def packets_gen(data, chaninfos, packet_filter):
i = 0
while data:
pheader_len, pheader = unwrap(data, PACKET_HEADER)
type = header_type(pheader)
if packet_filter == '*' or type == packet_filter.lower():
if type == 'sonar':
sheader_len, sheader = unwrap(data[pheader_len:],
SONAR_HEADER, 'XTFPINGHEADER')
assert pheader_len + sheader_len == 256
assert pheader['num_chans_to_follow'] <= 6
if pheader['num_chans_to_follow'] > 1:
raise NotImplementedError('Multiple channels in a packet')
cheader_len, cheader = unwrap(data[pheader_len + sheader_len:],
SONAR_CHANNEL_HEADER,
'XTFPINGCHANHEADER')
assert cheader_len == 64
dstart = (pheader_len + sheader_len +
cheader_len * pheader['num_chans_to_follow'])
n = cheader['num_samples']
s = chaninfos[cheader['channel_number']]['bytes_per_sample']
raw_trace = data[dstart:dstart+s*n].tobytes()
trace = np.frombuffer(raw_trace, {1: np.int8, 2: np.int16}[s])
yield SonarPacket(pheader, sheader, cheader, trace, raw_trace)
#elif type == 'notes':
# nheader_len, nheader = unwrap(data[pheader_len:],
# """H year
# B month
# B day
# B hour
# B minute
# B second
# 35s reserved
# 200s notes_text
# """)
# pprint(nheader)
# assert nheader_len + pheader_len == \
# pheader['num_bytes_this_record']
else:
yield Packet(pheader, data[:pheader['num_bytes_this_record']])
sys.stdout.write('Packet: %d\r' % i)
# only the last message is shown without flush(), but flushing too
# often slows things down
if i % 42 == 0:
sys.stdout.flush()
data = data[pheader['num_bytes_this_record']:]
i += 1
sys.stdout.write('\n')
def read_XTF(infile, packet_filter):
file_data = memoryview(open(infile, 'rb').read())
header_len, header = unwrap(file_data, HEADER, data_factory = OrderedDict)
nchannels = (header['number_of_sonar_channels'] +
header['number_of_bathymetry_channels'])
assert nchannels <= 6
chaninfos = []
for i in range(nchannels):
chaninfo_len, chaninfo = unwrap(file_data[header_len+i*CHANINFO_LEN:],
CHANINFO)
assert chaninfo_len == CHANINFO_LEN
chaninfos.append(chaninfo)
pstart = HEADER_LEN
return header, chaninfos, packets_gen(file_data[pstart:], chaninfos,
packet_filter)
