lib/addext.c

   1 /* addext.c -- add an extension to a file name
   2    Copyright (C) 1990, 1997 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    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 /* Written by David MacKenzie <djm@gnu.ai.mit.edu> and Paul Eggert */
  20
  21 #if HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #ifndef HAVE_DOS_FILE_NAMES
  26 #define HAVE_DOS_FILE_NAMES 0
  27 #endif
  28 #ifndef HAVE_LONG_FILE_NAMES
  29 #define HAVE_LONG_FILE_NAMES 0
  30 #endif
  31
  32 #include <backupfile.h>
  33
  34 #if HAVE_LIMITS_H
  35 # include <limits.h>
  36 #endif
  37 #ifndef _POSIX_NAME_MAX
  38 #define _POSIX_NAME_MAX 14
  39 #endif
  40
  41 #include <sys/types.h>
  42 #if HAVE_STRING_H
  43 # include <string.h>
  44 #else
  45 # include <strings.h>
  46 #endif
  47
  48 #if HAVE_UNISTD_H
  49 # include <unistd.h>
  50 #endif
  51
  52 /* Append to FILENAME the extension EXT, unless the result would be too long,
  53    in which case just append the character E.  */
  54
  55 void
  56 addext (filename, ext, e)
  57      char *filename;
  58      char const *ext;
  59      int e;
  60 {
  61   char *s = base_name (filename);
  62   size_t slen = strlen (s), extlen = strlen (ext);
  63   long slen_max = -1;
  64
  65 #if HAVE_PATHCONF && defined _PC_NAME_MAX
  66   if (slen + extlen <= _POSIX_NAME_MAX && ! HAVE_DOS_FILE_NAMES)
  67     /* The file name is so short there's no need to call pathconf.  */
  68     slen_max = _POSIX_NAME_MAX;
  69   else if (s == filename)
  70     slen_max = pathconf (".", _PC_NAME_MAX);
  71   else
  72     {
  73       char c = *s;
  74       *s = 0;
  75       slen_max = pathconf (filename, _PC_NAME_MAX);
  76       *s = c;
  77     }
  78 #endif
  79   if (slen_max < 0)
  80     slen_max = HAVE_LONG_FILE_NAMES ? 255 : 14;
  81
  82   if (HAVE_DOS_FILE_NAMES && slen_max <= 12)
  83     {
  84       /* Live within DOS's 8.3 limit.  */
  85       char *dot = strchr (s, '.');
  86       if (dot)
  87         {
  88           slen -= dot + 1 - s;
  89           s = dot + 1;
  90           slen_max = 3;
  91         }
  92       else
  93         slen_max = 8;
  94       extlen = 9; /* Don't use EXT.  */
  95     }
  96
  97   if (slen + extlen <= slen_max)
  98     strcpy (s + slen, ext);
  99   else
 100     {
 101       if (slen_max <= slen)
 102         slen = slen_max - 1;
 103       s[slen] = e;
 104       s[slen + 1] = 0;
 105     }
 106 }