Line data    Source code

       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        2749 : last_component (char const *name)
      33             : {
      34        2749 :   char const *base = name + FILE_SYSTEM_PREFIX_LEN (name);
      35             :   char const *p;
      36        2749 :   bool saw_slash = false;
      37             : 
      38        7628 :   while (ISSLASH (*base))
      39        2130 :     base++;
      40             : 
      41        5510 :   for (p = base; *p; p++)
      42             :     {
      43        2761 :       if (ISSLASH (*p))
      44          79 :         saw_slash = true;
      45        2682 :       else if (saw_slash)
      46             :         {
      47          31 :           base = p;
      48          31 :           saw_slash = false;
      49             :         }
      50             :     }
      51             : 
      52        2749 :   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          11 : base_name (char const *name)
      75             : {
      76          11 :   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          11 :   if (! *base)
      82           5 :     return xstrndup (name, base_len (name));
      83             : 
      84             :   /* Collapse a sequence of trailing slashes into one.  */
      85           6 :   length = base_len (base);
      86           6 :   if (ISSLASH (base[length]))
      87           1 :     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           6 :   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        2360 : base_len (char const *name)
     112             : {
     113             :   size_t len;
     114        2360 :   size_t prefix_len = FILE_SYSTEM_PREFIX_LEN (name);
     115             : 
     116        2395 :   for (len = strlen (name);  1 < len && ISSLASH (name[len - 1]);  len--)
     117          35 :     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        2360 :   return len;
     128             : }