Raw, Unsafe, Pointy: CapnSwifty Babysteps

codename_watsonkitty.swift

// watsonkitty playground

import Cocoa

protocol CapnSwiftyReader {

}

protocol CapnSwiftyBuilder {

}

class CapnSwiftyVersion {

    private let pointer: UnsafeMutableRawPointer

    init(pointer: UnsafeMutableRawPointer) {
        self.pointer = pointer
        initPointer()
    }

    init() {
        pointer = UnsafeMutableRawPointer.allocate(bytes: 4, alignedTo: 1)
        initPointer()
    }

    private func initPointer() {
        pointer.storeBytes(of: 0, toByteOffset: 0, as: UInt16.self)
        pointer.storeBytes(of: 0, toByteOffset: 2, as: UInt8.self)
        pointer.storeBytes(of: 0, toByteOffset: 3, as: UInt8.self)
    }

    deinit {
        pointer.deallocate(bytes: 4, alignedTo: 1)
    }

    var major: UInt16 {
        @inline(__always) get {
            return pointer.load(as: UInt16.self)
        }
        @inline(__always) set {
            pointer.storeBytes(of: newValue, toByteOffset: 0, as: UInt16.self)
        }
    }
    var minor: UInt8 {
        @inline(__always) get {
            return (pointer + 2).load(as: UInt8.self)
        }
        @inline(__always) set {
//            let maxDist = newValue.distance(to: UInt8.max)
//            let minDist = newValue.distance(to: UInt8.min)
//            assert(maxDist >= 0 && minDist <= 0, "newValue is within bounds of UInt8") // not working in Playground? =(

            pointer.storeBytes(of: newValue, toByteOffset: 2, as: UInt8.self)
        }
    }
    var micro: UInt8 {
        @inline(__always) get {
            return (pointer + 3).load(as: UInt8.self)
        }
        @inline(__always) set {
            pointer.storeBytes(of: newValue, toByteOffset: 3, as: UInt8.self)
        }
    }
}

let version = CapnSwiftyVersion()
version.major = 256
version.minor = 255
let major = version.major
let minor = version.minor
let micro = version.micro