Added GpsGate protocol (fix #138)

1 files changed, 10 insertions, 0 deletions

diff --git a/src/org/traccar/helper/Crc.java b/src/org/traccar/helper/Crc.java
index cef0cc482..a7adca874 100644
--- a/src/org/traccar/helper/Crc.java
+++ b/src/org/traccar/helper/Crc.java
@@ -16,6 +16,7 @@
 package org.traccar.helper;
 
 import java.nio.ByteBuffer;
+import java.nio.charset.Charset;
 
 /**
  * CRC functions
@@ -126,5 +127,14 @@ public class Crc {
     public static int crc16CcittSeed(ByteBuffer buf, int seed) {
         return crc16Reflected(buf, seed, crc16CcittTableReverse) ^ crc16CcittXorout;
     }
+    
+    public static String nmeaChecksum(String msg) {
+        int checksum = 0;
+        byte bytes[] = msg.getBytes(Charset.defaultCharset());
+        for (int i = 1; i < msg.length(); i++) {
+            checksum ^= bytes[i];
+        }
+        return String.format("*%02x", checksum).toUpperCase();
+    }
 
 }