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   /*
    * Copyright 2014 The Netty Project
    *
    * The Netty Project licenses this file to you 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.netty.handler.codec.http.websocketx.extensions.compression;
  
  import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.WebSocketFrame;
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionFilter;
  
  /**
   * Per-frame implementation of deflate decompressor.
   */
  class PerFrameDeflateDecoder extends DeflateDecoder {
  
      /**
       * Constructor
       *
       * @param noContext true to disable context takeover.
       */
      PerFrameDeflateDecoder(boolean noContext) {
          super(noContext, WebSocketExtensionFilter.NEVER_SKIP);
      }
  
      /**
       * Constructor
       *
       * @param noContext true to disable context takeover.
       * @param extensionDecoderFilter extension decoder filter for per frame deflate decoder.
       */
      PerFrameDeflateDecoder(boolean noContext, WebSocketExtensionFilter extensionDecoderFilter) {
          super(noContext, extensionDecoderFilter);
      }
  
      @Override
      public boolean acceptInboundMessage(Object msg) throws Exception {
          if (!super.acceptInboundMessage(msg)) {
              return false;
          }
  
          WebSocketFrame wsFrame = (WebSocketFrame) msg;
          if (extensionDecoderFilter().mustSkip(wsFrame)) {
              return false;
          }
  
          return (msg instanceof TextWebSocketFrame || msg instanceof BinaryWebSocketFrame ||
                  msg instanceof ContinuationWebSocketFrame) &&
                 (wsFrame.rsv() & WebSocketExtension.RSV1) > 0;
      }
  
      @Override
      protected int newRsv(WebSocketFrame msg) {
          return msg.rsv() ^ WebSocketExtension.RSV1;
      }
  
      @Override
      protected boolean appendFrameTail(WebSocketFrame msg) {
          return true;
      }
  
  }