content: /*
   * Copyright 2014-2025 Real Logic Limited.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * https://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package io.aeron.driver;
  
  import io.aeron.protocol.ErrorFlyweight;
  import io.aeron.protocol.StatusMessageFlyweight;
  
  import java.net.InetSocketAddress;
  
  import static org.agrona.BitUtil.SIZE_OF_INT;
  import static org.agrona.BitUtil.SIZE_OF_LONG;
  
  /**
   * Minimum multicast sender flow control strategy only for tagged members identified by a receiver tag or ASF key.
   * <p>
   * Flow control is set to minimum of tracked tagged receivers.
   * <p>
   * Tracking of tagged receivers is done as long as they continue to send Status Messages. Once SMs stop, the receiver
   * tracking for that receiver will time out after a given number of nanoseconds.
   */
  public class TaggedMulticastFlowControl extends AbstractMinMulticastFlowControl
  {
      /**
       * URI param value to identify this {@link FlowControl} strategy.
       */
      public static final String FC_PARAM_VALUE = "tagged";
  
      TaggedMulticastFlowControl()
      {
          super(true);
      }
  
      /**
       * {@inheritDoc}
       */
      public long onStatusMessage(
          final StatusMessageFlyweight flyweight,
          final InetSocketAddress receiverAddress,
          final long senderLimit,
          final int initialTermId,
          final int positionBitsToShift,
          final long timeNs)
      {
          return processStatusMessage(
              flyweight, senderLimit, initialTermId, positionBitsToShift, timeNs, matchesTag(flyweight));
      }
  
      /**
       * {@inheritDoc}
       */
      public void onTriggerSendSetup(
          final StatusMessageFlyweight flyweight,
          final InetSocketAddress receiverAddress,
          final long timeNs)
      {
          processSendSetupTrigger(flyweight, receiverAddress, timeNs, matchesTag(flyweight));
      }
  
      /**
       * {@inheritDoc}
       */
      public void onError(final ErrorFlyweight errorFlyweight, final InetSocketAddress receiverAddress, final long timeNs)
      {
          processError(errorFlyweight, receiverAddress, timeNs, matchesTag(errorFlyweight));
      }
  
      @SuppressWarnings("deprecation")
      private boolean matchesTag(final StatusMessageFlyweight flyweight)
      {
          final int asfLength = flyweight.asfLength();
          boolean result = false;
  
          if (asfLength == SIZE_OF_LONG)
          {
              if (flyweight.groupTag() == super.groupTag())
              {
                  result = true;
              }
          }
          else if (asfLength >= SIZE_OF_INT)
          {
              // compatible check for ASF of first 4 bytes
              final int offset = StatusMessageFlyweight.groupTagFieldOffset();
  
              if (flyweight.getByte(offset) == PreferredMulticastFlowControl.PREFERRED_ASF_BYTES[0] &&
                  flyweight.getByte(offset + 1) == PreferredMulticastFlowControl.PREFERRED_ASF_BYTES[1] &&
                  flyweight.getByte(offset + 2) == PreferredMulticastFlowControl.PREFERRED_ASF_BYTES[2] &&
                  flyweight.getByte(offset + 3) == PreferredMulticastFlowControl.PREFERRED_ASF_BYTES[3])
              {
                  result = true;
              }
          }
  
          return result;
      }
  
      private boolean matchesTag(final ErrorFlyweight errorFlyweight)
      {
          return errorFlyweight.hasGroupTag() && errorFlyweight.groupTag() == super.groupTag();
      }
  }
  