Add helper method that allows to create a ChannelBuffer out of a hex dump String. See #449

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

@@ -867,6 +867,19 @@ public final class ChannelBuffers {
         return new ReadOnlyChannelBuffer(buffer);
     }
 
+    /**
+     * Create a {@link ChannelBuffer} from the given <a href="http://en.wikipedia.org/wiki/Hex_dump">hex dump</a>
+     */
+    public static ChannelBuffer hexDump(String hexString) {
+        int len = hexString.length();
+        byte[] hexData = new byte[len / 2];
+        for (int i = 0; i < len; i += 2) {
+            hexData[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4)
+                                 + Character.digit(hexString.charAt(i + 1), 16));
+        }
+        return wrappedBuffer(hexData);
+    }
+
     /**
      * Returns a <a href="http://en.wikipedia.org/wiki/Hex_dump">hex dump</a>
      * of the specified buffer's readable bytes.

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

@@ -28,6 +28,7 @@ import java.util.Map;
 import java.util.Map.Entry;
 
 import org.easymock.EasyMock;
+import org.jboss.netty.util.CharsetUtil;
 import org.junit.Test;
 
 /**
@@ -425,4 +426,18 @@ public class ChannelBuffersTest {
             // Expected
         }
     }
+    
+    /**
+     * Test for https://github.com/netty/netty/issues/449
+     */
+    @Test
+    public void testHexDumpOperations() {
+        ChannelBuffer buffer = ChannelBuffers.copiedBuffer("This is some testdata", CharsetUtil.ISO_8859_1);
+        String hexDump = ChannelBuffers.hexDump(buffer);
+        ChannelBuffer buffer2 = ChannelBuffers.hexDump(hexDump);
+        assertEquals(buffer, buffer2);
+        
+        String hexDump2 = ChannelBuffers.hexDump(buffer2);
+        assertEquals(hexDump, hexDump2);
+    }
 }