root/maint/gnulib/lib/unistdio/u-vsprintf.h

/* */

INCLUDED FROM

DEFINITIONS

1. VSPRINTF

   1 /* Formatted output to strings.
   2    Copyright (C) 1999, 2002, 2006-2021 Free Software Foundation, Inc.
   3 
   4    This file is free software.
   5    It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
   6    You can redistribute it and/or modify it under either
   7      - the terms of the GNU Lesser General Public License as published
   8        by the Free Software Foundation; either version 3, or (at your
   9        option) any later version, or
  10      - the terms of the GNU General Public License as published by the
  11        Free Software Foundation; either version 2, or (at your option)
  12        any later version, or
  13      - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
  14 
  15    This file is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18    Lesser General Public License and the GNU General Public License
  19    for more details.
  20 
  21    You should have received a copy of the GNU Lesser General Public
  22    License and of the GNU General Public License along with this
  23    program.  If not, see <https://www.gnu.org/licenses/>.  */
  24 
  25 #ifndef SIZE_MAX
  26 # define SIZE_MAX ((size_t) -1)
  27 #endif
  28 
  29 int
  30 VSPRINTF (DCHAR_T *buf, const FCHAR_T *format, va_list args)
     /*  */
  31 {
  32   /* Pass an infinite length.  But note that *vasnprintf may fail if the buffer
  33      argument is larger than INT_MAX (if that fits into a 'size_t' at all).
  34      Also note that glibc's iconv fails with E2BIG when we pass a length that
  35      is so large that buf + length wraps around, i.e.
  36      (uintptr_t) (buf + length) < (uintptr_t) buf.  */
  37   size_t length;
  38   DCHAR_T *result;
  39 
  40   /* Set length = min (SIZE_MAX, INT_MAX, - (uintptr_t) buf - 1).  */
  41   length = (SIZE_MAX < INT_MAX ? SIZE_MAX : INT_MAX);
  42   if (length > (~ (uintptr_t) buf) / sizeof (DCHAR_T))
  43     length = (~ (uintptr_t) buf) / sizeof (DCHAR_T);
  44 
  45   result = VASNPRINTF (buf, &length, format, args);
  46   if (result == NULL)
  47     return -1;
  48 
  49   /* The infinite buffer size guarantees that the result is not malloc()ed.  */
  50   if (result != buf)
  51     {
  52       /* length is near SIZE_MAX.  */
  53       free (result);
  54       errno = EOVERFLOW;
  55       return -1;
  56     }
  57 
  58   if (length > INT_MAX)
  59     {
  60       errno = EOVERFLOW;
  61       return -1;
  62     }
  63 
  64   /* Return the number of resulting units, excluding the trailing NUL.  */
  65   return length;
  66 }

/* */