diff options
Diffstat (limited to 'Lib/pickle.py')
| -rw-r--r-- | Lib/pickle.py | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/Lib/pickle.py b/Lib/pickle.py index 399e4ab99d..5106ec9932 100644 --- a/Lib/pickle.py +++ b/Lib/pickle.py @@ -1291,6 +1291,11 @@ import binascii as _binascii def encode_long(x): r"""Encode a long to a two's complement little-endian binary string. + Note that 0L is a special case, returning an empty string, to save a + byte in the LONG1 pickling context. + + >>> encode_long(0L) + '' >>> encode_long(255L) '\xff\x00' >>> encode_long(32767L) @@ -1307,7 +1312,7 @@ def encode_long(x): """ if x == 0: - return '\x00' + return '' if x > 0: ashex = hex(x) assert ashex.startswith("0x") @@ -1316,7 +1321,7 @@ def encode_long(x): if nibbles & 1: # need an even # of nibbles for unhexlify ashex = "0x0" + ashex[2:] - elif ashex[2] >= '8': + elif int(ashex[2], 16) >= 8: # "looks negative", so need a byte of sign bits ashex = "0x00" + ashex[2:] else: @@ -1330,11 +1335,11 @@ def encode_long(x): if nibbles & 1: # need an even # of nibbles for unhexlify nibbles += 1 - nbytes = nibbles >> 1 - x += 1L << (nbytes * 8) + nbits = nibbles * 4 + x += 1L << nbits assert x > 0 ashex = hex(x) - if x >> (nbytes * 8 - 1) == 0: + if x >> (nbits - 1) == 0: # "looks positive", so need a byte of sign bits ashex = "0xff" + x[2:] @@ -1348,6 +1353,9 @@ def encode_long(x): def decode_long(data): r"""Decode a long from a two's complement little-endian binary string. + + >>> decode_long('') + 0L >>> decode_long("\xff\x00") 255L >>> decode_long("\xff\x7f") @@ -1362,10 +1370,13 @@ def decode_long(data): 127L """ + nbytes = len(data) + if nbytes == 0: + return 0L ashex = _binascii.hexlify(data[::-1]) n = long(ashex, 16) if data[-1] >= '\x80': - n -= 1L << (len(data) * 8) + n -= 1L << (nbytes * 8) return n # Shorthands |