swift 2.2で整数配列の汎用変換を行うことは可能ですか？

Question

私は以下のポイントを超えて進歩することができませんでした。

私が取得しています：私は「T」に「要素」からデータを移動していますライン上

Cannot convert value of type 'Element' to expected argument type 'IntegerLiteralType' (aka 'Int') 

を。また、私はまだUIntに切り捨てる方法を理解していません。

ご協力いただければ幸いです。

protocol Truncating { 
    init(truncatingBitPattern: IntegerLiteralType) 
} 

extension Int { 
    init(truncatingBitPattern value: Int) { self.init(truncatingBitPattern: value.toIntMax()) } 
} 

protocol Bitshiftable { 
    func <<(lhs: Self, rhs: Self) -> Self 
    func >>(lhs: Self, rhs: Self) -> Self 
    func <<=(inout lhs: Self, rhs: Self) 
    func >>=(inout lhs: Self, rhs: Self) 
} 

protocol ArrayConvertable: IntegerType, Bitshiftable, Truncating {} 

extension Int : ArrayConvertable {} 
extension Int8 : ArrayConvertable {} 
extension Int16 : ArrayConvertable {} 
extension Int32 : ArrayConvertable {} 
extension Int64 : ArrayConvertable {} 
//extension UInt : ArrayConvertable {} 
extension UInt8 : ArrayConvertable {} 
extension UInt16 : ArrayConvertable {} 
extension UInt32 : ArrayConvertable {} 
extension UInt64 : ArrayConvertable {} 

extension Array where Element: ArrayConvertable { 
    func toInt<T: ArrayConvertable>() -> T? 
    { 
     let targetSize = sizeof(T) 
     let sourceSize = sizeof(Element) 
     let sourceByteCount = count * sourceSize 
     guard targetSize == sourceByteCount else { return nil } 

     var n: T = 0 
     for e in self { 
      var dataChunk = e 
      for i in 0..<sourceSize { 
       n = n | T(truncatingBitPattern: dataChunk) 
       if i + 1 < sourceSize { 
        n = n << 8 
        dataChunk = dataChunk >> 8 
       } 
      } 
     } 

     return n 
    } 
} 

func test() { 
    let a8: [UInt8] = [0xab, 0xba, 0xda, 0xba, 0xd0, 0xd1, 0xd2, 0xd3, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10] 
    let a16: [UInt16] = [0xabba, 0xdaba, 0xd0d1, 0xd2d3, 0xfedc, 0xba98, 0x7654, 0x3210] 
    let a32: [UInt32] = [0xabbadaba, 0xd0d1d2d3, 0xfedcba98, 0x] 
    let a64: [UInt64] = [0xabbadabad0d1d2d3, 0xfedcba] 

    var n8: UInt8 = 0 
    var n16: UInt16 = 0 
    var n32: UInt32 = 0 
    var n64: UInt64 = 0 

    print("--- 08 bit source") 
    n8 = a8.toInt()! 
    n16 = a8.toInt()! 
    n32 = a8.toInt()! 
    n64 = a8.toInt()! 
    print(n8, n16, n32, n64) 

    print("--- 16 bit source") 
    n8 = a16.toInt()! 
    n16 = a16.toInt()! 
    n32 = a16.toInt()! 
    n64 = a16.toInt()! 
    print(n8, n16, n32, n64) 

    print("--- 32 bit source") 
    n8 = a32.toInt()! 
    n16 = a32.toInt()! 
    n32 = a32.toInt()! 
    n64 = a32.toInt()! 
    print(n8, n16, n32, n64) 

    print("--- 64 bit source") 
    n8 = a64.toInt()! 
    n16 = a64.toInt()! 
    n32 = a64.toInt()! 
    n64 = a64.toInt()! 
    print(n8, n16, n32, n64) 
} 

test() 

Answer 1

ここでは、データを再解釈することのできる解決策があります。 ないプロトコルが必要とされている：

extension Array where Element: IntegerType { 
    func toInt<T: IntegerType>() -> T? { 
     guard sizeof(T) <= count * sizeof(Element) else { return nil } 
     return UnsafePointer<T>(self).memory 
    } 
} 

例：

にかかわらず、実装の

let a32: [UInt32] = [0x11223344, 0x55667788, 0x99AABBCC, 0xDDEEFF00] 
if let u16: UInt16 = a32.toInt() { 
    print(String(format:"%#04x", u16)) // 0x3344 
}