From 90ddc7b95e3879c20d6d8f7e8b96df87e0ec1f66 Mon Sep 17 00:00:00 2001
From: Anton Tananaev <anton.tananaev@gmail.com>
Date: Thu, 16 Jul 2020 19:52:16 -0700
Subject: Fix coordinates decoding

---
 src/main/java/org/traccar/protocol/NiotProtocolDecoder.java  | 12 ++++++++++--
 .../java/org/traccar/protocol/NiotProtocolDecoderTest.java   |  4 ++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/main/java/org/traccar/protocol/NiotProtocolDecoder.java b/src/main/java/org/traccar/protocol/NiotProtocolDecoder.java
index 81b6efc91..58de0d38f 100644
--- a/src/main/java/org/traccar/protocol/NiotProtocolDecoder.java
+++ b/src/main/java/org/traccar/protocol/NiotProtocolDecoder.java
@@ -24,6 +24,7 @@ import org.traccar.DeviceSession;
 import org.traccar.NetworkMessage;
 import org.traccar.Protocol;
 import org.traccar.helper.BcdUtil;
+import org.traccar.helper.BitUtil;
 import org.traccar.helper.Checksum;
 import org.traccar.helper.DateBuilder;
 import org.traccar.helper.UnitsConverter;
@@ -55,6 +56,12 @@ public class NiotProtocolDecoder extends BaseProtocolDecoder {
         }
     }
 
+    private double readCoordinate(ByteBuf buf) {
+        long value = buf.readUnsignedInt();
+        double result = BitUtil.to(value, 31) / 1800000.0;
+        return BitUtil.check(value, 31) ? -result : result;
+    }
+
     @Override
     protected Object decode(
             Channel channel, SocketAddress remoteAddress, Object msg) throws Exception {
@@ -88,8 +95,9 @@ public class NiotProtocolDecoder extends BaseProtocolDecoder {
                     .setSecond(BcdUtil.readInteger(buf, 2));
             position.setTime(dateBuilder.getDate());
 
-            position.setLatitude(BcdUtil.readCoordinate(buf));
-            position.setLongitude(BcdUtil.readCoordinate(buf));
+            position.setValid(true);
+            position.setLatitude(readCoordinate(buf));
+            position.setLongitude(readCoordinate(buf));
             position.setSpeed(UnitsConverter.knotsFromKph(BcdUtil.readInteger(buf, 4)));
             position.setCourse(BcdUtil.readInteger(buf, 4));
 
diff --git a/src/test/java/org/traccar/protocol/NiotProtocolDecoderTest.java b/src/test/java/org/traccar/protocol/NiotProtocolDecoderTest.java
index 8787e8c51..e436fb4ed 100644
--- a/src/test/java/org/traccar/protocol/NiotProtocolDecoderTest.java
+++ b/src/test/java/org/traccar/protocol/NiotProtocolDecoderTest.java
@@ -10,6 +10,10 @@ public class NiotProtocolDecoderTest extends ProtocolTest {
 
         NiotProtocolDecoder decoder = new NiotProtocolDecoder(null);
 
+        verifyPosition(decoder, binary(
+                "585880004c08675430347318522007161451458024b28003f566ee00000328f8000748217ffc500729007a280000000000160001383932353430323130363431363738373136323100050002004e00570d"),
+                position("2020-07-16 14:51:45.000", true, -1.33611, 36.89684));
+
         verifyPosition(decoder, binary(
                 "585880004c08675430355777182005201100468024121b03f390ba00000105f8000b8d207ffc5f0f290084500000000000160001383932353430323130363431363839323430303700050002004e55940d"));
 
-- 
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