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# bencode structured encoding
#
# Written by Petru Paler
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# The Software is provided "AS IS", without warranty of any kind,
# express or implied, including but not limited to the warranties of
# merchantability, fitness for a particular purpose and
# noninfringement. In no event shall the authors or copyright holders
# be liable for any claim, damages or other liability, whether in an
# action of contract, tort or otherwise, arising from, out of or in
# connection with the Software or the use or other dealings in the
# Software.
def decode_int(x, f):
f += 1
newf = x.index('e', f)
try:
n = int(x[f:newf])
except (OverflowError, ValueError):
n = long(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)
try:
n = int(x[f:colon])
except (OverflowError, ValueError):
n = long(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)
r.append(v)
return (r, f + 1)
def decode_dict(x, f):
r, f = {}, f+1
lastkey = None
while x[f] != 'e':
k, f = decode_string(x, f)
if lastkey >= k:
raise ValueError
lastkey = k
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):
try:
r, l = decode_func[x[0]](x, 0)
except (IndexError, KeyError):
raise ValueError
if l != len(x):
raise ValueError
return r
def test_bdecode():
try:
bdecode('0:0:')
assert 0
except ValueError:
pass
try:
bdecode('ie')
assert 0
except ValueError:
pass
try:
bdecode('i341foo382e')
assert 0
except ValueError:
pass
assert bdecode('i4e') == 4L
assert bdecode('i0e') == 0L
assert bdecode('i123456789e') == 123456789L
assert bdecode('i-10e') == -10L
try:
bdecode('i-0e')
assert 0
except ValueError:
pass
try:
bdecode('i123')
assert 0
except ValueError:
pass
try:
bdecode('')
assert 0
except ValueError:
pass
try:
bdecode('i6easd')
assert 0
except ValueError:
pass
try:
bdecode('35208734823ljdahflajhdf')
assert 0
except ValueError:
pass
try:
bdecode('2:abfdjslhfld')
assert 0
except ValueError:
pass
assert bdecode('0:') == ''
assert bdecode('3:abc') == 'abc'
assert bdecode('10:1234567890') == '1234567890'
try:
bdecode('02:xy')
assert 0
except ValueError:
pass
try:
bdecode('l')
assert 0
except ValueError:
pass
assert bdecode('le') == []
try:
bdecode('leanfdldjfh')
assert 0
except ValueError:
pass
assert bdecode('l0:0:0:e') == ['', '', '']
try:
bdecode('relwjhrlewjh')
assert 0
except ValueError:
pass
assert bdecode('li1ei2ei3ee') == [1, 2, 3]
assert bdecode('l3:asd2:xye') == ['asd', 'xy']
assert bdecode('ll5:Alice3:Bobeli2ei3eee') == [['Alice', 'Bob'], [2, 3]]
try:
bdecode('d')
assert 0
except ValueError:
pass
try:
bdecode('defoobar')
assert 0
except ValueError:
pass
assert bdecode('de') == {}
assert bdecode('d3:agei25e4:eyes4:bluee') == {'age': 25, 'eyes': 'blue'}
assert bdecode('d8:spam.mp3d6:author5:Alice6:lengthi100000eee') == {'spam.mp3': {'author': 'Alice', 'length': 100000}}
try:
bdecode('d3:fooe')
assert 0
except ValueError:
pass
try:
bdecode('di1e0:e')
assert 0
except ValueError:
pass
try:
bdecode('d1:b0:1:a0:e')
assert 0
except ValueError:
pass
try:
bdecode('d1:a0:1:a0:e')
assert 0
except ValueError:
pass
try:
bdecode('i03e')
assert 0
except ValueError:
pass
try:
bdecode('l01:ae')
assert 0
except ValueError:
pass
try:
bdecode('9999:x')
assert 0
except ValueError:
pass
try:
bdecode('l0:')
assert 0
except ValueError:
pass
try:
bdecode('d0:0:')
assert 0
except ValueError:
pass
try:
bdecode('d0:')
assert 0
except ValueError:
pass
try:
bdecode('00:')
assert 0
except ValueError:
pass
try:
bdecode('l-3:e')
assert 0
except ValueError:
pass
try:
bdecode('i-03e')
assert 0
except ValueError:
pass
bdecode('d0:i3ee')
from types import StringType, IntType, LongType, DictType, ListType, TupleType
class Bencached(object):
__slots__ = ['bencoded']
def __init__(self, s):
self.bencoded = s
def encode_bencached(x,r):
r.append(x.bencoded)
def encode_int(x, r):
r.extend(('i', str(x), 'e'))
def encode_string(x, r):
r.extend((str(len(x)), ':', x))
def encode_list(x, r):
r.append('l')
for i in x:
encode_func[type(i)](i, r)
r.append('e')
def encode_dict(x,r):
r.append('d')
ilist = x.items()
ilist.sort()
for k, v in ilist:
r.extend((str(len(k)), ':', k))
encode_func[type(v)](v, r)
r.append('e')
encode_func = {}
encode_func[type(Bencached(0))] = 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
try:
from types import BooleanType
encode_func[BooleanType] = encode_int
except ImportError:
pass
def bencode(x):
r = []
encode_func[type(x)](x, r)
return ''.join(r)
def test_bencode():
assert bencode(4) == 'i4e'
assert bencode(0) == 'i0e'
assert bencode(-10) == 'i-10e'
assert bencode(12345678901234567890L) == 'i12345678901234567890e'
assert bencode('') == '0:'
assert bencode('abc') == '3:abc'
assert bencode('1234567890') == '10:1234567890'
assert bencode([]) == 'le'
assert bencode([1, 2, 3]) == 'li1ei2ei3ee'
assert bencode([['Alice', 'Bob'], [2, 3]]) == 'll5:Alice3:Bobeli2ei3eee'
assert bencode({}) == 'de'
assert bencode({'age': 25, 'eyes': 'blue'}) == 'd3:agei25e4:eyes4:bluee'
assert bencode({'spam.mp3': {'author': 'Alice', 'length': 100000}}) == 'd8:spam.mp3d6:author5:Alice6:lengthi100000eee'
assert bencode(Bencached(bencode(3))) == 'i3e'
try:
bencode({1: 'foo'})
except TypeError:
return
assert 0
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