--- a
+++ b/functions/@memmapdata/memmapdata.m
@@ -0,0 +1,69 @@
+% 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
+