Improve compatibility with megastek devices

Megastek devices send some data which either is not
fully compliant with the megastek protocol (by omitting
some data) or which is (for our purposes) garbage data,
which is only delimited with a single LF (0x0A).

4 files changed, 32 insertions, 14 deletions

diff --git a/src/main/java/org/traccar/protocol/MegastekFrameDecoder.java b/src/main/java/org/traccar/protocol/MegastekFrameDecoder.java
index 347fa24b1..a4091436c 100644
--- a/src/main/java/org/traccar/protocol/MegastekFrameDecoder.java
+++ b/src/main/java/org/traccar/protocol/MegastekFrameDecoder.java
@@ -46,6 +46,9 @@ public class MegastekFrameDecoder extends BaseFrameDecoder {
             if (delimiter == -1) {
                 delimiter = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '!');
             }
+            if (delimiter == -1) {
+                delimiter = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '\n');
+            }
             if (delimiter != -1) {
                 ByteBuf result = buf.readRetainedSlice(delimiter - buf.readerIndex());
                 buf.skipBytes(1);
diff --git a/src/main/java/org/traccar/protocol/MegastekProtocolDecoder.java b/src/main/java/org/traccar/protocol/MegastekProtocolDecoder.java
index f0c0df8a6..2ce5b9dae 100644
--- a/src/main/java/org/traccar/protocol/MegastekProtocolDecoder.java
+++ b/src/main/java/org/traccar/protocol/MegastekProtocolDecoder.java
@@ -141,6 +141,9 @@ public class MegastekProtocolDecoder extends BaseProtocolDecoder {
 
             beginIndex = endIndex + 2;
             endIndex = sentence.indexOf('*', beginIndex) + 3;
+            if (beginIndex > endIndex) {
+                return null;
+            }
             location = sentence.substring(beginIndex, endIndex);
 
             beginIndex = endIndex + 1;
@@ -243,13 +246,13 @@ public class MegastekProtocolDecoder extends BaseProtocolDecoder {
             .number("dd,")
             .number("(dd),")                     // satellites
             .number("dd,")
-            .number("(d+.d+),")                  // hdop
+            .number("(d+.d+)?,")                 // hdop
             .number("(d+.d+)?,")                 // speed
             .number("(d+.d+)?,")                 // course
             .number("(-?d+.d+)?,")               // altitude
             .number("(d+.d+)?,")                 // odometer
-            .number("(d+),")                     // mcc
-            .number("(d+),")                     // mnc
+            .number("(d+)?,")                    // mcc
+            .number("(d+)?,")                    // mnc
             .number("(xxxx)?,")                  // lac
             .number("(x+)?,")                    // cid
             .number("(d+)?,")                    // gsm
@@ -276,7 +279,7 @@ public class MegastekProtocolDecoder extends BaseProtocolDecoder {
             .groupEnd("?").text(",")
             .number("(d+)?,")                    // rfid
             .number("([01])(d)?").optional()     // charge and belt status
-            .expression("[^,]*,").optional()
+            .expression("[^,]*,")
             .number("(d+)?,")                    // battery
             .expression("([^,]*)[,;]")           // alert
             .any()
@@ -318,17 +321,19 @@ public class MegastekProtocolDecoder extends BaseProtocolDecoder {
             position.set(Position.KEY_ODOMETER, parser.nextDouble(0) * 1000);
         }
 
-        int mcc = parser.nextInt();
-        int mnc = parser.nextInt();
-        Integer lac = parser.nextHexInt();
-        Integer cid = parser.nextHexInt();
-        Integer rssi = parser.nextInt();
-        if (lac != null && cid != null) {
-            CellTower tower = CellTower.from(mcc, mnc, lac, cid);
-            if (rssi != null) {
-                tower.setSignalStrength(rssi);
+        if (parser.hasNext(5)) {
+            int mcc = parser.nextInt();
+            int mnc = parser.nextInt();
+            Integer lac = parser.nextHexInt();
+            Integer cid = parser.nextHexInt();
+            Integer rssi = parser.nextInt();
+            if (lac != null && cid != null) {
+                CellTower tower = CellTower.from(mcc, mnc, lac, cid);
+                if (rssi != null) {
+                    tower.setSignalStrength(rssi);
+                }
+                position.setNetwork(new Network(tower));
             }
-            position.setNetwork(new Network(tower));
         }
 
         if (parser.hasNext(5)) {
diff --git a/src/test/java/org/traccar/protocol/MegastekFrameDecoderTest.java b/src/test/java/org/traccar/protocol/MegastekFrameDecoderTest.java
index f1650b1b2..19e5cb0ab 100644
--- a/src/test/java/org/traccar/protocol/MegastekFrameDecoderTest.java
+++ b/src/test/java/org/traccar/protocol/MegastekFrameDecoderTest.java
@@ -22,6 +22,10 @@ public class MegastekFrameDecoderTest extends ProtocolTest {
                 binary("53545832363034373520202020202020202020024f244750524d432c3133313131302e30302c562c2c2c2c2c2c2c3036303931332c2c2c4e2a37362c3232322c30312c383135412c443435352c31312c39372c303030302c303030312c302c54696d65723b3735"),
                 decoder.decode(null, null, binary("53545832363034373520202020202020202020024f244750524d432c3133313131302e30302c562c2c2c2c2c2c2c3036303931332c2c2c4e2a37362c3232322c30312c383135412c443435352c31312c39372c303030302c303030312c302c54696d65723b37350d0a")));
 
+        verifyFrame(
+                binary("636d643d6169643b757365723d2a2a2a3b7077643d2a2a2a3b6c61743d33382e35353239353338333b6c6f6e3d32312e30353337343530303b706163633d31303030"),
+                decoder.decode(null, null, binary("636d643d6169643b757365723d2a2a2a3b7077643d2a2a2a3b6c61743d33382e35353239353338333b6c6f6e3d32312e30353337343530303b706163633d313030300a")));
+
     }
 
 }
diff --git a/src/test/java/org/traccar/protocol/MegastekProtocolDecoderTest.java b/src/test/java/org/traccar/protocol/MegastekProtocolDecoderTest.java
index 3c8377b51..83d62e766 100644
--- a/src/test/java/org/traccar/protocol/MegastekProtocolDecoderTest.java
+++ b/src/test/java/org/traccar/protocol/MegastekProtocolDecoderTest.java
@@ -10,6 +10,12 @@ public class MegastekProtocolDecoderTest extends ProtocolTest {
     public void testDecode() throws Exception {
 
         var decoder = new MegastekProtocolDecoder(null);
+        
+        verifyPosition(decoder, text(
+                "$MGV002,860719020193193,,S,070521,160748,V,2255.09165,N,11404.01322,E,00,00,00,,,,,,,,,,,,,,,,,,,10,015,Restart;!"));
+
+        verifyPosition(decoder, text(
+                "$MGV002,860719020193193,,R,070621,115717,V,2255.09165,N,11404.01322,E,00,00,00,99.9,,,,,460,07,262C,0F54,20,,,,,,,,,10,039,Timer;!"));
 
         verifyPosition(decoder, text(
                 "0132$MGV002,869152024261561,,S,310818,133945,V,3814.35442,N,02144.50662,E,00,00,00,99.9,,,44.2,,202,10,,,13,0,0,0,0,90,,,,11,100,Timer;!"));