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* Move copyright notice to top and indicate derivation from sets.py and

Browse source 
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.
This commit is contained in:
Raymond Hettinger 2005-08-05 00:01:15 +00:00
parent ea9dcdc062
commit a9d9936d10
1 changed files with 17 additions and 22 deletions
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39
Objects/setobject.c
View file

@ -1,15 +1,19 @@
/* set object implementation
Written and maintained by Raymond D. Hettinger <python@rcn.com>
Derived from Lib/sets.py and Objects/dictobject.c.
/* Set object implementation using a hash table
Functions adapted from dictobject.c
Copyright (c) 2003-5 Python Software Foundation.
All rights reserved.
*/
#include "Python.h"
#include "structmember.h"
/* This must be >= 1. */
#define PERTURB_SHIFT 5
/* Object used as dummy key to fill deleted entries */
static PyObject *dummy; /* Initialized by first call to make_new_set() */
static PyObject *dummy = NULL; /* Initialized by first call to make_new_set() */
#define EMPTY_TO_MINSIZE(so) do { \
memset((so)->smalltable, 0, sizeof((so)->smalltable)); \
@ -515,7 +519,7 @@ set_contains_internal(PySetObject *so, PyObject *key)
return key != NULL && key != dummy;
}
/***** Set iterator types **********************************************/
/***** Set iterator type ***********************************************/
static PyTypeObject PySetIter_Type; /* Forward */
@ -558,7 +562,6 @@ setiter_len(setiterobject *si)
static PySequenceMethods setiter_as_sequence = {
(inquiry)setiter_len, /* sq_length */
0, /* sq_concat */
};
static PyObject *setiter_iternext(setiterobject *si)
@ -632,19 +635,6 @@ static PyTypeObject PySetIter_Type = {
(iternextfunc)setiter_iternext, /* tp_iternext */
};
/***** Derived functions (table accesses only done with above primitives *****/
#include "structmember.h"
/* set object implementation
written and maintained by Raymond D. Hettinger <python@rcn.com>
derived from sets.py written by Greg V. Wilson, Alex Martelli,
Guido van Rossum, Raymond Hettinger, and Tim Peters.
Copyright (c) 2003-5 Python Software Foundation.
All rights reserved.
*/
static int
set_len(PyObject *so)
{
@ -764,6 +754,7 @@ frozenset_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
void
PySet_Fini(void)
{
Py_XDECREF(dummy);
Py_XDECREF(emptyfrozenset);
}
@ -1309,22 +1300,26 @@ set_nocmp(PyObject *self)
static long
frozenset_hash(PyObject *self)
{
PyObject *key;
PySetObject *so = (PySetObject *)self;
int pos = 0;
long hash = 1927868237L;
int i, j;
if (so->hash != -1)
return so->hash;
hash *= set_len(self) + 1;
while (set_next_internal(so, &pos, &key)) {
for (i=0, j=so->used ; j ; j--, i++) {
setentry *entry;
long h;
while ((entry = &so->table[i])->key == NULL || entry->key==dummy)
i++;
/* Work to increase the bit dispersion for closely spaced hash
values. The is important because some use cases have many
combinations of a small number of elements with nearby
hashes so that many distinct combinations collapse to only
a handful of distinct hash values. */
long h = PyObject_Hash(key);
h = entry->hash;
hash ^= (h ^ (h << 16) ^ 89869747L) * 3644798167u;
}
hash = hash * 69069L + 907133923L;