From 3ead0772172daeb3d6fedab5f04a32c33b9d5ebb Mon Sep 17 00:00:00 2001
From: anton2920 <anton2920@gmail.com>
Date: Sun, 24 Jul 2022 17:53:21 +0100
Subject: Added NMEA parser (that doesn't s**ck)

---
 src/main/java/org/traccar/helper/NMEA.java | 126 +++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 src/main/java/org/traccar/helper/NMEA.java

(limited to 'src/main/java/org/traccar')

diff --git a/src/main/java/org/traccar/helper/NMEA.java b/src/main/java/org/traccar/helper/NMEA.java
new file mode 100644
index 000000000..cae47a8f6
--- /dev/null
+++ b/src/main/java/org/traccar/helper/NMEA.java
@@ -0,0 +1,126 @@
+package org.traccar.helper;
+
+import java.util.HashMap;
+import java.util.Map;
+
+
+public class NMEA {
+
+    // fucking java interfaces
+    interface SentenceParser {
+        public boolean parse(String[] tokens, GPSPosition position);
+    }
+
+    // utils
+    static float Latitude2Decimal(String lat, String NS) {
+        float med = Float.parseFloat(lat.substring(2)) / 60.0f;
+        med += Float.parseFloat(lat.substring(0, 2));
+        if (NS.startsWith("S")) {
+            med = -med;
+        }
+        return med;
+    }
+
+    static float Longitude2Decimal(String lon, String WE) {
+        float med = Float.parseFloat(lon.substring(3)) / 60.0f;
+        med += Float.parseFloat(lon.substring(0, 3));
+        if (WE.startsWith("W")) {
+            med = -med;
+        }
+        return med;
+    }
+
+    // parsers
+    class GPGGA implements SentenceParser {
+        public boolean parse(String[] tokens, GPSPosition position) {
+            position.time = Float.parseFloat(tokens[1]);
+            position.lat = Latitude2Decimal(tokens[2], tokens[3]);
+            position.lon = Longitude2Decimal(tokens[4], tokens[5]);
+            position.quality = Integer.parseInt(tokens[6]);
+            position.altitude = Float.parseFloat(tokens[9]);
+            return true;
+        }
+    }
+
+    class GPGGL implements SentenceParser {
+        public boolean parse(String[] tokens, GPSPosition position) {
+            position.lat = Latitude2Decimal(tokens[1], tokens[2]);
+            position.lon = Longitude2Decimal(tokens[3], tokens[4]);
+            position.time = Float.parseFloat(tokens[5]);
+            return true;
+        }
+    }
+
+    class GPRMC implements SentenceParser {
+        public boolean parse(String[] tokens, GPSPosition position) {
+            position.time = Float.parseFloat(tokens[1]);
+            position.lat = Latitude2Decimal(tokens[3], tokens[4]);
+            position.lon = Longitude2Decimal(tokens[5], tokens[6]);
+            position.velocity = Float.parseFloat(tokens[7]);
+            position.dir = Float.parseFloat(tokens[8]);
+            return true;
+        }
+    }
+
+    class GPVTG implements SentenceParser {
+        public boolean parse(String[] tokens, GPSPosition position) {
+            position.dir = Float.parseFloat(tokens[3]);
+            return true;
+        }
+    }
+
+    class GPRMZ implements SentenceParser {
+        public boolean parse(String[] tokens, GPSPosition position) {
+            position.altitude = Float.parseFloat(tokens[1]);
+            return true;
+        }
+    }
+
+    public class GPSPosition {
+        public float time = 0.0f;
+        public float lat = 0.0f;
+        public float lon = 0.0f;
+        public boolean fixed = false;
+        public int quality = 0;
+        public float dir = 0.0f;
+        public float altitude = 0.0f;
+        public float velocity = 0.0f;
+
+        public void updatefix() {
+            fixed = quality > 0;
+        }
+
+        public String toString() {
+            return String.format("POSITION: lat: %f, lon: %f, time: %f, Q: %d, dir: %f, alt: %f, vel: %f", lat, lon, time, quality, dir, altitude, velocity);
+        }
+    }
+
+    GPSPosition position = new GPSPosition();
+
+    private static final Map<String, SentenceParser> sentenceParsers = new HashMap<String, SentenceParser>();
+
+    public NMEA() {
+        sentenceParsers.put("GPGGA", new GPGGA());
+        sentenceParsers.put("GPGGL", new GPGGL());
+        sentenceParsers.put("GPRMC", new GPRMC());
+        sentenceParsers.put("GPRMZ", new GPRMZ());
+        //only really good GPS devices have this sentence but ...
+        sentenceParsers.put("GPVTG", new GPVTG());
+    }
+
+    public GPSPosition parse(String line) {
+
+        if (line.startsWith("$")) {
+            String nmea = line.substring(1);
+            String[] tokens = nmea.split(",");
+            String type = tokens[0];
+            //TODO check crc
+            if (sentenceParsers.containsKey(type)) {
+                sentenceParsers.get(type).parse(tokens, position);
+            }
+            position.updatefix();
+        }
+
+        return position;
+    }
+}
-- 
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