stdio/vfprintf.c

   1 /* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ctype.h>
  20 #include <errno.h>
  21 #include <float.h>
  22 #include <limits.h>
  23 #include <math.h>
  24 #include <printf.h>
  25 #include <stdarg.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <printf.h>
  29 #include <stddef.h>
  30 #include "_itoa.h"
  31 #include "../locale/localeinfo.h"
  32
  33 /* Include the shared code for parsing the format string.  */
  34 #include "printf-parse.h"
  35
  36
  37 /* This function from the GNU C library is also used in libio.
  38    To compile for use in libio, compile with -DUSE_IN_LIBIO.  */
  39
  40 #ifdef USE_IN_LIBIO
  41 /* This code is for use in libio.  */
  42 #include <libioP.h>
  43 #define PUT(f, s, n)    _IO_sputn (f, s, n)
  44 #define PAD(padchar)                                                          \
  45   if (specs[cnt].info.width > 0)                                              \
  46     done += _IO_padn (s, padchar, specs[cnt].info.width)
  47 #define PUTC(c, f)      _IO_putc (c, f)
  48 #define vfprintf        _IO_vfprintf
  49 #define size_t          _IO_size_t
  50 #define FILE            _IO_FILE
  51 #define va_list         _IO_va_list
  52 #undef  BUFSIZ
  53 #define BUFSIZ          _IO_BUFSIZ
  54 #define ARGCHECK(s, format)                                                   \
  55   do                                                                          \
  56     {                                                                         \
  57       /* Check file argument for consistence.  */                             \
  58       CHECK_FILE (s, -1);                                                     \
  59       if (s->_flags & _IO_NO_WRITES || format == NULL)                        \
  60         {                                                                     \
  61           MAYBE_SET_EINVAL;                                                   \
  62           return -1;                                                          \
  63         }                                                                     \
  64     } while (0)
  65 #define UNBUFFERED_P(s) ((s)->_IO_file_flags & _IO_UNBUFFERED)
  66 #else /* ! USE_IN_LIBIO */
  67 /* This code is for use in the GNU C library.  */
  68 #include <stdio.h>
  69 #define PUTC(c, f)      putc (c, f)
  70 #define PUT(f, s, n)    fwrite (s, 1, n, f)
  71 ssize_t __printf_pad __P ((FILE *, char pad, size_t n));
  72 #define PAD(padchar)                                                          \
  73   if (specs[cnt].info.width > 0)                                              \
  74     { if (__printf_pad (s, padchar, specs[cnt].info.width) == -1)             \
  75         return -1; else done += specs[cnt].info.width; }
  76 #define ARGCHECK(s, format) \
  77   do                                                                          \
  78     {                                                                         \
  79       /* Check file argument for consistence.  */                             \
  80       if (!__validfp(s) || !s->__mode.__write || format == NULL)              \
  81         {                                                                     \
  82           errno = EINVAL;                                                     \
  83           return -1;                                                          \
  84         }                                                                     \
  85       if (!s->__seen)                                                         \
  86         {                                                                     \
  87           if (__flshfp (s, EOF) == EOF)                                       \
  88             return -1;                                                        \
  89         }                                                                     \
  90     } while (0)
  91 #define UNBUFFERED_P(s) ((s)->__buffer == NULL)
  92 #endif /* USE_IN_LIBIO */
  93
  94
  95 #define outchar(x)                                                            \
  96   do                                                                          \
  97     {                                                                         \
  98       register const int outc = (x);                                          \
  99       if (putc (outc, s) == EOF)                                              \
 100         return -1;                                                            \
 101       else                                                                    \
 102         ++done;                                                               \
 103     } while (0)
 104
 105 #define outstring(string, len)                                                \
 106   do                                                                          \
 107     {                                                                         \
 108       if (len > 20)                                                           \
 109         {                                                                     \
 110           if (PUT (s, string, len) != len)                                    \
 111             return -1;                                                        \
 112           done += len;                                                        \
 113         }                                                                     \
 114       else                                                                    \
 115         {                                                                     \
 116           register const char *cp = string;                                   \
 117           register int l = len;                                               \
 118           while (l-- > 0)                                                     \
 119             outchar (*cp++);                                                  \
 120         }                                                                     \
 121     } while (0)
 122
 123 /* Helper function to provide temporary buffering for unbuffered streams.  */
 124 static int buffered_vfprintf __P ((FILE *stream, const char *fmt, va_list));
 125
 126 static printf_function printf_unknown;
 127
 128 extern printf_function **__printf_function_table;
 129
 130 static char *group_number __P ((char *, char *, const char *, wchar_t));
 131
 132
 133 int
 134 vfprintf (s, format, ap)
 135     register FILE *s;
 136     const char *format;
 137     va_list ap;
 138 {
 139   /* The character used as thousands separator.  */
 140   wchar_t thousands_sep;
 141
 142   /* The string describing the size of groups of digits.  */
 143   const char *grouping;
 144
 145   /* Array with information about the needed arguments.  This has to be
 146      dynamically extendable.  */
 147   size_t nspecs;
 148   size_t nspecs_max;
 149   struct printf_spec *specs;
 150
 151   /* The number of arguments the format string requests.  This will
 152      determine the size of the array needed to store the argument
 153      attributes.  */
 154   size_t nargs;
 155   int *args_type;
 156   union printf_arg *args_value;
 157
 158   /* Positional parameters refer to arguments directly.  This could also
 159      determine the maximum number of arguments.  Track the maximum number.  */
 160   size_t max_ref_arg;
 161
 162   /* End of leading constant string.  */
 163   const char *lead_str_end;
 164
 165   /* Number of characters written.  */
 166   register size_t done = 0;
 167
 168   /* Running pointer through format string.  */
 169   const char *f;
 170
 171   /* Just a counter.  */
 172   int cnt;
 173
 174   ARGCHECK (s, format);
 175
 176   if (UNBUFFERED_P (s))
 177     /* Use a helper function which will allocate a local temporary buffer
 178        for the stream and then call us again.  */
 179     return buffered_vfprintf (s, format, ap);
 180
 181   /* Reset multibyte characters to their initial state.  */
 182   (void) mblen ((char *) NULL, 0);
 183
 184   /* Figure out the thousands separator character.  */
 185   if (mbtowc (&thousands_sep, _NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP),
 186               strlen (_NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP))) <= 0)
 187     thousands_sep = (wchar_t) *_NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP);
 188   grouping = _NL_CURRENT (LC_NUMERIC, GROUPING);
 189   if (*grouping == '\0' || *grouping == CHAR_MAX || thousands_sep == L'\0')
 190     grouping = NULL;
 191
 192   nspecs_max = 32;              /* A more or less arbitrary start value.  */
 193   specs = alloca (nspecs_max * sizeof (struct printf_spec));
 194   nspecs = 0;
 195   nargs = 0;
 196   max_ref_arg = 0;
 197
 198   /* Find the first format specifier.  */
 199   lead_str_end = find_spec (format);
 200
 201   for (f = lead_str_end; *f != '\0'; f = specs[nspecs++].next_fmt)
 202     {
 203       if (nspecs >= nspecs_max)
 204         {
 205           /* Extend the array of format specifiers.  */
 206           struct printf_spec *old = specs;
 207
 208           nspecs_max *= 2;
 209           specs = alloca (nspecs_max * sizeof (struct printf_spec));
 210           if (specs == &old[nspecs])
 211             /* Stack grows up, OLD was the last thing allocated; extend it.  */
 212             nspecs_max += nspecs_max / 2;
 213           else
 214             {
 215               /* Copy the old array's elements to the new space.  */
 216               memcpy (specs, old, nspecs * sizeof (struct printf_spec));
 217               if (old == &specs[nspecs])
 218                 /* Stack grows down, OLD was just below the new SPECS.
 219                    We can use that space when the new space runs out.  */
 220                 nspecs_max += nspecs_max / 2;
 221             }
 222         }
 223
 224       /* Parse the format specifier.  */
 225       nargs += parse_one_spec (f, nargs, &specs[nspecs], &max_ref_arg);
 226     }
 227
 228   /* Determine the number of arguments the format string consumes.  */
 229   nargs = MAX (nargs, max_ref_arg);
 230
 231   /* Allocate memory for the argument descriptions.  */
 232   args_type = alloca (nargs * sizeof (int));
 233   args_value = alloca (nargs * sizeof (union printf_arg));
 234
 235   /* XXX Could do sanity check here:
 236      Initialize args_type elts to zero.
 237      If any is still zero after this loop, format is invalid.  */
 238
 239   /* Fill in the types of all the arguments.  */
 240   for (cnt = 0; cnt < nspecs; ++cnt)
 241     {
 242       /* If the width is determined by an argument this is an int.  */
 243       if (specs[cnt].width_arg != -1)
 244         args_type[specs[cnt].width_arg] = PA_INT;
 245
 246       /* If the precision is determined by an argument this is an int.  */
 247       if (specs[cnt].prec_arg != -1)
 248         args_type[specs[cnt].prec_arg] = PA_INT;
 249
 250       switch (specs[cnt].ndata_args)
 251         {
 252         case 0:                 /* No arguments.  */
 253           break;
 254         case 1:                 /* One argument; we already have the type.  */
 255           args_type[specs[cnt].data_arg] = specs[cnt].data_arg_type;
 256           break;
 257         default:
 258           /* We have more than one argument for this format spec.  We must
 259              call the arginfo function again to determine all the types.  */
 260           (void) (*__printf_arginfo_table[specs[cnt].info.spec])
 261             (&specs[cnt].info,
 262              specs[cnt].ndata_args, &args_type[specs[cnt].data_arg]);
 263           break;
 264         }
 265     }
 266
 267   /* Now we know all the types and the order.  Fill in the argument values.  */
 268   for (cnt = 0; cnt < nargs; ++cnt)
 269     switch (args_type[cnt])
 270       {
 271 #define T(tag, mem, type)                                                     \
 272       case tag:                                                               \
 273         args_value[cnt].mem = va_arg (ap, type);                              \
 274         break
 275
 276         T (PA_CHAR, pa_char, int); /* Promoted.  */
 277         T (PA_INT|PA_FLAG_SHORT, pa_short_int, int); /* Promoted.  */
 278         T (PA_INT, pa_int, int);
 279         T (PA_INT|PA_FLAG_LONG, pa_long_int, long int);
 280         T (PA_INT|PA_FLAG_LONG_LONG, pa_long_long_int, long long int);
 281         T (PA_FLOAT, pa_float, double); /* Promoted.  */
 282         T (PA_DOUBLE, pa_double, double);
 283         T (PA_DOUBLE|PA_FLAG_LONG_DOUBLE, pa_long_double, long double);
 284         T (PA_STRING, pa_string, const char *);
 285         T (PA_POINTER, pa_pointer, void *);
 286 #undef T
 287       default:
 288         if ((args_type[cnt] & PA_FLAG_PTR) != 0)
 289           args_value[cnt].pa_pointer = va_arg (ap, void *);
 290         break;
 291       }
 292
 293   /* Write the literal text before the first format.  */
 294   outstring (format, lead_str_end - format);
 295
 296   /* Now walk through all format specifiers and process them.  */
 297   for (cnt = 0; cnt < nspecs; ++cnt)
 298     {
 299       printf_function *function; /* Auxiliary function to do output.  */
 300       int is_neg;               /* Decimal integer is negative.  */
 301       int base;                 /* Base of a number to be written.  */
 302       unsigned long long int num; /* Integral number to be written.  */
 303       const char *str;          /* String to be written.  */
 304       char errorbuf[1024];      /* Buffer sometimes used by %m.  */
 305
 306       if (specs[cnt].width_arg != -1)
 307         {
 308           /* Extract the field width from an argument.  */
 309           specs[cnt].info.width = args_value[specs[cnt].width_arg].pa_int;
 310
 311           if (specs[cnt].info.width < 0)
 312             /* If the width value is negative left justification is selected
 313                and the value is taken as being positive.  */
 314             {
 315               specs[cnt].info.width = -specs[cnt].info.width;
 316               specs[cnt].info.left = 1;
 317             }
 318         }
 319
 320       if (specs[cnt].prec_arg != -1)
 321         {
 322           /* Extract the precision from an argument.  */
 323           specs[cnt].info.prec = args_value[specs[cnt].prec_arg].pa_int;
 324
 325           if (specs[cnt].info.prec < 0)
 326             /* If the precision is negative the precision is omitted.  */
 327             specs[cnt].info.prec = -1;
 328         }
 329
 330       /* Check for a user-defined handler for this spec.  */
 331       function = (__printf_function_table == NULL ? NULL :
 332                   __printf_function_table[specs[cnt].info.spec]);
 333
 334       if (function != NULL)
 335       use_function:             /* Built-in formats with helpers use this.  */
 336         {
 337           int function_done;
 338           unsigned int i;
 339           const void *ptr[specs[cnt].ndata_args];
 340
 341           /* Fill in an array of pointers to the argument values.  */
 342           for (i = 0; i < specs[cnt].ndata_args; ++i)
 343             ptr[i] = &args_value[specs[cnt].data_arg + i];
 344
 345           /* Call the function.  */
 346           function_done = (*function) (s, &specs[cnt].info, ptr);
 347
 348           /* If an error occured don't do any further work.  */
 349           if (function_done < 0)
 350             return -1;
 351
 352           done += function_done;
 353         }
 354       else
 355         switch (specs[cnt].info.spec)
 356           {
 357           case '%':
 358             /* Write a literal "%".  */
 359             outchar ('%');
 360             break;
 361           case 'i':
 362           case 'd':
 363             {
 364               long long int signed_num;
 365
 366               /* Decimal integer.  */
 367               base = 10;
 368               if (specs[cnt].info.is_longlong)
 369                 signed_num = args_value[specs[cnt].data_arg].pa_long_long_int;
 370               else if (specs[cnt].info.is_long)
 371                 signed_num = args_value[specs[cnt].data_arg].pa_long_int;
 372               else if (!specs[cnt].info.is_short)
 373                 signed_num = args_value[specs[cnt].data_arg].pa_int;
 374               else
 375                 signed_num = args_value[specs[cnt].data_arg].pa_short_int;
 376
 377               is_neg = signed_num < 0;
 378               num = is_neg ? (- signed_num) : signed_num;
 379               goto number;
 380             }
 381
 382           case 'u':
 383             /* Decimal unsigned integer.  */
 384             base = 10;
 385             goto unsigned_number;
 386
 387           case 'o':
 388             /* Octal unsigned integer.  */
 389             base = 8;
 390             goto unsigned_number;
 391
 392           case 'X':
 393             /* Hexadecimal unsigned integer.  */
 394           case 'x':
 395             /* Hex with lower-case digits.  */
 396             base = 16;
 397
 398           unsigned_number:
 399             /* Unsigned number of base BASE.  */
 400
 401             if (specs[cnt].info.is_longlong)
 402               num = args_value[specs[cnt].data_arg].pa_u_long_long_int;
 403             else if (specs[cnt].info.is_long)
 404               num = args_value[specs[cnt].data_arg].pa_u_long_int;
 405             else if (!specs[cnt].info.is_short)
 406               num = args_value[specs[cnt].data_arg].pa_u_int;
 407             else
 408               num = args_value[specs[cnt].data_arg].pa_u_short_int;
 409
 410             /* ANSI only specifies the `+' and
 411                ` ' flags for signed conversions.  */
 412             is_neg = 0;
 413             specs[cnt].info.showsign = 0;
 414             specs[cnt].info.space = 0;
 415
 416           number:
 417             /* Number of base BASE.  */
 418             {
 419               char work[BUFSIZ];
 420               char *const workend = &work[sizeof(work) - 1];
 421               register char *w;
 422
 423               /* Supply a default precision if none was given.  */
 424               if (specs[cnt].info.prec == -1)
 425                 specs[cnt].info.prec = 1;
 426
 427               /* Put the number in WORK.  */
 428               w = _itoa (num, workend + 1, base, specs[cnt].info.spec == 'X');
 429               w -= 1;
 430               if (specs[cnt].info.group && grouping)
 431                 w = group_number (w, workend, grouping, thousands_sep);
 432               specs[cnt].info.width -= workend - w;
 433               specs[cnt].info.prec -= workend - w;
 434
 435               if (num != 0 && specs[cnt].info.alt && base == 8
 436                   && specs[cnt].info.prec <= 0)
 437                 {
 438                   /* Add octal marker.  */
 439                   *w-- = '0';
 440                   --specs[cnt].info.width;
 441                 }
 442
 443               if (specs[cnt].info.prec > 0)
 444                 {
 445                   /* Add zeros to the precision.  */
 446                   specs[cnt].info.width -= specs[cnt].info.prec;
 447                   while (specs[cnt].info.prec-- > 0)
 448                     *w-- = '0';
 449                 }
 450
 451               if (num != 0 && specs[cnt].info.alt && base == 16)
 452                 /* Account for 0X hex marker.  */
 453                 specs[cnt].info.width -= 2;
 454
 455               if (is_neg || specs[cnt].info.showsign || specs[cnt].info.space)
 456                 --specs[cnt].info.width;
 457
 458               if (!specs[cnt].info.left && specs[cnt].info.pad == ' ')
 459                 PAD (' ');
 460
 461               if (is_neg)
 462                 outchar ('-');
 463               else if (specs[cnt].info.showsign)
 464                 outchar ('+');
 465               else if (specs[cnt].info.space)
 466                 outchar (' ');
 467
 468               if (num != 0 && specs[cnt].info.alt && base == 16)
 469                 {
 470                   outchar ('0');
 471                   outchar (specs[cnt].info.spec);
 472                 }
 473
 474               if (!specs[cnt].info.left && specs[cnt].info.pad == '0')
 475                 PAD ('0');
 476
 477               /* Write the number.  */
 478               while (++w <= workend)
 479                 outchar (*w);
 480
 481               if (specs[cnt].info.left)
 482                 PAD (' ');
 483             }
 484             break;
 485
 486           case 'e':
 487           case 'E':
 488           case 'f':
 489           case 'g':
 490           case 'G':
 491             {
 492               /* Floating-point number.  This is handled by printf_fp.c.  */
 493               extern printf_function __printf_fp;
 494               function = __printf_fp;
 495               goto use_function;
 496             }
 497
 498           case 'c':
 499             /* Character.  */
 500             if (!specs[cnt].info.left)
 501               {
 502                 --specs[cnt].info.width;
 503                 PAD (' ');
 504               }
 505             outchar ((unsigned char) args_value[specs[cnt].data_arg].pa_char);
 506             if (specs[cnt].info.left)
 507               PAD (' ');
 508             break;
 509
 510           case 's':
 511             {
 512               static const char null[] = "(null)";
 513               size_t len;
 514
 515               str = args_value[specs[cnt].data_arg].pa_string;
 516
 517             string:
 518
 519               if (str == NULL)
 520                 {
 521                   /* Write "(null)" if there's space.  */
 522                   if (specs[cnt].info.prec == -1
 523                       || specs[cnt].info.prec >= (int) sizeof (null) - 1)
 524                     {
 525                       str = null;
 526                       len = sizeof (null) - 1;
 527                     }
 528                   else
 529                     {
 530                       str = "";
 531                       len = 0;
 532                     }
 533                 }
 534               else if (specs[cnt].info.prec != -1)
 535                 {
 536                   /* Search for the end of the string, but don't search
 537                      past the length specified by the precision.  */
 538                   const char *end = memchr (str, '\0', specs[cnt].info.prec);
 539                   if (end)
 540                     len = end - str;
 541                   else
 542                     len = specs[cnt].info.prec;
 543                 }
 544               else
 545                 len = strlen (str);
 546
 547               specs[cnt].info.width -= len;
 548
 549               if (!specs[cnt].info.left)
 550                 PAD (' ');
 551               outstring (str, len);
 552               if (specs[cnt].info.left)
 553                 PAD (' ');
 554             }
 555             break;
 556
 557           case 'p':
 558             /* Generic pointer.  */
 559             {
 560               const void *ptr;
 561               ptr = args_value[specs[cnt].data_arg].pa_pointer;
 562               if (ptr != NULL)
 563                 {
 564                   /* If the pointer is not NULL, write it as a %#x spec.  */
 565                   base = 16;
 566                   num = (unsigned long long int) (unsigned long int) ptr;
 567                   is_neg = 0;
 568                   specs[cnt].info.alt = 1;
 569                   specs[cnt].info.spec = 'x';
 570                   specs[cnt].info.group = 0;
 571                   goto number;
 572                 }
 573               else
 574                 {
 575                   /* Write "(nil)" for a nil pointer.  */
 576                   str = "(nil)";
 577                   /* Make sure the full string "(nil)" is printed.  */
 578                   if (specs[cnt].info.prec < 5)
 579                     specs[cnt].info.prec = 5;
 580                   goto string;
 581                 }
 582             }
 583             break;
 584
 585           case 'n':
 586             /* Answer the count of characters written.  */
 587             if (specs[cnt].info.is_longlong)
 588               *(long long int *)
 589                 args_value[specs[cnt].data_arg].pa_pointer = done;
 590             else if (specs[cnt].info.is_long)
 591               *(long int *)
 592                 args_value[specs[cnt].data_arg].pa_pointer = done;
 593             else if (!specs[cnt].info.is_short)
 594               *(int *)
 595                 args_value[specs[cnt].data_arg].pa_pointer = done;
 596             else
 597               *(short int *)
 598                 args_value[specs[cnt].data_arg].pa_pointer = done;
 599             break;
 600
 601           case 'm':
 602             {
 603               extern char *_strerror_internal __P ((int, char *buf, size_t));
 604               str = _strerror_internal (errno, errorbuf, sizeof errorbuf);
 605               goto string;
 606             }
 607
 608           default:
 609             /* Unrecognized format specifier.  */
 610             function = printf_unknown;
 611             goto use_function;
 612           }
 613
 614       /* Write the following constant string.  */
 615       outstring (specs[cnt].end_of_fmt,
 616                  specs[cnt].next_fmt - specs[cnt].end_of_fmt);
 617     }
 618
 619   return done;
 620 }
 621
 622
 623 /* Handle an unknown format specifier.  This prints out a canonicalized
 624    representation of the format spec itself.  */
 625
 626 static int
 627 printf_unknown (s, info, args)
 628   FILE *s;
 629   const struct printf_info *info;
 630   const void **const args;
 631 {
 632   int done = 0;
 633   char work[BUFSIZ];
 634   char *const workend = &work[sizeof(work) - 1];
 635   register char *w;
 636
 637   outchar ('%');
 638
 639   if (info->alt)
 640     outchar ('#');
 641   if (info->group)
 642     outchar ('\'');
 643   if (info->showsign)
 644     outchar ('+');
 645   else if (info->space)
 646     outchar (' ');
 647   if (info->left)
 648     outchar ('-');
 649   if (info->pad == '0')
 650     outchar ('0');
 651
 652   if (info->width != 0)
 653     {
 654       w = _itoa (info->width, workend + 1, 10, 0);
 655       while (++w <= workend)
 656         outchar (*w);
 657     }
 658
 659   if (info->prec != -1)
 660     {
 661       outchar ('.');
 662       w = _itoa (info->prec, workend + 1, 10, 0);
 663       while (++w <= workend)
 664         outchar (*w);
 665     }
 666
 667   if (info->spec != '\0')
 668     outchar (info->spec);
 669
 670   return done;
 671 }
 672 \f
 673 /* Group the digits according to the grouping rules of the current locale.
 674    The interpretation of GROUPING is as in `struct lconv' from <locale.h>.  */
 675
 676 static char *
 677 group_number (char *w, char *workend, const char *grouping,
 678               wchar_t thousands_sep)
 679 {
 680   int len;
 681   char *src, *s;
 682
 683   /* We treat all negative values like CHAR_MAX.  */
 684
 685   if (*grouping == CHAR_MAX || *grouping < 0)
 686     /* No grouping should be done.  */
 687     return w;
 688
 689   len = *grouping;
 690
 691   /* Copy existing string so that nothing gets overwritten.  */
 692   src = (char *) alloca (workend - w);
 693   memcpy (src, w + 1, workend - w);
 694   s = &src[workend - w - 1];
 695   w = workend;
 696
 697   /* Process all characters in the string.  */
 698   while (s >= src)
 699     {
 700       *w-- = *s--;
 701
 702       if (--len == 0 && s >= src)
 703         {
 704           /* A new group begins.  */
 705           *w-- = thousands_sep;
 706
 707           len = *grouping++;
 708           if (*grouping == '\0')
 709             /* The previous grouping repeats ad infinitum.  */
 710             --grouping;
 711           else if (*grouping == CHAR_MAX || *grouping < 0)
 712             {
 713               /* No further grouping to be done.
 714                  Copy the rest of the number.  */
 715               do
 716                 *w-- = *s--;
 717               while (s >= src);
 718               break;
 719             }
 720         }
 721     }
 722   return w;
 723 }
 724 \f
 725 #ifdef USE_IN_LIBIO
 726 /* Helper "class" for `fprintf to unbuffered': creates a temporary buffer.  */
 727 struct helper_file
 728   {
 729     struct _IO_FILE_plus _f;
 730     _IO_FILE *_put_stream;
 731   };
 732
 733 static int
 734 _IO_helper_overflow (s, c)
 735   _IO_FILE *s;
 736   int c;
 737 {
 738   _IO_FILE *target = ((struct helper_file*) s)->_put_stream;
 739   int used = s->_IO_write_ptr - s->_IO_write_base;
 740   if (used)
 741     {
 742       _IO_size_t written = _IO_sputn (target, s->_IO_write_base, used);
 743       s->_IO_write_ptr -= written;
 744     }
 745   return _IO_putc (c, s);
 746 }
 747
 748 static const struct _IO_jump_t _IO_helper_jumps =
 749   {
 750     _IO_helper_overflow,
 751     _IO_default_underflow,
 752     _IO_default_xsputn,
 753     _IO_default_xsgetn,
 754     _IO_default_read,
 755     _IO_default_write,
 756     _IO_default_doallocate,
 757     _IO_default_pbackfail,
 758     _IO_default_setbuf,
 759     _IO_default_sync,
 760     _IO_default_finish,
 761     _IO_default_close,
 762     _IO_default_stat,
 763     _IO_default_seek,
 764     _IO_default_seekoff,
 765     _IO_default_seekpos,
 766     _IO_default_uflow
 767   };
 768
 769 static int
 770 buffered_vfprintf (s, format, args)
 771   register _IO_FILE *s;
 772   char const *format;
 773   _IO_va_list args;
 774 {
 775   char buf[_IO_BUFSIZ];
 776   struct helper_file helper;
 777   register _IO_FILE *hp = (_IO_FILE *) &helper;
 778   int result, to_flush;
 779
 780   /* Initialize helper.  */
 781   helper._put_stream = s;
 782   hp->_IO_write_base = buf;
 783   hp->_IO_write_ptr = buf;
 784   hp->_IO_write_end = buf + sizeof buf;
 785   hp->_IO_file_flags = _IO_MAGIC|_IO_NO_READS;
 786   hp->_jumps = (struct _IO_jump_t *) &_IO_helper_jumps;
 787
 788   /* Now print to helper instead.  */
 789   result = _IO_vfprintf (hp, format, args);
 790
 791   /* Now flush anything from the helper to the S. */
 792   if ((to_flush = hp->_IO_write_ptr - hp->_IO_write_base) > 0)
 793     {
 794       if (_IO_sputn (s, hp->_IO_write_base, to_flush) != to_flush)
 795         return -1;
 796     }
 797
 798   return result;
 799 }
 800
 801 #else /* !USE_IN_LIBIO */
 802
 803 static int
 804 buffered_vfprintf (s, format, args)
 805   register FILE *s;
 806   char const *format;
 807   va_list args;
 808 {
 809   char buf[BUFSIZ];
 810   int result;
 811
 812   s->__bufp = s->__buffer = buf;
 813   s->__bufsize = sizeof buf;
 814   s->__put_limit = s->__buffer + s->__bufsize;
 815   s->__get_limit = s->__buffer;
 816
 817   /* Now use buffer to print.  */
 818   result = vfprintf (s, format, args);
 819
 820   if (fflush (s) == EOF)
 821     result = -1;
 822   s->__buffer = s->__bufp = s->__get_limit = s->__put_limit = NULL;
 823   s->__bufsize = 0;
 824
 825   return result;
 826 }
 827
 828
 829 /* Pads string with given number of a specified character.
 830    This code is taken from iopadn.c of the GNU I/O library.  */
 831 #define PADSIZE 16
 832 static const char blanks[PADSIZE] =
 833 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
 834 static const char zeroes[PADSIZE] =
 835 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};
 836
 837 ssize_t
 838 __printf_pad (s, pad, count)
 839      FILE *s;
 840      char pad;
 841      size_t count;
 842 {
 843   const char *padptr;
 844   register size_t i;
 845
 846   padptr = pad == ' ' ? blanks : zeroes;
 847
 848   for (i = count; i >= PADSIZE; i -= PADSIZE)
 849     if (PUT (s, padptr, PADSIZE) != PADSIZE)
 850       return -1;
 851   if (i > 0)
 852     if (PUT (s, padptr, i) != i)
 853       return -1;
 854
 855   return count;
 856 }
 857 #undef PADSIZE
 858 #endif /* USE_IN_LIBIO */