1 /* basename.c -- return the last element in a file name
2
3 Copyright (C) 1990, 1998-2001, 2003-2006, 2009-2021 Free Software
4 Foundation, Inc.
5
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <https://www.gnu.org/licenses/>. */
18
19 #include <config.h>
20
21 #include "dirname.h"
22
23 #include <string.h>
24 #include "xalloc.h"
25
26 char *
base_name(char const * name)27 base_name (char const *name)
28 {
29 char const *base = last_component (name);
30 idx_t length;
31 int dotslash_len;
32 if (*base)
33 {
34 length = base_len (base);
35
36 /* Collapse a sequence of trailing slashes into one. */
37 length += ISSLASH (base[length]);
38
39 /* On systems with drive letters, "a/b:c" must return "./b:c" rather
40 than "b:c" to avoid confusion with a drive letter. On systems
41 with pure POSIX semantics, this is not an issue. */
42 dotslash_len = FILE_SYSTEM_PREFIX_LEN (base) != 0 ? 2 : 0;
43 }
44 else
45 {
46 /* There is no last component, so NAME is a file system root or
47 the empty string. */
48 base = name;
49 length = base_len (base);
50 dotslash_len = 0;
51 }
52
53 char *p = ximalloc (dotslash_len + length + 1);
54 if (dotslash_len)
55 {
56 p[0] = '.';
57 p[1] = '/';
58 }
59
60 /* Finally, copy the basename. */
61 memcpy (p + dotslash_len, base, length);
62 p[dotslash_len + length] = '\0';
63 return p;
64 }
65