UIColor extension and String substring extension

UIColor+String.swift

//
//  Color+Utils.swift
//  taskmanager
//
//  Created by Mike on 2014-07-30.
//  Copyright (c) 2014 Mike. All rights reserved.
//

import UIKit

extension String
{
    subscript (i: Int) -> String {
        return String(Array(self)[i])
    }
    
    subscript (r: Range<Int>) -> String {
        var start = advance(startIndex, r.startIndex)
        var end = advance(startIndex, r.endIndex)
        return substringWithRange(Range(start: start, end: end))
    }
    
}

extension UIColor {
    convenience init(string:String) {
        var scolor = string.stringByReplacingOccurrencesOfString("#", withString: "", options: NSStringCompareOptions.CaseInsensitiveSearch, range: nil)
        scolor = scolor.stringByReplacingOccurrencesOfString("0x", withString: "", options: NSStringCompareOptions.CaseInsensitiveSearch, range: nil)

        switch(countElements(scolor)) {
            case 3:
                let red = scolor[0]
                let green = scolor[1]
                let blue = scolor[2]
                scolor = red+red + green+green + blue+blue + "ff"
            case 6:
                scolor = scolor + "ff"
            case 8:
                scolor = scolor + ""
                // so compiler doesn't complain
            default:
                scolor = "00000000"
            
        }
        
        var r:CUnsignedInt = 0, g:CUnsignedInt = 0, b:CUnsignedInt = 0, a:CUnsignedInt = 0;
        NSScanner.scannerWithString(scolor[0..<2]).scanHexInt(&r)
        NSScanner.scannerWithString(scolor[2..<4]).scanHexInt(&g)
        NSScanner.scannerWithString(scolor[4..<6]).scanHexInt(&b)
        NSScanner.scannerWithString(scolor[6..<8]).scanHexInt(&a)

        var red:CGFloat = 0.0
        var green:CGFloat = 0.0
        var blue:CGFloat = 0.0
        var alpha:CGFloat = 0.0
        
        if let x = String(r).toInt() {
            red = CGFloat(x) / 255.0
        }
        if let x = String(g).toInt() {
            green = CGFloat(x) / 255.0
        }
        if let x = String(b).toInt() {
            blue = CGFloat(x) / 255.0
        }
        if let x = String(a).toInt() {
            alpha = CGFloat(x) / 255.0
        }
        
        self.init(red: red, green: green, blue: blue, alpha: alpha)

    }
}