/*
    sortAlphaNumeric
    -----------------------

    This function sorts alphaNumeric values e.g. 1, e, 1a, -23c, 54z
    
    Notice how the prepareData function actually returns an Array i.e. you are not limited
    in the type of data you return to the tableSort script.
*/
function sortAlphaNumericPrepareData(tdNode, innerText){
        var aa = innerText.toLowerCase().replace(" ", "");
        var reg = /((\-|\+)?(\s+)?[0-9]+\.([0-9]+)?|(\-|\+)?(\s+)?(\.)?[0-9]+)([a-z]+)/;

        if(reg.test(aa)) {
                var aaP = aa.match(reg);
                return [aaP[1], aaP[8]];
        };

        // Return an array
        return isNaN(aa) ? ["",aa] : [aa,""];
}

function sortAlphaNumeric(a, b){
        // Get the previously prepared array
        var aa = a[fdTableSort.pos];
        var bb = b[fdTableSort.pos];

        // If they are equal then return 0
        if(aa[0] == bb[0] && aa[1] == bb[1]) { return 0; };

        // Check numeric parts if not equal
        if(aa[0] != bb[0]) {
                if(aa[0] != "" && bb[0] != "") { return aa[0] - bb[0]; };
                if(aa[0] == "" && bb[0] != "") { return -1; };
                return 1;
        };
        
        // Check alpha parts if numeric parts equal
        if(aa[1] == bb[1]) return 0;
        if(aa[1] < bb[1])  return -1;
        return 1;
}

/*
        sortImage
        ---------

        This is the function called in order to sort the data previously prepared by the function
        "sortImagePrepareData". It does a basic case sensitive comparison on the data using the
        tableSort's in-built sortText method.
*/
var sortImage = fdTableSort.sortText;

/*
        This is the function used to prepare i.e. parse data, to be used during the sort
        of the images within the last table.

        In this case, we are checking to see if the TD node has any child nodes that are
        images and, if an image exists, return it's "src" attribute.
        If no image exists, then we return an empty string.

        The "prepareData" functions are passed the actual TD node and also the TD node inner text
        which means you are free to check for child nodes etc and are not just limited to
        sorting on the TD node's inner text.

        The prepareData functions are not required (only your bespoke sort function is required)
        and only called by the script should they exist.
*/
function sortImagePrepareData(td, innerText) {
        var img = td.getElementsByTagName('img');
        return img.length ? img[0].src: "";
}

/*
        sortFileSize
        ------------

        1 Byte = 8 Bit
        1 Kilobyte = 1024 Bytes
        1 Megabyte = 1048576 Bytes
        1 Gigabyte = 1073741824 Bytes
*/
var sortFileSize = fdTableSort.sortNumeric;

function sortFileSizePrepareData(td, innerText) {
        var regExp = /(kb|mb|gb)/i;

        var type = innerText.search(regExp) != -1 ? innerText.match(regExp)[0] : "";

        switch (type.toLowerCase()) {
                case "kb" :
                        mult = 1024;
                        break;
                case "mb" :
                        mult = 1048576;
                        break;
                case "gb" :
                        mult = 1073741824;
                        break;
                default :
                        mult = 1;
        };

        innerText = parseFloat(innerText.replace(/[^0-9\.\-]/g,''));

        return isNaN(innerText) ? "" : innerText * mult;
};