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#
# Copyright 2007 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# GNU Radio 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.
#
# GNU Radio 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 this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
import struct
FL_OVERRUN = 0x80000000
FL_UNDERRUN = 0x40000000
FL_DROPPED = 0x20000000
FL_END_OF_BURST = 0x10000000
FL_START_OF_BURST = 0x08000000
FL_ALL_FLAGS = 0xf8000000
FL_OVERRUN_SHIFT = 31
FL_UNDERRUN_SHIFT = 30
FL_DROPPED_SHIFT = 29
FL_END_OF_BURST_SHIFT = 28
FL_START_OF_BURST_SHIFT = 27
RSSI_MASK = 0x3f
RSSI_SHIFT = 21
CHAN_MASK = 0x1f
CHAN_SHIFT = 16
TAG_MASK = 0xf
TAG_SHIFT = 9
PAYLOAD_LEN_MASK = 0x1ff
PAYLOAD_LEN_SHIFT = 0
def make_header(flags, chan, payload_len, timestamp, rssi=0, tag=0):
word0 = ((flags & FL_ALL_FLAGS)
| ((rssi & RSSI_MASK) << RSSI_SHIFT)
| ((chan & CHAN_MASK) << CHAN_SHIFT)
| ((tag & TAG_MASK) << TAG_SHIFT)
| ((payload_len & PAYLOAD_LEN_MASK) << PAYLOAD_LEN_SHIFT))
word1 = timestamp
return struct.pack('<2I', word0, word1)
def _decode(pred, indicator):
if pred:
return indicator
else:
return '-'
class usb_packet(object):
def __init__(self, raw_pkt):
assert isinstance(raw_pkt, str) and len(raw_pkt) == 512
self._raw_pkt = raw_pkt;
(self._word0, self._word1) = struct.unpack('<2I', self._raw_pkt[0:8])
def timestamp(self):
return self._word1
def rssi(self):
return (self._word0 >> RSSI_SHIFT) & RSSI_MASK
def chan(self):
return (self._word0 >> CHAN_SHIFT) & CHAN_MASK
def tag(self):
return (self._word0 >> TAG_SHIFT) & TAG_MASK
def payload_len(self):
return (self._word0 >> PAYLOAD_LEN_SHIFT) & PAYLOAD_LEN_MASK
def flags(self):
return self._word0 & FL_ALL_FLAGS
def overrun(self):
return (self._word0 >> FL_OVERRUN_SHIFT) & 0x1
def underrun(self):
return (self._word0 >> FL_UNDERRUN_SHIFT) & 0x1
def start_of_burst(self):
return (self._word0 >> FL_START_OF_BURST_SHIFT) & 0x1
def end_of_burst(self):
return (self._word0 >> FL_END_OF_BURST_SHIFT) & 0x1
def dropped(self):
return (self._word0 >> FL_DROPPED_SHIFT) & 0x1
def payload(self):
return self._raw_pkt[8:8+self.payload_len()]
def decoded_flags(self):
s = (_decode(self.overrun(), 'O')
+ _decode(self.underrun(), 'U')
+ _decode(self.dropped(), 'D')
+ _decode(self.end_of_burst(), 'E')
+ _decode(self.start_of_burst(), 'S'))
return s
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