NetNewsWire/AppleEvents/AppleEventUtils.swift

//
//  AppleEventUtils.swift
//  NetNewsWireTests
//
//  Created by Olof Hellman on 1/7/18.
//  Copyright © 2018 Olof Hellman. All rights reserved.
//

import Foundation

/*
   @function FourCharCode()
   @brief    FourCharCode values like OSType, DescType or AEKeyword  are really just 
             4 byte values commonly represented as values like 'odoc' where each byte is 
             represented as its ASCII character.  This function turns a swift string into 
             its FourCharCode equivalent, as swift doesn't recognize FourCharCode types 
             natively just yet.  With this extension, one can use
                  "odoc".FourCharCode()
             where one would really want to use 'odoc'
*/
extension String {
    func FourCharCode() -> FourCharCode {
        var sum: UInt32 = 0
        guard ( self.count == 4) else {
            print ("error: FourCharCode() expected a 4 character string")
            return 0
        }
        for scalar in self.unicodeScalars {
            sum = (sum * 256) + scalar.value
        }
        return (sum)
    }
}
extension Int {
    func FourCharCode() -> FourCharCode {
        return (UInt32(self))
    }
}