Google directions polylines Javascript decoder

decode_polylines.js

function DecodePolylines(encoded) {
        var poly = [];
        var index = 0, len = encoded.length,
            lat = 0, lng = 0;

        while (index < len) {
            var b, shift = 0, result = 0;
            do {
                b = encoded.charCodeAt(index++) - 63;
                result |= (b & 0x1f) << shift;
                shift += 5;
            } while (b >= 0x20);
            var dlat = ((result & 1) ? ~(result >> 1) : (result >> 1));
            lat += dlat;

            shift = 0;
            result = 0;
            do {
                b = encoded.charCodeAt(index++) - 63;
                result |= (b & 0x1f) << shift;
                shift += 5;
            } while (b >= 0x20);
            var dlng = ((result & 1) ? ~(result >> 1) : (result >> 1));
            lng += dlng;

            var p = {
                latitude: lat * 1E-5,
                longitude: lng * 1E-5
            };
            poly.push(p);
        }

        return poly;
}