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import json
from ._base import *
lib.olm_inbound_group_session_size.argtypes = []
lib.olm_inbound_group_session_size.restype = c_size_t
lib.olm_inbound_group_session.argtypes = [c_void_p]
lib.olm_inbound_group_session.restype = c_void_p
lib.olm_inbound_group_session_last_error.argtypes = [c_void_p]
lib.olm_inbound_group_session_last_error.restype = c_char_p
def inbound_group_session_errcheck(res, func, args):
if res == ERR:
raise OlmError("%s: %s" % (
func.__name__, lib.olm_inbound_group_session_last_error(args[0])
))
return res
def inbound_group_session_function(func, *types):
func.argtypes = (c_void_p,) + types
func.restypes = c_size_t
func.errcheck = inbound_group_session_errcheck
inbound_group_session_function(
lib.olm_pickle_inbound_group_session, c_void_p, c_size_t, c_void_p, c_size_t
)
inbound_group_session_function(
lib.olm_unpickle_inbound_group_session, c_void_p, c_size_t, c_void_p, c_size_t
)
inbound_group_session_function(
lib.olm_init_inbound_group_session, c_uint32, c_void_p, c_size_t
)
inbound_group_session_function(
lib.olm_group_decrypt_max_plaintext_length, c_void_p, c_size_t
)
inbound_group_session_function(
lib.olm_group_decrypt,
c_void_p, c_size_t, # message
c_void_p, c_size_t, # plaintext
)
class InboundGroupSession(object):
def __init__(self):
self.buf = create_string_buffer(lib.olm_inbound_group_session_size())
self.ptr = lib.olm_inbound_group_session(self.buf)
def pickle(self, key):
key_buffer = create_string_buffer(key)
pickle_length = lib.olm_pickle_inbound_group_session_length(self.ptr)
pickle_buffer = create_string_buffer(pickle_length)
lib.olm_pickle_inbound_group_session(
self.ptr, key_buffer, len(key), pickle_buffer, pickle_length
)
return pickle_buffer.raw
def unpickle(self, key, pickle):
key_buffer = create_string_buffer(key)
pickle_buffer = create_string_buffer(pickle)
lib.olm_unpickle_inbound_group_session(
self.ptr, key_buffer, len(key), pickle_buffer, len(pickle)
)
def init(self, message_index, session_key):
key_buffer = create_string_buffer(session_key)
lib.olm_init_inbound_group_session(
self.ptr, message_index, key_buffer, len(session_key)
)
def decrypt(self, message):
message_buffer = create_string_buffer(message)
max_plaintext_length = lib.olm_group_decrypt_max_plaintext_length(
self.ptr, message_buffer, len(message)
)
plaintext_buffer = create_string_buffer(max_plaintext_length)
message_buffer = create_string_buffer(message)
plaintext_length = lib.olm_group_decrypt(
self.ptr, message_buffer, len(message),
plaintext_buffer, max_plaintext_length
)
return plaintext_buffer.raw[:plaintext_length]
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