1 /* Basic filename support macros.
2 Copyright (C) 2001-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 /* From Paul Eggert and Jim Meyering. */
20
21 #ifndef _FILENAME_H
22 #define _FILENAME_H
23
24 #include <string.h>
25
26 #ifdef __cplusplus
27 extern "C" {
28 #endif
29
30
31 /* Filename support.
32 ISSLASH(C) tests whether C is a directory separator
33 character.
34 HAS_DEVICE(Filename) tests whether Filename contains a device
35 specification.
36 FILE_SYSTEM_PREFIX_LEN(Filename) length of the device specification
37 at the beginning of Filename,
38 index of the part consisting of
39 alternating components and slashes.
40 FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE
41 1 when a non-empty device specification
42 can be followed by an empty or relative
43 part,
44 0 when a non-empty device specification
45 must be followed by a slash,
46 0 when device specification don't exist.
47 IS_ABSOLUTE_FILE_NAME(Filename)
48 tests whether Filename is independent of
49 any notion of "current directory".
50 IS_RELATIVE_FILE_NAME(Filename)
51 tests whether Filename may be concatenated
52 to a directory filename.
53 Note: On native Windows, OS/2, DOS, "c:" is neither an absolute nor a
54 relative file name!
55 IS_FILE_NAME_WITH_DIR(Filename) tests whether Filename contains a device
56 or directory specification.
57 */
58 #if defined _WIN32 || defined __CYGWIN__ \
59 || defined __EMX__ || defined __MSDOS__ || defined __DJGPP__
60 /* Native Windows, Cygwin, OS/2, DOS */
61 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
62 /* Internal macro: Tests whether a character is a drive letter. */
63 # define _IS_DRIVE_LETTER(C) \
64 (((C) >= 'A' && (C) <= 'Z') || ((C) >= 'a' && (C) <= 'z'))
65 /* Help the compiler optimizing it. This assumes ASCII. */
66 # undef _IS_DRIVE_LETTER
67 # define _IS_DRIVE_LETTER(C) \
68 (((unsigned int) (C) | ('a' - 'A')) - 'a' <= 'z' - 'a')
69 # define HAS_DEVICE(Filename) \
70 (_IS_DRIVE_LETTER ((Filename)[0]) && (Filename)[1] == ':')
71 # define FILE_SYSTEM_PREFIX_LEN(Filename) (HAS_DEVICE (Filename) ? 2 : 0)
72 # ifdef __CYGWIN__
73 # define FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE 0
74 # else
75 /* On native Windows, OS/2, DOS, the system has the notion of a
76 "current directory" on each drive. */
77 # define FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE 1
78 # endif
79 # if FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE
80 # define IS_ABSOLUTE_FILE_NAME(Filename) \
81 ISSLASH ((Filename)[FILE_SYSTEM_PREFIX_LEN (Filename)])
82 # else
83 # define IS_ABSOLUTE_FILE_NAME(Filename) \
84 (ISSLASH ((Filename)[0]) || HAS_DEVICE (Filename))
85 # endif
86 # define IS_RELATIVE_FILE_NAME(Filename) \
87 (! (ISSLASH ((Filename)[0]) || HAS_DEVICE (Filename)))
88 # define IS_FILE_NAME_WITH_DIR(Filename) \
89 (strchr ((Filename), '/') != NULL || strchr ((Filename), '\\') != NULL \
90 || HAS_DEVICE (Filename))
91 #else
92 /* Unix */
93 # define ISSLASH(C) ((C) == '/')
94 # define HAS_DEVICE(Filename) ((void) (Filename), 0)
95 # define FILE_SYSTEM_PREFIX_LEN(Filename) ((void) (Filename), 0)
96 # define FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE 0
97 # define IS_ABSOLUTE_FILE_NAME(Filename) ISSLASH ((Filename)[0])
98 # define IS_RELATIVE_FILE_NAME(Filename) (! ISSLASH ((Filename)[0]))
99 # define IS_FILE_NAME_WITH_DIR(Filename) (strchr ((Filename), '/') != NULL)
100 #endif
101
102 /* Deprecated macros. For backward compatibility with old users of the
103 'filename' module. */
104 #define IS_ABSOLUTE_PATH IS_ABSOLUTE_FILE_NAME
105 #define IS_PATH_WITH_DIR IS_FILE_NAME_WITH_DIR
106
107
108 #ifdef __cplusplus
109 }
110 #endif
111
112 #endif /* _FILENAME_H */