CryptoSwift/Sources/CryptoSwift/Utils.swift

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

func rotateLeft(_ value:UInt8, by:UInt8) -> UInt8 {
    return ((value << by) & 0xFF) | (value >> (8 - by))
}

func rotateLeft(_ value:UInt16, by:UInt16) -> UInt16 {
    return ((value << by) & 0xFFFF) | (value >> (16 - by))
}

func rotateLeft(_ value:UInt32, by:UInt32) -> UInt32 {
    return ((value << by) & 0xFFFFFFFF) | (value >> (32 - by))
}

func rotateLeft(_ value:UInt64, by:UInt64) -> UInt64 {
    return (value << by) | (value >> (64 - by))
}

func rotateRight(_ value:UInt16, by:UInt16) -> UInt16 {
    return (value >> by) | (value << (16 - by))
}

func rotateRight(_ value:UInt32, by:UInt32) -> UInt32 {
    return (value >> by) | (value << (32 - by))
}

func rotateRight(_ value:UInt64, by:UInt64) -> UInt64 {
    return ((value >> by) | (value << (64 - by)))
}

func reversed(_ uint8 : UInt8) -> UInt8 {
    var v = uint8
    v = (v & 0xF0) >> 4 | (v & 0x0F) << 4
    v = (v & 0xCC) >> 2 | (v & 0x33) << 2
    v = (v & 0xAA) >> 1 | (v & 0x55) << 1
    return v
}

func reversed(_ uint32 : UInt32) -> UInt32 {
    var v = uint32
    v = ((v >> 1) & 0x55555555) | ((v & 0x55555555) << 1)
    v = ((v >> 2) & 0x33333333) | ((v & 0x33333333) << 2)
    v = ((v >> 4) & 0x0f0f0f0f) | ((v & 0x0f0f0f0f) << 4)
    v = ((v >> 8) & 0x00ff00ff) | ((v & 0x00ff00ff) << 8)
    v = ((v >> 16) & 0xffff) | ((v & 0xffff) << 16)
    return v
}

func sliceToUInt32Array(_ slice: ArraySlice<UInt8>) -> Array<UInt32> {
    var result = Array<UInt32>()
    result.reserveCapacity(16)
    for idx in stride(from: slice.startIndex, to: slice.endIndex, by: sizeof(UInt32.self)) {
        let val1:UInt32 = (UInt32(slice[idx.advanced(by: 3)]) << 24)
        let val2:UInt32 = (UInt32(slice[idx.advanced(by: 2)]) << 16)
        let val3:UInt32 = (UInt32(slice[idx.advanced(by: 1)]) << 8)
        let val4:UInt32 = UInt32(slice[idx])
        let val:UInt32 = val1 | val2 | val3 | val4
        result.append(val)
    }
    return result
}

func sliceToUInt64Array(_ slice: ArraySlice<UInt8>) -> Array<UInt64> {
    var result = Array<UInt64>()
    result.reserveCapacity(32)
    for idx in stride(from: slice.startIndex, to: slice.endIndex, by: sizeof(UInt64.self)) {
        var val:UInt64 = 0
        val |= UInt64(slice[idx.advanced(by: 7)]) << 56
        val |= UInt64(slice[idx.advanced(by: 6)]) << 48
        val |= UInt64(slice[idx.advanced(by: 5)]) << 40
        val |= UInt64(slice[idx.advanced(by: 4)]) << 32
        val |= UInt64(slice[idx.advanced(by: 3)]) << 24
        val |= UInt64(slice[idx.advanced(by: 2)]) << 16
        val |= UInt64(slice[idx.advanced(by: 1)]) << 8
        val |= UInt64(slice[idx.advanced(by: 0)]) << 0
        result.append(val)
    }
    return result
}

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