Convert Simple Text With HTML Tags to NSAttributedString

NSAttributedString+SimpleHTMLTag.swift

extension NSAttributedString {
    func replaceHTMLTag(tag: String, withAttributes attributes: [String: AnyObject]) -> NSAttributedString {
        let openTag = "<\(tag)>"
        let closeTag = "</\(tag)>"
        let resultingText: NSMutableAttributedString = self.mutableCopy() as NSMutableAttributedString
        while true {
            let plainString = resultingText.string as NSString
            let openTagRange = plainString.rangeOfString(openTag)
            if openTagRange.length == 0 {
                break
            }

            let affectedLocation = openTagRange.location + openTagRange.length

            var searchRange = NSMakeRange(affectedLocation, plainString.length - affectedLocation)

            let closeTagRange = plainString.rangeOfString(closeTag, options: NSStringCompareOptions(0), range: searchRange)

            resultingText.setAttributes(attributes, range: NSMakeRange(affectedLocation, closeTagRange.location - affectedLocation))
            resultingText.deleteCharactersInRange(closeTagRange)
            resultingText.deleteCharactersInRange(openTagRange)
        }
        return resultingText as NSAttributedString
    }
}