[Python-Dev] cpython (3.2): bounds check for bad data (thanks amaury) (original) (raw)
Serhiy Storchaka storchaka at gmail.com
Sat Oct 27 11:30:53 CEST 2012
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On 27.10.12 03:05, philip.jenvey wrote:
http://hg.python.org/cpython/rev/74d65c746f63 changeset: 79953:74d65c746f63 branch: 3.2 parent: 79941:eb999002916c user: Philip Jenvey <pjenvey at underboss.org> date: Fri Oct 26 17:01:53 2012 -0700 summary: bounds check for bad data (thanks amaury)
+ if (strlen(p) > 2 &&
First, it produces compiler warning:
Python/codecs.c: In function ‘PyCodec_SurrogatePassErrors’: Python/codecs.c:794: warning: pointer targets in passing argument 1 of ‘strlen’ differ in signedness /usr/include/string.h:397: note: expected ‘const char *’ but argument is of type ‘unsigned char *’
Second, it slowdown the code to 10%:
$ ./python-orig -m timeit -s 'b=b"\xed\xa0\xa0"+b"x"*10000' 'b.decode("utf-8", "surrogatepass")' 100000 loops, best of 3: 12.2 usec per loop $ ./python -m timeit -s 'b=b"\xed\xa0\xa0"+b"x"*10000' 'b.decode("utf-8", "surrogatepass")' 100000 loops, best of 3: 13.3 usec per loop
I suggest to use the followed code instead:
if (PyBytes_GET_SIZE(object) - start >= 3 &&- Previous message: [Python-Dev] Anyone have a Universal setter example?
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