Resolved issue: NETTY-241 Add more ChannelBufferFactory.getBuffer() methods for less memory bandwidth consumption

src/main/java/org/jboss/netty/buffer/AbstractChannelBufferFactory.java

@@ -53,6 +53,10 @@ public abstract class AbstractChannelBufferFactory implements ChannelBufferFacto
         return getBuffer(getDefaultOrder(), capacity);
     }
 
+    public ChannelBuffer getBuffer(byte[] array, int offset, int length) {
+        return getBuffer(getDefaultOrder(), array, offset, length);
+    }
+
     public ByteOrder getDefaultOrder() {
         return defaultOrder;
     }

src/main/java/org/jboss/netty/buffer/ChannelBufferFactory.java

@@ -15,6 +15,7 @@
  */
 package org.jboss.netty.buffer;
 
+import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 
 /**
@@ -48,6 +49,54 @@ public interface ChannelBufferFactory {
      */
     ChannelBuffer getBuffer(ByteOrder endianness, int capacity);
 
+    /**
+     * Returns a {@link ChannelBuffer} whose content is equals to the sub-region
+     * of the specified {@code array}.  Depending on the factory implementation,
+     * the returned buffer could wrap the {@code array} or create a new copy of
+     * the {@code array}.
+     * This method is identical to {@code getBuffer(getDefaultOrder(), array, offset, length)}.
+     *
+     * @param array the byte array
+     * @param offset the offset of the byte array
+     * @param length the length of the byte array
+     *
+     * @return a {@link ChannelBuffer} with the specified content,
+     *         whose {@code readerIndex} and {@code writerIndex}
+     *         are {@code 0} and {@code (length - offset)} respectively
+     */
+    ChannelBuffer getBuffer(byte[] array, int offset, int length);
+
+    /**
+     * Returns a {@link ChannelBuffer} whose content is equals to the sub-region
+     * of the specified {@code array}.  Depending on the factory implementation,
+     * the returned buffer could wrap the {@code array} or create a new copy of
+     * the {@code array}.
+     *
+     * @param endianness the endianness of the returned {@link ChannelBuffer}
+     * @param array the byte array
+     * @param offset the offset of the byte array
+     * @param length the length of the byte array
+     *
+     * @return a {@link ChannelBuffer} with the specified content,
+     *         whose {@code readerIndex} and {@code writerIndex}
+     *         are {@code 0} and {@code (length - offset)} respectively
+     */
+    ChannelBuffer getBuffer(ByteOrder endianness, byte[] array, int offset, int length);
+
+    /**
+     * Returns a {@link ChannelBuffer} whose content is equals to the sub-region
+     * of the specified {@code nioBuffer}.  Depending on the factory
+     * implementation, the returned buffer could wrap the {@code nioBuffer} or
+     * create a new copy of the {@code nioBuffer}.
+     *
+     * @param nioBuffer the NIO {@link ByteBuffer}
+     *
+     * @return a {@link ChannelBuffer} with the specified content,
+     *         whose {@code readerIndex} and {@code writerIndex}
+     *         are {@code 0} and {@code nioBuffer.remaining()} respectively
+     */
+    ChannelBuffer getBuffer(ByteBuffer nioBuffer);
+
     /**
      * Returns the default endianness of the {@link ChannelBuffer} which is
      * returned by {@link #getBuffer(int)}.

src/main/java/org/jboss/netty/buffer/DirectChannelBufferFactory.java

@@ -16,6 +16,7 @@
 package org.jboss.netty.buffer;
 
 import java.lang.ref.ReferenceQueue;
+import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 
 /**
@@ -129,6 +130,37 @@ public class DirectChannelBufferFactory extends AbstractChannelBufferFactory {
         return slice;
     }
 
+    public ChannelBuffer getBuffer(ByteOrder order, byte[] array, int offset, int length) {
+        if (array == null) {
+            throw new NullPointerException("array");
+        }
+        if (offset < 0) {
+            throw new IndexOutOfBoundsException("offset: " + offset);
+        }
+        if (length == 0) {
+            return ChannelBuffers.EMPTY_BUFFER;
+        }
+        if (offset + length > array.length) {
+            throw new IndexOutOfBoundsException("length: " + length);
+        }
+
+        ChannelBuffer buf = getBuffer(order, length);
+        buf.writeBytes(array, offset, length);
+        return buf;
+    }
+
+    public ChannelBuffer getBuffer(ByteBuffer nioBuffer) {
+        if (nioBuffer.isDirect()) {
+            return ChannelBuffers.wrappedBuffer(nioBuffer);
+        }
+
+        ChannelBuffer buf = getBuffer(nioBuffer.order(), nioBuffer.remaining());
+        int pos = nioBuffer.position();
+        buf.writeBytes(nioBuffer);
+        nioBuffer.position(pos);
+        return buf;
+    }
+
     private ChannelBuffer allocateBigEndianBuffer(int capacity) {
         ChannelBuffer slice;
         synchronized (bigEndianLock) {

src/main/java/org/jboss/netty/buffer/HeapChannelBufferFactory.java

@@ -15,6 +15,7 @@
  */
 package org.jboss.netty.buffer;
 
+import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 
 /**
@@ -71,4 +72,20 @@ public class HeapChannelBufferFactory extends AbstractChannelBufferFactory {
     public ChannelBuffer getBuffer(ByteOrder order, int capacity) {
         return ChannelBuffers.buffer(order, capacity);
     }
+
+    public ChannelBuffer getBuffer(ByteOrder order, byte[] array, int offset, int length) {
+        return ChannelBuffers.wrappedBuffer(order, array, offset, length);
+    }
+
+    public ChannelBuffer getBuffer(ByteBuffer nioBuffer) {
+        if (!nioBuffer.isReadOnly() && nioBuffer.hasArray()) {
+            return ChannelBuffers.wrappedBuffer(nioBuffer);
+        }
+
+        ChannelBuffer buf = getBuffer(nioBuffer.order(), nioBuffer.remaining());
+        int pos = nioBuffer.position();
+        buf.writeBytes(nioBuffer);
+        nioBuffer.position(pos);
+        return buf;
+    }
 }