utlis.py

import base64

def normalize_address(a, to_raw):
    if len(a) == 48:
        raw = base64.urlsafe_b64decode(a)
        workchain = raw[1]
        if workchain == 255:
            workchain = -1
        addr = raw[2:34]
    elif ":" in a:
        parts = a.split(":")
        if len(parts) != 2:
            raise Exception("invalid address %s" % a)
        workchain = int(parts[0])
        addr = bytearray.fromhex(parts[1])
    else:
        raise Exception("invalid address %s" % a)
    if to_raw:
        return "%d:%s" % (workchain, addr.hex())

    if workchain == -1:
        workchain = 255
    human = bytearray(36)
    human[0] = 0x11
    human[1] = workchain
    human[2:34] = addr
    human[34:] = crc16(human[:34])
    return base64.urlsafe_b64encode(human).decode()


def crc16(data):
    POLY = 0x1021
    reg = 0
    message = bytes(data) + bytes(2)

    for byte in message:
        mask = 0x80
        while mask > 0:
            reg <<= 1
            if byte & mask:
                reg += 1
            mask >>= 1
            if reg > 0xffff:
                reg &= 0xffff
                reg ^= POLY
    return reg // 256, reg % 256