/* Return basename of given pathname according to the weird XPG specification.

   Copyright (C) 1997-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   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

   <http://www.gnu.org/licenses/>.  */

#include <string.h>

#include <libgen.h>

char *

__xpg_basename (char *filename)

{

  char *p;

  if (filename == NULL || filename[0] == '\0')

    /* We return a pointer to a static string containing ".".  */

    p = (char *) ".";

  else

    {

      p = strrchr (filename, '/');

      if (p == NULL)

	/* There is no slash in the filename.  Return the whole string.  */

	p = filename;

      else

	{

	  if (p[1] == '\0')

	    {

	      /* We must remove trailing '/'.  */

	      while (p > filename && p[-1] == '/')

		--p;

	      /* Now we can be in two situations:

		 a) the string only contains '/' characters, so we return

		    '/'

		 b) p points past the last component, but we have to remove

		    the trailing slash.  */

	      if (p > filename)

		{

		  *p-- = '\0';

		  while (p > filename && p[-1] != '/')

		    --p;

		}

	      else

		/* The last slash we already found is the right position

		   to return.  */

		while (p[1] != '\0')

		  ++p;

	    }

	  else

	    /* Go to the first character of the name.  */

	    ++p;

	}

    }

  return p;

}