Swift-Byte与Int互转

使用案例

    var index = 0
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        index += 150
        let bytes = index.hw_to4Bytes()
        HWPrint(bytes)
        let x = hw_getInt(bytes)
        HWPrint(x)
    }

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bytes转Int

func hw_getInt(_ array:[UInt8]) -> Int {
    var value : UInt32 = 0
    let data = NSData(bytes: array, length: array.count)
    data.getBytes(&value, length: array.count)
    value = UInt32(bigEndian: value)
    return Int(value)
}

Int转bytes

extension Int {
    // MARK:- 转成 2位byte
    func hw_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 hw_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 intToEightBytes() -> [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)]
    }
}