Java tutorial
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package tp; /** * * @author Tareq */ import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import java.util.List; import com.jcraft.jzlib.Inflater; import com.jcraft.jzlib.JZlib; import io.netty.handler.codec.compression.ZlibDecoder; import io.netty.handler.codec.compression.ZlibWrapper; public class MyJZLibDecoder extends ZlibDecoder { private final Inflater z = new Inflater(); private byte[] dictionary; private volatile boolean finished; private int totalBytes = 0; /** * Creates a new instance with the default wrapper ({@link ZlibWrapper#ZLIB}). * */ public MyJZLibDecoder() { this(ZlibWrapper.ZLIB); } /** * Creates a new instance with the specified wrapper. * * @param wrapper */ public MyJZLibDecoder(ZlibWrapper wrapper) { if (wrapper == null) { throw new NullPointerException("wrapper"); } int resultCode = z.init(ZlibUtil.convertWrapperType(wrapper)); if (resultCode != JZlib.Z_OK) { ZlibUtil.fail(z, "initialization failure", resultCode); } } /** * Creates a new instance with the specified preset dictionary. The wrapper * is always {@link ZlibWrapper#ZLIB} because it is the only format that * supports the preset dictionary. * * @param dictionary */ public MyJZLibDecoder(byte[] dictionary) { if (dictionary == null) { throw new NullPointerException("dictionary"); } this.dictionary = dictionary; int resultCode; resultCode = z.inflateInit(JZlib.W_ZLIB); if (resultCode != JZlib.Z_OK) { ZlibUtil.fail(z, "initialization failure", resultCode); } } /** * Returns {@code true} if and only if the end of the compressed stream * has been reached. * @return */ @Override public boolean isClosed() { return finished; } @Override protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception { if (!in.isReadable()) { return; } try { // Configure input. int inputLength = in.readableBytes(); //totalBytes += inputLength; z.avail_in = inputLength; if (in.hasArray()) { z.next_in = in.array(); z.next_in_index = in.arrayOffset() + in.readerIndex(); } else { byte[] array = new byte[inputLength]; in.getBytes(in.readerIndex(), array); z.next_in = array; z.next_in_index = 0; } int oldNextInIndex = z.next_in_index; // Configure output. int maxOutputLength = inputLength << 1; ByteBuf decompressed = ctx.alloc().heapBuffer(maxOutputLength); try { loop: for (;;) { z.avail_out = maxOutputLength; decompressed.ensureWritable(maxOutputLength); z.next_out = decompressed.array(); z.next_out_index = decompressed.arrayOffset() + decompressed.writerIndex(); int oldNextOutIndex = z.next_out_index; // Decompress 'in' into 'out' int resultCode = z.inflate(JZlib.Z_SYNC_FLUSH); int outputLength = z.next_out_index - oldNextOutIndex; if (outputLength > 0) { decompressed.writerIndex(decompressed.writerIndex() + outputLength); } switch (resultCode) { case JZlib.Z_NEED_DICT: if (dictionary == null) { ZlibUtil.fail(z, "decompression failure", resultCode); } else { resultCode = z.inflateSetDictionary(dictionary, dictionary.length); if (resultCode != JZlib.Z_OK) { ZlibUtil.fail(z, "failed to set the dictionary", resultCode); } } break; case JZlib.Z_STREAM_END: finished = true; // Do not decode anymore. z.inflateEnd(); break loop; case JZlib.Z_OK: break; case JZlib.Z_BUF_ERROR: if (z.avail_in <= 0) { //ZlibUtil.fail(z, "decompression failure [Z_BUF_ERROR] ", resultCode); break loop; } break; default: ZlibUtil.fail(z, "decompression failure", resultCode); } } } finally { in.skipBytes(z.next_in_index - oldNextInIndex); //System.err.println("[recived][numBytes] = "+inputLength); if (decompressed.isReadable()) { out.add(decompressed); } else { decompressed.release(); } } } 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; } } }