def _encode_msg(self,
start_pos,
offset,
timestamp,
key,
value,
attributes=0):
""" Encode msg data into the `msg_buffer`, which should be allocated
to at least the size of this message.
"""
magic = self._magic
buf = self._buffer
pos = start_pos
# Write key and value
pos += self.KEY_OFFSET_V0 if magic == 0 else self.KEY_OFFSET_V1
if key is None:
struct.pack_into(">i", buf, pos, -1)
pos += self.KEY_LENGTH
else:
key_size = len(key)
struct.pack_into(">i", buf, pos, key_size)
pos += self.KEY_LENGTH
buf[pos:pos + key_size] = key
pos += key_size
if value is None:
struct.pack_into(">i", buf, pos, -1)
pos += self.VALUE_LENGTH
else:
value_size = len(value)
struct.pack_into(">i", buf, pos, value_size)
pos += self.VALUE_LENGTH
buf[pos:pos + value_size] = value
pos += value_size
length = (pos - start_pos) - self.LOG_OVERHEAD
# Write msg header. Note, that Crc will be updated later
if magic == 0:
self.HEADER_STRUCT_V0.pack_into(buf, start_pos, offset, length, 0,
magic, attributes)
else:
self.HEADER_STRUCT_V1.pack_into(buf, start_pos, offset, length, 0,
magic, attributes, timestamp)
# Calculate CRC for msg
crc_data = memoryview(buf)[start_pos + self.MAGIC_OFFSET:]
crc = calc_crc32(crc_data)
struct.pack_into(">I", buf, start_pos + self.CRC_OFFSET, crc)
return crc
def _encode_msg(self, start_pos, offset, timestamp, key, value,
attributes=0):
""" Encode msg data into the `msg_buffer`, which should be allocated
to at least the size of this message.
"""
magic = self._magic
buf = self._buffer
pos = start_pos
# Write key and value
pos += self.KEY_OFFSET_V0 if magic == 0 else self.KEY_OFFSET_V1
if key is None:
struct.pack_into(">i", buf, pos, -1)
pos += self.KEY_LENGTH
else:
key_size = len(key)
struct.pack_into(">i", buf, pos, key_size)
pos += self.KEY_LENGTH
buf[pos: pos + key_size] = key
pos += key_size
if value is None:
struct.pack_into(">i", buf, pos, -1)
pos += self.VALUE_LENGTH
else:
value_size = len(value)
struct.pack_into(">i", buf, pos, value_size)
pos += self.VALUE_LENGTH
buf[pos: pos + value_size] = value
pos += value_size
length = (pos - start_pos) - self.LOG_OVERHEAD
# Write msg header. Note, that Crc will be updated later
if magic == 0:
self.HEADER_STRUCT_V0.pack_into(
buf, start_pos,
offset, length, 0, magic, attributes)
else:
self.HEADER_STRUCT_V1.pack_into(
buf, start_pos,
offset, length, 0, magic, attributes, timestamp)
# Calculate CRC for msg
crc_data = memoryview(buf)[start_pos + self.MAGIC_OFFSET:]
crc = calc_crc32(crc_data)
struct.pack_into(">I", buf, start_pos + self.CRC_OFFSET, crc)
return crc
def validate_crc(self):
crc = calc_crc32(self._buffer[self.MAGIC_OFFSET:])
return self._crc == crc
def validate_crc(self):
crc = calc_crc32(self._buffer[self.MAGIC_OFFSET:])
return self._crc == crc