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#
# Copyright 2005,2007 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 GNU Radio; see the file COPYING. If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
#
from gnuradio import gr
from hexint import *
import struct
def gen_and_append_crc32(s):
crc = gr.crc32(s)
return s + struct.pack(">I", hexint(crc) & 0xFFFFFFFF)
def check_crc32(s):
if len(s) < 4:
return (False, '')
msg = s[:-4]
#print "msg = '%s'" % (msg,)
actual = gr.crc32(msg)
(expected,) = struct.unpack(">I", s[-4:])
# print "actual =", hex(actual), "expected =", hex(expected)
return (actual == expected, msg)
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