2 files changed, 9 insertions, 5 deletions
diff --git a/src/org/traccar/helper/ChannelBufferTools.java b/src/org/traccar/helper/ChannelBufferTools.java
index ef9384138..1ebe89666 100644
--- a/src/org/traccar/helper/ChannelBufferTools.java
+++ b/src/org/traccar/helper/ChannelBufferTools.java
@@ -24,7 +24,11 @@ import org.traccar.protocol.IntellitracFrameDecoder;
  * ChannelBuffer helper methods
  */
 public class ChannelBufferTools {
-    
+
+    public static Integer find(ChannelBuffer buf, int start, String subString) {
+        return find(buf, start, buf.readerIndex() + buf.readableBytes(), subString);
+    }
+
     /**
      * Find string in network buffer
      */
diff --git a/src/org/traccar/protocol/XexunFrameDecoder.java b/src/org/traccar/protocol/XexunFrameDecoder.java
index 1b3446ff9..60fa02696 100644
--- a/src/org/traccar/protocol/XexunFrameDecoder.java
+++ b/src/org/traccar/protocol/XexunFrameDecoder.java
@@ -36,22 +36,22 @@ public class XexunFrameDecoder extends FrameDecoder {
         }
 
         // Find start
-        Integer beginIndex = ChannelBufferTools.find(buf, 0, length, "GPRMC");
+        Integer beginIndex = ChannelBufferTools.find(buf, buf.readerIndex(), "GPRMC");
         if (beginIndex == null) {
-            beginIndex = ChannelBufferTools.find(buf, 0, length, "GNRMC");
+            beginIndex = ChannelBufferTools.find(buf, buf.readerIndex(), "GNRMC");
             if (beginIndex == null) {
                 return null;
             }
         }
 
         // Find identifier
-        Integer idIndex = ChannelBufferTools.find(buf, beginIndex, length, "imei:");
+        Integer idIndex = ChannelBufferTools.find(buf, beginIndex, "imei:");
         if (idIndex == null) {
             return null;
         }
 
         // Find end
-        Integer endIndex = ChannelBufferTools.find(buf, idIndex, length, ",");
+        Integer endIndex = ChannelBufferTools.find(buf, idIndex, ",");
         if (endIndex == null) {
             return null;
         }