Forgot to add types.py (from the mlat_server branch).

python/types.py

@@ -0,0 +1,103 @@
+#
+# Copyright 2013 Nick Foster
+# 
+# This file is part of gr-air-modes
+# 
+# gr-air-modes is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# gr-air-modes is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with gr-air-modes; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+from collections import namedtuple
+
+#this is a timestamp that preserves precision when used with UTC timestamps.
+#ordinary double-precision timestamps lose significant fractional precision
+#when the exponent is as large as necessary for UTC.
+class stamp:
+    def __init__(self, secs, frac_secs):
+        self.secs = secs
+        self.frac_secs = frac_secs
+        self.secs += int(self.frac_secs)
+        self.frac_secs -= int(self.frac_secs)
+    def __lt__(self, other):
+        if isinstance(other, self.__class__):
+            if self.secs == other.secs:
+                return self.frac_secs < other.frac_secs
+            else:
+                return self.secs < other.secs
+        elif isinstance(other, float):
+            return float(self) > other
+        else:
+            raise TypeError
+    def __gt__(self, other):
+        if type(other) is type(self):
+            if self.secs == other.secs:
+                return self.frac_secs > other.frac_secs
+            else:
+                return self.secs > other.secs
+        elif type(other) is type(float):
+            return float(self) > other
+        else:
+            raise TypeError
+    def __eq__(self, other):
+        if isinstance(other, self.__class__):
+            return self.secs == other.secs and self.frac_secs == other.frac_secs
+        elif isinstance(other, float):
+            return float(self) == other
+        else:
+            raise TypeError
+    def __ne__(self, other):
+        return not (self == other)
+    def __le__(self, other):
+        return (self == other) or (self < other)
+    def __ge__(self, other):
+        return (self == other) or (self > other)
+
+    def __add__(self, other):
+        if isinstance(other, self.__class__):
+            ipart = self.secs + other.secs
+            fpart = self.frac_secs + other.frac_secs
+            return stamp(ipart, fpart)
+        elif isinstance(other, float) or isinstance(other, int):
+            return float(self) + other
+        else:
+            raise TypeError
+            
+    def __sub__(self, other):
+        if isinstance(other, self.__class__):
+            ipart = self.secs - other.secs
+            fpart = self.frac_secs - other.frac_secs
+            return stamp(ipart, fpart)
+        elif isinstance(other, float) or isinstance(other, int):
+            return float(self) - other
+        else:
+            raise TypeError
+
+    #to ensure we don't hash by stamp
+    #TODO fixme with a reasonable hash in case you feel like you'd hash by stamp
+    __hash__ = None
+    
+    #good to within ms for comparison
+    def __float__(self):
+        return self.secs + self.frac_secs
+
+    def __str__(self):
+        return "%f" % float(self)
+
+#a Mode S report including the modes_reply data object
+modes_report = namedtuple('modes_report', ['data', 'ecc', 'rssi', 'timestamp'])
+#lat, lon, alt
+#TODO: a position class internally represented as ECEF XYZ which can easily be used for multilateration and distance calculation
+llh = namedtuple('llh', ['lat', 'lon', 'alt'])
+mlat_report = namedtuple('mlat_report', ['data', 'nreps', 'timestamp', 'llh', 'hdop', 'vdop'])