% ---------------------------------------------------------------------------
% Function grload()
%    -- Xenios Papademetris papad@noodle.med.yale.edu 5th Sep 1995
%
%    -- used to load images stored in the simple format (.grl) used for the 
%    -- EE445a course, this has an unsigned short magic number (29571) 
%    -- and the width and height of the image in 4-byte integers
%    -- followed by the actual data in unsigned char format
%    -- Changed 28th Jan 1997 to test for big-endian / little endian formats
% ---------------------------------------------------------------------------

function outimage=grload(filename)

% ---------------------------------------------------------------------------
% Step 1 -- Check for right number of parameters
%        -- and check for valid filename
% ---------------------------------------------------------------------------


if nargin ~= 1	
  error('Requires one input argument eg grload(filename)');
elseif nargin == 1 & isstr(filename)
  if (isempty(findstr(filename,'.'))==1)
        filename=[filename,'.grl'];
  end
end

% ---------------------------------------------------------------------------
% Step 2 -- Open filename
%        -- Check for valid file
% ---------------------------------------------------------------------------

handle=fopen(filename,'r');

if handle == -1
	ff=['grload::cannot open file ' , filename];
	error (ff);
end

magic=fread(handle,1,'ushort');

if (magic~=29571 & magic ~=33651)
	ff=['grload::file ' , filename,' is not a grl file'];
	error (ff);
end

% ---------------------------------------------------------------------------
% Step 3 -- Read width and height	
% ---------------------------------------------------------------------------

%width=fread(handle,1,'int32')
%height=fread(handle,1,'int32')

w1=fread(handle,1,'uchar');
w2=fread(handle,1,'uchar');
w3=fread(handle,1,'uchar');
w4=fread(handle,1,'uchar');
width=w1*2^24+w2*2^16+w3*2^8+w4;
if (width>4096)
	width=w4*2^24+w3*2^16+w2*2^8+w1;
	end

h1=fread(handle,1,'uchar');
h2=fread(handle,1,'uchar');
h3=fread(handle,1,'uchar');
h4=fread(handle,1,'uchar');
height=h1*2^24+h2*2^16+h3*2^8+h4;
if (height>4096)
	height=h4*2^24+h3*2^16+h2*2^8+h1;
	end




% ---------------------------------------------------------------------------
% Step 4 -- Read actual Image
% ---------------------------------------------------------------------------

outimage=fread(handle,[height,width],'uchar');
outimage=outimage'/max(max(outimage));

% ---------------------------------------------------------------------------
% Step 5 -- Close file
% ---------------------------------------------------------------------------

fclose(handle);

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