function [s] = getsubfield(s, f);

% GETSUBFIELD returns a field from a structure just like the standard
% Matlab GETFIELD function, except that you can also specify nested fields
% using a '.' in the fieldname. The nesting can be arbitrary deep.
%
% Use as
%   f = getsubfield(s, 'fieldname')
% or as
%   f = getsubfield(s, 'fieldname.subfieldname')
%
% See also GETFIELD, ISSUBFIELD, SETSUBFIELD

% Copyright (C) 2005, Robert Oostenveld
%
% This file is part of FieldTrip, see http://www.ru.nl/neuroimaging/fieldtrip
% for the documentation and details.
%
%    FieldTrip 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 3 of the License, or
%    (at your option) any later version.
%
%    FieldTrip 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 FieldTrip. If not, see <http://www.gnu.org/licenses/>.
%
% $Id: getsubfield.m 2885 2011-02-16 09:41:58Z roboos $

if ~ischar(f)
  error('incorrect input argument for fieldname');
end

t = {};
while (1)
  [t{end+1}, f] = strtok(f, '.');
  if isempty(f)
    break
  end
end
s = getfield(s, t{:});
