function savexml(filename, varargin)
%SAVEXML Save workspace variables to disk in XML.
%  SAVEXML FILENAME saves all workspace variables to the XML-file
%  named FILENAME.xml. The data may be retrieved with LOADXML. if
%  FILENAME has no extension, .xml is assumed.
%  
%  SAVE, by itself, creates the XML-file named 'matlab.xml'. It is
%  an error if 'matlab.xml' is not writable.
%
%  SAVE FILENAME X saves only X.
%  SAVE FILENAME X Y Z saves X, Y, and Z. The wildcard '*' can be 
%  used to save only those variables that match a pattern.
%
%  SAVE ... -APPEND adds the variables to an existing file.
%
%  Use the functional form of SAVE, such as SAVE(filename','var1','var2'),
%  when the filename or variable names are stored in strings.
%
%  See also SAVE, MAT2XML, XMLTREE.

%  Copyright 2003 Guillaume Flandin. 
%  INRIA Sophia Antipolis / CEA-SHFJ
%  Revision: 1.0 $  $Date: 2003/07/10 13:50 $

if nargin == 0
	filename = 'matlab.xml';
	fprintf('\nSaving to: %s\n\n',filename);
else
	if ~ischar(filename)
		error('[SAVEXML] Argument must contain a string.');
	end
	[pathstr,name,ext] = fileparts(filename);
	if isempty(ext)
		filename = [filename '.xml'];
	end
end
if nargin <= 1, varargin = {'*'}; end

if nargout > 0
	error('[SAVEXML] Too many output arguments.');
end

if strcmpi(varargin{end},'-append')
	if length(varargin) > 1
		varargin = varargin(1:end-1);
	else
		varargin = {'*'};
	end
	if exist(filename,'file')
		% TODO % No need to parse the whole tree ? detect duplicate variables ?
		t = xmltree(filename);
	else
		error(sprintf(...
		'[SAVEXML] Unable to write file %s: file does not exist.',filename));
	end
else
	t = xmltree('<matfile/>');
end

for i=1:length(varargin)
	v = evalin('caller',['whos(''' varargin{i} ''')']);
	if isempty(v)
		error(['[SAVEXML] Variable ''' varargin{i} ''' not found.']);
	end
	for j=1:length(v)
		[t, uid] = add(t,root(t),'element',v(j).name);
		t = attributes(t,'add',uid,'type',v(j).class);
		t = attributes(t,'add',uid,'size',xml_num2str(v(j).size));
		t = xml_var2xml(t,evalin('caller',v(j).name),uid);
	end
end

save(t,filename);

%=======================================================================
function t = xml_var2xml(t,v,uid)

	switch class(v)
		case 'double'
			t = add(t,uid,'chardata',xml_num2str(v));
		case 'sparse'
			[i,j,s] = find(v);
			[t, uid2] = add(t,uid,'element','row');
			t = attributes(t,'add',uid2,'size',xml_num2str(size(i)));
			t = add(t,uid2,'chardata',xml_num2str(i));
			[t, uid2] = add(t,uid,'element','col');
			t = attributes(t,'add',uid2,'size',xml_num2str(size(j)));
			t = add(t,uid2,'chardata',xml_num2str(j));
			[t, uid2] = add(t,uid,'element','val');
			t = attributes(t,'add',uid2,'size',xml_num2str(size(s)));
			t = add(t,uid2,'chardata',xml_num2str(s));
		case 'struct'
			names = fieldnames(v);
			for j=1:prod(size(v))
				for i=1:length(names)
					[t, uid2] = add(t,uid,'element',names{i});
					t = attributes(t,'add',uid2,'index',num2str(j));
					t = attributes(t,'add',uid2,'type',...
						class(getfield(v(j),names{i})));
					t = attributes(t,'add',uid2,'size', ...
						xml_num2str(size(getfield(v(j),names{i}))));
					t = xml_var2xml(t,getfield(v(j),names{i}),uid2);
				end
			end
		case 'cell'
			for i=1:prod(size(v))
				[t, uid2] = add(t,uid,'element','cell'); 
				% TODO % special handling of cellstr ?
				t = attributes(t,'add',uid2,'index',num2str(i));
				t = attributes(t,'add',uid2,'type',class(v{i}));
				t = attributes(t,'add',uid2,'size',xml_num2str(size(v{i})));
				t = xml_var2xml(t,v{i},uid2);
			end
		case 'char'
			% TODO % char values should be in CData
			t = add(t,uid,'chardata',v);
		case {'int8','uint8','int16','uint16','int32','uint32'}
			[t, uid] = add(t,uid,'element',class(v));
			% TODO % Handle integer formats (cannot use sprintf or num2str)
		otherwise
			if ismember('serialize',methods(class(v)))
				% TODO % is CData necessary for class output ?
				t = add(t,uid,'cdata',serialize(v));
			else
				warning(sprintf(...
				'[SAVEXML] Cannot convert from %s to XML.',class(v)));
			end
	end

%=======================================================================
function s = xml_num2str(n)
	% TODO % use format ?
	if isempty(n)
		s = '[]';
	else
		s = ['[' sprintf('%g ',n(1:end-1))];
		s = [s num2str(n(end)) ']'];
	end