/* see http://v2studio.com/k/code/lib/ */

// ARRAY EXTENSIONS
if (!Array.prototype.push) Array.prototype.push = function() {
	 for (var i=0; i<arguments.length; i++) this[this.length] = arguments[i];
	 return this.length;
}

Array.prototype.find = function(value, start) {
	 start = start || 0;
	 for (var i=start; i<this.length; i++)
		  if (this[i]==value) return i;
	 return -1;
}

Array.prototype.has = function(value) {
	 return this.find(value)!==-1;
}

// FUNCTIONAL
function map(list, func) {
	 var result = [];
	 func = func || function(v) {return v};
	 for (var i=0; i < list.length; i++) result.push(func(list[i], i, list));
	 return result;
}

function filter(list, func) {
	 var result = [];
	 func = func || function(v) {return v};
	 map(list, function(v) { if (func(v)) result.push(v) } );
	 return result;
}

// DOM
function getElem(elem) {
	 if (document.getElementById) {
		  if (typeof elem == "string") {
				elem = document.getElementById(elem);
				if (elem===null) throw 'cannot get element: element does not exist';
		  } else if (typeof elem != "object") {
				throw 'cannot get element: invalid datatype';
		  }
	 } else throw 'cannot get element: unsupported DOM';
	 return elem;
}

function hasClass(elem, className) {
	 return getElem(elem).className.split(' ').has(className);
}

function getElementsByClass(className, tagName, parentNode) {
	 parentNode = !isUndefined(parentNode)? getElem(parentNode) : document;
	 if (isUndefined(tagName)) tagName = '*';
	 return filter(parentNode.getElementsByTagName(tagName),
		  function(elem) { return hasClass(elem, className) });
}

// DOM EVENTS
function listen(event, elem, func) {
	 elem = getElem(elem);
	 if (elem.addEventListener)  // W3C DOM
		  elem.addEventListener(event,func,false);
	 else if (elem.attachEvent)  // IE DOM
		  elem.attachEvent('on'+event, function(){ func(new W3CDOM_Event(elem)) } );
		  // for IE we use a wrapper function that passes in a simplified faux Event object.
	 else throw 'cannot add event listener';
}

function mlisten(event, elem_list, func) {
	 map(elem_list, function(elem) { listen(event, elem, func) } );
}

function W3CDOM_Event(currentTarget) {
	 this.currentTarget  = currentTarget;
	 this.preventDefault = function() { window.event.returnValue = false }
	 return this;
}

// MISC CLEANING-AFTER-MICROSOFT STUFF
function isUndefined(v) {
	 var undef;
	 return v===undef;
}