biliBv.py

# (C) 2019-2020 lifegpc
# This file is part of bili.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
table = 'fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF'
tr = {}
for i in range(58):
    tr[table[i]] = i
s = [11, 10, 3, 8, 4, 6]
xor = 177451812
add = 8728348608


def debv(x):
    if len(x) == 11:
        x = "BV1" + x[2:]
    r = 0
    for i in range(6):
        r += tr[x[s[i]]] * 58**i
    return (r - add) ^ xor


def enbv(x):
    x = (x ^ xor) + add
    r = list('BV1  4 1 7  ')
    for i in range(6):
        r[s[i]] = table[x // 58**i % 58]
    return ''.join(r)