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lokinet/contrib/bencode-dump.py
Jason Rhinelander 29418f7a7b bencode-dump.py: support reading from stdin
So that you can pipe bt-encoded output into it, e.g. from the
in-progress oxend bt-rpc interface.
2021-08-06 14:25:32 -03:00

94 lines
2.3 KiB
Python
Executable file

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