1 files changed, 147 insertions, 0 deletions
diff --git a/deluge/bencode.py b/deluge/bencode.py
new file mode 100644
index 0000000..df8cc85
--- /dev/null
+++ b/deluge/bencode.py
@@ -0,0 +1,147 @@
+# The contents of this file are subject to the Python Software Foundation
+# License Version 2.3 (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 http://www.python.org/license.
+#
+# 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
+# Updated by Calum Lind to support Python 3.
+
+
+class BTFailure(Exception):
+    pass
+
+
+DICT_DELIM = b'd'
+END_DELIM = b'e'
+INT_DELIM = b'i'
+LIST_DELIM = b'l'
+BYTE_SEP = b':'
+
+
+def decode_int(x, f):
+    f += 1
+    newf = x.index(END_DELIM, f)
+    n = int(x[f:newf])
+    if x[f : f + 1] == b'-' and x[f + 1 : 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(x, f):
+    colon = x.index(BYTE_SEP, 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(x, f):
+    r, f = [], f + 1
+    while x[f : f + 1] != END_DELIM:
+        v, f = decode_func[x[f : f + 1]](x, f)
+        r.append(v)
+    return (r, f + 1)
+
+
+def decode_dict(x, f):
+    r, f = {}, f + 1
+    while x[f : f + 1] != END_DELIM:
+        k, f = decode_string(x, f)
+        r[k], f = decode_func[x[f : f + 1]](x, f)
+    return (r, f + 1)
+
+
+decode_func = {}
+decode_func[LIST_DELIM] = decode_list
+decode_func[DICT_DELIM] = decode_dict
+decode_func[INT_DELIM] = decode_int
+decode_func[b'0'] = decode_string
+decode_func[b'1'] = decode_string
+decode_func[b'2'] = decode_string
+decode_func[b'3'] = decode_string
+decode_func[b'4'] = decode_string
+decode_func[b'5'] = decode_string
+decode_func[b'6'] = decode_string
+decode_func[b'7'] = decode_string
+decode_func[b'8'] = decode_string
+decode_func[b'9'] = decode_string
+
+
+def bdecode(x):
+    try:
+        r, __ = decode_func[x[0:1]](x, 0)
+    except (LookupError, TypeError, ValueError):
+        raise BTFailure('Not a valid bencoded string')
+    else:
+        return r
+
+
+class Bencached:
+    __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((INT_DELIM, str(x).encode('utf8'), END_DELIM))
+
+
+def encode_bool(x, r):
+    encode_int(1 if x else 0, r)
+
+
+def encode_string(x, r):
+    encode_bytes(x.encode('utf8'), r)
+
+
+def encode_bytes(x, r):
+    r.extend((str(len(x)).encode('utf8'), BYTE_SEP, x))
+
+
+def encode_list(x, r):
+    r.append(LIST_DELIM)
+    for i in x:
+        encode_func[type(i)](i, r)
+    r.append(END_DELIM)
+
+
+def encode_dict(x, r):
+    r.append(DICT_DELIM)
+    for k, v in sorted(x.items()):
+        try:
+            k = k.encode('utf8')
+        except AttributeError:
+            pass
+        r.extend((str(len(k)).encode('utf8'), BYTE_SEP, k))
+        encode_func[type(v)](v, r)
+    r.append(END_DELIM)
+
+
+encode_func = {}
+encode_func[Bencached] = encode_bencached
+encode_func[int] = encode_int
+encode_func[list] = encode_list
+encode_func[tuple] = encode_list
+encode_func[dict] = encode_dict
+encode_func[bool] = encode_bool
+encode_func[str] = encode_string
+encode_func[bytes] = encode_bytes
+
+
+def bencode(x):
+    r = []
+    encode_func[type(x)](x, r)
+    return b''.join(r)