function [data, dUnits, x0, dx, xUnits] = ReadIBW(filename,folder)
%
% DEFINITION
% Reads Igor's (Wavemetric) binary wave format, .ibw, files.
% 
% INPUT
% filename: string giving the filename ending in .ibw
% folder: string description of emplacement of file.
%
% OUTPUT
% data: vector (single precision) of values of the wave containted in the file
% dUnits: string: saved values of the units of data (char).
% 
% ALGORITHM
% Uses fread and the parsing proper to version 2, 3, or version 5 (see Technical notes TN003.ifn:
% http://mirror.optus.net.au/pub/wavemetrics/IgorPro/Technical_Notes/) and data
% type 2 or 4 (non complex, single or double precision vector, real values). 
%
% - R. Naud August 2008


%%%%%%%%%%%%%%%%%%%%%%% go to directory
if nargin >1
    cd(folder)
end 

%%%%%%%%%%%%%%%%%%%%%%% ORDERING
%[fid, message] = fopen(filename, permission, machineformat) 
% machine format ie: 'ieeeÐbe' , for IEEE floating point with big-endian
% byte ordering
%MacIgor use the Motorola big-endian 'b'
%WinIgor use Intel little-endian 'l'
%  If the first byte in the file is non-zero, then the file is a WinIgor
[fid, message] = fopen(filename,'r');
FirstByte = fread(fid,1,'int8');
fclose(fid);
if FirstByte ==0
    machineformat = 'b';
else
    machineformat = 'l';
end

%%%%%%%%%%%%%%%%%%%%%%%  CHECK VERSION
[fid, message] = fopen(filename,'r',machineformat);
version = fread(fid,1,'int16');
fclose(fid);

%%%%%%%%%%%%%%%%%%%%%%%  READ DATA AND ACCOMPANYING INFO
[fid, message] = fopen(filename,'r',machineformat);
if version == 2;

    % pre header
    version = fread(fid,1,'int16');
    wfmSize = fread(fid,1,'int32'); % The size of the WaveHeader2 data structure plus the wave data plus 16 bytes of padding.
    noteSize = fread(fid,1,'int32'); % The size of the note text.
    pictSize = fread(fid,1,'int32'); % Reserved. Write zero. Ignore on read.
    checksum = fread(fid,1,'uint16'); %  Checksum over this header and the wave header.

    % wave header
    type = fread(fid,1,'int16');
    if type == 2
        datatype = 'single';
    elseif type == 4
        datatype = 'double';
    else
        disp(['wave is of type ',num2str(type), ', not supported'])
        return
    end
    ignore = fread(fid,1,'uint32');
    bname = char(fread(fid,20,'char')');
    ignore = fread(fid,2,'int16');
    ignore = fread(fid,1,'uint32');
    dUnits = char(fread(fid,4,'char')');
    xUnits = char(fread(fid,4,'char')');
    npnts = fread(fid,1,'int32');
    amod = fread(fid,1,'int16');
    dx = fread(fid,1,'double');
    x0 = fread(fid,1,'double');
    ignore = fread(fid,2,'int16');
    fsValid = fread(fid,1,'int16');
    topFullScale = fread(fid,1,'double');
    botFullScale = fread(fid,1,'double');
    ignore = fread(fid,16,'int8');
    modDate = fread(fid,1,'uint32');
    creationDate = fread(fid,1,'uint32');
    wdata = fread(fid,npnts,datatype);
    x0 = double(x0*fsValid);
    dx = double(dx*fsValid);
    
    
elseif version == 3 % NOT CHECKED!! IF PB, REFER TO IGORBIN.H IN TN003.ZIP
    
    
    % pre header
    version = fread(fid,1,'int16');
    wfmSize = fread(fid,1,'int32'); % The size of the WaveHeader2 data structure plus the wave data plus 16 bytes of padding.
    noteSize = fread(fid,1,'int32'); % The size of the note text.
    formulaSize = fread(fid,1,'int32');
    pictSize = fread(fid,1,'int32'); % Reserved. Write zero. Ignore on read.
    checksum = fread(fid,1,'uint16'); %  Checksum over this header and the wave header.

    % wave header
    type = fread(fid,1,'int16');
    if type == 2
        datatype = 'single';
    elseif type == 4
        datatype = 'double';
    else
        disp(['wave is of type ',num2str(type), ', not supported'])
        return
    end
    ignore = fread(fid,1,'uint32');
    bname = char(fread(fid,20,'char')');
    ignore = fread(fid,2,'int16');
    ignore = fread(fid,1,'uint32');
    dUnits = char(fread(fid,4,'char')')
    xUnits = char(fread(fid,4,'char')');
    npnts = fread(fid,1,'int32');
    amod = fread(fid,1,'int16');
    dx = fread(fid,1,'double');
    x0 = fread(fid,1,'double');
    ignore = fread(fid,2,'int16');
    fsValid = fread(fid,1,'int16');
    topFullScale = fread(fid,1,'double');
    botFullScale = fread(fid,1,'double');
    ignore = fread(fid,16,'int8');
    modDate = fread(fid,1,'uint32');
    creationDate = fread(fid,1,'uint32');
    wdata = fread(fid,npnts,datatype);
    
    x0 = double(x0*fsValid);
    dx = double(dx*fsValid);

elseif version == 5
    % pre header
    version = fread(fid,1,'int16');
    checksum = fread(fid,1,'uint16'); %  Checksum over this header and the wave header.
    wfmSize = fread(fid,1,'int32'); % The size of the WaveHeader2 data structure plus the wave data plus 16 bytes of padding.
    formulaSize = fread(fid,1,'int32'); %
    noteSize = fread(fid,1,'int32'); % The size of the note text.
    dataEUnitsSize =  fread(fid,1,'int32'); %
    dimEUnitsSize=  fread(fid,4,'int32'); %
    dimLabelsSize =  fread(fid,4,'int32'); %
    sIndicesSize =  fread(fid,1,'int32'); %
    optionSize1 =  fread(fid,1,'int32'); %
    optionSize2 =  fread(fid,1,'int32'); %

    % header
    ignore =  fread(fid,1,'int32'); %
    CreationDate =  fread(fid,1,'uint32'); %
    modData =  fread(fid,1,'uint32'); %
    npnts =  fread(fid,1,'int32'); %
    type = fread(fid,1,'int16');
    if type == 2
        datatype = 'single';
    elseif type == 4
        datatype = 'double';
    else
        disp(['wave is of type ',num2str(type), ', not supported'])
        return
    end

    ignore = fread(fid,1,'int16'); %
    ignore = fread(fid,6,'schar'); %
    ignore = fread(fid,1,'int16'); %
    bname = char(fread(fid,32, 'char'))';
    ignore = fread(fid,1,'int32'); %
    ignore = fread(fid,1,'int32'); %
    ndims = fread(fid,4,'int32'); % Number of of items in a dimension -- 0 means no data.
    sfA = fread(fid,4,'double'); %
    sfB  = fread(fid,4,'double'); %
    dUnits = char(fread(fid,4,'char'))';
    xUnits = char(fread(fid,4*4, 'char'))';
    fsValid = fread(fid,1,'int16'); %
    whpad3 = fread(fid,1,'int16'); %
    ignore = fread(fid,2,'double'); %
    ignore = fread(fid,10,'int32');
    ignore = fread(fid,16,'int32');
    ignore = fread(fid,3,'int16');
    ignore = fread(fid,2,'char');
    ignore = fread(fid,1,'int32');
    ignore = fread(fid,2,'int16');
    ignore = fread(fid,1,'int32');
    modDate = fread(fid,1,'int32');
    creationDate = fread(fid,1,'int32');
    wdata = fread(fid,npnts,datatype); %
    
    x0 = double(sfB(1)*fsValid);
    dx = double(sfA(1)*fsValid);

    
else
       disp(['wave is in version ',num2str(version), ', not supported'])
       data = [];
       dUnits = [];
       return
end

data = wdata;

fclose(fid);