Two exceedingly unlikely errors in dictresize():
1. The loop for finding the new size had an off-by-one error at the
end (could over-index the polys[] vector).
2. The polys[] vector ended with a 0, apparently intended as a sentinel
value but never used as such; i.e., it was never checked, so 0 could
have been used *as* a polynomial.
Neither bug could trigger unless a dict grew to 2**30 slots; since that
would consume at least 12GB of memory just to hold the dict pointers,
I'm betting it's not the cause of the bug Fred's tracking down <wink>.
If we have a PyCFunction (builtin) and it is METH_VARARGS only, load
the args and dispatch to call_cfunction() directly. This provides a
small speedup for perhaps the most common function calls -- builtins.
derived from but not quite compatible with that of sgmllib, so it's a
new file. I suppose it needs documentation, and htmllib needs to be
changed to use this instead of sgmllib, and sgmllib needs to be
declared obsolete. But that can all be done later.
This code was first published as part of TAL (part of Zope Page
Templates), but that was strongly based on sgmllib anyway. Authors
are Fred drake and Guido van Rossum.
in the comments for using two passes was bogus, as the only object that
can get decref'ed due to the copy is the dummy key, and decref'ing dummy
can't have side effects (for one thing, dummy is immortal! for another,
it's a string object, not a potentially dangerous user-defined object).
And these can now be vectored through glue routines (by defining USE_TOOLBOX_OBJECT_GLUE) which will do the necessary imports, whereupon the module's init routine will tell the glue routine about the real conversion routine address and everything is fine again.
codec files to codecs.py and added logic so that multi mappings
in the decoding maps now result in mappings to None (undefined mapping)
in the encoding maps.
1. Omit the early-out EQ/NE "lengths different?" test. Was unable to find
any real code where it triggered, but it always costs. The same is not
true of list richcmps, where different-size lists appeared to get
compared about half the time.
2. Because tuples are immutable, there's no need to refetch the lengths of
both tuples from memory again on each loop trip.
BUG ALERT: The tuple (and list) richcmp algorithm is arguably wrong,
because it won't believe there's any difference unless Py_EQ returns false
for some corresponding elements:
>>> class C:
... def __lt__(x, y): return 1
... __eq__ = __lt__
...
>>> C() < C()
1
>>> (C(),) < (C(),)
0
>>>
That doesn't make sense -- provided you believe the defn. of C makes sense.
and introduces a new method .decode().
The major change is that strg.encode() will no longer try to convert
Unicode returns from the codec into a string, but instead pass along
the Unicode object as-is. The same is now true for all other codec
return types. The underlying C APIs were changed accordingly.
Note that even though this does have the potential of breaking
existing code, the chances are low since conversion from Unicode
previously took place using the default encoding which is normally
set to ASCII rendering this auto-conversion mechanism useless for
most Unicode encodings.
The good news is that you can now use .encode() and .decode() with
much greater ease and that the door was opened for better accessibility
of the builtin codecs.
As demonstration of the new feature, the patch includes a few new
codecs which allow string to string encoding and decoding (rot13,
hex, zip, uu, base64).
Written by Marc-Andre Lemburg. Copyright assigned to the PSF.
*are* obsolete; three variables and the maketrans() function are not
(yet) obsolete.
Add a compensating warnings.filterwarnings() call to test_strop.py.
Add this to the NEWS.
return a (C) long: PyArg_ParseTuple and Py_BuildValue may not let us get
at the size_t we really want, but C int is clearly too small for a 64-bit
box, and both the start parameter and the return value should work for
large mapped files even on 32-bit boxes. The code really needs to be
rethought from scratch (not by me, though ...).
elements when crunching a list, dict or tuple. Now takes linear time
instead -- huge speedup for even moderately large containers, and the
code is notably simpler too.
Added some basic "is the output correct?" tests to test_pprint.
1) it didn't obey the "start" parameter (and when it does, we must validate
the value)
2) the return value needs to be an absolute index, rather than relative to
some arbitrary point in the file
(checking CVS, it appears this method never worked; these changes bring it
into line with typical .find() behavior)
to reason that me_key is much more likely to match the key we're looking
for than to match dummy, and if the key is absent me_key is much more
likely to be NULL than dummy: most dicts don't even have a dummy entry.
Running instrumented dict code over the test suite and some apps confirmed
that matching dummy was 200-300x less frequent than matching key in
practice. So this reorders the tests to try the common case first.
It can lose if a large dict with many collisions is mostly deleted, not
resized, and then frequently searched, but that's hardly a case we
should be favoring.
The comment following used to say:
/* We use ~hash instead of hash, as degenerate hash functions, such
as for ints <sigh>, can have lots of leading zeros. It's not
really a performance risk, but better safe than sorry.
12-Dec-00 tim: so ~hash produces lots of leading ones instead --
what's the gain? */
That is, there was never a good reason for doing it. And to the contrary,
as explained on Python-Dev last December, it tended to make the *sum*
(i + incr) & mask (which is the first table index examined in case of
collison) the same "too often" across distinct hashes.
Changing to the simpler "i = hash & mask" reduced the number of string-dict
collisions (== # number of times we go around the lookup for-loop) from about
6 million to 5 million during a full run of the test suite (these are
approximate because the test suite does some random stuff from run to run).
The number of collisions in non-string dicts also decreased, but not as
dramatically.
Note that this may, for a given dict, change the order (wrt previous
releases) of entries exposed by .keys(), .values() and .items(). A number
of std tests suffered bogus failures as a result. For dicts keyed by
small ints, or (less so) by characters, the order is much more likely to be
in increasing order of key now; e.g.,
>>> d = {}
>>> for i in range(10):
... d[i] = i
...
>>> d
{0: 0, 1: 1, 2: 2, 3: 3, 4: 4, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9}
>>>
Unfortunately. people may latch on to that in small examples and draw a
bogus conclusion.
test_support.py
Moved test_extcall's sortdict() into test_support, made it stronger,
and imported sortdict into other std tests that needed it.
test_unicode.py
Excluced cp875 from the "roundtrip over range(128)" test, because
cp875 doesn't have a well-defined inverse for unicode("?", "cp875").
See Python-Dev for excruciating details.
Cookie.py
Chaged various output functions to sort dicts before building
strings from them.
test_extcall
Fiddled the expected-result file. This remains sensitive to native
dict ordering, because, e.g., if there are multiple errors in a
keyword-arg dict (and test_extcall sets up many cases like that), the
specific error Python complains about first depends on native dict
ordering.
are including Carbon/Carbon.h in stead of the old headers (unless WITHOUT_FRAMEWORKS
is defined, as it will be for classic MacPython) and selectively disabling all the
stuff that is unneeded in a unix-Python (event handling, etc).
Jack Jansen
Tim Peters
Fred Drake
Jeremy Hylton
Guido van Rossum
Marc-André Lemburg
Mark Hammond
Greg Stein