[Python-checkins] cpython: Issue #23290: Optimize set_merge() for cases where the target is empty.
raymond.hettinger
python-checkins at python.org
Wed May 13 10:26:19 CEST 2015
https://hg.python.org/cpython/rev/79c884cc9625
changeset: 96011:79c884cc9625
user: Raymond Hettinger <python at rcn.com>
date: Wed May 13 01:26:14 2015 -0700
summary:
Issue #23290: Optimize set_merge() for cases where the target is empty.
(Contributed by Serhiy Storchaka.)
files:
Misc/NEWS | 3 +
Objects/setobject.c | 50 ++++++++++++++++++++++++++------
2 files changed, 43 insertions(+), 10 deletions(-)
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
- Issue #15027: The UTF-32 encoder is now 3x to 7x faster.
+- Issue #23290: Optimize set_merge() for cases where the target is empty.
+ (Contributed by Serhiy Storchaka.)
+
- Issue #20274: When calling a _sqlite.Connection, it now complains if passed
any keyword arguments. Previously it silently ignored them.
diff --git a/Objects/setobject.c b/Objects/setobject.c
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -548,16 +548,16 @@
{
PySetObject *other;
PyObject *key;
- Py_hash_t hash;
Py_ssize_t i;
- setentry *entry;
+ setentry *so_entry;
+ setentry *other_entry;
assert (PyAnySet_Check(so));
assert (PyAnySet_Check(otherset));
other = (PySetObject*)otherset;
if (other == so || other->used == 0)
- /* a.update(a) or a.update({}); nothing to do */
+ /* a.update(a) or a.update(set()); nothing to do */
return 0;
/* Do one big resize at the start, rather than
* incrementally resizing as we insert new keys. Expect
@@ -567,14 +567,44 @@
if (set_table_resize(so, (so->used + other->used)*2) != 0)
return -1;
}
- for (i = 0; i <= other->mask; i++) {
- entry = &other->table[i];
- key = entry->key;
- hash = entry->hash;
- if (key != NULL &&
- key != dummy) {
+ so_entry = so->table;
+ other_entry = other->table;
+
+ /* If our table is empty, and both tables have the same size, and
+ there are no dummies to eliminate, then just copy the pointers. */
+ if (so->fill == 0 && so->mask == other->mask && other->fill == other->used) {
+ for (i = 0; i <= other->mask; i++, so_entry++, other_entry++) {
+ key = other_entry->key;
+ if (key != NULL) {
+ assert(so_entry->key == NULL);
+ Py_INCREF(key);
+ so_entry->key = key;
+ so_entry->hash = other_entry->hash;
+ }
+ }
+ so->fill = other->fill;
+ so->used = other->used;
+ return 0;
+ }
+
+ /* If our table is empty, we can use set_insert_clean() */
+ if (so->fill == 0) {
+ for (i = 0; i <= other->mask; i++, other_entry++) {
+ key = other_entry->key;
+ if (key != NULL && key != dummy) {
+ Py_INCREF(key);
+ set_insert_clean(so, key, other_entry->hash);
+ }
+ }
+ return 0;
+ }
+
+ /* We can't assure there are no duplicates, so do normal insertions */
+ for (i = 0; i <= other->mask; i++, other_entry++) {
+ key = other_entry->key;
+ if (key != NULL && key != dummy) {
Py_INCREF(key);
- if (set_insert_key(so, key, hash) == -1) {
+ if (set_insert_key(so, key, other_entry->hash)) {
Py_DECREF(key);
return -1;
}
--
Repository URL: https://hg.python.org/cpython
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