function [t, newdir] = isdirectory(dir)
%ISDIRECTORY True if argument is a directory.
%
%   ISDIRECTORY(DIR) returns 1 if DIR is a directory and 0 otherwise.  [T,
%   NEWDIR] = ISDIRECTORY(DIR) also returns the name of the directory as
%   returned by CD.  NEWDIR is empty if DIR is not a directory.
%
%   Using EXIST(DIR, 'dir') is too unreliable.  For instance, under Windows it
%   returns false if DIR is 'c:' (where c: is an existing drive) and it returns
%   false and if DIR is a directory which is in the path but does not exist.

%   Author:      Peter John Acklam
%   Time-stamp:  2003-10-13 13:06:17 +0200
%   E-mail:      pjacklam@online.no
%   URL:         http://home.online.no/~pjacklam

   cwd    = cd;
   t      = 1;
   newdir = '';

   try
      cd(dir);          % Try to chdir to the specified directory.
      newdir = cd;      % If that succeeded, get the new directory name.
   catch
      t = 0;            % chdir failed, so the directory does not exist.
   end

   if t                 % If the chdir succeeded
      cd(cwd);          %   chdir back to where we started from.
   end