Add bencode library

- will be used for new message encoding
Peter Šurda 8 years ago
parent 1a40c29d22
commit 4b559bbe66
Signed by untrusted user: PeterSurda
GPG Key ID: 0C5F50C0B5F37D87

@ -0,0 +1,2 @@
class BTFailure(Exception):

@ -0,0 +1,142 @@
# coding: utf-8
# The contents of this file are subject to the BitTorrent Open Source License
# Version 1.1 (the License). You may not copy or use this file, in either
# source code or executable form, except in compliance with the License. You
# may obtain a copy of the License at
# Software distributed under the License is distributed on an AS IS basis,
# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
# for the specific language governing rights and limitations under the
# License.
# Written by Petru Paler
# Modifed by Peter Šurda
from BTL import BTFailure
def decode_int(x, f):
f += 1
newf = x.index('e', f)
n = int(x[f:newf])
if x[f] == '-':
if x[f + 1] == '0':
raise ValueError
elif x[f] == '0' and newf != f+1:
raise ValueError
return (n, newf+1)
def decode_string(x, f):
colon = x.index(':', f)
n = int(x[f:colon])
if x[f] == '0' and colon != f+1:
raise ValueError
colon += 1
return (x[colon:colon+n], colon+n)
def decode_list(x, f):
r, f = [], f+1
while x[f] != 'e':
v, f = decode_func[x[f]](x, f)
return (r, f + 1)
def decode_dict(x, f):
r, f = {}, f+1
while x[f] != 'e':
k, f = decode_string(x, f)
r[k], f = decode_func[x[f]](x, f)
return (r, f + 1)
decode_func = {}
decode_func['l'] = decode_list
decode_func['d'] = decode_dict
decode_func['i'] = decode_int
decode_func['0'] = decode_string
decode_func['1'] = decode_string
decode_func['2'] = decode_string
decode_func['3'] = decode_string
decode_func['4'] = decode_string
decode_func['5'] = decode_string
decode_func['6'] = decode_string
decode_func['7'] = decode_string
decode_func['8'] = decode_string
decode_func['9'] = decode_string
def bdecode(x):
r, l = decode_func[x[0]](x, 0)
except (IndexError, KeyError, ValueError):
raise BTFailure("not a valid bencoded string")
if l != len(x):
raise BTFailure("invalid bencoded value (data after valid prefix)")
return r
from types import StringType, IntType, LongType, DictType, ListType, TupleType, UnicodeType, NoneType
class Bencached(object):
__slots__ = ['bencoded']
def __init__(self, s):
self.bencoded = s
def encode_bencached(x,r):
def encode_int(x, r):
r.extend(('i', str(x), 'e'))
def encode_bool(x, r):
if x:
encode_int(1, r)
encode_int(0, r)
def encode_string(x, r):
r.extend((str(len(x)), ':', x))
def encode_unicode(x, r):
raw = x.encode('utf8')
r.extend((str(len(raw)), ':', raw))
def encode_none(x, r):
def encode_list(x, r):
for i in x:
encode_func[type(i)](i, r)
def encode_dict(x,r):
ilist = x.items()
for k, v in ilist:
r.extend((str(len(k)), ':', k))
encode_func[type(v)](v, r)
encode_func = {}
encode_func[Bencached] = encode_bencached
encode_func[IntType] = encode_int
encode_func[LongType] = encode_int
encode_func[StringType] = encode_string
encode_func[ListType] = encode_list
encode_func[TupleType] = encode_list
encode_func[DictType] = encode_dict
encode_func[UnicodeType] = encode_unicode
encode_func[NoneType] = encode_none
from types import BooleanType
encode_func[BooleanType] = encode_bool
except ImportError:
def bencode(x):
r = []
encode_func[type(x)](x, r)
return ''.join(r)