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| 1 /* basename.c -- return the last element in a file name |
| 2 |
| 3 Copyright (C) 1990, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006 Free |
| 4 Software 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 #include "xstrndup.h" |
| 26 |
| 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. */ |
| 30 |
| 31 char * |
| 32 last_component (char const *name) |
| 33 { |
| 34 char const *base = name + FILE_SYSTEM_PREFIX_LEN (name); |
| 35 char const *p; |
| 36 bool saw_slash = false; |
| 37 |
| 38 while (ISSLASH (*base)) |
| 39 base++; |
| 40 |
| 41 for (p = base; *p; p++) |
| 42 { |
| 43 if (ISSLASH (*p)) |
| 44 saw_slash = true; |
| 45 else if (saw_slash) |
| 46 { |
| 47 base = p; |
| 48 saw_slash = false; |
| 49 } |
| 50 } |
| 51 |
| 52 return (char *) base; |
| 53 } |
| 54 |
| 55 |
| 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. |
| 59 |
| 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 |
| 65 stripped. |
| 66 |
| 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. */ |
| 72 |
| 73 char * |
| 74 base_name (char const *name) |
| 75 { |
| 76 char const *base = last_component (name); |
| 77 size_t length; |
| 78 |
| 79 /* If there is no last component, then name is a file system root or the |
| 80 empty string. */ |
| 81 if (! *base) |
| 82 return xstrndup (name, base_len (name)); |
| 83 |
| 84 /* Collapse a sequence of trailing slashes into one. */ |
| 85 length = base_len (base); |
| 86 if (ISSLASH (base[length])) |
| 87 length++; |
| 88 |
| 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)) |
| 93 { |
| 94 char *p = xmalloc (length + 3); |
| 95 p[0] = '.'; |
| 96 p[1] = '/'; |
| 97 memcpy (p + 2, base, length); |
| 98 p[length + 2] = '\0'; |
| 99 return p; |
| 100 } |
| 101 |
| 102 /* Finally, copy the basename. */ |
| 103 return xstrndup (base, length); |
| 104 } |
| 105 |
| 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. */ |
| 109 |
| 110 size_t |
| 111 base_len (char const *name) |
| 112 { |
| 113 size_t len; |
| 114 size_t prefix_len = FILE_SYSTEM_PREFIX_LEN (name); |
| 115 |
| 116 for (len = strlen (name); 1 < len && ISSLASH (name[len - 1]); len--) |
| 117 continue; |
| 118 |
| 119 if (DOUBLE_SLASH_IS_DISTINCT_ROOT && len == 1 |
| 120 && ISSLASH (name[0]) && ISSLASH (name[1]) && ! name[2]) |
| 121 return 2; |
| 122 |
| 123 if (FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE && prefix_len |
| 124 && len == prefix_len && ISSLASH (name[prefix_len])) |
| 125 return prefix_len + 1; |
| 126 |
| 127 return len; |
| 128 } |
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