def encode_msg(self, context_id, max_pdu_length):
"""Yield P-DATA primitive(s) for the current DIMSE Message.
**Encoding**
The encoding of the Command Set shall be Little Endian Implicit VR,
while the Data Set will be encoded as per the agreed presentation
context.
A P-DATA request PDV List parameter shall contain one or more PDVs.
Each PDV is wholly contained in a given P-DATA request and doesn't
span across several P-DATA request primitives.
The fragmentation of any message results in a series of PDVs that shall
be sent, on a given association, by a corresponding series of P-DATA
requests preserving the ordering of the fragments of any message.
No fragments of any other messages shall be sent until all fragments
of the current message have been sent.
Parameters
----------
context_id : int
The ID of the agreed presentation context.
max_pdu_length : int
The maximum PDV length in bytes.
Yields
------
pdu_primitives.P_DATA
The current DIMSE message as one or more P-DATA service
primitives.
References
----------
* DICOM Standard, Part 7, Section 6.3.1
* DICOM Standard, Part 8, Annex E
"""
self.ID = context_id
# The Command Set is always Little Endian Implicit VR (PS3.7 6.3.1)
# encode(dataset, is_implicit_VR, is_little_endian)
encoded_command_set = encode(self.command_set, True, True)
# COMMAND SET (always)
# Split the command set into fragments with maximum size max_pdu_length
no_fragments = ceil(len(encoded_command_set) / (max_pdu_length - 6))
cmd_fragments = self._generate_pdv_fragments(encoded_command_set,
max_pdu_length)
# First to (n - 1)th command data fragment - bits xxxxxx01
for ii in range(int(no_fragments - 1)):
pdata = P_DATA()
pdata.presentation_data_value_list.append(
[context_id, b'\x01' + next(cmd_fragments)]
)
yield pdata
# Last command data fragment - bits xxxxxx11
pdata = P_DATA()
pdata.presentation_data_value_list.append(
[context_id, b'\x03' + next(cmd_fragments)]
)
yield pdata
# DATASET (if available)
# Check that the Data Set is not empty
if self.data_set is not None:
encoded_data_set = self.data_set.getvalue()
if encoded_data_set:
# Split the data set into fragments with maximum
# size max_pdu_length
no_fragments = ceil(
len(encoded_data_set) / (max_pdu_length - 6)
)
ds_fragments = self._generate_pdv_fragments(encoded_data_set,
max_pdu_length)
# First to (n - 1)th dataset fragment - bits xxxxxx00
for ii in range(int(no_fragments - 1)):
pdata = P_DATA()
pdata.presentation_data_value_list.append(
[context_id, b'\x00' + next(ds_fragments)]
)
yield pdata
# Last dataset fragment - bits xxxxxx10
pdata = P_DATA()
pdata.presentation_data_value_list.append(
[context_id, b'\x02' + next(ds_fragments)]
)
yield pdata
def test_assignment(self):
""" Check assignment works correctly """
primitive = P_DATA()
primitive.presentation_data_value_list = [[1, b'\x00']]
self.assertEqual(primitive.presentation_data_value_list, [[1, b'\x00']])