| xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame^] | 1 | /* dirname - return directory part of PATH. |
| 2 | Copyright (C) 1996-2016 Free Software Foundation, Inc. |
| 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 |
| 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. |
| 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 |
| 14 | Lesser General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU Lesser General Public |
| 17 | License along with the GNU C Library; if not, see |
| 18 | <http://www.gnu.org/licenses/>. */ |
| 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 | |
| 33 | if (last_slash != NULL && last_slash != path && last_slash[1] == '\0') |
| 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 | } |
| 46 | |
| 47 | if (last_slash != NULL) |
| 48 | { |
| 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 | |
| 56 | /* Terminate the path. */ |
| 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 | } |
| 68 | else |
| 69 | last_slash = runp; |
| 70 | |
| 71 | last_slash[0] = '\0'; |
| 72 | } |
| 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 | } |