Type Casts in Swift

Type Casts.swift

func typecast<T,U>(_ a:T) -> U {
    var _a = a
    return withUnsafePointer(to: &_a) { (ptr:UnsafePointer<T>) -> U in
        return UnsafeRawPointer(ptr).load(as: U.self)
    }
}

func typecast_inplace<T,U>(_ a:inout T) -> U {
    return withUnsafePointer(to: &a) { (ptr:UnsafePointer<T>) -> U in
        return UnsafeRawPointer(ptr).load(as: U.self)
    }
}

// Usage:
let bignum:UInt64 = 0xAAAAAAAABBBBBBBB
struct parts {
    var a:UInt32
    var b:UInt32
}
let a:parts = typecast(bignum)