# -*- coding: utf-8 -*-
"""
Module to hold and decode a SeedLink packet.
Part of Python implementation of libslink of Chad Trabant and
JSeedLink of Anthony Lomax
:copyright:
The ObsPy Development Team (devs@obspy.org) & Anthony Lomax
:license:
GNU Lesser General Public License, Version 3
(https://www.gnu.org/copyleft/lesser.html)
"""
from __future__ import (absolute_import, division, print_function,
unicode_literals)
from future.builtins import * # NOQA
import ctypes as C # NOQA
import numpy as np
from obspy.core.compatibility import from_buffer
from obspy.core.trace import Trace
from obspy.io.mseed.headers import clibmseed
from obspy.io.mseed.util import (_convert_msr_to_dict,
_ctypes_array_2_numpy_array,
_convert_mstime_to_datetime)
from .seedlinkexception import SeedLinkException
[docs]class SLPacket(object):
"""
Class to hold and decode a SeedLink packet.
:var TYPE_SLINFT: Packet type is terminated info packet.
:type TYPE_SLINFT: int
:var TYPE_SLINF: Packet type is non-terminated info packet.
:type TYPE_SLINF: int
:var SLTERMINATE: Terminate flag - connection was closed by the server or
the termination sequence completed.
:type SLTERMINATE: str
:var SLNOPACKET: No packet flag - indicates no data available.
:type SLNOPACKET: bytes
:var SLERROR: Error flag - indicates server reported an error.
:type SLERROR: str
:var SLHEADSIZE: SeedLink packet header size.
:type SLHEADSIZE: int
:var SLRECSIZE: Mini-SEED record size.
:type SLRECSIZE: int
:var SIGNATURE: SeedLink header signature.
:type SIGNATURE: str
:var INFOSIGNATURE: SeedLink INFO packet signature.
:type INFOSIGNATURE: str
:var ERRORSIGNATURE: SeedLink ERROR signature.
:type ERRORSIGNATURE: str
:var ENDSIGNATURE: SeedLink END signature.
:type ENDSIGNATURE: str
:var slhead: The SeedLink header.
:type slhead: bytes
:var msrecord: The MiniSEED record.
:type msrecord: bytes
"""
TYPE_SLINFT = -101
TYPE_SLINF = -102
SLTERMINATE = b"SLTERMINATE"
SLNOPACKET = b"SLNOPACKET"
SLERROR = b"SLERROR"
SLHEADSIZE = 8
SLRECSIZE = 512
SIGNATURE = b"SL"
INFOSIGNATURE = b"SLINFO"
ERRORSIGNATURE = b"ERROR\r\n"
ENDSIGNATURE = b"END"
[docs] def __init__(self, data=None, offset=None):
if data is None or offset is None:
return
if len(data) - offset < self.SLHEADSIZE + self.SLRECSIZE:
msg = "not enough bytes in sub array to construct a new SLPacket"
raise SeedLinkException(msg)
self.slhead = data[offset: offset + self.SLHEADSIZE]
self.msrecord = data[offset + self.SLHEADSIZE:
offset + self.SLHEADSIZE + self.SLRECSIZE]
self.trace = None
[docs] def get_sequence_number(self):
# print "DEBUG: repr(self.slhead):", repr(self.slhead)
# print "DEBUG: self.slhead[0 : len(self.INFOSIGNATURE)].lower():",
# print self.slhead[0 : len(self.INFOSIGNATURE)].lower()
# print "DEBUG: self.INFOSIGNATURE.lower():",
# self.INFOSIGNATURE.lower()
if self.slhead[0: len(self.INFOSIGNATURE)].lower() == \
self.INFOSIGNATURE.lower():
return 0
# print "DEBUG: self.slhead[0 : len(self.SIGNATURE)].lower():",
# print self.slhead[0 : len(self.SIGNATURE)].lower()
# print "DEBUG: self.SIGNATURE.lower():", self.SIGNATURE.lower()
if not self.slhead[0: len(self.SIGNATURE)].lower() == \
self.SIGNATURE.lower():
return -1
seqbytes = bytes(self.slhead[2:8])
# print "DEBUG: seqbytes:", seqbytes,", int(seqbytes, 16):", \
# int(seqbytes, 16)
seqnum = -1
try:
seqnum = int(seqbytes, 16)
except Exception:
msg = "SLPacket.get_sequence_number(): bad packet sequence number:"
print(msg, seqbytes)
return -1
return seqnum
[docs] def get_ms_record(self):
# following from obspy.io.mseed.tests.test_libmseed.py -> test_msrParse
msr = clibmseed.msr_init(None)
pyobj = from_buffer(self.msrecord, dtype=np.int8)
errcode = \
clibmseed.msr_parse(pyobj, len(pyobj), C.pointer(msr), -1, 1, 1)
if errcode != 0:
msg = "failed to decode mini-seed record: msr_parse errcode: %s"
raise SeedLinkException(msg % (errcode))
# print "DEBUG: msr:", msr
msrecord_py = msr.contents
# print "DEBUG: msrecord_py:", msrecord_py
return msr, msrecord_py
[docs] def free_ms_record(self, msr, msrecord_py):
clibmseed.msr_free(msr)
[docs] def get_trace(self):
if self.trace is not None:
return self.trace
msr, msrecord_py = self.get_ms_record()
try:
header = _convert_msr_to_dict(msrecord_py)
# XXX Workaround: in Python 3 msrecord_py.sampletype is a byte
# (e.g. b'i'), while keys of mseed.headers.SAMPLESIZES are
# unicode ('i') (see above)
sampletype = msrecord_py.sampletype
if not isinstance(sampletype, str):
sampletype = sampletype.decode()
data = _ctypes_array_2_numpy_array(msrecord_py.datasamples,
msrecord_py.numsamples,
sampletype)
finally:
self.free_ms_record(msr, msrecord_py)
# XXX Workaround: the fields in the returned struct of type
# obspy.io.mseed.header.MsrecordS have byte values in Python 3, while
# the rest of the code still expects them to be string (see #770)
# -> convert
convert = ('network', 'station', 'location', 'channel',
'dataquality', 'sampletype')
for key, value in header.items():
if key in convert and not isinstance(value, str):
header[key] = value.decode()
# 20111201 AJL - bug fix?
header['starttime'] = _convert_mstime_to_datetime(header['starttime'])
# 20111205 AJL - bug fix?
if 'samprate' in header:
header['sampling_rate'] = header['samprate']
del header['samprate']
# Access data directly as NumPy array.
self.trace = Trace(data, header)
return self.trace
[docs] def get_string_payload(self):
"""
Get the MiniSEED payload, parsed as string.
"""
msr, msrecord_py = self.get_ms_record()
try:
# This is the same data buffer that is accessed by
# _ctypes_array_2_numpy_array in get_trace above.
payload = C.string_at(msrecord_py.datasamples,
msrecord_py.samplecnt)
finally:
self.free_ms_record(msr, msrecord_py)
return payload
[docs] def get_type(self):
# print "DEBUG: self.slhead:", repr(self.slhead)
if self.slhead[0: len(SLPacket.INFOSIGNATURE)].lower() == \
SLPacket.INFOSIGNATURE.lower():
if (chr(self.slhead[self.SLHEADSIZE - 1]) != '*'):
return self.TYPE_SLINFT
else:
return self.TYPE_SLINF
msr, msrecord_py = self.get_ms_record()
try:
ret = msrecord_py.blkts.contents.blkt_type
finally:
self.free_ms_record(msr, msrecord_py)
return ret