Issue #10227: Add an allocation cache for a single slice object.
Patch by Stefan Behnel.
diff --git a/Include/pythonrun.h b/Include/pythonrun.h
index bdad15c..fc6c854 100644
--- a/Include/pythonrun.h
+++ b/Include/pythonrun.h
@@ -211,6 +211,7 @@
PyAPI_FUNC(void) PyFloat_Fini(void);
PyAPI_FUNC(void) PyOS_FiniInterrupts(void);
PyAPI_FUNC(void) _PyGC_Fini(void);
+PyAPI_FUNC(void) PySlice_Fini(void);
PyAPI_DATA(PyThreadState *) _Py_Finalizing;
#endif
diff --git a/Misc/NEWS b/Misc/NEWS
index 0a1c67b..183e4ed 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@
Core and Builtins
-----------------
+- Issue #10227: Add an allocation cache for a single slice object. Patch by
+ Stefan Behnel.
+
- Issue #13393: BufferedReader.read1() now asks the full requested size to
the raw stream instead of limiting itself to the buffer size.
diff --git a/Objects/sliceobject.c b/Objects/sliceobject.c
index 2f5c045..c4a1907 100644
--- a/Objects/sliceobject.c
+++ b/Objects/sliceobject.c
@@ -80,19 +80,38 @@
};
-/* Slice object implementation
+/* Slice object implementation */
- start, stop, and step are python objects with None indicating no
+/* Using a cache is very effective since typically only a single slice is
+ * created and then deleted again
+ */
+static PySliceObject *slice_cache = NULL;
+void PySlice_Fini(void)
+{
+ PySliceObject *obj = slice_cache;
+ if (obj != NULL) {
+ slice_cache = NULL;
+ PyObject_Del(obj);
+ }
+}
+
+/* start, stop, and step are python objects with None indicating no
index is present.
*/
PyObject *
PySlice_New(PyObject *start, PyObject *stop, PyObject *step)
{
- PySliceObject *obj = PyObject_New(PySliceObject, &PySlice_Type);
-
- if (obj == NULL)
- return NULL;
+ PySliceObject *obj;
+ if (slice_cache != NULL) {
+ obj = slice_cache;
+ slice_cache = NULL;
+ _Py_NewReference((PyObject *)obj);
+ } else {
+ obj = PyObject_New(PySliceObject, &PySlice_Type);
+ if (obj == NULL)
+ return NULL;
+ }
if (step == NULL) step = Py_None;
Py_INCREF(step);
@@ -260,7 +279,10 @@
Py_DECREF(r->step);
Py_DECREF(r->start);
Py_DECREF(r->stop);
- PyObject_Del(r);
+ if (slice_cache == NULL)
+ slice_cache = r;
+ else
+ PyObject_Del(r);
}
static PyObject *
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 0f2f050..0c267fc 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -531,6 +531,7 @@
PyLong_Fini();
PyFloat_Fini();
PyDict_Fini();
+ PySlice_Fini();
/* Cleanup Unicode implementation */
_PyUnicode_Fini();