text: /****************************************************************************
   * libc/libgen/lib_dirname.c
   *
   *   Copyright (C) 2007, 2009, 2011-2012 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <string.h>
  #include <libgen.h>
  
  /****************************************************************************
   * Private Data
   ****************************************************************************/
  
  static char g_retchar[2];
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Function: dirname
   *
   * Description:
   *   dirname() extracts the directory component from a null-terminated
   *   pathname string. In the usual case, dirname() returns the string up
   *   to, but not including, the final '/'. Trailing '/' characters are not
   *   counted as part of the pathname.
   *
   *   If path does not contain a slash, dirname() returns the string ".". If
   *   path is the string "/", then dirname() returns the string "/". If path
   *   is a NULL pointer or points to an empty string, then dirname() returns
   *   the string ".".
   *
   *   dirname() may modify the contents of path, so copies should be passed.
   *   dirname() may return pointers to statically allocated memory which may
   *   be overwritten by subsequent calls.
   *
   * Parameter:
   *   path The null-terminated string referring to the path to be decomposed
   *
   * Return:
   *   On success the directory component of the path is returned.
   *
   ****************************************************************************/
  
  FAR char *dirname(FAR char *path)
  {
    char *p;
    int   len;
    int   ch;
  
    /* Handle some corner cases */
  
    if (!path || *path == '\0')
      {
        ch = '.';
        goto out_retchar;
      }
  
    /* Check for trailing slash characters */
  
    len = strlen(path);
    while (path[len-1] == '/')
      {
        /* Remove trailing '/' UNLESS this would make a zero length string */
        if (len > 1)
          {
            path[len-1] = '\0';
            len--;
          }
        else
          {
            ch = '/';
            goto out_retchar;
          }
      }
  
    /* Get the address of the last '/' which is not at the end of the path and,
     * therefor, must be the end of the directory component.
     */
  
    p = strrchr(path, '/');
    if (p)
      {
        /* Handle the case where the only '/' in the string is the at the beginning
         * of the path.
         */
  
        if (p == path)
          {
            ch = '/';
            goto out_retchar;
          }
  
        /* No, the directory component is the substring before the '/'. */
  
        *p = '\0';
        return path;
      }
  
    /* There is no '/' in the path */
  
    ch = '.';
  
  out_retchar:
    g_retchar[0] = ch;
    g_retchar[1] = '\0';
    return g_retchar;
  }
  