diff options
Diffstat (limited to 'Lib/pickle.py')
| -rw-r--r-- | Lib/pickle.py | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/Lib/pickle.py b/Lib/pickle.py index 4abc046..f6cbea8 100644 --- a/Lib/pickle.py +++ b/Lib/pickle.py @@ -243,18 +243,25 @@ class Pickler: def save_int(self, object): if self.bin: - i = mdumps(object)[1:] - if i[-2:] == '\000\000': - if i[-3] == '\000': - self.write(BININT1 + i[:-3]) - return - - self.write(BININT2 + i[:-2]) + # If the int is small enough to fit in a signed 4-byte 2's-comp + # format, we can store it more efficiently than the general + # case. + high_bits = object >> 31 # note that Python shift sign-extends + if high_bits == 0 or high_bits == -1: + # All high bits are copies of bit 2**31, so the value + # fits in a 4-byte signed int. + i = mdumps(object)[1:] + assert len(i) == 4 + if i[-2:] == '\000\000': # fits in 2-byte unsigned int + if i[-3] == '\000': # fits in 1-byte unsigned int + self.write(BININT1 + i[0]) + else: + self.write(BININT2 + i[:2]) + else: + self.write(BININT + i) return - - self.write(BININT + i) - else: - self.write(INT + `object` + '\n') + # Text pickle, or int too big to fit in signed 4-byte format. + self.write(INT + `object` + '\n') dispatch[IntType] = save_int def save_long(self, object): |