Home | History | Annotate | Download | only in lib
      1 /* Formatted output to strings.
      2    Copyright (C) 2004, 2006-2012 Free Software Foundation, Inc.
      3    Written by Simon Josefsson and Yoann Vandoorselaere <yoann (at) prelude-ids.org>.
      4 
      5    This program is free software; you can redistribute it and/or modify
      6    it under the terms of the GNU General Public License as published by
      7    the Free Software Foundation; either version 3, or (at your option)
      8    any later version.
      9 
     10    This program is distributed in the hope that it will be useful,
     11    but WITHOUT ANY WARRANTY; without even the implied warranty of
     12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     13    GNU General Public License for more details.
     14 
     15    You should have received a copy of the GNU General Public License along
     16    with this program; if not, see <http://www.gnu.org/licenses/>.  */
     17 
     18 #if 1
     19 # include <config.h>
     20 #endif
     21 
     22 /* Specification.  */
     23 #include <stdio.h>
     24 
     25 #include <errno.h>
     26 #include <limits.h>
     27 #include <stdarg.h>
     28 #include <stdlib.h>
     29 #include <string.h>
     30 
     31 #include "vasnprintf.h"
     32 
     33 /* Print formatted output to string STR.  Similar to vsprintf, but
     34    additional length SIZE limit how much is written into STR.  Returns
     35    string length of formatted string (which may be larger than SIZE).
     36    STR may be NULL, in which case nothing will be written.  On error,
     37    return a negative value.  */
     38 int
     39 vsnprintf (char *str, size_t size, const char *format, va_list args)
     40 {
     41   char *output;
     42   size_t len;
     43   size_t lenbuf = size;
     44 
     45   output = vasnprintf (str, &lenbuf, format, args);
     46   len = lenbuf;
     47 
     48   if (!output)
     49     return -1;
     50 
     51   if (output != str)
     52     {
     53       if (size)
     54         {
     55           size_t pruned_len = (len < size ? len : size - 1);
     56           memcpy (str, output, pruned_len);
     57           str[pruned_len] = '\0';
     58         }
     59 
     60       free (output);
     61     }
     62 
     63   if (len > INT_MAX)
     64     {
     65       errno = EOVERFLOW;
     66       return -1;
     67     }
     68 
     69   return len;
     70 }
     71