var runtil = /Until$/,
	rparentsprev = /^(?:parents|prevUntil|prevAll)/,
	// Note: This RegExp should be improved, or likely pulled from Sizzle
	rmultiselector = /,/,
	slice = Array.prototype.slice;

// Implement the identical functionality for filter and not
var winnow = function( elements, qualifier, keep ) {
	if ( jQuery.isFunction( qualifier ) ) {
		return jQuery.grep(elements, function( elem, i ) {
			return !!qualifier.call( elem, i, elem ) === keep;
		});

	} else if ( qualifier.nodeType ) {
		return jQuery.grep(elements, function( elem, i ) {
			return (elem === qualifier) === keep;
		});

	} else if ( typeof qualifier === "string" ) {
		var filtered = jQuery.grep(elements, function( elem ) {
			return elem.nodeType === 1;
		});

		if ( isSimple.test( qualifier ) ) {
			return jQuery.filter(qualifier, filtered, !keep);
		} else {
			qualifier = jQuery.filter( qualifier, filtered );
		}
	}

	return jQuery.grep(elements, function( elem, i ) {
		return (jQuery.inArray( elem, qualifier ) >= 0) === keep;
	});
};

jQuery.fn.extend({
	find: function( selector ) {
		var ret = this.pushStack( "", "find", selector ), length = 0;

		for ( var i = 0, l = this.length; i < l; i++ ) {
			length = ret.length;
			jQuery.find( selector, this[i], ret );

			if ( i > 0 ) {
				// Make sure that the results are unique
				for ( var n = length; n < ret.length; n++ ) {
					for ( var r = 0; r < length; r++ ) {
						if ( ret[r] === ret[n] ) {
							ret.splice(n--, 1);
							break;
						}
					}
				}
			}
		}

		return ret;
	},

	has: function( target ) {
		var targets = jQuery( target );
		return this.filter(function() {
			for ( var i = 0, l = targets.length; i < l; i++ ) {
				if ( jQuery.contains( this, targets[i] ) ) {
					return true;
				}
			}
		});
	},

	not: function( selector ) {
		return this.pushStack( winnow(this, selector, false), "not", selector);
	},

	filter: function( selector ) {
		return this.pushStack( winnow(this, selector, true), "filter", selector );
	},
	
	is: function( selector ) {
		return !!selector && jQuery.filter( selector, this ).length > 0;
	},

	closest: function( selectors, context ) {
		if ( jQuery.isArray( selectors ) ) {
			var ret = [], cur = this[0], match, matches = {}, selector;

			if ( cur && selectors.length ) {
				for ( var i = 0, l = selectors.length; i < l; i++ ) {
					selector = selectors[i];

					if ( !matches[selector] ) {
						matches[selector] = jQuery.expr.match.POS.test( selector ) ? 
							jQuery( selector, context || this.context ) :
							selector;
					}
				}

				while ( cur && cur.ownerDocument && cur !== context ) {
					for ( selector in matches ) {
						match = matches[selector];

						if ( match.jquery ? match.index(cur) > -1 : jQuery(cur).is(match) ) {
							ret.push({ selector: selector, elem: cur });
							delete matches[selector];
						}
					}
					cur = cur.parentNode;
				}
			}

			return ret;
		}

		var pos = jQuery.expr.match.POS.test( selectors ) ? 
			jQuery( selectors, context || this.context ) : null;

		return this.map(function( i, cur ) {
			while ( cur && cur.ownerDocument && cur !== context ) {
				if ( pos ? pos.index(cur) > -1 : jQuery(cur).is(selectors) ) {
					return cur;
				}
				cur = cur.parentNode;
			}
			return null;
		});
	},
	
	// Determine the position of an element within
	// the matched set of elements
	index: function( elem ) {
		if ( !elem || typeof elem === "string" ) {
			return jQuery.inArray( this[0],
				// If it receives a string, the selector is used
				// If it receives nothing, the siblings are used
				elem ? jQuery( elem ) : this.parent().children() );
		}
		// Locate the position of the desired element
		return jQuery.inArray(
			// If it receives a jQuery object, the first element is used
			elem.jquery ? elem[0] : elem, this );
	},

	add: function( selector, context ) {
		var set = typeof selector === "string" ?
				jQuery( selector, context || this.context ) :
				jQuery.makeArray( selector ),
			all = jQuery.merge( this.get(), set );

		return this.pushStack( isDisconnected( set[0] ) || isDisconnected( all[0] ) ?
			all :
			jQuery.unique( all ) );
	},

	andSelf: function() {
		return this.add( this.prevObject );
	}
});

// A painfully simple check to see if an element is disconnected
// from a document (should be improved, where feasible).
function isDisconnected( node ) {
	return !node || !node.parentNode || node.parentNode.nodeType === 11;
}

jQuery.each({
	parent: function( elem ) {
		var parent = elem.parentNode;
		return parent && parent.nodeType !== 11 ? parent : null;
	},
	parents: function( elem ) {
		return jQuery.dir( elem, "parentNode" );
	},
	parentsUntil: function( elem, i, until ) {
		return jQuery.dir( elem, "parentNode", until );
	},
	next: function( elem ) {
		return jQuery.nth( elem, 2, "nextSibling" );
	},
	prev: function( elem ) {
		return jQuery.nth( elem, 2, "previousSibling" );
	},
	nextAll: function( elem ) {
		return jQuery.dir( elem, "nextSibling" );
	},
	prevAll: function( elem ) {
		return jQuery.dir( elem, "previousSibling" );
	},
	nextUntil: function( elem, i, until ) {
		return jQuery.dir( elem, "nextSibling", until );
	},
	prevUntil: function( elem, i, until ) {
		return jQuery.dir( elem, "previousSibling", until );
	},
	siblings: function( elem ) {
		return jQuery.sibling( elem.parentNode.firstChild, elem );
	},
	children: function( elem ) {
		return jQuery.sibling( elem.firstChild );
	},
	contents: function( elem ) {
		return jQuery.nodeName( elem, "iframe" ) ?
			elem.contentDocument || elem.contentWindow.document :
			jQuery.makeArray( elem.childNodes );
	}
}, function( name, fn ) {
	jQuery.fn[ name ] = function( until, selector ) {
		var ret = jQuery.map( this, fn, until );
		
		if ( !runtil.test( name ) ) {
			selector = until;
		}

		if ( selector && typeof selector === "string" ) {
			ret = jQuery.filter( selector, ret );
		}

		ret = this.length > 1 ? jQuery.unique( ret ) : ret;

		if ( (this.length > 1 || rmultiselector.test( selector )) && rparentsprev.test( name ) ) {
			ret = ret.reverse();
		}

		return this.pushStack( ret, name, slice.call(arguments).join(",") );
	};
});

jQuery.extend({
	filter: function( expr, elems, not ) {
		if ( not ) {
			expr = ":not(" + expr + ")";
		}

		return jQuery.find.matches(expr, elems);
	},
	
	dir: function( elem, dir, until ) {
		var matched = [], cur = elem[dir];
		while ( cur && cur.nodeType !== 9 && (until === undefined || cur.nodeType !== 1 || !jQuery( cur ).is( until )) ) {
			if ( cur.nodeType === 1 ) {
				matched.push( cur );
			}
			cur = cur[dir];
		}
		return matched;
	},

	nth: function( cur, result, dir, elem ) {
		result = result || 1;
		var num = 0;

		for ( ; cur; cur = cur[dir] ) {
			if ( cur.nodeType === 1 && ++num === result ) {
				break;
			}
		}

		return cur;
	},

	sibling: function( n, elem ) {
		var r = [];

		for ( ; n; n = n.nextSibling ) {
			if ( n.nodeType === 1 && n !== elem ) {
				r.push( n );
			}
		}

		return r;
	}
});