trezor-firmware/src/apps/common/address_type.py

def length(address_type):
    if address_type <= 0xFF:
        return 1
    if address_type <= 0xFFFF:
        return 2
    if address_type <= 0xFFFFFF:
        return 3
    # else
    return 4


def check(address_type, raw_address):
    if address_type <= 0xFF:
        return address_type == raw_address[0]
    if address_type <= 0xFFFF:
        return address_type == (raw_address[0] << 8) | raw_address[1]
    if address_type <= 0xFFFFFF:
        return address_type == (raw_address[0] << 16) | (raw_address[1] << 8) | raw_address[2]
    # else
    return address_type == (raw_address[0] << 24) | (raw_address[1] << 16) | (raw_address[2] << 8) | raw_address[3]


def strip(address_type, raw_address):
    if not check(address_type, raw_address):
        raise ValueError('Invalid address')
    l = length(address_type)
    return raw_address[l:]


def split(coin, raw_address):
    for f in ('address_type',
              'address_type_p2sh',
              'address_type_p2wpkh',
              'address_type_p2wsh'):
        at = getattr(coin, f)
        if at is not None and check(at, raw_address):
            l = length(at)
            return raw_address[:l], raw_address[l:]
    raise ValueError('Invalid address')