/*!
     验证身份证

     - returns: true/false
     */
    func chk18PaperId() -> Bool {
        //判断位数
        if self.length != 15 && self.length != 18 {
            return false
        }
        var carid = self

        var lSumQT = 0

        //加权因子
        let R = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2]

        //校验码
        let sChecker: [Int8] = [49,48,88, 57, 56, 55, 54, 53, 52, 51, 50]

        //将15位身份证号转换成18位
        let mString = NSMutableString.init(string: self)

        if self.length == 15 {
            mString.insertString("19", atIndex: 6)
            var p = 0
            let pid = mString.UTF8String
            for i in 0...16 {
                p += (pid[i]-48) * R[i]
            }
            let o = p % 11
            let stringContent = NSString(format: "%c", sChecker[o])
            mString.insertString(stringContent as String, atIndex: mString.length)
            carid = mString
        }

        //判断年月日是否有效
        //年份
        let strYear = Int(carid.substringWithRange(NSMakeRange(6, 4)))
        //月份
        let strMonth = Int(carid.substringWithRange(NSMakeRange(10, 2)))
        //日
        let strDay = Int(carid.substringWithRange(NSMakeRange(12, 2)))

        let localZone = NSTimeZone.localTimeZone()

        let dateFormatter = NSDateFormatter()
        dateFormatter.dateStyle = .MediumStyle
        dateFormatter.timeStyle = .NoStyle
        dateFormatter.timeZone = localZone
        dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
        let date = dateFormatter.dateFromString("\(String(format: "%02d",strYear!))-\(String(format: "%02d",strMonth!))-\(String(format: "%02d",strDay!)) 12:01:01")

        if date == nil {
            return false
        }

        let paperId = carid.UTF8String
        //检验长度
        if 18 != carid.length {
            return false
        }
        //校验数字
        func isDigit(c: Int8) -> Bool {
            return 0 <= c && c <= 9
        }
        for i in 0...18 {
            if isDigit(paperId[i]) && !(88 == paperId[i] || 120 == paperId[i]) && 17 == i {
                return false
            }
        }

        //验证最末的校验码
        for i in 0...16 {
            lSumQT += (paperId[i]-48) * R[i]
        }
        if sChecker[lSumQT%11] != paperId[17] {
            return false
        }
        return true
    }