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1   /*
2    * Copyright 2014 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.handler.codec.http.websocketx.extensions.compression;
17  
18  import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
19  import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
20  import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
21  import io.netty.handler.codec.http.websocketx.WebSocketFrame;
22  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
23  
24  /**
25   * Per-frame implementation of deflate decompressor.
26   */
27  class PerFrameDeflateDecoder extends DeflateDecoder {
28  
29      /**
30       * Constructor
31       * @param noContext true to disable context takeover.
32       */
33      public PerFrameDeflateDecoder(boolean noContext) {
34          super(noContext);
35      }
36  
37      @Override
38      public boolean acceptInboundMessage(Object msg) throws Exception {
39          return (msg instanceof TextWebSocketFrame ||
40                  msg instanceof BinaryWebSocketFrame ||
41                  msg instanceof ContinuationWebSocketFrame) &&
42                      (((WebSocketFrame) msg).rsv() & WebSocketExtension.RSV1) > 0;
43      }
44  
45      @Override
46      protected int newRsv(WebSocketFrame msg) {
47          return msg.rsv() ^ WebSocketExtension.RSV1;
48      }
49  
50      @Override
51      protected boolean appendFrameTail(WebSocketFrame msg) {
52          return true;
53      }
54  }