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| 1 /* dirname.c -- return all but the last element in a file name |
| 2 |
| 3 Copyright (C) 1990, 1998, 2000, 2001, 2003, 2004, 2005, 2006 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 <http://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 /* Return the length of the prefix of FILE that will be used by |
| 27 dir_name. If FILE is in the working directory, this returns zero |
| 28 even though `dir_name (FILE)' will return ".". Works properly even |
| 29 if there are trailing slashes (by effectively ignoring them). */ |
| 30 |
| 31 size_t |
| 32 dir_len (char const *file) |
| 33 { |
| 34 size_t prefix_length = FILE_SYSTEM_PREFIX_LEN (file); |
| 35 size_t length; |
| 36 |
| 37 /* Advance prefix_length beyond important leading slashes. */ |
| 38 prefix_length += (prefix_length != 0 |
| 39 ? (FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE |
| 40 && ISSLASH (file[prefix_length])) |
| 41 : (ISSLASH (file[0]) |
| 42 ? ((DOUBLE_SLASH_IS_DISTINCT_ROOT |
| 43 && ISSLASH (file[1]) && ! ISSLASH (file[2]) |
| 44 ? 2 : 1)) |
| 45 : 0)); |
| 46 |
| 47 /* Strip the basename and any redundant slashes before it. */ |
| 48 for (length = last_component (file) - file; |
| 49 prefix_length < length; length--) |
| 50 if (! ISSLASH (file[length - 1])) |
| 51 break; |
| 52 return length; |
| 53 } |
| 54 |
| 55 |
| 56 /* In general, we can't use the builtin `dirname' function if available, |
| 57 since it has different meanings in different environments. |
| 58 In some environments the builtin `dirname' modifies its argument. |
| 59 |
| 60 Return the leading directories part of FILE, allocated with xmalloc. |
| 61 Works properly even if there are trailing slashes (by effectively |
| 62 ignoring them). Unlike POSIX dirname(), FILE cannot be NULL. |
| 63 |
| 64 If lstat (FILE) would succeed, then { chdir (dir_name (FILE)); |
| 65 lstat (base_name (FILE)); } will access the same file. Likewise, |
| 66 if the sequence { chdir (dir_name (FILE)); |
| 67 rename (base_name (FILE), "foo"); } succeeds, you have renamed FILE |
| 68 to "foo" in the same directory FILE was in. */ |
| 69 |
| 70 char * |
| 71 dir_name (char const *file) |
| 72 { |
| 73 size_t length = dir_len (file); |
| 74 bool append_dot = (length == 0 |
| 75 || (FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE |
| 76 && length == FILE_SYSTEM_PREFIX_LEN (file) |
| 77 && file[2] != '\0' && ! ISSLASH (file[2]))); |
| 78 char *dir = xmalloc (length + append_dot + 1); |
| 79 memcpy (dir, file, length); |
| 80 if (append_dot) |
| 81 dir[length++] = '.'; |
| 82 dir[length] = '\0'; |
| 83 return dir; |
| 84 } |
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