HMACAlgorithm.swift

/*
 CommonHMac defines the following enumeration
 
 enum {
    kCCHmacAlgSHA1,
    kCCHmacAlgMD5,
    kCCHmacAlgSHA256,
    kCCHmacAlgSHA384,
    kCCHmacAlgSHA512,
    kCCHmacAlgSHA224
};
typedef uint32_t CCHmacAlgorithm;

So we would like to be able to say:

enum HMacAlgorithm : CCHmacAlgorithm
{
    case SHA1 = kCCHmacAlgSHA1
    case MD5 = kCCHmacAlgMD5
    case SHA224 = kCCHmacAlgSHA224
    case SHA256 = kCCHmacAlgSHA256
    case SHA384 = kCCHmacAlgSHA384
    case SHA512 = kCCHmacAlgSHA512
    
}

but does not work. Error is "Raw value for enum case must be a literal."

So we have to do:

*/
enum HMACAlgorithm
{
    case SHA1, MD5, SHA224, SHA256, SHA384, SHA512
    
    func nativeValue() -> CCHmacAlgorithm {
        switch self {
        case .SHA1:
            return CCHmacAlgorithm(kCCHmacAlgSHA1)
        case .MD5:
            return CCHmacAlgorithm(kCCHmacAlgMD5)
        case .SHA224:
            return CCHmacAlgorithm(kCCHmacAlgSHA224)
        case .SHA256:
            return CCHmacAlgorithm(kCCHmacAlgSHA256)
        case .SHA384:
            return CCHmacAlgorithm(kCCHmacAlgSHA384)
        case .SHA512:
            return CCHmacAlgorithm(kCCHmacAlgSHA512)
            
        }
    }
}