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2c6fe0bd | 1 | /* dirname - return directory part of PATH. |
04277e02 | 2 | Copyright (C) 1996-2019 Free Software Foundation, Inc. |
2c6fe0bd UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
2c6fe0bd UD |
10 | |
11 | The GNU C Library 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 GNU | |
41bdb6e2 | 14 | Lesser General Public License for more details. |
2c6fe0bd | 15 | |
41bdb6e2 | 16 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 17 | License along with the GNU C Library; if not, see |
5a82c748 | 18 | <https://www.gnu.org/licenses/>. */ |
2c6fe0bd UD |
19 | |
20 | #include <libgen.h> | |
21 | #include <string.h> | |
22 | ||
23 | ||
24 | char * | |
25 | dirname (char *path) | |
26 | { | |
27 | static const char dot[] = "."; | |
28 | char *last_slash; | |
29 | ||
30 | /* Find last '/'. */ | |
31 | last_slash = path != NULL ? strrchr (path, '/') : NULL; | |
32 | ||
887e7ab6 | 33 | if (last_slash != NULL && last_slash != path && last_slash[1] == '\0') |
c891b2df UD |
34 | { |
35 | /* Determine whether all remaining characters are slashes. */ | |
36 | char *runp; | |
37 | ||
38 | for (runp = last_slash; runp != path; --runp) | |
39 | if (runp[-1] != '/') | |
40 | break; | |
41 | ||
42 | /* The '/' is the last character, we have to look further. */ | |
43 | if (runp != path) | |
44 | last_slash = __memrchr (path, '/', runp - path); | |
45 | } | |
2c6fe0bd UD |
46 | |
47 | if (last_slash != NULL) | |
887e7ab6 | 48 | { |
c891b2df UD |
49 | /* Determine whether all remaining characters are slashes. */ |
50 | char *runp; | |
51 | ||
52 | for (runp = last_slash; runp != path; --runp) | |
53 | if (runp[-1] != '/') | |
54 | break; | |
55 | ||
887e7ab6 | 56 | /* Terminate the path. */ |
c891b2df UD |
57 | if (runp == path) |
58 | { | |
59 | /* The last slash is the first character in the string. We have to | |
60 | return "/". As a special case we have to return "//" if there | |
61 | are exactly two slashes at the beginning of the string. See | |
62 | XBD 4.10 Path Name Resolution for more information. */ | |
63 | if (last_slash == path + 1) | |
64 | ++last_slash; | |
65 | else | |
66 | last_slash = path + 1; | |
67 | } | |
d3d48616 UD |
68 | else |
69 | last_slash = runp; | |
887e7ab6 UD |
70 | |
71 | last_slash[0] = '\0'; | |
72 | } | |
2c6fe0bd UD |
73 | else |
74 | /* This assignment is ill-designed but the XPG specs require to | |
75 | return a string containing "." in any case no directory part is | |
76 | found and so a static and constant string is required. */ | |
77 | path = (char *) dot; | |
78 | ||
79 | return path; | |
80 | } |