diff options
Diffstat (limited to 'Lib/pickle.py')
| -rw-r--r-- | Lib/pickle.py | 98 |
1 files changed, 37 insertions, 61 deletions
diff --git a/Lib/pickle.py b/Lib/pickle.py index 5275991662..aca8fd183c 100644 --- a/Lib/pickle.py +++ b/Lib/pickle.py @@ -1235,9 +1235,7 @@ class _Unpickler: raise _Stop(value) dispatch[STOP[0]] = load_stop -# Encode/decode longs in linear time. - -import binascii as _binascii +# Encode/decode longs. def encode_long(x): r"""Encode a long to a two's complement little-endian binary string. @@ -1260,50 +1258,14 @@ def encode_long(x): b'\x7f' >>> """ - if x == 0: return b'' - if x > 0: - ashex = hex(x) - assert ashex.startswith("0x") - njunkchars = 2 + ashex.endswith('L') - nibbles = len(ashex) - njunkchars - if nibbles & 1: - # need an even # of nibbles for unhexlify - ashex = "0x0" + ashex[2:] - elif int(ashex[2], 16) >= 8: - # "looks negative", so need a byte of sign bits - ashex = "0x00" + ashex[2:] - else: - # Build the 256's-complement: (1L << nbytes) + x. The trick is - # to find the number of bytes in linear time (although that should - # really be a constant-time task). - ashex = hex(-x) - assert ashex.startswith("0x") - njunkchars = 2 + ashex.endswith('L') - nibbles = len(ashex) - njunkchars - if nibbles & 1: - # Extend to a full byte. - nibbles += 1 - nbits = nibbles * 4 - x += 1 << nbits - assert x > 0 - ashex = hex(x) - njunkchars = 2 + ashex.endswith('L') - newnibbles = len(ashex) - njunkchars - if newnibbles < nibbles: - ashex = "0x" + "0" * (nibbles - newnibbles) + ashex[2:] - if int(ashex[2], 16) < 8: - # "looks positive", so need a byte of sign bits - ashex = "0xff" + ashex[2:] - - if ashex.endswith('L'): - ashex = ashex[2:-1] - else: - ashex = ashex[2:] - assert len(ashex) & 1 == 0, (x, ashex) - binary = _binascii.unhexlify(ashex) - return bytes(binary[::-1]) + nbytes = (x.bit_length() >> 3) + 1 + result = x.to_bytes(nbytes, byteorder='little', signed=True) + if x < 0 and nbytes > 1: + if result[-1] == 0xff and (result[-2] & 0x80) != 0: + result = result[:-1] + return result def decode_long(data): r"""Decode a long from a two's complement little-endian binary string. @@ -1323,21 +1285,7 @@ def decode_long(data): >>> decode_long(b"\x7f") 127 """ - - nbytes = len(data) - if nbytes == 0: - return 0 - ashex = _binascii.hexlify(data[::-1]) - n = int(ashex, 16) # quadratic time before Python 2.3; linear now - if data[-1] >= 0x80: - n -= 1 << (nbytes * 8) - return n - -# Use the faster _pickle if possible -try: - from _pickle import * -except ImportError: - Pickler, Unpickler = _Pickler, _Unpickler + return int.from_bytes(data, byteorder='little', signed=True) # Shorthands @@ -1362,10 +1310,38 @@ def loads(s, *, fix_imports=True, encoding="ASCII", errors="strict"): return Unpickler(file, fix_imports=fix_imports, encoding=encoding, errors=errors).load() +# Use the faster _pickle if possible +try: + from _pickle import * +except ImportError: + Pickler, Unpickler = _Pickler, _Unpickler + # Doctest def _test(): import doctest return doctest.testmod() if __name__ == "__main__": - _test() + import sys, argparse + parser = argparse.ArgumentParser( + description='display contents of the pickle files') + parser.add_argument( + 'pickle_file', type=argparse.FileType('br'), + nargs='*', help='the pickle file') + parser.add_argument( + '-t', '--test', action='store_true', + help='run self-test suite') + parser.add_argument( + '-v', action='store_true', + help='run verbosely; only affects self-test run') + args = parser.parse_args() + if args.test: + _test() + else: + if not args.pickle_file: + parser.print_help() + else: + import pprint + for f in args.pickle_file: + obj = load(f) + pprint.pprint(obj) |