examples: add example that extracts gps raw data from a log file

examples/canlog2gps.py

@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+import dronecan
+import sys
+# progress bar
+from tqdm import tqdm
+
+if len(sys.argv) != 4:
+    print("Usage: python3 canlog2gps.py <messageName> <logfile> <outputfile>")
+    sys.exit(1)
+
+# Create a CAN bus instance
+global node
+print('Starting server as Node ID', 10)
+
+filename = sys.argv[2]
+out_file = open(sys.argv[3],'wb')
+node = dronecan.make_node("filein:"+filename, node_id=10, bitrate=1000000,speedup=-1)
+
+def handle_Data(msg):
+    # dump the message data to a file
+    out_file.write(msg.message.data.to_bytes())
+
+# message type by key name
+message_type = getattr(dronecan.ardupilot.gnss, sys.argv[1])
+node.add_handler(message_type, handle_Data)
+
+# progress bar
+pbar = tqdm(total=100)
+
+while True:
+    try:
+        node.spin(0.001)
+        # print(node.can_driver.stream_progress())
+        # show the progress of the stream
+        pbar.update(node.can_driver.stream_progress() - pbar.n)
+        if node.can_driver.end_of_stream():
+            print('End of stream')
+            out_file.flush()
+            out_file.close()
+            sys.exit(0)
+    except KeyboardInterrupt:
+        out_file.flush()
+        out_file.close()
+        sys.exit(0)