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      1 /* addext.c -- add an extension to a file name
      2    Copyright (C) 1990, 1997-1999, 2001-2003, 2005-2006 Free Software Foundation, Inc.
      3 
      4    This program is free software; you can redistribute it and/or modify
      5    it under the terms of the GNU General Public License as published by
      6    the Free Software Foundation; either version 2, or (at your option)
      7    any later version.
      8 
      9    This program 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
     12    GNU General Public License for more details.
     13 
     14    You should have received a copy of the GNU General Public License
     15    along with this program; see the file COPYING.
     16    If not, write to the Free Software Foundation,
     17    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
     18 
     19 /* Written by David MacKenzie <djm (at) gnu.ai.mit.edu> and Paul Eggert */
     20 
     21 #include <config.h>
     22 
     23 #ifndef HAVE_DOS_FILE_NAMES
     24 # define HAVE_DOS_FILE_NAMES 0
     25 #endif
     26 #ifndef HAVE_LONG_FILE_NAMES
     27 # define HAVE_LONG_FILE_NAMES 0
     28 #endif
     29 
     30 #include "backupfile.h"
     31 
     32 #include <limits.h>
     33 #ifndef _POSIX_NAME_MAX
     34 # define _POSIX_NAME_MAX 14
     35 #endif
     36 
     37 #include <sys/types.h>
     38 #if HAVE_STRING_H
     39 # include <string.h>
     40 #else
     41 # include <strings.h>
     42 #endif
     43 
     44 #include <unistd.h>
     45 
     46 #include "basename.h"
     47 
     48 /* Append to FILENAME the extension EXT, unless the result would be too long,
     49    in which case just append the character E.  */
     50 
     51 void
     52 addext (char *filename, char const *ext, char e)
     53 {
     54   char *s = basename (filename);
     55   size_t slen = strlen (s), extlen = strlen (ext);
     56   long slen_max = -1;
     57 
     58 #if HAVE_PATHCONF && defined _PC_NAME_MAX
     59   if (slen + extlen <= _POSIX_NAME_MAX && ! HAVE_DOS_FILE_NAMES)
     60     /* The file name is so short there's no need to call pathconf.  */
     61     slen_max = _POSIX_NAME_MAX;
     62   else if (s == filename)
     63     slen_max = pathconf (".", _PC_NAME_MAX);
     64   else
     65     {
     66       char c = *s;
     67       *s = 0;
     68       slen_max = pathconf (filename, _PC_NAME_MAX);
     69       *s = c;
     70     }
     71 #endif
     72   if (slen_max < 0)
     73     slen_max = HAVE_LONG_FILE_NAMES ? 255 : 14;
     74 
     75   if (HAVE_DOS_FILE_NAMES && slen_max <= 12)
     76     {
     77       /* Live within DOS's 8.3 limit.  */
     78       char *dot = strchr (s, '.');
     79       if (dot)
     80 	{
     81 	  slen -= dot + 1 - s;
     82 	  s = dot + 1;
     83 	  slen_max = 3;
     84 	}
     85       else
     86 	slen_max = 8;
     87       extlen = 9; /* Don't use EXT.  */
     88     }
     89 
     90   if (slen + extlen <= slen_max)
     91     strcpy (s + slen, ext);
     92   else
     93     {
     94       if (slen_max <= slen)
     95 	slen = slen_max - 1;
     96       s[slen] = e;
     97       s[slen + 1] = 0;
     98     }
     99 }
    100