lib/filename.h

   1 /* Basic filename support macros.
   2    Copyright (C) 2001-2004, 2007-2020 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* From Paul Eggert and Jim Meyering.  */
  18
  19 #ifndef _FILENAME_H
  20 #define _FILENAME_H
  21
  22 #include <string.h>
  23
  24 #ifdef __cplusplus
  25 extern "C" {
  26 #endif
  27
  28
  29 /* Filename support.
  30    ISSLASH(C)                  tests whether C is a directory separator
  31                                character.
  32    HAS_DEVICE(Filename)        tests whether Filename contains a device
  33                                specification.
  34    FILE_SYSTEM_PREFIX_LEN(Filename)  length of the device specification
  35                                      at the beginning of Filename,
  36                                      index of the part consisting of
  37                                      alternating components and slashes.
  38    FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE
  39                                1 when a non-empty device specification
  40                                can be followed by an empty or relative
  41                                part,
  42                                0 when a non-empty device specification
  43                                must be followed by a slash,
  44                                0 when device specification don't exist.
  45    IS_ABSOLUTE_FILE_NAME(Filename)
  46                                tests whether Filename is independent of
  47                                any notion of "current directory".
  48    IS_RELATIVE_FILE_NAME(Filename)
  49                                tests whether Filename may be concatenated
  50                                to a directory filename.
  51    Note: On native Windows, OS/2, DOS, "c:" is neither an absolute nor a
  52    relative file name!
  53    IS_FILE_NAME_WITH_DIR(Filename)  tests whether Filename contains a device
  54                                     or directory specification.
  55  */
  56 #if defined _WIN32 || defined __CYGWIN__ \
  57     || defined __EMX__ || defined __MSDOS__ || defined __DJGPP__
  58   /* Native Windows, Cygwin, OS/2, DOS */
  59 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
  60   /* Internal macro: Tests whether a character is a drive letter.  */
  61 # define _IS_DRIVE_LETTER(C) \
  62     (((C) >= 'A' && (C) <= 'Z') || ((C) >= 'a' && (C) <= 'z'))
  63   /* Help the compiler optimizing it.  This assumes ASCII.  */
  64 # undef _IS_DRIVE_LETTER
  65 # define _IS_DRIVE_LETTER(C) \
  66     (((unsigned int) (C) | ('a' - 'A')) - 'a' <= 'z' - 'a')
  67 # define HAS_DEVICE(Filename) \
  68     (_IS_DRIVE_LETTER ((Filename)[0]) && (Filename)[1] == ':')
  69 # define FILE_SYSTEM_PREFIX_LEN(Filename) (HAS_DEVICE (Filename) ? 2 : 0)
  70 # ifdef __CYGWIN__
  71 #  define FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE 0
  72 # else
  73    /* On native Windows, OS/2, DOS, the system has the notion of a
  74       "current directory" on each drive.  */
  75 #  define FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE 1
  76 # endif
  77 # if FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE
  78 #  define IS_ABSOLUTE_FILE_NAME(Filename) \
  79      ISSLASH ((Filename)[FILE_SYSTEM_PREFIX_LEN (Filename)])
  80 # else
  81 #  define IS_ABSOLUTE_FILE_NAME(Filename) \
  82      (ISSLASH ((Filename)[0]) || HAS_DEVICE (Filename))
  83 # endif
  84 # define IS_RELATIVE_FILE_NAME(Filename) \
  85     (! (ISSLASH ((Filename)[0]) || HAS_DEVICE (Filename)))
  86 # define IS_FILE_NAME_WITH_DIR(Filename) \
  87     (strchr ((Filename), '/') != NULL || strchr ((Filename), '\\') != NULL \
  88      || HAS_DEVICE (Filename))
  89 #else
  90   /* Unix */
  91 # define ISSLASH(C) ((C) == '/')
  92 # define HAS_DEVICE(Filename) ((void) (Filename), 0)
  93 # define FILE_SYSTEM_PREFIX_LEN(Filename) ((void) (Filename), 0)
  94 # define FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE 0
  95 # define IS_ABSOLUTE_FILE_NAME(Filename) ISSLASH ((Filename)[0])
  96 # define IS_RELATIVE_FILE_NAME(Filename) (! ISSLASH ((Filename)[0]))
  97 # define IS_FILE_NAME_WITH_DIR(Filename) (strchr ((Filename), '/') != NULL)
  98 #endif
  99
 100 /* Deprecated macros.  For backward compatibility with old users of the
 101    'filename' module.  */
 102 #define IS_ABSOLUTE_PATH IS_ABSOLUTE_FILE_NAME
 103 #define IS_PATH_WITH_DIR IS_FILE_NAME_WITH_DIR
 104
 105
 106 #ifdef __cplusplus
 107 }
 108 #endif
 109
 110 #endif /* _FILENAME_H */