Commit Graph

130 Commits

Author SHA1 Message Date
Guido van Rossum efae8862fe In doc strings, use 'k in D' rather than D.has_key(k). 2002-09-04 11:29:45 +00:00
Guido van Rossum 45ec02aed1 SF patch 576101, by Oren Tirosh: alternative implementation of
interning.  I modified Oren's patch significantly, but the basic idea
and most of the implementation is unchanged.  Interned strings created
with PyString_InternInPlace() are now mortal, and you must keep a
reference to the resulting string around; use the new function
PyString_InternImmortal() to create immortal interned strings.
2002-08-19 21:43:18 +00:00
Jeremy Hylton 938ace69a0 staticforward bites the dust.
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.
2002-07-17 16:30:39 +00:00
Guido van Rossum 2147df748f Make StopIteration a sink state. This is done by clearing out the
di_dict field when the end of the list is reached.  Also make the
error ("dictionary changed size during iteration") a sticky state.

Also remove the next() method -- one is supplied automatically by
PyType_Ready() because the tp_iternext slot is set.  That's a good
thing, because the implementation given here was buggy (it never
raised StopIteration).
2002-07-16 20:30:22 +00:00
Martin v. Löwis 14f8b4cfcb Patch #568124: Add doc string macros. 2002-06-13 20:33:02 +00:00
Guido van Rossum e027d9818f Add Raymond Hettinger's d.pop(). See SF patch 539949. 2002-04-12 15:11:59 +00:00
Neil Schemenauer 6189b89cc5 PyObject_GC_Del and PyObject_Del can now be used as a function
designators.

Remove PyMalloc_New.
2002-04-12 02:43:00 +00:00
Guido van Rossum 77f6a65eb0 Add the 'bool' type and its values 'False' and 'True', as described in
PEP 285.  Everything described in the PEP is here, and there is even
some documentation.  I had to fix 12 unit tests; all but one of these
were printing Boolean outcomes that changed from 0/1 to False/True.
(The exception is test_unicode.py, which did a type(x) == type(y)
style comparison.  I could've fixed that with a single line using
issubtype(x, type(y)), but instead chose to be explicit about those
places where a bool is expected.

Still to do: perhaps more documentation; change standard library
modules to return False/True from predicates.
2002-04-03 22:41:51 +00:00
Tim Peters 1f7df3595a Remove the CACHE_HASH and INTERN_STRINGS preprocessor symbols. 2002-03-29 03:29:08 +00:00
Guido van Rossum ff413af605 This is Neil's fix for SF bug 535905 (Evil Trashcan and GC interaction).
The fix makes it possible to call PyObject_GC_UnTrack() more than once
on the same object, and then move the PyObject_GC_UnTrack() call to
*before* the trashcan code is invoked.

BUGFIX CANDIDATE!
2002-03-28 20:34:59 +00:00
Neil Schemenauer dcc819a5c9 Use pymalloc if it's enabled. 2002-03-22 15:33:15 +00:00
Tim Peters f582b82fe9 SF bug #491415 PyDict_UpdateFromSeq2() unused
PyDict_UpdateFromSeq2():  removed it.
PyDict_MergeFromSeq2():  made it public and documented it.
PyDict_Merge() docs:  updated to reveal <wink> that the second
argument can be any mapping object.
2001-12-11 18:51:08 +00:00
Guido van Rossum dbb53d9918 Fix of SF bug #475877 (Mutable subtype instances are hashable).
Rather than tweaking the inheritance of type object slots (which turns
out to be too messy to try), this fix adds a __hash__ to the list and
dict types (the only mutable types I'm aware of) that explicitly
raises an error.  This has the advantage that list.__hash__([]) also
raises an error (previously, this would invoke object.__hash__([]),
returning the argument's address); ditto for dict.__hash__.

The disadvantage for this fix is that 3rd party mutable types aren't
automatically fixed.  This should be added to the rules for creating
subclassable extension types: if you don't want your object to be
hashable, add a tp_hash function that raises an exception.

Also, it's possible that I've forgotten about other mutable types for
which this should be done.
2001-12-03 16:32:18 +00:00
Tim Peters a427a2b8d0 Rename "dictionary" (type and constructor) to "dict". 2001-10-29 22:25:45 +00:00
Tim Peters 4d85953fe6 dictionary() constructor:
+ Change keyword arg name from "x" to "items".  People passing a mapping
  object can stretch their imaginations <wink>.
+ Simplify the docstring text.
2001-10-27 18:27:48 +00:00
Tim Peters 1fc240e851 Generalize dictionary() to accept a sequence of 2-sequences. At the
outer level, the iterator protocol is used for memory-efficiency (the
outer sequence may be very large if fully materialized); at the inner
level, PySequence_Fast() is used for time-efficiency (these should
always be sequences of length 2).

dictobject.c, new functions PyDict_{Merge,Update}FromSeq2.  These are
wholly analogous to PyDict_{Merge,Update}, but process a sequence-of-2-
sequences argument instead of a mapping object.  For now, I left these
functions file static, so no corresponding doc changes.  It's tempting
to change dict.update() to allow a sequence-of-2-seqs argument too.

Also changed the name of dictionary's keyword argument from "mapping"
to "x".  Got a better name?  "mapping_or_sequence_of_pairs" isn't
attractive, although more so than "mosop" <wink>.

abstract.h, abstract.tex:  Added new PySequence_Fast_GET_SIZE function,
much faster than going thru the all-purpose PySequence_Size.

libfuncs.tex:
- Document dictionary().
- Fiddle tuple() and list() to admit that their argument is optional.
- The long-winded repetitions of "a sequence, a container that supports
  iteration, or an iterator object" is getting to be a PITA.  Many
  months ago I suggested factoring this out into "iterable object",
  where the definition of that could include being explicit about
  generators too (as is, I'm not sure a reader outside of PythonLabs
  could guess that "an iterator object" includes a generator call).
- Please check my curly braces -- I'm going blind <0.9 wink>.

abstract.c, PySequence_Tuple():  When PyObject_GetIter() fails, leave
its error msg alone now (the msg it produces has improved since
PySequence_Tuple was generalized to accept iterable objects, and
PySequence_Tuple was also stomping on the msg in cases it shouldn't
have even before PyObject_GetIter grew a better msg).
2001-10-26 05:06:50 +00:00
Guido van Rossum 9475a2310d Enable GC for new-style instances. This touches lots of files, since
many types were subclassable but had a xxx_dealloc function that
called PyObject_DEL(self) directly instead of deferring to
self->ob_type->tp_free(self).  It is permissible to set tp_free in the
type object directly to _PyObject_Del, for non-GC types, or to
_PyObject_GC_Del, for GC types.  Still, PyObject_DEL was a tad faster,
so I'm fearing that our pystone rating is going down again.  I'm not
sure if doing something like

void xxx_dealloc(PyObject *self)
{
	if (PyXxxCheckExact(self))
		PyObject_DEL(self);
	else
		self->ob_type->tp_free(self);
}

is any faster than always calling the else branch, so I haven't
attempted that -- however those types whose own dealloc is fancier
(int, float, unicode) do use this pattern.
2001-10-05 20:51:39 +00:00
Tim Peters 0ab085c4cb Changed the dict implementation to take "string shortcuts" only when
keys are true strings -- no subclasses need apply.  This may be debatable.

The problem is that a str subclass may very well want to override __eq__
and/or __hash__ (see the new example of case-insensitive strings in
test_descr), but go-fast shortcuts for strings are ubiquitous in our dicts
(and subclass overrides aren't even looked for then).  Another go-fast
reason for the change is that PyCheck_StringExact() is a quicker test
than PyCheck_String(), and we make such a test on virtually every access
to every dict.

OTOH, a str subclass may also be perfectly happy using the base str eq
and hash, and this change slows them a lot.  But those cases are still
hypothetical, while Python's own reliance on true-string dicts is not.
2001-09-14 00:25:33 +00:00
Tim Peters b95ec09a44 Repair typo in comment. 2001-09-02 18:35:54 +00:00
Tim Peters 25786c0851 Make dictionary() a real constructor. Accepts at most one argument, "a
mapping object", in the same sense dict.update(x) requires of x (that x
has a keys() method and a getitem).
Questionable:  The other type constructors accept a keyword argument, so I
did that here too (e.g., dictionary(mapping={1:2}) works).  But type_call
doesn't pass the keyword args to the tp_new slot (it passes NULL), it only
passes them to the tp_init slot, so getting at them required adding a
tp_init slot to dicts.  Looks like that makes the normal case (i.e., no
args at all) a little slower (the time it takes to call dict.tp_init and
have it figure out there's nothing to do).
2001-09-02 08:22:48 +00:00
Neil Schemenauer e83c00efd0 Use new GC API. 2001-08-29 23:54:21 +00:00
Martin v. Löwis e3eb1f2b23 Patch #427190: Implement and use METH_NOARGS and METH_O. 2001-08-16 13:15:00 +00:00
Guido van Rossum 05ac6de2d5 Add PyDict_Merge(a, b, override):
PyDict_Merge(a, b, 1) is the same as PyDict_Update(a, b).
PyDict_Merge(a, b, 0) does something similar but leaves existing items
unchanged.
2001-08-10 20:28:28 +00:00
Tim Peters 6d6c1a35e0 Merge of descr-branch back into trunk. 2001-08-02 04:15:00 +00:00
Barry Warsaw 66a0d1d9b9 dict_update(): Generalize this method so {}.update() accepts any
"mapping" object, specifically one that supports PyMapping_Keys() and
PyObject_GetItem().  This allows you to say e.g. {}.update(UserDict())

We keep the special case for concrete dict objects, although that
seems moderately questionable.  OTOH, the code exists and works, so
why change that?

.update()'s docstring already claims that D.update(E) implies calling
E.keys() so it's appropriate not to transform AttributeErrors in
PyMapping_Keys() to TypeErrors.

Patch eyeballed by Tim.
2001-06-26 20:08:32 +00:00
Tim Peters c605784174 dict_repr: Reuse one of the int vars (minor code simplification). 2001-06-16 07:52:53 +00:00
Tim Peters a7259597f1 SF bug 433228: repr(list) woes when len(list) big.
Gave Python linear-time repr() implementations for dicts, lists, strings.
This means, e.g., that repr(range(50000)) is no longer 50x slower than
pprint.pprint() in 2.2 <wink>.

I don't consider this a bugfix candidate, as it's a performance boost.

Added _PyString_Join() to the internal string API.  If we want that in the
public API, fine, but then it requires runtime error checks instead of
asserts.
2001-06-16 05:11:17 +00:00
Tim Peters afb6ae8452 Store the mask instead of the size in dictobjects. The mask is more
frequently used, and in particular this allows to drop the last
remaining obvious time-waster in the crucial lookdict() and
lookdict_string() functions.  Other changes consist mostly of changing
"i < ma_size" to "i <= ma_mask" everywhere.
2001-06-04 21:00:21 +00:00
Tim Peters 453163d842 lookdict: stop more insane core-dump mutating comparison cases. Should
be possible to provoke unbounded recursion now, but leaving that to someone
else to provoke and repair.
Bugfix candidate -- although this is getting harder to backstitch, and the
cases it's protecting against are mondo contrived.
2001-06-03 04:54:32 +00:00
Tim Peters 7b5d0afb1e lookdict: Reduce obfuscating code duplication with a judicious goto.
This code is likely to get even hairier to squash core dumps due to
mutating comparisons, and it's hard enough to follow without that.
2001-06-03 04:14:43 +00:00
Tim Peters 19b77cfc4b Finish the dict->string coredump fix. Need sleep.
Bugfix candidate.
2001-06-02 08:27:39 +00:00
Tim Peters 23cf6be23c Coredumpers from Michael Hudson, mutating dicts while printing or
converting to string.
Critical bugfix candidate -- if you take this seriously <wink>.
2001-06-02 08:02:56 +00:00
Tim Peters f4b33f61fb dict_popitem(): Repaired last-second 2.1 comment, which misidentified the
true reason for allocating the tuple before checking the dict size.
2001-06-02 05:42:29 +00:00
Tim Peters eb28ef209e New collision resolution scheme: no polynomials, simpler, faster, less
code, less memory.  Tests have uncovered no drawbacks.  Christian and
Vladimir are the other two people who have burned many brain cells on the
dict code in recent years, and they like the approach too, so I'm checking
it in without further ado.
2001-06-02 05:27:19 +00:00
Tim Peters 15d4929ae4 Implement an old idea of Christian Tismer's: use polynomial division
instead of multiplication to generate the probe sequence.  The idea is
recorded in Python-Dev for Dec 2000, but that version is prone to rare
infinite loops.

The value is in getting *all* the bits of the hash code to participate;
and, e.g., this speeds up querying every key in a dict with keys
 [i << 16 for i in range(20000)] by a factor of 500.  Should be equally
valuable in any bad case where the high-order hash bits were getting
ignored.

Also wrote up some of the motivations behind Python's ever-more-subtle
hash table strategy.
2001-05-27 07:39:22 +00:00
Martin v. Löwis cd35306a25 Patch #424335: Implement string_richcompare, remove string_compare.
Use new _PyString_Eq in lookdict_string.
2001-05-24 16:56:35 +00:00
Tim Peters f8a548c23c dictresize(): Rebuild small tables if there are any dummies, not just if
they're entirely full.  Not a question of correctness, but of temporarily
misplaced common sense.
2001-05-24 16:26:40 +00:00
Tim Peters 0c6010be75 Jack Jansen hit a bug in the new dict code, reported on python-dev.
dictresize() was too aggressive about never ever resizing small dicts.
If a small dict is entirely full, it needs to rebuild it despite that
it won't actually resize it, in order to purge old dummy entries thus
creating at least one virgin slot (lookdict assumes at least one such
exists).

Also took the opportunity to add some high-level comments to dictresize.
2001-05-23 23:33:57 +00:00
Fred Drake 0c23231f6e Remove unused variable. 2001-05-22 22:36:52 +00:00
Tim Peters dea48ec581 SF patch #425242: Patch which "inlines" small dictionaries.
The idea is Marc-Andre Lemburg's, the implementation is Tim's.
Add a new ma_smalltable member to dictobjects, an embedded vector of
MINSIZE (8) dictentry structs.  Short course is that this lets us avoid
additional malloc(s) for dicts with no more than 5 entries.

The changes are widespread but mostly small.

Long course:  WRT speed, all scalar operations (getitem, setitem, delitem)
on non-empty dicts benefit from no longer needing NULL-pointer checks
(ma_table is never NULL anymore).  Bulk operations (copy, update, resize,
clearing slots during dealloc) benefit in some cases from now looping
on the ma_fill count rather than on ma_size, but that was an unexpected
benefit:  the original reason to loop on ma_fill was to let bulk
operations on empty dicts end quickly (since the NULL-pointer checks
went away, empty dicts aren't special-cased any more).

Special considerations:

For dicts that remain empty, this change is a lose on two counts:
the dict object contains 8 new dictentry slots now that weren't
needed before, and dict object creation also spends time memset'ing
these doomed-to-be-unsused slots to NULLs.

For dicts with one or two entries that never get larger than 2, it's
a mix:  a malloc()/free() pair is no longer needed, and the 2-entry case
gets to use 8 slots (instead of 4) thus decreasing the chance of
collision.  Against that, dict object creation spends time memset'ing
4 slots that aren't strictly needed in this case.

For dicts with 3 through 5 entries that never get larger than 5, it's a
pure win:  the dict is created with all the space they need, and they
never need to resize.  Before they suffered two malloc()/free() calls,
plus 1 dict resize, to get enough space.  In addition, the 8-slot
table they ended with consumed more memory overall, because of the
hidden overhead due to the additional malloc.

For dicts with 6 or more entries, the ma_smalltable member is wasted
space, but then these are large(r) dicts so 8 slots more or less doesn't
make much difference.  They still benefit all the time from removing
ubiquitous dynamic null-pointer checks, and get a small benefit (but
relatively smaller the larger the dict) from not having to do two
mallocs, two frees, and a resize on the way *to* getting their sixth
entry.

All in all it appears a small but definite general win, with larger
benefits in specific cases.  It's especially nice that it allowed to
get rid of several branches, gotos and labels, and overall made the
code smaller.
2001-05-22 20:40:22 +00:00
Tim Peters 91a364df17 Bugfix candidate.
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>.
2001-05-19 07:04:38 +00:00
Tim Peters 1928314ef4 Speed dictresize by collapsing its two passes into one; the reason given
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).
2001-05-17 22:25:34 +00:00
Tim Peters 342c65e19a Aggressive reordering of dict comparisons. In case of collision, it stands
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.
2001-05-13 06:43:53 +00:00
Tim Peters 2f228e75e4 Get rid of the superstitious "~" in dict hashing's "i = (~hash) & mask".
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.
2001-05-13 00:19:31 +00:00
Tim Peters 4fa58bfac2 Restore dicts' tp_compare slot, and change dict_richcompare to say it
doesn't know how to do LE, LT, GE, GT.  dict_richcompare can't do the
latter any faster than dict_compare can.  More importantly, for
cmp(dict1, dict2), Python *first* tries rich compares with EQ, LT, and
GT one at a time, even if the tp_compare slot is defined, and
dict_richcompare called dict_compare for the latter two because
it couldn't do them itself.  The result was a lot of wasted calls to
dict_compare.  Now dict_richcompare gives up at once the times Python
calls it with LT and GT from try_rich_to_3way_compare(), and dict_compare
is called only once (when Python gets around to trying the tp_compare
slot).
Continued mystery:  despite that this cut the number of calls to
dict_compare approximately in half in test_mutants.py, the latter still
runs amazingly slowly.  Running under the debugger doesn't show excessive
activity in the dict comparison code anymore, so I'm guessing the culprit
is somewhere else -- but where?  Perhaps in the element (key/value)
comparison code?  We clearly spend a lot of time figuring out how to
compare things.
2001-05-10 21:45:19 +00:00
Tim Peters 3918fb2549 Repair typo in comment. 2001-05-10 18:58:31 +00:00
Tim Peters 95bf9390a4 SF bug #422121 Insecurities in dict comparison.
Fixed a half dozen ways in which general dict comparison could crash
Python (even cause Win98SE to reboot) in the presence of kay and/or
value comparison routines that mutate the dict during dict comparison.
Bugfix candidate.
2001-05-10 08:32:44 +00:00
Tim Peters e63415ead8 SF patch #421922: Implement rich comparison for dicts.
d1 == d2 and d1 != d2 now work even if the keys and values in d1 and d2
don't support comparisons other than ==, and testing dicts for equality
is faster now (especially when inequality obtains).
2001-05-08 04:38:29 +00:00
Guido van Rossum b1f35bffe5 Mchael Hudson pointed out that the code for detecting changes in
dictionary size was comparing ma_size, the hash table size, which is
always a power of two, rather than ma_used, wich changes on each
insertion or deletion.  Fixed this.
2001-05-02 15:13:44 +00:00
Guido van Rossum 09e563abb4 Add experimental iterkeys(), itervalues(), iteritems() to dict
objects.

Tests show that iteritems() is 5-10% faster than iterating over the
dict and extracting the value with dict[key].
2001-05-01 12:10:21 +00:00