public SpdyHeaderBlockJZlibEncoder(
      SpdyVersion version, int compressionLevel, int windowBits, int memLevel) {
    super(version);
    if (compressionLevel < 0 || compressionLevel > 9) {
      throw new IllegalArgumentException(
          "compressionLevel: " + compressionLevel + " (expected: 0-9)");
    }
    if (windowBits < 9 || windowBits > 15) {
      throw new IllegalArgumentException("windowBits: " + windowBits + " (expected: 9-15)");
    }
    if (memLevel < 1 || memLevel > 9) {
      throw new IllegalArgumentException("memLevel: " + memLevel + " (expected: 1-9)");
    }

    int resultCode = z.deflateInit(compressionLevel, windowBits, memLevel, JZlib.W_ZLIB);
    if (resultCode != JZlib.Z_OK) {
      throw new CompressionException(
          "failed to initialize an SPDY header block deflater: " + resultCode);
    } else {
      resultCode = z.deflateSetDictionary(SPDY_DICT, SPDY_DICT.length);
      if (resultCode != JZlib.Z_OK) {
        throw new CompressionException("failed to set the SPDY dictionary: " + resultCode);
      }
    }
  }
 private void setInput(ByteBuf decompressed) {
   byte[] in = new byte[decompressed.readableBytes()];
   decompressed.readBytes(in);
   z.next_in = in;
   z.next_in_index = 0;
   z.avail_in = in.length;
 }
 @Override
 public void end() {
   if (finished) {
     return;
   }
   finished = true;
   z.deflateEnd();
   z.next_in = null;
   z.next_out = null;
 }
  private void encode(ByteBuf compressed) {
    try {
      byte[] out = new byte[(int) Math.ceil(z.next_in.length * 1.001) + 12];
      z.next_out = out;
      z.next_out_index = 0;
      z.avail_out = out.length;

      int resultCode = z.deflate(JZlib.Z_SYNC_FLUSH);
      if (resultCode != JZlib.Z_OK) {
        throw new CompressionException("compression failure: " + resultCode);
      }

      if (z.next_out_index != 0) {
        compressed.writeBytes(out, 0, z.next_out_index);
      }
    } finally {
      // Deference the external references explicitly to tell the VM that
      // the allocated byte arrays are temporary so that the call stack
      // can be utilized.
      // I'm not sure if the modern VMs do this optimization though.
      z.next_in = null;
      z.next_out = null;
    }
  }