have the type.  */
	  args_type[specs[cnt].data_arg] = specs[cnt].data_arg_type;
	  break;
	default:
	  /* We have more than one argument for this format spec.  We must
	     call the arginfo function again to determine all the types.  */
	  (void) (*__printf_arginfo_table[specs[cnt].info.spec])
	    (&specs[cnt].info,
	     specs[cnt].ndata_args, &args_type[specs[cnt].data_arg]);
	  break;
	}
    }

  /* Now we know all the types and the order.  Fill in the argument values.  */
  for (cnt = 0; cnt < nargs; ++cnt)
    switch (args_type[cnt])
      {
#define T(tag, mem, type)						      \
      case tag:								      \
	args_value[cnt].mem = va_arg (ap, type);			      \
	break

	T (PA_CHAR, pa_char, int); /* Promoted.  */
	T (PA_INT|PA_FLAG_SHORT, pa_short_int, int); /* Promoted.  */
	T (PA_INT, pa_int, int);
	T (PA_INT|PA_FLAG_LONG, pa_long_int, long int);
	T (PA_INT|PA_FLAG_LONG_LONG, pa_long_long_int, long long int);
	T (PA_FLOAT, pa_float, double);	/* Promoted.  */
	T (PA_DOUBLE, pa_double, double);
	T (PA_DOUBLE|PA_FLAG_LONG_DOUBLE, pa_long_double, long double);
	T (PA_STRING, pa_string, const char *);
	T (PA_POINTER, pa_pointer, void *);
#undef T
      default:
	if ((args_type[cnt] & PA_FLAG_PTR) != 0)
	  args_value[cnt].pa_pointer = va_arg (ap, void *);
	break;
      }

  /* Write the literal text before the first format.  */
  outstring (format, lead_str_end - format);

  /* Now walk through all format specifiers and process them.  */
  for (cnt = 0; cnt < nspecs; ++cnt)
    {
      printf_function *function; /* Auxiliary function to do output.  */
      int is_neg;		/* Decimal integer is negative.  */
      int base;			/* Base of a number to be written.  */
      unsigned long long int num; /* Integral number to be written.  */
      const char *str;		/* String to be written.  */
      char errorbuf[1024];      /* Buffer sometimes used by %m.  */

      if (specs[cnt].width_arg != -1)
	{
	  /* Extract the field width from an argument.  */
	  specs[cnt].info.width = args_value[specs[cnt].width_arg].pa_int;

	  if (specs[cnt].info.width < 0)
	    /* If the width value is negative left justification is selected
	       and the value is taken as being positive.  */
	    {
	      specs[cnt].info.width = -specs[cnt].info.width;
	      specs[cnt].info.left = 1;
	    }
	}

      if (specs[cnt].prec_arg != -1)
	{
	  /* Extract the precision from an argument.  */
	  specs[cnt].info.prec = args_value[specs[cnt].prec_arg].pa_int;

	  if (specs[cnt].info.prec < 0)
	    /* If the precision is negative the precision is omitted.  */
	    specs[cnt].info.prec = -1;
	}

      /* Check for a user-defined handler for this spec.  */
      function = (__printf_function_table == NULL ? NULL :
                  __printf_function_table[specs[cnt].info.spec]);

      if (function != NULL)
      use_function:		/* Built-in formats with helpers use this.  */
	{
	  int function_done;
	  unsigned int i;
	  const void *ptr[specs[cnt].ndata_args];

	  /* Fill in an array of pointers to the argument values.  */
	  for (i = 0; i < specs[cnt].ndata_args; ++i)
	    ptr[i] = &args_value[specs[cnt].data_arg + i];

	  /* Call the function.  */
	  function_done = (*function) (s, &specs[cnt].info, ptr);

	  /* If an error occured don't do any further work.  */
	  if (function_done < 0)
	    return -1;

	  done += function_done;
	}
      else
	switch (specs[cnt].info.spec)
	  {
	  case '%':
	    /* Write a literal "%".  */
	    outchar ('%');
	    break;
	  case 'i':
	  case 'd':
	    {
	      long long int signed_num;

	      /* Decimal integer.  */
	      base = 10;
	      if (specs[cnt].info.is_longlong)
		signed_num = args_value[specs[cnt].data_arg].pa_long_long_int;
	      else if (specs[cnt].info.is_long)
		signed_num = args_value[specs[cnt].data_arg].pa_long_int;
	      else if (!specs[cnt].info.is_short)
		signed_num = args_value[specs[cnt].data_arg].pa_int;
	      else
		signed_num = args_value[specs[cnt].data_arg].pa_short_int;

	      is_neg = signed_num < 0;
	      num = is_neg ? (- signed_num) : signed_num;
	      goto number;
	    }

	  case 'u':
	    /* Decimal unsigned integer.  */
            base = 10;
            goto unsigned_number;

	  case 'o':
            /* Octal unsigned integer.  */
            base = 8;
            goto unsigned_number;

          case 'X':
            /* Hexadecimal unsigned integer.  */
          case 'x':
            /* Hex with lower-case digits.  */
            base = 16;

	  unsigned_number:
            /* Unsigned number of base BASE.  */

            if (specs[cnt].info.is_longlong)
	      num = args_value[specs[cnt].data_arg].pa_u_long_long_int;
            else if (specs[cnt].info.is_long)
	      num = args_value[specs[cnt].data_arg].pa_u_long_int;
            else if (!specs[cnt].info.is_short)
	      num = args_value[specs[cnt].data_arg].pa_u_int;
            else
	      num = args_value[specs[cnt].data_arg].pa_u_short_int;

            /* ANSI only specifies the `+' and
               ` ' flags for signed conversions.  */
            is_neg = 0;
	    specs[cnt].info.showsign = 0;
	    specs[cnt].info.space = 0;

	  number:
	    /* Number of base BASE.  */
            {
              char work[BUFSIZ];
              char *const workend = &work[sizeof(work) - 1];
              register char *w;

              /* Supply a default precision if none was given.  */
              if (specs[cnt].info.prec == -1)
                specs[cnt].info.prec = 1;

              /* Put the number in WORK.  */
              w = _itoa (num, workend + 1, base, specs[cnt].info.spec == 'X');
	      w -= 1;
              if (specs[cnt].info.group && grouping)
                w = group_number (w, workend, grouping, thousands_sep);
              specs[cnt].info.width -= workend - w;
              specs[cnt].info.prec -= workend - w;

              if (num != 0 && specs[cnt].info.alt && base == 8
		  && specs[cnt].info.prec <= 0)
                {
		  /* Add octal marker.  */
                  *w-- = '0';
                  --specs[cnt].info.width;
                }

              if (specs[cnt].info.prec > 0)
                {
		  /* Add zeros to the precision.  */
                  specs[cnt].info.width -= specs[cnt].info.prec;
                  while (specs[cnt].info.prec-- > 0)
                    *w-- = '0';
                }

              if (num != 0 && specs[cnt].info.alt && base == 16)
		/* Account for 0X hex marker.  */
                specs[cnt].info.width -= 2;

              if (is_neg || specs[cnt].info.showsign || specs[cnt].info.space)
                --specs[cnt].info.width;

              if (!specs[cnt].info.left && specs[cnt].info.pad == ' ')
                PAD (' ');

              if (is_neg)
                outchar ('-');
              else if (specs[cnt].info.showsign)
                outchar ('+');
              else if (specs[cnt].info.space)
                outchar (' ');

              if (num != 0 && specs[cnt].info.alt && base == 16)
                {
                  outchar ('0');
                  outchar (specs[cnt].info.spec);
                }

              if (!specs[cnt].info.left && specs[cnt].info.pad == '0')
                PAD ('0');

              /* Write the number.  */
              while (++w <= workend)
                outchar (*w);

              if (specs[cnt].info.left)
                PAD (' ');
            }
            break;

          case 'e':
          case 'E':
          case 'f':
          case 'g':
          case 'G':
            {
              /* Floating-point number.  This is handled by printf_fp.c.  */
              extern printf_function __printf_fp;
              function = __printf_fp;
              goto use_function;
            }

          case 'c':
            /* Character.  */
            if (!specs[cnt].info.left)
              {
                --specs[cnt].info.width;
                PAD (' ');
              }
            outchar ((unsigned char) args_value[specs[cnt].data_arg].pa_char);
            if (specs[cnt].info.left)
              PAD (' ');
            break;

          case 's':
            {
              static const char null[] = "(null)";
              size_t len;

	      str = args_value[specs[cnt].data_arg].pa_string;

	    string:

              if (str == NULL)
		{
		  /* Write "(null)" if there's space.  */
		  if (specs[cnt].info.prec == -1
		      || specs[cnt].info.prec >= (int) sizeof (null) - 1)
		    {
		      str = null;
		      len = sizeof (null) - 1;
		    }
		  else
		    {
		      str = "";
		      len = 0;
		    }
		}
              else if (specs[cnt].info.prec != -1)
		{
		  /* Search for the end of the string, but don't search
		     past the length specified by the precision.  */
		  const char *end = memchr (str, '\0', specs[cnt].info.prec);
		  if (end)
		    len = end - str;
		  else
		    len = specs[cnt].info.prec;
		}
	      else
		len = strlen (str);

              specs[cnt].info.width -= len;

              if (!specs[cnt].info.left)
                PAD (' ');
              outstring (str, len);
              if (specs[cnt].info.left)
                PAD (' ');
            }
            break;

          case 'p':
            /* Generic pointer.  */
            {
              const void *ptr;
              ptr = args_value[specs[cnt].data_arg].pa_pointer;
              if (ptr != NULL)
                {
                  /* If the pointer is not NULL, write it as a %#x spec.  */
                  base = 16;
                  num = (unsigned long long int) (unsigned long int) ptr;
                  is_neg = 0;
                  specs[cnt].info.alt = 1;
		  specs[cnt].info.spec = 'x';
                  specs[cnt].info.group = 0;
                  goto number;
                }
              else
                {
                  /* Write "(nil)" for a nil pointer.  */
                  str = "(nil)";
		  /* Make sure the full string "(nil)" is printed.  */
		  if (specs[cnt].info.prec < 5)
		    specs[cnt].info.prec = 5;
                  goto string;
                }
            }
            break;

          case 'n':
            /* Answer the count of characters written.  */
            if (specs[cnt].info.is_longlong)
	      *(long long int *) 
		args_value[specs[cnt].data_arg].pa_pointer = done;
            else if (specs[cnt].info.is_long)
	      *(long int *) 
		args_value[specs[cnt].data_arg].pa_pointer = done;
            else if (!specs[cnt].info.is_short)
	      *(int *) 
		args_value[specs[cnt].data_arg].pa_pointer = done;
            else
	      *(short int *) 
		args_value[specs[cnt].data_arg].pa_pointer = done;
            break;

          case 'm':
            {
              extern char *_strerror_internal __P ((int, char *buf, size_t));
              str = _strerror_internal (errno, errorbuf, sizeof errorbuf);
              goto string;
            }

          default:
            /* Unrecognized format specifier.  */
            function = printf_unknown;
            goto use_function;
	  }

      /* Write the following constant string.  */
      outstring (specs[cnt].end_of_fmt,
		 specs[cnt].next_fmt - specs[cnt].end_of_fmt);
    }

  return done;
}


/* Handle an unknown format specifier.  This prints out a canonicalized
   representation of the format spec itself.  */

static int
printf_unknown (s, info, args)
  FILE *s;
  const struct printf_info *info;
  const void **const args;
{
  int done = 0;
  char work[BUFSIZ];
  char *const workend = &work[sizeof(work) - 1];
  register char *w;

  outchar ('%');

  if (info->alt)
    outchar ('#');
  if (info->group)
    outchar ('\'');
  if (info->showsign)
    outchar ('+');
  else if (info->space)
    outchar (' ');
  if (info->left)
    outchar ('-');
  if (info->pad == '0')
    outchar ('0');

  if (info->width != 0)
    {
      w = _itoa (info->width, workend + 1, 10, 0);
      while (++w <= workend)
	outchar (*w);
    }

  if (info->prec != -1)
    {
      outchar ('.');
      w = _itoa (info->prec, workend + 1, 10, 0);
      while (++w <= workend)
	outchar (*w);
    }

  if (info->spec != '\0')
    outchar (info->spec);

  return done;
}

/* Group the digits according to the grouping rules of the current locale.
   The interpretation of GROUPING is as in `struct lconv' from <locale.h>.  */

static char *
group_number (char *w, char *workend, const char *grouping,
	      wchar_t thousands_sep)
{
  int len;
  char *src, *s;

  /* We treat all negative values like CHAR_MAX.  */

  if (*grouping == CHAR_MAX || *grouping < 0)
    /* No grouping should be done.  */
    return w;

  len = *grouping;

  /* Copy existing string so that nothing gets overwritten.  */
  src = (char *) alloca (workend - w);
  memcpy (src, w + 1, workend - w);
  s = &src[workend - w - 1];
  w = workend;

  /* Process all characters in the string.  */
  while (s >= src)
    {
      *w-- = *s--;

      if (--len == 0 && s >= src)
	{
	  /* A new group begins.  */
	  *w-- = thousands_sep;

	  len = *grouping++;
	  if (*grouping == '\0')
	    /* The previous grouping repeats ad infinitum.  */
	    --grouping;
	  else if (*grouping == CHAR_MAX || *grouping < 0)
	    {
	      /* No further grouping to be done.
		 Copy the rest of the number.  */
	      do
		*w-- = *s--;
	      while (s >= src);
	      break;
	    }
	}
    }
  return w;
}

#ifdef USE_IN_LIBIO
/* Helper "class" for `fprintf to unbuffered': creates a temporary buffer.  */
struct helper_file
  {
    struct _IO_FILE_plus _f;
    _IO_FILE *_put_stream;
  };

static int
_IO_helper_overflow (s, c)
  _IO_FILE *s;
  int c;
{
  _IO_FILE *target = ((struct helper_file*) s)->_put_stream;
  int used = s->_IO_write_ptr - s->_IO_write_base;
  if (used)
    {
      _IO_size_t written = _IO_sputn (target, s->_IO_write_base, used);
      s->_IO_write_ptr -= written;
    }
  return _IO_putc (c, s);
}

static const struct _IO_jump_t _IO_helper_jumps =
  {
    _IO_helper_overflow,
    _IO_default_underflow,
    _IO_default_xsputn,
    _IO_default_xsgetn,
    _IO_default_read,
    _IO_default_write,
    _IO_default_doallocate,
    _IO_default_pbackfail,
    _IO_default_setbuf,
    _IO_default_sync,
    _IO_default_finish,
    _IO_default_close,
    _IO_default_stat,
    _IO_default_seek,
    _IO_default_seekoff,
    _IO_default_seekpos,
    _IO_default_uflow
  };

static int
buffered_vfprintf (s, format, args)
  register _IO_FILE *s;
  char const *format;
  _IO_va_list args;
{
  char buf[_IO_BUFSIZ];
  struct helper_file helper;
  register _IO_FILE *hp = (_IO_FILE *) &helper;
  int result, to_flush;

  /* Initialize helper.  */
  helper._put_stream = s;
  hp->_IO_write_base = buf;
  hp->_IO_write_ptr = buf;
  hp->_IO_write_end = buf + sizeof buf;
  hp->_IO_file_flags = _IO_MAGIC|_IO_NO_READS;
  hp->_jumps = (struct _IO_jump_t *) &_IO_helper_jumps;
  
  /* Now print to helper instead.  */
  result = _IO_vfprintf (hp, format, args);

  /* Now flush anything from the helper to the S. */
  if ((to_flush = hp->_IO_write_ptr - hp->_IO_write_base) > 0)
    {
      if (_IO_sputn (s, hp->_IO_write_base, to_flush) != to_flush)
	return -1;
    }

  return result;
}

#else /* !USE_IN_LIBIO */

static int
buffered_vfprintf (s, format, args)
  register FILE *s;
  char const *format;
  va_list args;
{
  char buf[BUFSIZ];
  int result;

  s->__bufp = s->__buffer = buf;
  s->__bufsize = sizeof buf;
  s->__put_limit = s->__buffer + s->__bufsize;
  s->__get_limit = s->__buffer;

  /* Now use buffer to print.  */
  result = vfprintf (s, format, args);

  if (fflush (s) == EOF)
    result = -1;
  s->__buffer = s->__bufp = s->__get_limit = s->__put_limit = NULL;
  s->__bufsize = 0;

  return result;
}


/* Pads string with given number of a specified character.
   This code is taken from iopadn.c of the GNU I/O library.  */
#define PADSIZE 16
static const char blanks[PADSIZE] =
{' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
static const char zeroes[PADSIZE] =
{'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};

ssize_t
__printf_pad (s, pad, count)
     FILE *s;
     char pad;
     size_t count;
{
  const char *padptr;
  register size_t i;

  padptr = pad == ' ' ? blanks : zeroes;

  for (i = count; i >= PADSIZE; i -= PADSIZE)
    if (PUT (s, padptr, PADSIZE) != PADSIZE)
      return -1;
  if (i > 0)
    if (PUT (s, padptr, i) != i)
      return -1;

  return count;
}
#undef PADSIZE
#endif /* USE_IN_LIBIO */