content: package redis.clients.jedis;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  
  import redis.clients.jedis.commands.ProtocolCommand;
  import redis.clients.jedis.exceptions.JedisAskDataException;
  import redis.clients.jedis.exceptions.JedisClusterException;
  import redis.clients.jedis.exceptions.JedisConnectionException;
  import redis.clients.jedis.exceptions.JedisDataException;
  import redis.clients.jedis.exceptions.JedisMovedDataException;
  import redis.clients.util.RedisInputStream;
  import redis.clients.util.RedisOutputStream;
  import redis.clients.util.SafeEncoder;
  
  public final class Protocol {
  
    private static final String ASK_RESPONSE = "ASK";
    private static final String MOVED_RESPONSE = "MOVED";
    private static final String CLUSTERDOWN_RESPONSE = "CLUSTERDOWN";
    public static final String DEFAULT_HOST = "localhost";
    public static final int DEFAULT_PORT = 6379;
    public static final int DEFAULT_SENTINEL_PORT = 26379;
    public static final int DEFAULT_TIMEOUT = 2000;
    public static final int DEFAULT_DATABASE = 0;
  
    public static final String CHARSET = "UTF-8";
  
    public static final byte DOLLAR_BYTE = '$';
    public static final byte ASTERISK_BYTE = '*';
    public static final byte PLUS_BYTE = '+';
    public static final byte MINUS_BYTE = '-';
    public static final byte COLON_BYTE = ':';
  
    public static final String SENTINEL_MASTERS = "masters";
    public static final String SENTINEL_GET_MASTER_ADDR_BY_NAME = "get-master-addr-by-name";
    public static final String SENTINEL_RESET = "reset";
    public static final String SENTINEL_SLAVES = "slaves";
    public static final String SENTINEL_FAILOVER = "failover";
    public static final String SENTINEL_MONITOR = "monitor";
    public static final String SENTINEL_REMOVE = "remove";
    public static final String SENTINEL_SET = "set";
  
    public static final String CLUSTER_NODES = "nodes";
    public static final String CLUSTER_MEET = "meet";
    public static final String CLUSTER_RESET = "reset";
    public static final String CLUSTER_ADDSLOTS = "addslots";
    public static final String CLUSTER_DELSLOTS = "delslots";
    public static final String CLUSTER_INFO = "info";
    public static final String CLUSTER_GETKEYSINSLOT = "getkeysinslot";
    public static final String CLUSTER_SETSLOT = "setslot";
    public static final String CLUSTER_SETSLOT_NODE = "node";
    public static final String CLUSTER_SETSLOT_MIGRATING = "migrating";
    public static final String CLUSTER_SETSLOT_IMPORTING = "importing";
    public static final String CLUSTER_SETSLOT_STABLE = "stable";
    public static final String CLUSTER_FORGET = "forget";
    public static final String CLUSTER_FLUSHSLOT = "flushslots";
    public static final String CLUSTER_KEYSLOT = "keyslot";
    public static final String CLUSTER_COUNTKEYINSLOT = "countkeysinslot";
    public static final String CLUSTER_SAVECONFIG = "saveconfig";
    public static final String CLUSTER_REPLICATE = "replicate";
    public static final String CLUSTER_SLAVES = "slaves";
    public static final String CLUSTER_FAILOVER = "failover";
    public static final String CLUSTER_SLOTS = "slots";
    public static final String PUBSUB_CHANNELS = "channels";
    public static final String PUBSUB_NUMSUB = "numsub";
    public static final String PUBSUB_NUM_PAT = "numpat";
  
    public static final byte[] BYTES_TRUE = toByteArray(1);
    public static final byte[] BYTES_FALSE = toByteArray(0);
  
    private Protocol() {
      // this prevent the class from instantiation
    }
  
    public static void sendCommand(final RedisOutputStream os, final ProtocolCommand command,
        final byte[]... args) {
      sendCommand(os, command.getRaw(), args);
    }
  
    private static void sendCommand(final RedisOutputStream os, final byte[] command,
        final byte[]... args) {
      try {
        os.write(ASTERISK_BYTE);
        os.writeIntCrLf(args.length + 1);
        os.write(DOLLAR_BYTE);
        os.writeIntCrLf(command.length);
        os.write(command);
        os.writeCrLf();
  
        for (final byte[] arg : args) {
          os.write(DOLLAR_BYTE);
          os.writeIntCrLf(arg.length);
          os.write(arg);
          os.writeCrLf();
        }
      } catch (IOException e) {
        throw new JedisConnectionException(e);
      }
    }
  
    private static void processError(final RedisInputStream is) {
      String message = is.readLine();
      // TODO: I'm not sure if this is the best way to do this.
      // Maybe Read only first 5 bytes instead?
      if (message.startsWith(MOVED_RESPONSE)) {
        String[] movedInfo = parseTargetHostAndSlot(message);
        throw new JedisMovedDataException(message, new HostAndPort(movedInfo[1],
            Integer.valueOf(movedInfo[2])), Integer.valueOf(movedInfo[0]));
      } else if (message.startsWith(ASK_RESPONSE)) {
        String[] askInfo = parseTargetHostAndSlot(message);
        throw new JedisAskDataException(message, new HostAndPort(askInfo[1],
            Integer.valueOf(askInfo[2])), Integer.valueOf(askInfo[0]));
      } else if (message.startsWith(CLUSTERDOWN_RESPONSE)) {
        throw new JedisClusterException(message);
      }
      throw new JedisDataException(message);
    }
  
    public static String readErrorLineIfPossible(RedisInputStream is) {
      final byte b = is.readByte();
      // if buffer contains other type of response, just ignore.
      if (b != MINUS_BYTE) {
        return null;
      }
      return is.readLine();
    }
  
    private static String[] parseTargetHostAndSlot(String clusterRedirectResponse) {
      String[] response = new String[3];
      String[] messageInfo = clusterRedirectResponse.split(" ");
      String[] targetHostAndPort = messageInfo[2].split(":");
      response[0] = messageInfo[1];
      response[1] = targetHostAndPort[0];
      response[2] = targetHostAndPort[1];
      return response;
    }
  
    private static Object process(final RedisInputStream is) {
  
      final byte b = is.readByte();
      if (b == PLUS_BYTE) {
        return processStatusCodeReply(is);
      } else if (b == DOLLAR_BYTE) {
        return processBulkReply(is);
      } else if (b == ASTERISK_BYTE) {
        return processMultiBulkReply(is);
      } else if (b == COLON_BYTE) {
        return processInteger(is);
      } else if (b == MINUS_BYTE) {
        processError(is);
        return null;
      } else {
        throw new JedisConnectionException("Unknown reply: " + (char) b);
      }
    }
  
    private static byte[] processStatusCodeReply(final RedisInputStream is) {
      return is.readLineBytes();
    }
  
    private static byte[] processBulkReply(final RedisInputStream is) {
      final int len = is.readIntCrLf();
      if (len == -1) {
        return null;
      }
  
      final byte[] read = new byte[len];
      int offset = 0;
      while (offset < len) {
        final int size = is.read(read, offset, (len - offset));
        if (size == -1) throw new JedisConnectionException(
            "It seems like server has closed the connection.");
        offset += size;
      }
  
      // read 2 more bytes for the command delimiter
      is.readByte();
      is.readByte();
  
      return read;
    }
  
    private static Long processInteger(final RedisInputStream is) {
      return is.readLongCrLf();
    }
  
    private static List<Object> processMultiBulkReply(final RedisInputStream is) {
      final int num = is.readIntCrLf();
      if (num == -1) {
        return null;
      }
      final List<Object> ret = new ArrayList<Object>(num);
      for (int i = 0; i < num; i++) {
        try {
          ret.add(process(is));
        } catch (JedisDataException e) {
          ret.add(e);
        }
      }
      return ret;
    }
  
    public static Object read(final RedisInputStream is) {
      return process(is);
    }
  
    public static final byte[] toByteArray(final boolean value) {
      return value ? BYTES_TRUE : BYTES_FALSE;
    }
  
    public static final byte[] toByteArray(final int value) {
      return SafeEncoder.encode(String.valueOf(value));
    }
  
    public static final byte[] toByteArray(final long value) {
      return SafeEncoder.encode(String.valueOf(value));
    }
  
    public static final byte[] toByteArray(final double value) {
      return SafeEncoder.encode(String.valueOf(value));
    }
  
    public static enum Command implements ProtocolCommand {
      PING, SET, GET, QUIT, EXISTS, DEL, TYPE, FLUSHDB, KEYS, RANDOMKEY, RENAME, RENAMENX, RENAMEX, DBSIZE, EXPIRE, EXPIREAT, TTL, SELECT, MOVE, FLUSHALL, GETSET, MGET, SETNX, SETEX, MSET, MSETNX, DECRBY, DECR, INCRBY, INCR, APPEND, SUBSTR, HSET, HGET, HSETNX, HMSET, HMGET, HINCRBY, HEXISTS, HDEL, HLEN, HKEYS, HVALS, HGETALL, RPUSH, LPUSH, LLEN, LRANGE, LTRIM, LINDEX, LSET, LREM, LPOP, RPOP, RPOPLPUSH, SADD, SMEMBERS, SREM, SPOP, SMOVE, SCARD, SISMEMBER, SINTER, SINTERSTORE, SUNION, SUNIONSTORE, SDIFF, SDIFFSTORE, SRANDMEMBER, ZADD, ZRANGE, ZREM, ZINCRBY, ZRANK, ZREVRANK, ZREVRANGE, ZCARD, ZSCORE, MULTI, DISCARD, EXEC, WATCH, UNWATCH, SORT, BLPOP, BRPOP, AUTH, SUBSCRIBE, PUBLISH, UNSUBSCRIBE, PSUBSCRIBE, PUNSUBSCRIBE, PUBSUB, ZCOUNT, ZRANGEBYSCORE, ZREVRANGEBYSCORE, ZREMRANGEBYRANK, ZREMRANGEBYSCORE, ZUNIONSTORE, ZINTERSTORE, ZLEXCOUNT, ZRANGEBYLEX, ZREVRANGEBYLEX, ZREMRANGEBYLEX, SAVE, BGSAVE, BGREWRITEAOF, LASTSAVE, SHUTDOWN, INFO, MONITOR, SLAVEOF, CONFIG, STRLEN, SYNC, LPUSHX, PERSIST, RPUSHX, ECHO, LINSERT, DEBUG, BRPOPLPUSH, SETBIT, GETBIT, BITPOS, SETRANGE, GETRANGE, EVAL, EVALSHA, SCRIPT, SLOWLOG, OBJECT, BITCOUNT, BITOP, SENTINEL, DUMP, RESTORE, PEXPIRE, PEXPIREAT, PTTL, INCRBYFLOAT, PSETEX, CLIENT, TIME, MIGRATE, HINCRBYFLOAT, SCAN, HSCAN, SSCAN, ZSCAN, WAIT, CLUSTER, ASKING, PFADD, PFCOUNT, PFMERGE, READONLY, GEOADD, GEODIST, GEOHASH, GEOPOS, GEORADIUS, GEORADIUSBYMEMBER;
  
      private final byte[] raw;
  
      Command() {
        raw = SafeEncoder.encode(this.name());
      }
  
      @Override
      public byte[] getRaw() {
        return raw;
      }
    }
  
    public static enum Keyword {
      AGGREGATE, ALPHA, ASC, BY, DESC, GET, LIMIT, MESSAGE, NO, NOSORT, PMESSAGE, PSUBSCRIBE, PUNSUBSCRIBE, OK, ONE, QUEUED, SET, STORE, SUBSCRIBE, UNSUBSCRIBE, WEIGHTS, WITHSCORES, RESETSTAT, RESET, FLUSH, EXISTS, LOAD, KILL, LEN, REFCOUNT, ENCODING, IDLETIME, AND, OR, XOR, NOT, GETNAME, SETNAME, LIST, MATCH, COUNT;
      public final byte[] raw;
  
      Keyword() {
        raw = SafeEncoder.encode(this.name().toLowerCase());
      }
    }
  }
  