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    1   /*
    2    * Copyright 2012 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 org.jboss.netty.handler.codec.spdy;
    17
    18  import static org.jboss.netty.handler.codec.spdy.SpdyCodecUtil.*;
    19
    20  import java.util.zip.DataFormatException;
    21  import java.util.zip.Inflater;
    22
    23  import org.jboss.netty.buffer.ChannelBuffer;
    24
    25  class SpdyHeaderBlockZlibDecompressor extends SpdyHeaderBlockDecompressor {
    26
    27      private final int version;
    28      private final byte[] out = new byte[8192];
    29      private final Inflater decompressor = new Inflater();
    30
    31      public SpdyHeaderBlockZlibDecompressor(int version) {
    32          if (version < SPDY_MIN_VERSION || version > SPDY_MAX_VERSION) {
    33              throw new IllegalArgumentException(
    34                      "unsupported version: " + version);
    35          }
    36          this.version = version;
    37      }
    38
    39      @Override
    40      public void setInput(ChannelBuffer compressed) {
    41          byte[] in = new byte[compressed.readableBytes()];
    42          compressed.readBytes(in);
    43          decompressor.setInput(in);
    44      }
    45
    46      @Override
    47      public void decode(ChannelBuffer decompressed) throws Exception {
    48          try {
    49              int numBytes = decompressor.inflate(out);
    50              if (numBytes == 0 && decompressor.needsDictionary()) {
    51                  if (version < 3) {
    52                      decompressor.setDictionary(SPDY2_DICT);
    53                  } else {
    54                      decompressor.setDictionary(SPDY_DICT);
    55                  }
    56                  numBytes = decompressor.inflate(out);
    57              }
    58              decompressed.writeBytes(out, 0, numBytes);
    59          } catch (DataFormatException e) {
    60              throw new SpdyProtocolException(
    61                      "Received invalid header block", e);
    62          }
    63      }
    64
    65      @Override
    66      public void end() {
    67          decompressor.end();
    68      }
    69  }