Decode raw MySQL 5.6 datetime data

decode_datetime.py

import ctypes
import datetime

c_uint64 = ctypes.c_uint64

class MySQLDT(ctypes.BigEndianStructure):
    _fields_ = [
        ("sign", c_uint64, 1),
        ("yearmonth", c_uint64, 17),
        ("day", c_uint64, 5),
        ("hour", c_uint64, 5),
        ("minute", c_uint64, 6),
        ("second", c_uint64, 6)
    ]

    @property
    def year(self):
        return self.yearmonth // 13

    @property
    def month(self):
        return self.yearmonth % 13


    def as_datetime(self):
        return datetime.datetime(year=self.year,
                                 month=self.month,
                                 day=self.day,
                                 hour=self.hour,
                                 minute=self.minute,
                                 second=self.second)

    @classmethod
    def from_bytes(cls, data):
        instance = cls()
        fit = min(len(data), ctypes.sizeof(instance))
        ctypes.memmove(ctypes.addressof(instance), data, fit)
        return instance

# encoded information for 1980-01-01 12:34:56
# extracted from the defaults buffer of a sample .frm file
raw = '\x99#B\xc8\xb8'
dt = MySQLDT.from_bytes(raw)

print dt.as_datetime()