Remove unnessary memory copy when doing Bzip2 encoding

Motivation:

We did an unessary memory copy when doing bzip2 encoding.

Modifications:

Remove memory copy and just use a ByteProcessor.

Result:

Less memory copies and so faster.

codec/src/main/java/io/netty/handler/codec/compression/Bzip2BlockCompressor.java

@@ -16,6 +16,7 @@
 package io.netty.handler.codec.compression;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.util.ByteProcessor;
 
 import static io.netty.handler.codec.compression.Bzip2Constants.*;
 
@@ -32,6 +33,13 @@ import static io.netty.handler.codec.compression.Bzip2Constants.*;
  * 7. Huffman encode and write data - {@link #close(ByteBuf)} (through {@link Bzip2HuffmanStageEncoder})
  */
 final class Bzip2BlockCompressor {
+    private final ByteProcessor writeProcessor = new ByteProcessor() {
+        @Override
+        public boolean process(byte value) throws Exception {
+            return write(value);
+        }
+    };
+
     /**
      * A writer that provides bit-level writes.
      */
@@ -197,22 +205,15 @@ final class Bzip2BlockCompressor {
 
     /**
      * Writes an array to the block.
-     * @param data The array to write
+     * @param buffer The buffer to write
      * @param offset The offset within the input data to write from
      * @param length The number of bytes of input data to write
      * @return The actual number of input bytes written. May be less than the number requested, or
      *         zero if the block is already full
      */
-    int write(final byte[] data, int offset, int length) {
+    int write(final ByteBuf buffer, int offset, int length) {
-        int written = 0;
+        int index = buffer.forEachByte(offset, length, writeProcessor);
-
+        return index == -1 ? length : index - offset;
-        while (length-- > 0) {
-            if (!write(data[offset++])) {
-                break;
-            }
-            written++;
-        }
-        return written;
     }
 
     /**

codec/src/main/java/io/netty/handler/codec/compression/Bzip2Encoder.java

@@ -121,19 +121,8 @@ public class Bzip2Encoder extends MessageToByteEncoder<ByteBuf> {
                         return;
                     }
                     Bzip2BlockCompressor blockCompressor = this.blockCompressor;
-                    final int length = in.readableBytes() < blockCompressor.availableSize() ?
+                    final int length = Math.min(in.readableBytes(), blockCompressor.availableSize());
-                                    in.readableBytes() : blockCompressor.availableSize();
+                    final int bytesWritten = blockCompressor.write(in, in.readerIndex(), length);
-                    final int offset;
-                    final byte[] array;
-                    if (in.hasArray()) {
-                        array = in.array();
-                        offset = in.arrayOffset() + in.readerIndex();
-                    } else {
-                        array = new byte[length];
-                        in.getBytes(in.readerIndex(), array);
-                        offset = 0;
-                    }
-                    final int bytesWritten = blockCompressor.write(array, offset, length);
                     in.skipBytes(bytesWritten);
                     if (!blockCompressor.isFull()) {
                         if (in.isReadable()) {