xml2struct( file )

function [ s ] = xml2struct( file )
%Convert xml file into a MATLAB structure
% [ s ] = xml2struct( file )
%
% A file containing:
% <XMLname attrib1="Some value">
%   <Element>Some text</Element>
%   <DifferentElement attrib2="2">Some more text</Element>
%   <DifferentElement attrib3="2" attrib4="1">Even more text</DifferentElement>
% </XMLname>
%
% Will produce:
% s.XMLname.Attributes.attrib1 = "Some value";
% s.XMLname.Element.Text = "Some text";
% s.XMLname.DifferentElement{1}.Attributes.attrib2 = "2";
% s.XMLname.DifferentElement{1}.Text = "Some more text";
% s.XMLname.DifferentElement{2}.Attributes.attrib3 = "2";
% s.XMLname.DifferentElement{2}.Attributes.attrib4 = "1";
% s.XMLname.DifferentElement{2}.Text = "Even more text";
%
% Note the characters : - and . are not supported in structure fieldnames and
% are replaced by _
%
% Written by W. Falkena, ASTI, TUDelft, 21-08-2010
    
    if (nargin < 1)
        clc;
        help xml2struct
        return
    end
    
    if (isempty(strfind(file,'.')))
        file = [file '.xml'];
    end
    
    if (exist(file,'file') == 0)
        error(['The file ' file ' could not be found']);
    end

    xDoc = xmlread(file);
    s = parseChildNodes(xDoc);
    
end

% ----- Subfunction parseChildNodes -----
function [children,ptext] = parseChildNodes(theNode)
    % Recurse over node children.
    children = struct;
    ptext = [];
    if theNode.hasChildNodes
        childNodes = theNode.getChildNodes;
        numChildNodes = childNodes.getLength;

        for count = 1:numChildNodes
            theChild = childNodes.item(count-1);
            [text,name,attr,childs] = getNodeData(theChild);
                        
            if (~strcmp(name,'#text') && ~strcmp(name,'#comment'))
                %XML allows the same elements to be defined multiple times,
                %put each in a different cell
                if (isfield(children,name))
                    if (~iscell(children.(name)))
                        %put existsing element into cell format
                        children.(name) = {children.(name)};
                    end
                    index = length(children.(name))+1;
                    %add new element
                    children.(name){index} = childs;
                    if(~isempty(text)) 
                        children.(name){index}.('Text') = text; 
                    end
                    if(~isempty(attr)) 
                        children.(name){index}.('Attributes') = attr; 
                    end
                else
                    %add previously unkown new element to the structure
                    children.(name) = childs;
                    if(~isempty(text)) 
                        children.(name).('Text') = text; 
                    end
                    if(~isempty(attr)) 
                        children.(name).('Attributes') = attr; 
                    end
                end
            elseif (strcmp(name,'#text'))
                %this is the text in an element (i.e. the parentNode) 
                if (~isempty(regexprep(text,'[\s]*','')))
                    ptext = text;
                end
            end
        end
    end
end

% ----- Subfunction getNodeData -----
function [text,name,attr,childs] = getNodeData(theNode)
    % Create structure of node info.
    
    %make sure name is allowed as structure name
    name = regexprep(char(theNode.getNodeName),'[-:.]','_');

    attr = parseAttributes(theNode);
    if (isempty(fieldnames(attr))) 
        attr = []; 
    end
    
    %parse child nodes
    [childs,text] = parseChildNodes(theNode);
    
    if (isempty(fieldnames(childs)))
        %get the data of any childless nodes
        try
            %faster then if any(strcmp(methods(theNode), 'getData'))
            text = char(theNode.getData);
        catch
            %no data
        end
    end
    
end

% ----- Subfunction parseAttributes -----
function attributes = parseAttributes(theNode)
    % Create attributes structure.

    attributes = struct;
    if theNode.hasAttributes
       theAttributes = theNode.getAttributes;
       numAttributes = theAttributes.getLength;

       for count = 1:numAttributes
          attrib = theAttributes.item(count-1);
          attr_name = regexprep(char(attrib.getName),'[-:.]','_');
          attributes.(attr_name) = char(attrib.getValue);
       end
    end
end