coreutils/lib/basename.c

/* basename.c -- return the last element in a path
   Copyright (C) 1990, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#if HAVE_CONFIG_H
# include <config.h>
#endif

#if STDC_HEADERS || HAVE_STRING_H
# include <string.h>
#endif
#include "dirname.h"

/* In general, we can't use the builtin `basename' function if available,
   since it has different meanings in different environments.
   In some environments the builtin `basename' modifies its argument.

   Return the address of the last file name component of NAME.  If
   NAME has no file name components because it is all slashes, return
   NAME if it is empty, the address of its last slash otherwise.  */

char *
base_name (char const *name)
{
  char const *base = name + FILESYSTEM_PREFIX_LEN (name);
  char const *p;

  for (p = base; *p; p++)
    {
      if (ISSLASH (*p))
	{
	  /* Treat multiple adjacent slashes like a single slash.  */
	  do p++;
	  while (ISSLASH (*p));

	  /* If the file name ends in slash, use the trailing slash as
	     the basename if no non-slashes have been found.  */
	  if (! *p)
	    {
	      if (ISSLASH (*base))
		base = p - 1;
	      break;
	    }

	  /* *P is a non-slash preceded by a slash.  */
	  base = p;
	}
    }

  return (char *) base;
}

/* Return the length of of the basename NAME.  Typically NAME is the
   value returned by base_name.  Act like strlen (NAME), except omit
   redundant trailing slashes.  */

size_t
base_len (char const *name)
{
  size_t len;

  for (len = strlen (name);  1 < len && ISSLASH (name[len - 1]);  len--)
    continue;

  return len;
}