/* Basic filename support macros.
Copyright (C) 2001-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* From Paul Eggert and Jim Meyering. */
#ifndef _FILENAME_H
#define _FILENAME_H
#include <string.h>
#ifdef __cplusplus
extern "C" {
#endif
/* Filename support.
ISSLASH(C) tests whether C is a directory separator
character.
HAS_DEVICE(Filename) tests whether Filename contains a device
specification.
FILE_SYSTEM_PREFIX_LEN(Filename) length of the device specification
at the beginning of Filename,
index of the part consisting of
alternating components and slashes.
FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE
1 when a non-empty device specification
can be followed by an empty or relative
part,
0 when a non-empty device specification
must be followed by a slash,
0 when device specification don't exist.
IS_ABSOLUTE_FILE_NAME(Filename)
tests whether Filename is independent of
any notion of "current directory".
IS_RELATIVE_FILE_NAME(Filename)
tests whether Filename may be concatenated
to a directory filename.
Note: On native Windows, OS/2, DOS, "c:" is neither an absolute nor a
relative file name!
IS_FILE_NAME_WITH_DIR(Filename) tests whether Filename contains a device
or directory specification.
*/
#if defined _WIN32 || defined __CYGWIN__ \
|| defined __EMX__ || defined __MSDOS__ || defined __DJGPP__
/* Native Windows, Cygwin, OS/2, DOS */
# define ISSLASH(C) ((C) == '/' || (C) == '\\')
/* Internal macro: Tests whether a character is a drive letter. */
# define _IS_DRIVE_LETTER(C) \
(((C) >= 'A' && (C) <= 'Z') || ((C) >= 'a' && (C) <= 'z'))
/* Help the compiler optimizing it. This assumes ASCII. */
# undef _IS_DRIVE_LETTER
# define _IS_DRIVE_LETTER(C) \
(((unsigned int) (C) | ('a' - 'A')) - 'a' <= 'z' - 'a')
# define HAS_DEVICE(Filename) \
(_IS_DRIVE_LETTER ((Filename)[0]) && (Filename)[1] == ':')
# define FILE_SYSTEM_PREFIX_LEN(Filename) (HAS_DEVICE (Filename) ? 2 : 0)
# ifdef __CYGWIN__
# define FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE 0
# else
/* On native Windows, OS/2, DOS, the system has the notion of a
"current directory" on each drive. */
# define FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE 1
# endif
# if FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE
# define IS_ABSOLUTE_FILE_NAME(Filename) \
ISSLASH ((Filename)[FILE_SYSTEM_PREFIX_LEN (Filename)])
# else
# define IS_ABSOLUTE_FILE_NAME(Filename) \
(ISSLASH ((Filename)[0]) || HAS_DEVICE (Filename))
# endif
# define IS_RELATIVE_FILE_NAME(Filename) \
(! (ISSLASH ((Filename)[0]) || HAS_DEVICE (Filename)))
# define IS_FILE_NAME_WITH_DIR(Filename) \
(strchr ((Filename), '/') != NULL || strchr ((Filename), '\\') != NULL \
|| HAS_DEVICE (Filename))
#else
/* Unix */
# define ISSLASH(C) ((C) == '/')
# define HAS_DEVICE(Filename) ((void) (Filename), 0)
# define FILE_SYSTEM_PREFIX_LEN(Filename) ((void) (Filename), 0)
# define FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE 0
# define IS_ABSOLUTE_FILE_NAME(Filename) ISSLASH ((Filename)[0])
# define IS_RELATIVE_FILE_NAME(Filename) (! ISSLASH ((Filename)[0]))
# define IS_FILE_NAME_WITH_DIR(Filename) (strchr ((Filename), '/') != NULL)
#endif
/* Deprecated macros. For backward compatibility with old users of the
'filename' module. */
#define IS_ABSOLUTE_PATH IS_ABSOLUTE_FILE_NAME
#define IS_PATH_WITH_DIR IS_FILE_NAME_WITH_DIR
#ifdef __cplusplus
}
#endif
#endif /* _FILENAME_H */
