(function()
{
    function BitWriter()
    {
        // encodes as URL-BASE64
        this.str = "";
        this.partial = 0;
        this.partialSize = 0;
        this.table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
        this.addBits = function( bits, size ) 
        {
            this.partial = (this.partial << size) | bits;
            this.partialSize += size;
            while ( this.partialSize >= 6 ) {
                this.str += this.table.charAt((this.partial >> 
                                               (this.partialSize - 6)) & 0x3f);
                this.partialSize -= 6;
            }
        };
        this.finish = function() {
            if ( this.partialSize ) {
                this.str += this.table.charAt( 
                    ( this.partial << ( 6 - this.partialSize ) ) & 0x3f );
                this.partialSize = 0;
                this.partial = 0;
            }
        };
    }

    function encodeBase64(str)
    {
        var writer = new BitWriter();
        for (var n = 0; n < str.length; n++) {
            writer.addBits( str.charCodeAt( n ), 8 );
        }

        writer.finish();

        return writer.str;
    }

    function encodeUtf8(string) {
        // fronm http://www.webtoolkit.info/
        string = string.replace(/\r\n/g,"\n");
        var utftext = "";

        for (var n = 0; n < string.length; n++) {

            var c = string.charCodeAt(n);

            if (c < 128) {
                utftext += String.fromCharCode(c);
            }
            else if((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192);
                utftext += String.fromCharCode((c & 63) | 128);
            }
            else {
                utftext += String.fromCharCode((c >> 12) | 224);
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                utftext += String.fromCharCode((c & 63) | 128);
            }

        }

        return utftext;
    }

    function encodeNumber(num)
    {
        // encodes a number in only as many bytes as required, 7 bits at a time.
        // bit 8 is used to indicate whether another byte follows.
        if ( num >= 0x3FFF ) {
            return String.fromCharCode( 0x80 | ( (num >> 14) & 0x7f ) ) +
                   String.fromCharCode( 0x80 | ( (num >>  7) & 0x7f ) ) + 
                   String.fromCharCode( num & 0x7f );
        } else if ( num >= 0x7F ) {            
            return String.fromCharCode( 0x80 | ( (num >>  7) & 0x7f ) ) + 
                   String.fromCharCode( num & 0x7f );
        } else {
            return String.fromCharCode( num );
        }
    }

    function encodeLz77( input )
    {
        var MinStringLength = 4;

        var output = "";
        var pos = 0;
        var hash = {};

        // set last pos to just after the last chunk.
        var lastPos = input.length - MinStringLength;

        for ( var i = MinStringLength; i < input.length; i++ ) {
            var subs = input.substr(i-MinStringLength, MinStringLength);
            if ( hash[subs] === undefined ) {
                hash[subs] = [];
            }
            hash[subs].push( i-MinStringLength );
            //document.write("subs[" + subs + "]=" + (pos - MinStringLength) + "<br>");
        }

        // loop until pos reaches the last chunk.
        while (pos < lastPos) {

            // search start is the current position minus the window size, capped
            // at the beginning of the string.
            var matchLength = MinStringLength;
            var foundMatch = false;
            var bestMatch = {distance: 0, length: 0};
            var prefix = input.substr(pos, MinStringLength);
            var matches = hash[prefix];
            
            // loop until the end of the matched region reaches the current
            // position.
            //while ((searchStart + matchLength) < pos) {
            if ( matches !== undefined ) {
                for ( var i = 0; i < matches.length; i++ ) {
                    var searchStart = matches[i];
                    if ( searchStart + matchLength >= pos ) {
                        break;
                    }
                    
                    while( searchStart + matchLength < pos ) {
                        // check if string matches.
                        var isValidMatch = (
                                (input.substr(searchStart, matchLength) == input.substr(pos, matchLength))
                                );
                        if (isValidMatch) {
                            // we found at least one match. try for a larger one.
                            var realMatchLength = matchLength;
                            matchLength++;
                            if (foundMatch && (realMatchLength > bestMatch.length)) {
                                bestMatch.distance = pos - searchStart - realMatchLength;
                                bestMatch.length = realMatchLength;
                            }
                            foundMatch = true;
                        } else {
                            break;
                        }
                    }
                }
            }

            if (bestMatch.length) {
                output += String.fromCharCode( 0 ) + 
                    encodeNumber(bestMatch.distance) +
                    encodeNumber(bestMatch.length);

                pos += bestMatch.length;
            } else {
                if (input.charCodeAt(pos) !== 0) {
                    output += input.charAt(pos);
                } else {
                    output += String.fromCharCode( 0 ) + 
                        String.fromCharCode( 0 );
                }
                pos++;
            }
        }
        return output + input.slice(pos).replace(/\0/g, "\0\0");
    }

    function getText( node )
    {
        var text = "";
        for( var i = 0; i < node.childNodes.length; i++ ) {
            var child = node.childNodes[i];
            if ( child.nodeType == 3 ) {
                text += child.data;
            } else {
                text += getText( child );
            }
        }

        return text;
    }

    function process(divs) {
        for ( var i = 0; i < divs.length; i++ ) {
            if ( divs[i].className == "wsd" && !divs[i].wsd_processed ) {
                divs[i].wsd_processed = true;

                var style = "";
                if ( divs[i].attributes["wsd_style"] ) {
                    style = "&s=" + divs[i].attributes["wsd_style"].value;
                }
                
                var text = encodeBase64( encodeLz77( encodeUtf8( getText( divs[i] ) ) ) );
                var str =
                "http://www.websequencediagrams.com/cgi-bin/cdraw?" +
                    "lz=" + text + style;

                if ( str.length < 2048 ) {
                    for( var j = divs[i].childNodes.length-1; j >= 0; j-- ) {
                        divs[i].removeChild( divs[i].childNodes[j] );
                    }

                    var img = document.createElement("img");
                    img.setAttribute("src", str);
                    divs[i].appendChild( img );
                } else {
                    divs[i].insertBefore( document.createTextNode("Diagram too large for web service."), divs[i].firstChild );
                }
            }
        }
    }

    process( document.getElementsByTagName("div") );
    process( document.getElementsByTagName("span") );
})();