discid.py

import hashlib
from base64 import b64encode

def discid(toc):
    u"""
    'first':int,
    'last':int,
    'offsets':[int]
    """
    discid=hashlib.sha1()
    discid.update(('%02x'%toc['first']).upper())
    discid.update(('%02x'%toc['last']).upper())
    for i in toc['offsets']: discid.update(('%08x'%i).upper())
    for i in range(100-toc['first']-toc['last']): discid.update('%08x'%0)
    return b64encode(discid.digest(),['.','_']).replace('=','-')