Extension Data

Data.uint16.swift

import Foundation

extension Data {
    func uint16() -> AnySequence<UInt16>? {
        guard self.count % 2 == 0
            else { return nil }

        return AnySequence<UInt16> { () -> AnyIterator<UInt16> in 
            let size = self.count / 2
            var currentIndex = 0

            return AnyIterator<UInt16> {

                self.withUnsafeBytes { (head: UnsafePointer<UInt16>) -> (UInt16?) in 
                    guard currentIndex < size 
                        else { return nil }

                    defer { currentIndex += 1 }
                    return head[currentIndex]
                }
            }
        }
    }
}

let data = "abcdefg".data(using: .utf16)!
data.uint16().flatMap {
    for uint16 in $0 {
        print(String(uint16, radix: 16))
    }
}