Line data    Source code

       1             : /* dirname.c -- return all but the last element in a file name
       2             : 
       3             :    Copyright (C) 1990, 1998, 2000-2001, 2003-2006, 2009-2016 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 <stdlib.h>
      24             : #include <string.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           0 : dir_len (char const *file)
      33             : {
      34           0 :   size_t prefix_length = FILE_SYSTEM_PREFIX_LEN (file);
      35             :   size_t length;
      36             : 
      37             :   /* Advance prefix_length beyond important leading slashes.  */
      38           0 :   prefix_length += (prefix_length != 0
      39             :                     ? (FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE
      40             :                        && ISSLASH (file[prefix_length]))
      41           0 :                     : (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           0 :   for (length = last_component (file) - file;
      49           0 :        prefix_length < length; length--)
      50           0 :     if (! ISSLASH (file[length - 1]))
      51           0 :       break;
      52           0 :   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 malloc.
      61             :    Works properly even if there are trailing slashes (by effectively
      62             :    ignoring them).  Return NULL on failure.
      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           0 : mdir_name (char const *file)
      72             : {
      73           0 :   size_t length = dir_len (file);
      74           0 :   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           0 :   char *dir = malloc (length + append_dot + 1);
      79           0 :   if (!dir)
      80           0 :     return NULL;
      81           0 :   memcpy (dir, file, length);
      82           0 :   if (append_dot)
      83           0 :     dir[length++] = '.';
      84           0 :   dir[length] = '\0';
      85           0 :   return dir;
      86             : }