Fix IndexOutOfBoundException when using CompositeChannelBuffer and the readerIndex is at the last position and an empty array is passed to read to. See #474

buffer/src/main/java/io/netty/buffer/DefaultCompositeByteBuf.java

@@ -578,14 +578,19 @@ public class DefaultCompositeByteBuf extends AbstractByteBuf implements Composit
 
     @Override
     public void getBytes(int index, byte[] dst, int dstIndex, int length) {
-        int componentId = toComponentIndex(index);
         if (index > capacity() - length || dstIndex > dst.length - length) {
             throw new IndexOutOfBoundsException("Too many bytes to read - Needs "
                     + (index + length) + ", maximum is " + capacity() + " or "
                     + dst.length);
         }
+        if (index < 0) {
+            throw new IndexOutOfBoundsException("index must be >= 0");
+        }
+        if (length == 0) {
+            return;
+        }
+        int i = toComponentIndex(index);
 
-        int i = componentId;
         while (length > 0) {
             Component c = components.get(i);
             ByteBuf s = c.buf;
@@ -601,15 +606,20 @@ public class DefaultCompositeByteBuf extends AbstractByteBuf implements Composit
 
     @Override
     public void getBytes(int index, ByteBuffer dst) {
-        int componentId = toComponentIndex(index);
         int limit = dst.limit();
         int length = dst.remaining();
+
         if (index > capacity() - length) {
             throw new IndexOutOfBoundsException("Too many bytes to be read - Needs "
                     + (index + length) + ", maximum is " + capacity());
         }
-
-        int i = componentId;
+        if (index < 0) {
+            throw new IndexOutOfBoundsException("index must be >= 0");
+        }
+        if (length == 0) {
+            return;
+        }
+        int i = toComponentIndex(index);
         try {
             while (length > 0) {
                 Component c = components.get(i);
@@ -629,14 +639,18 @@ public class DefaultCompositeByteBuf extends AbstractByteBuf implements Composit
 
     @Override
     public void getBytes(int index, ByteBuf dst, int dstIndex, int length) {
-        int componentId = toComponentIndex(index);
         if (index > capacity() - length || dstIndex > dst.capacity() - length) {
             throw new IndexOutOfBoundsException("Too many bytes to be read - Needs "
                     + (index + length) + " or " + (dstIndex + length) + ", maximum is "
                     + capacity() + " or " + dst.capacity());
         }
-
-        int i = componentId;
+        if (index < 0) {
+            throw new IndexOutOfBoundsException("index must be >= 0");
+        }
+        if (length == 0) {
+            return;
+        }
+        int i = toComponentIndex(index);
         while (length > 0) {
             Component c = components.get(i);
             ByteBuf s = c.buf;
@@ -670,13 +684,18 @@ public class DefaultCompositeByteBuf extends AbstractByteBuf implements Composit
     @Override
     public void getBytes(int index, OutputStream out, int length)
             throws IOException {
-        int componentId = toComponentIndex(index);
         if (index > capacity() - length) {
             throw new IndexOutOfBoundsException("Too many bytes to be read - needs "
                     + (index + length) + ", maximum of " + capacity());
         }
+        if (index < 0) {
+            throw new IndexOutOfBoundsException("index must be >= 0");
+        }
+        if (length == 0) {
+            return;
+        }
 
-        int i = componentId;
+        int i = toComponentIndex(index);
         while (length > 0) {
             Component c = components.get(i);
             ByteBuf s = c.buf;
@@ -1031,11 +1050,17 @@ public class DefaultCompositeByteBuf extends AbstractByteBuf implements Composit
 
     @Override
     public ByteBuffer[] nioBuffers(int index, int length) {
-        int componentId = toComponentIndex(index);
         if (index + length > capacity()) {
             throw new IndexOutOfBoundsException("Too many bytes to convert - Needs"
                     + (index + length) + ", maximum is " + capacity());
         }
+        if (index < 0) {
+            throw new IndexOutOfBoundsException("index must be >= 0");
+        }
+        if (length == 0) {
+            return new ByteBuffer[0];
+        }
+        int componentId = toComponentIndex(index);
 
         List<ByteBuffer> buffers = new ArrayList<ByteBuffer>(components.size());
 

buffer/src/test/java/io/netty/buffer/AbstractCompositeChannelBufferTest.java

@@ -410,4 +410,11 @@ public abstract class AbstractCompositeChannelBufferTest extends
                 wrappedBuffer(new byte[] { 0, 1, 2, 3, 4, 6, 7, 8, 5, 9, 10, 11 }, 6, 5).order(order));
         assertFalse(ByteBufUtil.equals(a, b));
     }
+
+    @Test 
+    public void testEmptyBuffer() {
+        ByteBuf b = wrappedBuffer(new byte[] {1, 2}, new byte[] {3, 4});
+        b.readBytes(new byte[4]);
+        b.readBytes(new byte[0]);
+    }
 }