/brz/remove-bazaar

# 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.

#

# Modifications copyright (C) 2008 Canonical Ltd

from __future__ import absolute_import

import sys

class BDecoder(object):

    def __init__(self, yield_tuples=False):

        """Constructor.

        :param yield_tuples: if true, decode "l" elements as tuples rather than

            lists.

        """

        self.yield_tuples = yield_tuples

        decode_func = {}

        decode_func[b'l'] = self.decode_list

        decode_func[b'd'] = self.decode_dict

        decode_func[b'i'] = self.decode_int

        decode_func[b'0'] = self.decode_string

        decode_func[b'1'] = self.decode_string

        decode_func[b'2'] = self.decode_string

        decode_func[b'3'] = self.decode_string

        decode_func[b'4'] = self.decode_string

        decode_func[b'5'] = self.decode_string

        decode_func[b'6'] = self.decode_string

        decode_func[b'7'] = self.decode_string

        decode_func[b'8'] = self.decode_string

        decode_func[b'9'] = self.decode_string

        self.decode_func = decode_func

    def decode_int(self, x, f):

        f += 1

        newf = x.index(b'e', f)

        n = int(x[f:newf])

        if x[f:f+2] == b'-0':

            raise ValueError

        elif x[f:f+1] == b'0' and newf != f+1:

            raise ValueError

        return (n, newf+1)

    def decode_string(self, x, f):

        colon = x.index(b':', f)

        n = int(x[f:colon])

        if x[f:f+1] == b'0' and colon != f+1:

            raise ValueError

        colon += 1

        return (x[colon:colon+n], colon+n)

    def decode_list(self, x, f):

        r, f = [], f+1

        while x[f:f+1] != b'e':

            v, f = self.decode_func[x[f:f+1]](x, f)

            r.append(v)

        if self.yield_tuples:

            r = tuple(r)

        return (r, f + 1)

    def decode_dict(self, x, f):

        r, f = {}, f+1

        lastkey = None

        while x[f:f+1] != b'e':

            k, f = self.decode_string(x, f)

            if lastkey is not None and lastkey >= k:

                raise ValueError

            lastkey = k

            r[k], f = self.decode_func[x[f:f+1]](x, f)

        return (r, f + 1)

    def bdecode(self, x):

        if not isinstance(x, bytes):

            raise TypeError

        try:

            r, l = self.decode_func[x[:1]](x, 0)

        except (IndexError, KeyError, OverflowError) as e:

            raise ValueError(str(e))

        if l != len(x):

            raise ValueError

        return r

_decoder = BDecoder()

bdecode = _decoder.bdecode

_tuple_decoder = BDecoder(True)

bdecode_as_tuple = _tuple_decoder.bdecode

class Bencached(object):

    __slots__ = ['bencoded']

    def __init__(self, s):

        self.bencoded = s

def encode_bencached(x,r):

    r.append(x.bencoded)

def encode_bool(x,r):

    encode_int(int(x), r)

def encode_int(x, r):

    r.extend((b'i', int_to_bytes(x), b'e'))

def encode_string(x, r):

    r.extend((int_to_bytes(len(x)), b':', x))

def encode_list(x, r):

    r.append(b'l')

    for i in x:

        encode_func[type(i)](i, r)

    r.append(b'e')

def encode_dict(x,r):

    r.append(b'd')

    ilist = sorted(x.items())

    for k, v in ilist:

        r.extend((int_to_bytes(len(k)), b':', k))

        encode_func[type(v)](v, r)

    r.append(b'e')

encode_func = {}

encode_func[type(Bencached(0))] = encode_bencached

encode_func[int] = encode_int

if sys.version_info < (3,):

    encode_func[long] = encode_int

    int_to_bytes = str

else:

    def int_to_bytes(n):

        return b'%d' % n

encode_func[bytes] = encode_string

encode_func[list] = encode_list

encode_func[tuple] = encode_list

encode_func[dict] = encode_dict

encode_func[bool] = encode_bool

from breezy._static_tuple_py import StaticTuple

encode_func[StaticTuple] = encode_list

try:

    from breezy._static_tuple_c import StaticTuple

except ImportError:

    pass

else:

    encode_func[StaticTuple] = encode_list

def bencode(x):

    r = []

    encode_func[type(x)](x, r)

    return b''.join(r)