% MEMMAPDATA - create a memory-mapped data class

%

% Usage:

%   >> data_class = memmapdata(data);

%

% Inputs:

%   data         - input data or data file

%

% Outputs:

%   data_class    - output dataset class

%

% Author: Arnaud Delorme, SCCN, INC, UCSD, Nov. 2008

% Copyright (C) 2008 Arnaud Delorme, SCCN, INC, UCSD

%

% This file is part of EEGLAB, see http://www.eeglab.org

% for the documentation and details.

%

% 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.

%

% 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 HOLDER 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.

function dataout = memmapdata(data, datadims);

    dataout.fileformat = 'normal';

    if ischar(data)

        if length(data) > 3

            if strcmpi('.dat', data(end-3:end))

                dataout.fileformat = 'transposed';

            end

        end

        % check that the file is not empty

        % --------------------------------

        a = dir(data);

        if isempty(a)

            error([ 'Data file ''' data '''not found' ]);

        elseif a(1).bytes == 0

            error([ 'Empty data file ''' data '''' ]);

        end

        if ~strcmpi(dataout.fileformat, 'transposed')

            dataout.data = memmapfile(data, 'writable', false, 'format', { 'single' datadims 'x' });

        else

            dataout.data = memmapfile(data, 'writable', false, 'format', { 'single' [ datadims(2:end) datadims(1) ] 'x' });            

        end

        dataout = class(dataout,'memmapdata');

    else 

        dataout = data;

    end