svn+ssh://pythondev@svn.python.org/python/trunk
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r76295 | mark.dickinson | 2009-11-15 12:31:13 +0000 (Sun, 15 Nov 2009) | 5 lines
Avoid signed overflow in some xrange calculations, and extend
xrange tests to cover some special cases that caused problems
in py3k. This is a partial backport of r76292-76293 (see
issue #7298.)
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least as big as a long. I believe this to be a safe assumption that is being
made in many parts of CPython, but a check could be added.
len(xrange(sys.maxint)) works now, so fix the testsuite's odd exception for
64-bit platforms too. It also fixes 'zip(xrange(sys.maxint), it)' as a
portable-ish (if expensive) alternative to enumerate(it); since zip() now
calls len(), this was breaking on (real) 64-bit platforms. No additional
test was added for that behaviour.
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.
for xrange and list objects).
* list.__reversed__ now checks the length of the sequence object before
calling PyList_GET_ITEM() because the mutable could have changed length.
* all three implementations are now tranparent with respect to length and
maintain the invariant len(it) == len(list(it)) even when the underlying
sequence mutates.
* __builtin__.reversed() now frees the underlying sequence as soon
as the iterator is exhausted.
* the code paths were rearranged so that the most common paths
do not require a jump.
but returns r->len which is a long. This doesn't even cause a warning
on 32-bit platforms, but can return bogus values on 64-bit platforms
(and should cause a compiler warning). Fix this by inserting a range
check when LONG_MAX != INT_MAX, and adding an explicit cast to (int)
when the test passes. When r->len is out of range, PySequence_Size()
and hence len() will report an error (but an iterator will still
work).
The staticforward define was needed to support certain broken C
compilers (notably SCO ODT 3.0, perhaps early AIX as well) botched the
static keyword when it was used with a forward declaration of a static
initialized structure. Standard C allows the forward declaration with
static, and we've decided to stop catering to broken C compilers. (In
fact, we expect that the compilers are all fixed eight years later.)
I'm leaving staticforward and statichere defined in object.h as
static. This is only for backwards compatibility with C extensions
that might still use it.
XXX I haven't updated the documentation.
handlers were both set, but were not compatible. This change uses only the
tp_getattro handler with a more "modern" approach.
This fixes SF bug #551285.
object.
This fixes potential overflows in xrange()'s internal calculations on
64-bit platforms. The fix is complicated because the sq_length slot
function can only return an int; we want to support
xrange(sys.maxint), which is a 64-bit quantity on most 64-bit
platforms (except Win64). The solution is hacky but the best
possible: when the range is that long, we can use it in a for loop but
we can't ask for its length (nor can we actually iterate beyond
2**31-1, because the sq_item slot function has the same restrictions
on its arguments. Fixing those restrictions is a project for another
day...
Mark Dickinson
Alexandre Vassalotti
Gregory P. Smith
Christian Heimes
Raymond Hettinger
Martin v. Löwis
Thomas Wouters
Georg Brandl
Armin Rigo
Tim Peters
Michael W. Hudson
Guido van Rossum
Jeremy Hylton
Neal Norwitz
Fred Drake
Neil Schemenauer
Barry Warsaw