Diff: device/GPSTracker.cpp

Revision:

1:cac9b2960637

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/device/GPSTracker.cpp	Sun Feb 15 22:04:12 2015 +0000
@@ -0,0 +1,74 @@
+#include "GPSTracker.h"
+#include <stdlib.h>
+#include <string.h>
+
+GPSTracker::GPSTracker(GPSI2C& gps) :
+    _gps(gps),
+    _thread(GPSTracker::thread_func, this),
+    _positionSet(false)
+{
+}
+
+bool GPSTracker::position(GPSTracker::Position *position)
+{
+    bool result;
+    
+    _mutex.lock();
+    if (_positionSet) {
+        memcpy(position, &_position, sizeof(GPSTracker::Position));
+        _positionSet = false;
+        result = true;
+    } else {
+        result = false;
+    }
+    _mutex.unlock();
+    
+    return result;
+}
+
+void GPSTracker::thread()
+{
+    char buf[256], chr; // needs to be that big otherwise mdm isn't working
+    int ret, len, n;
+    double altitude, latitude, longitude;
+    
+    while (true) {
+        ret = _gps.getMessage(buf, sizeof(buf));
+        if (ret <= 0) {
+            Thread::wait(100);
+            continue;
+        }
+        
+        len = LENGTH(ret);
+        if ((PROTOCOL(ret) != GPSParser::NMEA) || (len <= 6))
+            continue;
+
+        // we're only interested in fixed GPS positions
+        // we are not interested in invalid data
+        if ((strncmp("$GPGGA", buf, 6) != 0) ||
+            (!_gps.getNmeaItem(6, buf, len, n, 10)) || (n == 0))
+            continue;
+        
+        // get altitude, latitude and longitude
+        if ((!_gps.getNmeaAngle(2, buf, len, latitude)) ||
+            (!_gps.getNmeaAngle(4, buf, len, longitude)) ||
+            (!_gps.getNmeaItem(9, buf, len, altitude)) ||
+            (!_gps.getNmeaItem(10, buf, len, chr)) ||
+            (chr != 'M'))
+            continue;
+
+        _mutex.lock();
+        _position.altitude = altitude;
+        _position.latitude = latitude;
+        _position.longitude = longitude;
+        _positionSet = true;
+        _mutex.unlock();
+    }
+}
+
+void GPSTracker::thread_func(void const *arg)
+{
+    GPSTracker *that;
+    that = (GPSTracker*)arg;
+    that->thread();
+}