mirror of https://github.com/oxen-io/lokinet
110 lines
2.7 KiB
Python
Executable File
110 lines
2.7 KiB
Python
Executable File
#!/usr/bin/python3
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import sys
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import pprint
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if len(sys.argv) == 1 or (len(sys.argv) == 2 and sys.argv[1] == '-'):
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f = sys.stdin.buffer
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elif len(sys.argv) != 2 or sys.argv[1].startswith('-'):
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print("Usage: {} FILE -- dumps a bencoded file".format(sys.argv[0]), file=sys.stderr)
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sys.exit(1)
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else:
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f = open(sys.argv[1], 'rb')
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initial = f.peek(2)
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is_hex = False
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if initial.startswith(b'64') or initial.startswith(b'6c'):
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print("Input looks like hex bencoded data; parsing as hex input", file=sys.stderr)
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is_hex = True
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class HexPrinter():
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def __init__(self, data):
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self.data = data
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def __repr__(self):
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return "hex({} bytes):'{}'".format(len(self.data), self.data.hex())
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def next_byte():
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if is_hex:
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pair = f.read(2)
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assert pair is not None and len(pair) == 2
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b = int(pair, 16).to_bytes(1, 'big')
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else:
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b = f.read(1)
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assert b is not None and len(b) == 1
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return b
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def parse_int():
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s = b''
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x = next_byte()
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while x in b"0123456789-":
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s += x
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x = next_byte()
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assert x == b'e' and len(s) > 0, "Invalid integer encoding"
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return int(s)
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def parse_string(s):
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x = next_byte()
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while x in b"0123456789":
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s += x
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x = next_byte()
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assert x == b':', "Invalid string encoding"
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s = int(s)
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if is_hex:
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data = bytes.fromhex(f.read(2*s).decode('ascii'))
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else:
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data = f.read(s)
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assert len(data) == s, "Truncated string data"
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# If the string is ascii then convert to string:
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if all(0x20 <= b <= 0x7e for b in data):
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return data.decode()
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# Otherwise display as hex:
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return HexPrinter(data)
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def parse_dict():
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d = {}
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last_key = None
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while True:
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t = next_byte()
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if t == b'e':
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return d
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assert t in b"0123456789", "Invalid dict: dict keys must be strings"
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key = parse_string(t)
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raw_key = key.data if isinstance(key, HexPrinter) else key.encode()
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if last_key is not None and raw_key <= last_key:
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print("Warning: found out-of-order dict keys ({} after {})".format(raw_key, last_key), file=sys.stderr)
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last_key = raw_key
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t = next_byte()
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d[key] = parse_thing(t)
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def parse_list():
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l = []
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while True:
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t = next_byte()
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if t == b'e':
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return l
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l.append(parse_thing(t))
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def parse_thing(t):
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if t == b'd':
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return parse_dict()
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if t == b'l':
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return parse_list()
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if t == b'i':
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return parse_int()
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if t in b"0123456789":
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return parse_string(t)
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assert False, "Parsing error: encountered invalid type '{}'".format(t)
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pprint.PrettyPrinter(
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indent=2
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).pprint(parse_thing(next_byte()))
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