* set_merge() cannot assume that the table doesn't resize during iteration.
* convert some unnecessary tests to asserts -- they were necessary in
dictobject.c because PyDict_Next() is a public function. The same is
not true for set_next().
* re-arrange the order of functions to more closely match the order
in dictobject.c. This makes it must easier to compare the two
and ought to simplify any issues of maintaining both.
was never called during interpreter shutdown GC, so the f_back!=NULL
assertion was correct. Now that generators get close()d during GC,
the assertion was being triggered because the generator close() was being
called as the top-level frame. However, nothing actually is broken by
this; it's just that the condition was unexpected in previous Python
versions.
a frozenset conversion when the initial search attempt fails with a
TypeError and the key is some type of set. Add a testcase.
* Eliminate a duplicate if-stmt.
s|=s, s&=s, s-=s, or s^=s). Add related tests.
* Improve names for several variables and functions.
* Provide alternate table access functions (next, contains, add, and discard)
that work with an entry argument instead of just a key. This improves
set-vs-set operations because we already have a hash value for each key
and can avoid unnecessary calls to PyObject_Hash(). Provides a 5% to 20%
speed-up for quick hashing elements like strings and integers. Provides
much more substantial improvements for slow hashing elements like tuples
or objects defining a custom __hash__() function.
* Have difference operations resize() when 1/5 of the elements are dummies.
Formerly, it was 1/6. The new ratio triggers less frequently and only
in cases that it can resize quicker and with greater benefit. The right
answer is probably either 1/4, 1/5, or 1/6. Picked the middle value for
an even trade-off between resize time and the space/time costs of dummy
entries.
* Bring in free list from dictionary code.
* Improve several comments.
* Differencing can leave many dummy entries. If more than
1/6 are dummies, then resize them away.
* Factor-out common code with new macro, PyAnySet_CheckExact.
* Give set_lookkey_string() a fast alternate path when no dummy entries
are present.
* Have set_swap_bodies() reset the hash field to -1 whenever either of
bodies is not a frozenset. Maintains the invariant of regular sets
always having -1 in the hash field; otherwise, any mutation would make
the hash value invalid.
* Use an entry pointer to simplify the code in frozenset_hash().
dictobject.c.
* Have frozenset_hash() use entry->hash instead of re-computing each
individual hash with PyObject_Hash(o);
* Finalize the dummy entry before a system exit.
- Handle both frozenset() and frozenset([]).
- Do not use singleton for frozenset subclasses.
- Finalize the singleton.
- Add test cases.
* Factor-out set_update_internal() from set_update(). Simplifies the
code for several internal callers.
* Factor constant expressions out of loop in set_merge_internal().
* Minor comment touch-ups.
In addition, long_pow() skipped a necessary (albeit extremely unlikely
to trigger) error check when converting an int modulus to long.
Alas, I was unable to write a test case that crashed due to either
cause.
Bugfix candidate.
[ 1229429 ] missing Py_DECREF in PyObject_CallMethod
Add a test in test_enumerate, which is a bit random, but suffices
(reversed_new calls PyObject_CallMethod under some circumstances).
managed by C, because it's possible for the block to be smaller than the
new requested size, and at the end of allocated VM. Trying to copy over
nbytes bytes to a Python small-object block can segfault then, and there's
no portable way to avoid this (we would have to know how many bytes
starting at p are addressable, and std C has no means to determine that).
Bugfix candidate. Should be backported to 2.4, but I'm out of time.
[ 1181301 ] make float packing copy bytes when they can
which hasn't been reviewed, despite numerous threats to check it in
anyway if noone reviews it. Please read the diff on the checkin list,
at least!
The basic idea is to examine the bytes of some 'probe values' to see if
the current platform is a IEEE 754-ish platform, and if so
_PyFloat_{Pack,Unpack}{4,8} just copy bytes around.
The rest is hair for testing, and tests.
conversion using the proper magic slot (e.g., __int__()). Also move conversion
code out of PyNumber_*() functions in the C API into the nb_* function.
Applied patch #1109424. Thanks Walter Doewald.
[ 1165306 ] Property access with decorator makes interpreter crash
Don't allow the creation of unbound methods with NULL im_class, because
attempting to call such crashes.
Backport candidate.
* Speed-up "x in y" where x has more than one character.
The existing code made excessive calls to the expensive memcmp() function.
The new code uses memchr() to rapidly find a start point for memcmp().
In addition to knowing that the first character is a match, the new code
also checks that the last character is a match. This significantly reduces
the incidence of false starts (saving memcmp() calls and making quadratic
behavior less likely).
Improves the timings on:
python -m timeit -r7 -s"x='a'*1000" "'ab' in x"
python -m timeit -r7 -s"x='a'*1000" "'bc' in x"
Once this code has proven itself, then string_find_internal() should refer
to it rather than running its own version. Also, something similar may
apply to unicode objects.
[ 1124295 ] Function's __name__ no longer accessible in restricted mode
which I introduced with a bit of mindless copy-paste when making
__name__ writable. You can't assign to __name__ in restricted mode,
which I'm going to pretend was intentional :)
* Added missing error checks.
* Fixed O(n**2) growth pattern. Modeled after lists to achieve linear
amortized resizing. Improves construction of "tuple(it)" when "it" is
large and does not have a __len__ method. Other cases are unaffected.
In cyclic gc, clear weakrefs to unreachable objects before allowing any
Python code (weakref callbacks or __del__ methods) to run.
This is a critical bugfix, affecting all versions of Python since weakrefs
were introduced. I'll backport to 2.3.
exposed in header files. Fixed a few comments in these headers.
As we might have expected, writing down invariants systematically exposed a
(minor) bug. In this case, function objects have a writeable func_code
attribute, which could be set to code objects with the wrong number of
free variables. Calling the resulting function segfaulted the interpreter.
Added a corresponding test.
Also, add a testcase.
Formerly, the list_extend() code used several local variables to remember
its state across iterations. Since an iteration could call arbitrary
Python code, it was possible for the list state to be changed. The new
code uses dynamic structure references instead of C locals. So, they
are always up-to-date.
After list_resize() is called, its size has been updated but the new
cells are filled with NULLs. These needed to be filled before arbitrary
iteration code was called; otherwise, that code could attempt to modify
a list that was in a semi-invalid state. The solution was to change
the ob->size field back to a value reflecting the actual number of valid
cells.
When an integer is compared to a float now, the int isn't coerced to float.
This avoids spurious overflow exceptions and insane results. This should
compute correct results, without raising spurious exceptions, in all cases
now -- although I expect that what happens when an int/long is compared to
a NaN is still a platform accident.
Note that we had potential problems here even with "short" ints, on boxes
where sizeof(long)==8. There's #ifdef'ed code here to handle that, but
I can't test it as intended. I tested it by changing the #ifdef to
trigger on my 32-bit box instead.
I suppose this is a bugfix candidate, but I won't backport it. It's
long-winded (for speed) and messy (because the problem is messy). Note
that this also depends on a previous 2.4 patch that introduced
_Py_SwappedOp[] as an extern.
Make PySequence_Check() and PyMapping_Check() handle NULL inputs. This
goes beyond what most of the other checks do, but it is nice defensive
programming and solves the OP's problem.
module type with silly arguments. (The exact name can be quibbled
over, if you care).
This was partially inspired by bug #1014215 and so on, but is also
just a good idea.
The list resizing scheme only downsized when more than 16 elements were
removed in a single step: del a[100:120]. As a result, the list would
never shrink when popping elements off one at a time.
This patch makes it shrink whenever more than half of the space is unused.
Also, at Tim's suggestion, renamed _new_size to new_allocated. This makes
the code easier to understand.
decoding incomplete input (when the input stream is temporarily exhausted).
codecs.StreamReader now implements buffering, which enables proper
readline support for the UTF-16 decoders. codecs.StreamReader.read()
has a new argument chars which specifies the number of characters to
return. codecs.StreamReader.readline() and codecs.StreamReader.readlines()
have a new argument keepends. Trailing "\n"s will be stripped from the lines
if keepends is false. Added C APIs PyUnicode_DecodeUTF8Stateful and
PyUnicode_DecodeUTF16Stateful.
This checkin is adapted from part 2 (of 3) of Trevor Perrin's patch set.
BACKWARD INCOMPATIBILITY: SHIFT must now be divisible by 5. AFAIK,
nobody will care. long_pow() could be complicated to worm around that,
if necessary.
long_pow():
- BUGFIX: This leaked the base and power when the power was negative
(and so the computation delegated to float pow).
- Instead of doing right-to-left exponentiation, do left-to-right. This
is more efficient for small bases, which is the common case.
- In addition, if the exponent is large (more than FIVEARY_CUTOFF
digits), precompute [a**i % c for i in range(32)], and go left to
right 5 bits at a time.
l_divmod():
- The signature changed so that callers who don't want the quotient,
or don't want the remainder, can pass NULL in the slot they don't
want. This saves them from having to declare a vrbl for unwanted
stuff, and remembering to decref it.
long_mod(), long_div(), long_classic_div():
- Adjust to new l_divmod() signature, and simplified as a result.
This checkin is adapted from part 1 (of 3) of Trevor Perrin's patch set.
x_mul()
- sped a little by optimizing the C
- sped a lot (~2X) if it's doing a square; note that long_pow() squares
often
k_mul()
- more cache-friendly now if it's doing a square
KARATSUBA_CUTOFF
- boosted; gradeschool mult is quicker now, and it may have been too low
for many platforms anyway
KARATSUBA_SQUARE_CUTOFF
- new
- since x_mul is a lot faster at squaring now, the point at which
Karatsuba pays for squaring is much higher than for general mult
need to convert str objects from the iterable to unicode. So, if
someone set the system default encoding to something nasty enough,
the conversion process could mutate the input iterable as a side
effect, and PySequence_Fast doesn't hide that from us if the input was
a list. IOW, can't assume the size of PySequence_Fast's result is
invariant across PyUnicode_FromObject() calls.
much to reduce the size of the code, but greatly improves its clarity.
It's also quicker in what's probably the most common case (the argument
iterable is a list). Against it, if the iterable isn't a list or a tuple,
a temp tuple is materialized containing the entire input sequence, and
that's a bigger temp memory burden. Yawn.
1. u1.join([u2]) is u2
2. Be more careful about C-level int overflow.
Since PySequence_Fast() isn't needed to achieve #1, it's not used -- but
the code could sure be simpler if it were.
happen in 2.3, but nobody noticed it still was getting generated (the
warning was disabled by default). OverflowWarning and
PyExc_OverflowWarning should be removed for 2.5, and left notes all over
saying so.
(Patch contributed by Nick Coghlan.)
Now joining string subtypes will always return a string.
Formerly, if there were only one item, it was returned unchanged.
Added XXX comment about why the undocumented PyRange_New() API function
is too broken to be worth the considerable pain of repairing.
Changed range_new() to stop using PyRange_New(). This fixes a variety
of bogus errors. Nothing in the core uses PyRange_New() now.
Documented that xrange() is intended to be simple and fast, and that
CPython restricts its arguments, and length of its result sequence, to
native C longs.
Added some tests that failed before the patch, and repaired a test that
relied on a bogus OverflowError getting raised.
hack: it would resize *interned* strings in-place! This occurred because
their reference counts do not have their expected value -- stringobject.c
hacks them. Mea culpa.
Raymond Hettinger
Phillip J. Eby
Neil Schemenauer
Hye-Shik Chang
Tim Peters
Michael W. Hudson
Anthony Baxter
Skip Montanaro
Armin Rigo
Brett Cannon
Barry Warsaw
Martin v. Löwis
Marc-André Lemburg
Peter Astrand
Thomas Heller
Walter Dörwald
Andrew M. Kuchling
Neal Norwitz