Binary Search in Random Access Collections

struct FindMiddeleBetweenTwo<Point: Strideable> where Point.Stride: SignedInteger {
    let left: Point
    let right: Point
    func divide() -> Point {
        let distance = left.distance(to: right)
        let middle = distance / 2
        let outpoint = left.advanced(by: middle)
        return outpoint
    }
}

extension RandomAccessCollection where Index: Strideable, Index.Stride: SignedInteger, Element: Comparable {

    /// Binary Search in Ransom Access Collection
    /// - Returns: index of an element

    public func binarySearch(element: Element) -> Index? {

        var left: Index = startIndex
        var right: Index = index(before: endIndex)

        while left <= right {
            let finder = FindMiddeleBetweenTwo(left: left, right: right)
            let indexdivaded = finder.divide()
            let candidate = self[indexdivaded]
            if candidate < element {
                left = index(after: indexdivaded)
            } else if element < candidate {
                right = index(before: indexdivaded)
            } else {
                return indexdivaded
            }
        }

        return nil
    }
}