[Bug-gnulib] How about a vasprintf()?

[Simon Josefsson]

I found this in GNU Mailutils, not sure where it comes from.
Something for gnulib?

/* Like vsprintf but provides a pointer to malloc'd storage, which must
   be freed by the caller.
   Copyright (C) 1994 Free Software Foundation, Inc.

This program 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 program 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 program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdio.h>
#include <string.h>

#if __STDC__
# include <stdarg.h>
#else
# include <varargs.h>
#endif

#ifdef TEST
int global_total_width;
#endif

unsigned long strtoul ();
char *malloc ();

static int
int_vasprintf (result, format, args)
     char **result;
     const char *format;
     va_list *args;
{
  const char *p = format;
  /* Add one to make sure that it is never zero, which might cause malloc
     to return NULL.  */
  int total_width = strlen (format) + 1;
  va_list ap;

  memcpy (&ap, args, sizeof (va_list));

  while (*p != '\0')
    {
      if (*p++ == '%')
        {
          while (strchr ("-+ #0", *p))
            ++p;
          if (*p == '*')
            {
              ++p;
              total_width += abs (va_arg (ap, int));
            }
          else
            total_width += strtoul (p, &p, 10);
          if (*p == '.')
            {
              ++p;
              if (*p == '*')
                {
                  ++p;
                  total_width += abs (va_arg (ap, int));
                }
              else
                total_width += strtoul (p, &p, 10);
            }
          while (strchr ("hlL", *p))
            ++p;
          /* Should be big enough for any format specifier except %s.  */
          total_width += 30;
          switch (*p)
            {
            case 'd':
            case 'i':
            case 'o':
            case 'u':
            case 'x':
            case 'X':
            case 'c':
              (void) va_arg (ap, int);
              break;
            case 'f':
            case 'e':
            case 'E':
            case 'g':
            case 'G':
              (void) va_arg (ap, double);
              break;
            case 's':
              total_width += strlen (va_arg (ap, char *));
              break;
            case 'p':
            case 'n':
              (void) va_arg (ap, char *);
              break;
            }
        }
    }
#ifdef TEST
  global_total_width = total_width;
#endif
  *result = malloc (total_width);
  if (*result != NULL)
    return vsprintf (*result, format, *args);
  else
    return 0;
}

int
vasprintf (result, format, args)
     char **result;
     const char *format;
     va_list args;
{
  return int_vasprintf (result, format, &args);
}

int
asprintf
#if __STDC__
     (char **result, const char *format, ...)
#else
     (result, va_alist)
     char **result;
     va_dcl
#endif
{
  va_list args;
  int done;

#if __STDC__
  va_start (args, format);
#else
  char *format;
  va_start (args);
  format = va_arg (args, char *);
#endif
  done = vasprintf (result, format, args);
  va_end (args);

  return done;
} 

#ifdef TEST
void
checkit
#if __STDC__
     (const char* format, ...)
#else
     (va_alist)
     va_dcl
#endif
{
  va_list args;
  char *result;

#if __STDC__
  va_start (args, format);
#else
  char *format;
  va_start (args);
  format = va_arg (args, char *);
#endif
  vasprintf (&result, format, args);
  va_end (args);
  if (strlen (result) < global_total_width)
    printf ("PASS: ");
  else
    printf ("FAIL: ");
  printf ("%d %s\n", global_total_width, result);
}

int
main ()
{
  checkit ("%d", 0x12345678);
  checkit ("%200d", 5);
  checkit ("%.300d", 6);
  checkit ("%100.150d", 7);
  checkit ("%s", "jjjjjjjjjiiiiiiiiiiiiiiioooooooooooooooooppppppppppppaa\n\
777777777777777777333333333333366666666666622222222222777777777777733333");
  checkit ("%f%s%d%s", 1.0, "foo", 77, "asdjffffffffffffffiiiiiiiiiiixxxxx");
}
#endif /* TEST */