Shift [UInt8] / Data in Swift

DataExtensions.swift

extension Data {
    /// Returns a new `Data` shifted by the number of given bits.
    ///
    /// - parameter bits: Number of bits the data to be shifted.
    /// - returns: The shifted data.
    func shifted(byBits bits: Int) -> Data {
        let bitWidth = UInt8.bitWidth
        var previousByte = UInt8()
        return Data(bytes: self.shifted(byBytes: bits / bitWidth).map {
            let result: UInt8 = ($0 >> (bits % bitWidth)) | (previousByte << (bits % bitWidth))
            previousByte = $0
            return result
        })
    }
    
    /// Returns a new `Data` shifted by the number of given bytes.
    ///
    /// - parameter bytes: Number of bytes the data to be shifted.
    /// - returns: The shifted data.
    func shifted(byBytes bytes: Int) -> Data {
        return self.dropLast(bytes)
    }
}