python类getcontext()的实例源码

def base_round_zero(self, val, n):
        if val is not None:
            val = Decimal(val, getcontext())
        else:
            val = Decimal(0, getcontext())
        return val.__round__(n)

def get_rpc_request_bytes(connection, procname, params=[]):
    buf = _int_to_4bytes(22)
    buf += _int_to_4bytes(18)
    buf += _int_to_2bytes(2)
    buf += connection.transaction_id
    buf += _int_to_4bytes(1)        # request count

    buf += _int_to_2bytes(len(procname))
    buf += _str_to_bytes(procname)
    buf += bytes([0x00, 0x00])      # OptionFlags

    for p in params:
        buf += bytes([0, 0])     # name="", StatusFlags
        if p is None:
            buf += bytes([INTNTYPE, 2])
            buf += bytes([0])
        elif isinstance(p, int):
            buf += bytes([INTNTYPE, 4])
            buf += bytes([4]) + p.to_bytes(4, byteorder='little')
        elif isinstance(p, str):
            ln = len(p) * 2
            buf += bytes([NCHARTYPE]) + ln.to_bytes(2, byteorder='little')
            buf += _int_to_2bytes(connection.lcid) + bytes([0, 0, 0])
            buf += ln.to_bytes(2, byteorder='little') + _str_to_bytes(p)
        elif isinstance(p, decimal.Decimal):
            sign, digits, disponent = p.as_tuple()
            if disponent > 0:
                exp = 256 - disponent
            else:
                exp = -disponent
            v = 0
            ln = len(digits)
            for i in range(ln):
                v += digits[i] * (10 ** (ln - i - 1))
            buf += bytes([DECIMALNTYPE, 9])
            buf += bytes([decimal.getcontext().prec, exp])
            buf += bytes([9, bool(not sign)]) + _int_to_8bytes(v)
        else:
            # another type. pack as string parameter
            s = str(p)
            ln = len(s) * 2
            buf += bytes([NCHARTYPE]) + ln.to_bytes(2, byteorder='little')
            buf += _int_to_2bytes(connection.lcid) + bytes([0, 0, 0])
            buf += ln.to_bytes(2, byteorder='little') + _str_to_bytes(s)

    return buf

def __init__(self):
        decimal.getcontext().prec = 5
        self.config_file = ConfigurationFile.ConfigurationFile()
        self.port = 8989
        self.listen_address = "localhost"
        self.server_socket = None
        self.wallets = []
        self.authority_wallet = None
        self.clients = []
        self.ca_name = "unnamed"
        self.transactions = []
        self.coins_per_challenge = 0
        self.minutes_per_challenge = 0
        self.ssl_on = True
        self.ssl_cert = ""
        self.available_challenges = []
        self.prefix_length = 4
        self.challenge_thread = None
        self.max_requests_per_minutes = 30
        self.initial_cooldown_length = 60
        self.invalid_submission_allowed = 5  # within 5 minutes
        self.supervisor_key = ''
        self.emit_coins = False

        self.min_transaction_amount = 0
        self.submissions_allowed_ips = []
        self.statistic = ServerStatistic.ServerStatistic()
        self.read_vars_from_config()
        self.database = ServerDatabase.ServerDatabase(
            self.config_file.get_string(
                "db_user", "cacoins"), self.config_file.get_string(
                "db_password", ""), self.config_file.get_string(
                "db_name", "cacoins"))

        # commands handler
        self.commands_handler = []
        self.fill_commands_handler()

        self.ca_private_key = None
        self.ca_public_key = None
        self.ca_wallet_id = None

        self.wallet_keys = {}