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#
# 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):
return self + stamp(0, other)
elif isinstance(other, int):
return self + stamp(other, 0)
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):
return self - stamp(0, other)
elif isinstance(other, int):
return self - stamp(other, 0)
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'])
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