Backport getBuffer(..) method in CompositeChannelBuffer. See #414 and #415

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

@@ -559,6 +559,35 @@ public class CompositeChannelBuffer extends AbstractChannelBuffer {
         dst.writerIndex(dst.capacity());
     }
 
+    /**
+    * Returns the {@link ChannelBuffer} portion of this {@link CompositeChannelBuffer} that
+    * contains the specified {@code index}. <strong>This is an expert method!</strong>
+    *
+    * <p>
+    * Please note that since a {@link CompositeChannelBuffer} is made up of
+    * multiple {@link ChannelBuffer}s, this does <em>not</em> return the full buffer.
+    * Instead, it only returns a portion of the composite buffer where the
+    * index is located
+    * </p>
+    *
+    *
+    * @param index The {@code index} to search for and include in the returned {@link ByteBuf}
+    * @return The {@link ByteBuf} that contains the specified {@code index}
+    * @throws IndexOutOfBoundsException when the specified {@code index} is
+    * less than zero, or larger than {@code capacity()}
+    */
+    public ChannelBuffer getBuffer(int index) throws IndexOutOfBoundsException {
+        if (index < 0 || index >= capacity()) {
+            throw new IndexOutOfBoundsException("Invalid index: " + index
+                    + " - Bytes needed: " + index + ", maximum is "
+                    + capacity());
+        }
+
+        //Return the component byte buffer
+        return components[componentId(index)];
+
+    }
+
     public ChannelBuffer slice(int index, int length) {
         if (index == 0) {
             if (length == 0) {

src/test/java/org/jboss/netty/buffer/AbstractCompositeChannelBufferTest.java

@@ -90,6 +90,25 @@ public abstract class AbstractCompositeChannelBufferTest extends
         return false;
     }
 
+    @Test
+    public void testGetBuffer() {
+        CompositeChannelBuffer buf = (CompositeChannelBuffer) ChannelBuffers.wrappedBuffer(new byte[] { 1, 2, 3, 4, 5 }, new byte[] {4, 5, 6, 7, 8, 9, 26});
+
+        //Ensure that a random place will be fine
+        assertEquals(buf.getBuffer(2).capacity(), 5);
+
+        //Loop through each byte
+        byte index = 0;
+
+        while (index < buf.capacity()) {
+            ChannelBuffer _buf = buf.getBuffer(index++);
+            assertNotNull(_buf);
+            assertTrue(_buf.capacity() > 0);
+            assertNotNull(_buf.getByte(0));
+            assertNotNull(_buf.getByte(_buf.readableBytes() - 1));
+        }
+    }
+
     @Test
     public void testDiscardReadBytes3() {
         ChannelBuffer a, b;