Swift Int与Data 互转

extension Data {
    //1bytes转Int
    func lyz_1BytesToInt() -> Int {
        var value : UInt8 = 0
        let data = NSData(bytes: [UInt8](self), length: self.count)
        data.getBytes(&value, length: self.count)
        value = UInt8(bigEndian: value)
        return Int(value)
    }
    
    //2bytes转Int
    func lyz_2BytesToInt() -> Int {
        var value : UInt16 = 0
        let data = NSData(bytes: [UInt8](self), length: self.count)
        data.getBytes(&value, length: self.count)
        value = UInt16(bigEndian: value)
        return Int(value)
    }
    
    //4bytes转Int
    func lyz_4BytesToInt() -> Int {
        var value : UInt32 = 0
        let data = NSData(bytes: [UInt8](self), length: self.count)
        data.getBytes(&value, length: self.count)
        value = UInt32(bigEndian: value)
        return Int(value)
    }
    
}


extension Int {
    // MARK:- 转成 2位byte
    func lyz_to2Bytes() -> [UInt8] {
        let UInt = UInt16.init(Double.init(self))
        return [UInt8(truncatingIfNeeded: UInt >> 8),UInt8(truncatingIfNeeded: UInt)]
    }
    // MARK:- 转成 4字节的bytes
    func lyz_to4Bytes() -> [UInt8] {
        let UInt = UInt32.init(Double.init(self))
        return [UInt8(truncatingIfNeeded: UInt >> 24),
                UInt8(truncatingIfNeeded: UInt >> 16),
                UInt8(truncatingIfNeeded: UInt >> 8),
                UInt8(truncatingIfNeeded: UInt)]
    }
    // MARK:- 转成 8位 bytes
    func lyz_toEightBytes() -> [UInt8] {
        let UInt = UInt64.init(Double.init(self))
        return [UInt8(truncatingIfNeeded: UInt >> 56),
                UInt8(truncatingIfNeeded: UInt >> 48),
                UInt8(truncatingIfNeeded: UInt >> 40),
                UInt8(truncatingIfNeeded: UInt >> 32),
                UInt8(truncatingIfNeeded: UInt >> 24),
                UInt8(truncatingIfNeeded: UInt >> 16),
                UInt8(truncatingIfNeeded: UInt >> 8),
                UInt8(truncatingIfNeeded: UInt)]
    }
}