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@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
addext(char * filename,char const * ext,char e)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