fix incorrect caputation of timestamp in some cases

aprslib/parsing/common.py

@@ -1,5 +1,4 @@
 import re
-import time
 from datetime import datetime
 from aprslib import base91
 from aprslib.exceptions import ParseError
@@ -100,8 +99,7 @@ def parse_timestamp(body, packet_type=''):
                 else:
                     timestamp = "19700101000000"
 
-                timestamp = utc.strptime(timestamp, "%Y%m%d%H%M%S")
-                timestamp = time.mktime(timestamp.timetuple())
+                timestamp = int((utc.strptime(timestamp, "%Y%m%d%H%M%S") - datetime(1970, 1, 1)).total_seconds())
             except Exception as exp:
                 timestamp = 0
                 logger.debug(exp)

tests/test_parse_common.py

@@ -2,7 +2,6 @@ import unittest2 as unittest
 import string
 from random import randint, randrange, sample
 from datetime import datetime
-import time
 
 from aprslib import base91
 from aprslib.parsing.common import *
@@ -180,7 +179,7 @@ class TimestampTC(unittest.TestCase):
 
     def test_timestamp_valid(self):
         date = datetime.utcnow()
-        timestamp = time.mktime(date.timetuple())
+        timestamp = int((date - datetime(1970, 1, 1)).total_seconds())
 
         # hhmmss format
         body = date.strftime("%H%M%Shtext")