CryptoSwift/CryptoSwift/Utils.swift

//
//  Utils.swift
//  CryptoSwift
//
//  Created by Marcin Krzyzanowski on 26/08/14.
//  Copyright (c) 2014 Marcin Krzyzanowski. All rights reserved.
//

import Foundation

func rotateLeft(v:UInt8, n:UInt8) -> UInt8 {
    return ((v << n) & 0xFF) | (v >> (8 - n))
}

func rotateLeft(v:UInt16, n:UInt16) -> UInt16 {
    return ((v << n) & 0xFFFF) | (v >> (16 - n))
}

func rotateLeft(v:UInt32, n:UInt32) -> UInt32 {
    return ((v << n) & 0xFFFFFFFF) | (v >> (32 - n))
}

func rotateLeft(x:UInt64, n:UInt64) -> UInt64 {
    return (x << n) | (x >> (64 - n))
}

func rotateRight(x:UInt16, n:UInt16) -> UInt16 {
    return (x >> n) | (x << (16 - n))
}

func rotateRight(x:UInt32, n:UInt32) -> UInt32 {
    return (x >> n) | (x << (32 - n))
}

func rotateRight(x:UInt64, n:UInt64) -> UInt64 {
    return ((x >> n) | (x << (64 - n)))
}

func reverseBytes(value: UInt32) -> UInt32 {
    // rdar://18060945 - not working since Xcode6-Beta6, need to split in two variables
    // return = ((value & 0x000000FF) << 24) | ((value & 0x0000FF00) << 8) | ((value & 0x00FF0000) >> 8)  | ((value & 0xFF000000) >> 24);
    
    // workaround
    var tmp1 = ((value & 0x000000FF) << 24) | ((value & 0x0000FF00) << 8)
    var tmp2 = ((value & 0x00FF0000) >> 8)  | ((value & 0xFF000000) >> 24)
    return tmp1 | tmp2
}

func xor(a: [UInt8], b:[UInt8]) -> [UInt8] {
    var xored = [UInt8](count: a.count, repeatedValue: 0)
    for i in 0..<xored.count {
        xored[i] = a[i] ^ b[i]
    }
    return xored
}

func perf(text: String, closure: () -> ()) {
    let measurementStart = NSDate();
    
    closure()
    
    let measurementStop = NSDate();
    let executionTime = measurementStop.timeIntervalSinceDate(measurementStart)
    
    println("\(text) \(executionTime)");
}