Fisher-Yates shuffle of `NSMutableArray` in Swift

gistfile1.txt

/// Shuffle NSMutableArray
///
/// Applies Fisher-Yates to ensure even distribution.
/// See http://en.wikipedia.org/wiki/Fisher–Yates_shuffle

func shuffle(array: NSMutableArray) {
    let count = array.count
    for i in 0 ..< (count - 1) {
        let j = Int(arc4random_uniform(UInt32(count - i))) + i
        array.exchangeObjectAtIndex(i, withObjectAtIndex: j)
    }
}