1 /* basename.c -- return the last element in a file name
3 Copyright (C) 1990, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006 Free
4 Software Foundation, Inc.
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.
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.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
27 /* Return the address of the last file name component of NAME. If
28 NAME has no relative file name components because it is a file
29 system root, return the empty string. */
32 last_component (char const *name)
34 char const *base = name + FILE_SYSTEM_PREFIX_LEN (name);
36 bool saw_slash = false;
38 while (ISSLASH (*base))
41 for (p = base; *p; p++)
56 /* In general, we can't use the builtin `basename' function if available,
57 since it has different meanings in different environments.
58 In some environments the builtin `basename' modifies its argument.
60 Return the last file name component of NAME, allocated with
61 xmalloc. On systems with drive letters, a leading "./"
62 distinguishes relative names that would otherwise look like a drive
63 letter. Unlike POSIX basename(), NAME cannot be NULL,
64 base_name("") returns "", and the first trailing slash is not
67 If lstat (NAME) would succeed, then { chdir (dir_name (NAME));
68 lstat (base_name (NAME)); } will access the same file. Likewise,
69 if the sequence { chdir (dir_name (NAME));
70 rename (base_name (NAME), "foo"); } succeeds, you have renamed NAME
71 to "foo" in the same directory NAME was in. */
74 base_name (char const *name)
76 char const *base = last_component (name);
79 /* If there is no last component, then name is a file system root or the
82 return xstrndup (name, base_len (name));
84 /* Collapse a sequence of trailing slashes into one. */
85 length = base_len (base);
86 if (ISSLASH (base[length]))
89 /* On systems with drive letters, `a/b:c' must return `./b:c' rather
90 than `b:c' to avoid confusion with a drive letter. On systems
91 with pure POSIX semantics, this is not an issue. */
92 if (FILE_SYSTEM_PREFIX_LEN (base))
94 char *p = xmalloc (length + 3);
97 memcpy (p + 2, base, length);
102 /* Finally, copy the basename. */
103 return xstrndup (base, length);
106 /* Return the length of the basename NAME. Typically NAME is the
107 value returned by base_name or last_component. Act like strlen
108 (NAME), except omit all trailing slashes. */
111 base_len (char const *name)
114 size_t prefix_len = FILE_SYSTEM_PREFIX_LEN (name);
116 for (len = strlen (name); 1 < len && ISSLASH (name[len - 1]); len--)
119 if (DOUBLE_SLASH_IS_DISTINCT_ROOT && len == 1
120 && ISSLASH (name[0]) && ISSLASH (name[1]) && ! name[2])
123 if (FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE && prefix_len
124 && len == prefix_len && ISSLASH (name[prefix_len]))
125 return prefix_len + 1;