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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.Deflater;
    21
    22  import org.jboss.netty.buffer.ChannelBuffer;
    23
    24  class SpdyHeaderBlockZlibCompressor extends SpdyHeaderBlockCompressor {
    25
    26      private final byte[] out = new byte[8192];
    27      private final Deflater compressor;
    28
    29      public SpdyHeaderBlockZlibCompressor(int version, int compressionLevel) {
    30          if (version < SPDY_MIN_VERSION || version > SPDY_MAX_VERSION) {
    31              throw new IllegalArgumentException(
    32                      "unsupported version: " + version);
    33          }
    34          if (compressionLevel < 0 || compressionLevel > 9) {
    35              throw new IllegalArgumentException(
    36                      "compressionLevel: " + compressionLevel + " (expected: 0-9)");
    37          }
    38          compressor = new Deflater(compressionLevel);
    39          if (version < 3) {
    40              compressor.setDictionary(SPDY2_DICT);
    41          } else {
    42              compressor.setDictionary(SPDY_DICT);
    43          }
    44      }
    45
    46      @Override
    47      public void setInput(ChannelBuffer decompressed) {
    48          byte[] in = new byte[decompressed.readableBytes()];
    49          decompressed.readBytes(in);
    50          compressor.setInput(in);
    51      }
    52
    53      @Override
    54      public void encode(ChannelBuffer compressed) {
    55          while (!compressor.needsInput()) {
    56              int numBytes = compressor.deflate(out, 0, out.length, Deflater.SYNC_FLUSH);
    57              compressed.writeBytes(out, 0, numBytes);
    58          }
    59      }
    60
    61      @Override
    62      public void end() {
    63          compressor.end();
    64      }
    65  }