source: binutils/vendor/current/libiberty/vprintf-support.c@ 1968

/* Estimate the length of the string generated by a vprintf-like
   function.  Used by vasprintf and xvasprintf.
   Copyright (C) 1994, 2003, 2011, 2013, 2014 Free Software Foundation, Inc.

This file is part of the libiberty library.
Libiberty 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.

Libiberty 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 libiberty; see the file COPYING.LIB.  If not, write
to the Free Software Foundation, Inc., 51 Franklin Street - Fifth
Floor, Boston, MA 02110-1301, USA.  */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <ansidecl.h>
#include <stdarg.h>
#if !defined (va_copy) && defined (__va_copy)
# define va_copy(d,s)  __va_copy((d),(s))
#endif
#include <stdio.h>
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#else
extern unsigned long strtoul ();
#endif
#include "libiberty.h"

int
libiberty_vprintf_buffer_size (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;

#ifdef va_copy
  va_copy (ap, args);
#else
  memcpy ((PTR) &ap, (PTR) &args, sizeof (va_list));
#endif

  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, (char **) &p, 10);
          if (*p == '.')
            {
              ++p;
              if (*p == '*')
                {
                  ++p;
                  total_width += abs (va_arg (ap, int));
                }
              else
              total_width += strtoul (p, (char **) &p, 10);
            }
          while (strchr ("hlL", *p))
            ++p;
          /* Should be big enough for any format specifier except %s and floats.  */
          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);
              /* Since an ieee double can have an exponent of 307, we'll
                 make the buffer wide enough to cover the gross case. */
              total_width += 307;
              break;
            case 's':
              total_width += strlen (va_arg (ap, char *));
              break;
            case 'p':
            case 'n':
              (void) va_arg (ap, char *);
              break;
            }
          p++;
        }
    }
#ifdef va_copy
  va_end (ap);
#endif
  return total_width;
}