1 files changed, 41 insertions, 57 deletions

diff --git a/src/net/sourceforge/opentracking/protocol/xexun/XexunFrameDecoder.java b/src/net/sourceforge/opentracking/protocol/xexun/XexunFrameDecoder.java
index be0a92dc6..d864b10ba 100644
--- a/src/net/sourceforge/opentracking/protocol/xexun/XexunFrameDecoder.java
+++ b/src/net/sourceforge/opentracking/protocol/xexun/XexunFrameDecoder.java
@@ -16,82 +16,66 @@ import org.jboss.netty.buffer.ChannelBuffer;
  */
 public class XexunFrameDecoder extends FrameDecoder {
 
-    protected Object decode(
-            ChannelHandlerContext ctx,
-            Channel channel,
-            ChannelBuffer buf) throws Exception {
-
-        //System.out.println("read: " + buf.readableBytes());
-
-        // Check minimum length
-        int length = buf.readableBytes();
-        if (length < 100) {
-            return null;
-        }
+    /**
+     * Find string in network buffer
+     */
+    private static Integer find(
+            ChannelBuffer buf,
+            Integer start,
+            Integer length,
+            String subString) {
+
+        int index = start;
+        boolean match;
 
-        // Find identifier
-        int index = 0;
-        int countDigit = 0;
         for (; index < length; index++) {
-
-            // Check byte
-            char c = (char) buf.getByte(index);
-            if (Character.isDigit(c)) {
-                countDigit++;
+            match = true;
+
+            for (int i = 0; i < subString.length(); i++) {
+                char c = (char) buf.getByte(index + i);
+                if (c != subString.charAt(i)) {
+                    match = false;
+                    break;
+                }
             }
 
-            // Check count
-            if (countDigit == 10) {
-                break;
+            if (match) {
+                return index;
             }
         }
 
-        if (countDigit < 10) {
-            return null;
-        }
+        return null;
+    }
 
-        // Find begin
-        int beginIndex = 0;
-        for (; index < length; index++) {
+    protected Object decode(
+            ChannelHandlerContext ctx,
+            Channel channel,
+            ChannelBuffer buf) throws Exception {
 
-            char c = (char) buf.getByte(index);
-            if (c == ',') {
-                beginIndex = index;
-                break;
-            }
-        }
+        System.out.println("read: " + buf.readableBytes());
+        System.out.println("buffer: " + buf.toString("UTF-8"));
 
-        if (beginIndex == 0) {
+        // Check minimum length
+        int length = buf.readableBytes();
+        if (length < 100) {
             return null;
         }
 
-        // Find imei
-        int imeiIndex = 0;
-        for (; index < length; index++) {
-
-            char c = (char) buf.getByte(index);
-            if (c == ':') {
-                imeiIndex = index;
-                break;
-            }
+        // Find start
+        Integer beginIndex = find(buf, 0, length, "GPRMC");
+        if (beginIndex == null) {
+            return null;
         }
 
-        if (imeiIndex == 0) {
+        // Find identifier
+        Integer idIndex = find(buf, beginIndex, length, "imei:");
+        if (idIndex == null) {
             return null;
         }
 
         // Find end
-        int endIndex = 0;
-        for (; index < length; index++) {
-
-            char c = (char) buf.getByte(index);
-            if (c == ',') {
-                endIndex = index;
-                break;
-            }
-        }
-
-        if (endIndex == 0) {
+        Integer endIndex = find(buf, idIndex, length, ",");
+        if (endIndex == null) {
             return null;
         }