Swift - 对String的扩展

enum CryptoAlgorithm {
    case MD5, SHA1, SHA224, SHA256, SHA384, SHA512
    
    var HMACAlgorithm: CCHmacAlgorithm {
        var result: Int = 0
        switch self {
        case .MD5:      result = kCCHmacAlgMD5
        case .SHA1:     result = kCCHmacAlgSHA1
        case .SHA224:   result = kCCHmacAlgSHA224
        case .SHA256:   result = kCCHmacAlgSHA256
        case .SHA384:   result = kCCHmacAlgSHA384
        case .SHA512:   result = kCCHmacAlgSHA512
        }
        return CCHmacAlgorithm(result)
    }
    
    var digestLength: Int {
        var result: Int32 = 0
        switch self {
        case .MD5:      result = CC_MD5_DIGEST_LENGTH
        case .SHA1:     result = CC_SHA1_DIGEST_LENGTH
        case .SHA224:   result = CC_SHA224_DIGEST_LENGTH
        case .SHA256:   result = CC_SHA256_DIGEST_LENGTH
        case .SHA384:   result = CC_SHA384_DIGEST_LENGTH
        case .SHA512:   result = CC_SHA512_DIGEST_LENGTH
        }
        return Int(result)
    }
}

extension String  {
    var md5: String! {
        let str = self.cStringUsingEncoding(NSUTF8StringEncoding)
        let strLen = CC_LONG(self.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
        let digestLen = Int(CC_MD5_DIGEST_LENGTH)
        let result = UnsafeMutablePointer.alloc(digestLen)
        CC_MD5(str!, strLen, result)
        return stringFromBytes(result, length: digestLen)
    }
    
    
    var sha1: String! {
        let str = self.cStringUsingEncoding(NSUTF8StringEncoding)
        let strLen = CC_LONG(self.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
        let digestLen = Int(CC_SHA1_DIGEST_LENGTH)
        let result = UnsafeMutablePointer.alloc(digestLen)
        CC_SHA1(str!, strLen, result)
        return stringFromBytes(result, length: digestLen)
    }
    
    var sha256String: String! {
        let str = self.cStringUsingEncoding(NSUTF8StringEncoding)
        let strLen = CC_LONG(self.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
        let digestLen = Int(CC_SHA256_DIGEST_LENGTH)
        let result = UnsafeMutablePointer.alloc(digestLen)
        CC_SHA256(str!, strLen, result)
        return stringFromBytes(result, length: digestLen)
    }
    
    var sha512String: String! {
        let str = self.cStringUsingEncoding(NSUTF8StringEncoding)
        let strLen = CC_LONG(self.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
        let digestLen = Int(CC_SHA512_DIGEST_LENGTH)
        let result = UnsafeMutablePointer.alloc(digestLen)
        CC_SHA512(str!, strLen, result)
        return stringFromBytes(result, length: digestLen)
    }
    
    func stringFromBytes(bytes: UnsafeMutablePointer, length: Int) -> String{
        let hash = NSMutableString()
        for i in 0.. String {
        let str = self.cStringUsingEncoding(NSUTF8StringEncoding)
        let strLen = Int(self.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
        let digestLen = algorithm.digestLength
        let result = UnsafeMutablePointer.alloc(digestLen)
        let keyStr = key.cStringUsingEncoding(NSUTF8StringEncoding)
        let keyLen = Int(key.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
        
        CCHmac(algorithm.HMACAlgorithm, keyStr!, keyLen, str!, strLen, result)
        
        let digest = stringFromResult(result, length: digestLen)
        
        result.dealloc(digestLen)
        
        return digest
    }
    
    private func stringFromResult(result: UnsafeMutablePointer, length: Int) -> String {
        let hash = NSMutableString()
        for i in 0.. CGRect {
        let attributes = [NSFontAttributeName: font]
        let option = NSStringDrawingOptions.UsesLineFragmentOrigin
        let rect = self.boundingRectWithSize(size, options: option, attributes: attributes, context: nil)
        return rect
    }
    
    /**
     获取应用的UUID
     - returns: UUID字符串
     */
    
   static func getUUID() -> String {
        var deviceID = NSUUID().UUIDString
        deviceID = deviceID.stringByReplacingOccurrencesOfString("-", withString: "")
        return deviceID
    }
    
    /**
     获取时间戳(秒)
     - returns: 时间戳字符串
     */
  static  func getTimeSince() -> String {
      let time = Int(NSDate().timeIntervalSince1970)
        return "\(time)"
        
    }
}