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Model set.pop() after dict.popitem().

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This commit is contained in:
Raymond Hettinger 2005-08-02 03:45:16 +00:00
parent 6a694508ae
commit 67962ab1bb
2 changed files with 34 additions and 12 deletions
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42
Objects/setobject.c
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@ -1508,24 +1508,42 @@ static PyObject *
set_pop(PySetObject *so)
{
PyObject *key;
int pos = 0;
int rv;
register setentry *entry;
register int i = 0;
if (!set_next_internal(so, &pos, &key)) {
assert (PyAnySet_Check(so));
if (so->used == 0) {
PyErr_SetString(PyExc_KeyError, "pop from an empty set");
return NULL;
}
Py_INCREF(key);
rv = set_discard_internal(so, key);
if (rv == -1) {
Py_DECREF(key);
return NULL;
} else if (rv == DISCARD_NOTFOUND) {
Py_DECREF(key);
PyErr_SetObject(PyExc_KeyError, key);
return NULL;
/* Set entry to "the first" unused or dummy set entry. We abuse
* the hash field of slot 0 to hold a search finger:
* If slot 0 has a value, use slot 0.
* Else slot 0 is being used to hold a search finger,
* and we use its hash value as the first index to look.
*/
entry = &so->table[0];
if (entry->key == NULL || entry->key == dummy) {
i = (int)entry->hash;
/* The hash field may be a real hash value, or it may be a
* legit search finger, or it may be a once-legit search
* finger that's out of bounds now because it wrapped around
* or the table shrunk -- simply make sure it's in bounds now.
*/
if (i > so->mask || i < 1)
i = 1; /* skip slot 0 */
while ((entry = &so->table[i])->key == NULL || entry->key==dummy) {
i++;
if (i > so->mask)
i = 1;
}
}
key = entry->key;
Py_INCREF(dummy);
entry->key = dummy;
so->used--;
so->table[0].hash = i + 1; /* next place to start */
return key;
}