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#!/usr/bin/env python2
#
# Read an EDI dump file and transmit over UDP
#
# The MIT License (MIT)
#
# Copyright (c) 2015 Matthias P. Braendli
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
import sys
import struct
from crc import crc16
from reedsolo import RSCodec
import socket
import time
UDP_IP = "239.20.64.1"
UDP_PORT = 12002
class BufferedFile:
def __init__(self, fname):
self.buf = []
if fname == "-":
self.fd = sys.stdin
else:
self.fd = open(fname, "rb")
def read(self, n):
if not self.buf:
return self.fd.read(n)
else:
if len(self.buf) < n:
self.buf.extend(self.fd.read(n - len(self.buf)))
if len(self.buf) == n:
ret = b"".join(self.buf)
self.buf = []
else:
ret = b"".join(self.buf[:n])
del self.buf[:n]
return ret
def peek(self, n):
dat = self.fd.read(n)
self.buf.extend(dat)
return dat
pft_head_struct = "!2sH3B3BH"
pft_rs_head_struct = "!2B"
pft_addr_head_struct = "!2H"
af_head_struct = "!2sLHBc"
class EDI:
def __init__(self):
self.last_send_time = time.time()
self.sock = socket.socket(socket.AF_INET, # Internet
socket.SOCK_DGRAM) # UDP
def send_udp(self, message):
self.sock.sendto(message, (UDP_IP, UDP_PORT))
def decode(self, stream):
sync = stream.peek(2)
if len(sync) < 2:
return False
if sync == "PF":
return self.decode_pft(stream)
elif sync == "AF":
return self.decode_af(stream, is_stream=True)
def decode_pft(self, stream):
headerdata = stream.read(12)
header = struct.unpack(pft_head_struct, headerdata)
psync, pseq, findex1, findex2, findex3, fcount1, fcount2, fcount3, fec_ad_plen = header
findex = (findex1 << 16) | (findex2 << 8) | findex3
fcount = (fcount1 << 16) | (fcount2 << 8) | fcount3
fec = (fec_ad_plen & 0x8000) != 0x00
addr = (fec_ad_plen & 0x4000) != 0x00
plen = fec_ad_plen & 0x3FFF
rs_k = 0
rs_z = 0
if fec:
rs_head = stream.read(2)
rs_k, rs_z = struct.unpack(pft_rs_head_struct, rs_head)
headerdata += rs_head
addr_source = 0
addr_dest = 0
if addr:
addr_head = stream.read(4)
addr_source, addr_dest = struct.unpack(pft_addr_head_struct, addr_head)
headerdata += addr_head
# read CRC
crc_data = stream.read(2)
crc = struct.unpack("!H", crc_data)[0]
crc_calc = crc16(headerdata)
crc_calc ^= 0xFFFF
crc_ok = crc_calc == crc
time_now = time.time()
if findex == 0:
if self.last_send_time + 24e-3 > time_now:
delay = self.last_send_time + 24e-3 - time_now
print("Sleeping for {} ms".format(1000 * delay))
time.sleep(delay)
self.last_send_time = time_now
if crc_ok:
payload = stream.read(plen)
self.send_udp(headerdata + crc_data + payload)
return crc_ok
def decode_af(self, in_data, is_stream=False):
if is_stream:
headerdata = in_data.read(10)
else:
headerdata = in_data[:10]
sync, plen, seq, ar, pt = struct.unpack(af_head_struct, headerdata)
if sync != "AF":
return False
crc_flag = (ar & 0x80) != 0x00
revision = ar & 0x7F
if is_stream:
payload = in_data.read(plen)
crc_data = in_data.read(2)
crc = struct.unpack("!H", crc_data)[0]
else:
payload = in_data[10:10+plen]
crc_data = in_data[10+plen:10+plen+2]
crc = struct.unpack("!H", crc_data)[0]
crc_calc = crc16(headerdata)
crc_calc = crc16(payload, crc_calc)
crc_calc ^= 0xFFFF
crc_ok = crc_calc == crc
if crc_ok:
self.send_udp(headerdata + payload + crc_data)
return crc_ok
if len(sys.argv) > 1:
filename = sys.argv[1]
edi_fd = BufferedFile(filename)
else:
edi_fd = BufferedFile("-")
edi = EDI()
while edi.decode(edi_fd):
pass
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