package redis.clients.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public interface Hashing {
    public static final Hashing MURMUR_HASH = new MurmurHash();

    public static final Hashing MD5 = new Hashing() {
        private MessageDigest md5 = null; // avoid recurring construction

        public long hash(String key) {
            return hash(SafeEncoder.encode(key));
        }

        public long hash(byte[] key) {
            if (md5 == null) {
                try {
                    md5 = MessageDigest.getInstance("MD5");
                } catch (NoSuchAlgorithmException e) {
                    throw new IllegalStateException(
                            "++++ no md5 algorythm found");
                }
            }

            md5.reset();
            md5.update(key);
            byte[] bKey = md5.digest();
            long res = ((long) (bKey[3] & 0xFF) << 24)
                    | ((long) (bKey[2] & 0xFF) << 16)
                    | ((long) (bKey[1] & 0xFF) << 8) | (long) (bKey[0] & 0xFF);
            return res;
        }
    };

    public long hash(String key);

    public long hash(byte[] key);
}