def _unpack_C0_data_fast(packets): # noqa
"""
Unpacks sample data from a packet array that uses 'C0' data encoding.
Unfortunately the whole data cannot be unpacked with one call to
libmseed as some payloads do not take the full 960 bytes. They are
thus padded which would results in padded pieces directly in a large
array and libmseed (understandably) does not support that.
Thus we resort to *tada* pointer arithmetics in Python ;-) This is
quite a bit faster then correctly casting to an integer pointer so
it's worth it.
Also avoid a data copy.
Writing this directly in C would be about 3 times as fast so it might
be worth it.
:type packets: :class:`numpy.ndarray` (dtype ``PACKET_FINAL_DTYPE``)
:param packets: Array of data packets (``packet_type`` ``'DT'``) from which
to unpack the sample data (with data encoding 'C0').
"""
npts = packets["number_of_samples"].sum()
unpacked_data = np.empty(npts, dtype=np.int32)
pos = 0
s = packets[0]["payload"][40:].ctypes.data
if len(packets) > 1:
offset = (
packets[1]["payload"][40:].ctypes.data - s)
else:
offset = 0
for _npts in packets["number_of_samples"]:
clibmseed.msr_decode_steim1(
s, 960, _npts, unpacked_data[pos:], _npts, None,
1)
pos += _npts
s += offset
return unpacked_data
def _unpack_C0_data_safe(packets): # noqa
"""
Unpacks sample data from a packet array that uses 'C0' data encoding.
If the packet array is *not* contiguous in memory, fall back to slightly
slower unpacking with looking up the memory position of the first packed
byte in each packet individually.
:type packets: :class:`numpy.ndarray` (dtype ``PACKET_FINAL_DTYPE``)
:param packets: Array of data packets (``packet_type`` ``'DT'``) from which
to unpack the sample data (with data encoding 'C0').
"""
npts = packets["number_of_samples"].sum()
unpacked_data = np.empty(npts, dtype=np.int32)
pos = 0
# Sample data starts at byte 40 in the DT packet's
# payload.
for p in packets:
_npts = p["number_of_samples"]
clibmseed.msr_decode_steim1(p["payload"][40:].ctypes.data, 960, _npts,
unpacked_data[pos:], _npts, None, 1)
pos += _npts
return unpacked_data
def _unpack_C0_data_fast(packets): # noqa
"""
Unpacks sample data from a packet array that uses 'C0' data encoding.
Unfortunately the whole data cannot be unpacked with one call to
libmseed as some payloads do not take the full 960 bytes. They are
thus padded which would results in padded pieces directly in a large
array and libmseed (understandably) does not support that.
Thus we resort to *tada* pointer arithmetics in Python ;-) This is
quite a bit faster then correctly casting to an integer pointer so
it's worth it.
Also avoid a data copy.
Writing this directly in C would be about 3 times as fast so it might
be worth it.
:type packets: :class:`numpy.ndarray` (dtype ``PACKET_FINAL_DTYPE``)
:param packets: Array of data packets (``packet_type`` ``'DT'``) from which
to unpack the sample data (with data encoding 'C0').
"""
npts = packets["number_of_samples"].sum()
unpacked_data = np.empty(npts, dtype=np.int32)
pos = 0
s = packets[0]["payload"][40:].ctypes.data
if len(packets) > 1:
offset = (packets[1]["payload"][40:].ctypes.data - s)
else:
offset = 0
for _npts in packets["number_of_samples"]:
clibmseed.msr_decode_steim1(s, 960, _npts, unpacked_data[pos:], _npts,
None, 1)
pos += _npts
s += offset
return unpacked_data
def _unpack_C0_data_safe(packets): # noqa
"""
Unpacks sample data from a packet array that uses 'C0' data encoding.
If the packet array is *not* contiguous in memory, fall back to slightly
slower unpacking with looking up the memory position of the first packed
byte in each packet individually.
:type packets: :class:`numpy.ndarray` (dtype ``PACKET_FINAL_DTYPE``)
:param packets: Array of data packets (``packet_type`` ``'DT'``) from which
to unpack the sample data (with data encoding 'C0').
"""
npts = packets["number_of_samples"].sum()
unpacked_data = np.empty(npts, dtype=np.int32)
pos = 0
# Sample data starts at byte 40 in the DT packet's
# payload.
for p in packets:
_npts = p["number_of_samples"]
clibmseed.msr_decode_steim1(
p["payload"][40:].ctypes.data, 960, _npts,
unpacked_data[pos:], _npts, None, 1)
pos += _npts
return unpacked_data
