changeset: 73617:fa2f8dd077e0 user: Antoine Pitrou date: Fri Nov 18 20:14:34 2011 +0100 files: Include/pythonrun.h Misc/NEWS Objects/sliceobject.c Python/pythonrun.c description: Issue #10227: Add an allocation cache for a single slice object. Patch by Stefan Behnel. diff -r 196d485ed26d -r fa2f8dd077e0 Include/pythonrun.h --- a/Include/pythonrun.h Fri Nov 18 19:01:01 2011 +0200 +++ b/Include/pythonrun.h Fri Nov 18 20:14:34 2011 +0100 @@ -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 -r 196d485ed26d -r fa2f8dd077e0 Misc/NEWS --- a/Misc/NEWS Fri Nov 18 19:01:01 2011 +0200 +++ b/Misc/NEWS Fri Nov 18 20:14:34 2011 +0100 @@ -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 -r 196d485ed26d -r fa2f8dd077e0 Objects/sliceobject.c --- a/Objects/sliceobject.c Fri Nov 18 19:01:01 2011 +0200 +++ b/Objects/sliceobject.c Fri Nov 18 20:14:34 2011 +0100 @@ -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 -r 196d485ed26d -r fa2f8dd077e0 Python/pythonrun.c --- a/Python/pythonrun.c Fri Nov 18 19:01:01 2011 +0200 +++ b/Python/pythonrun.c Fri Nov 18 20:14:34 2011 +0100 @@ -531,6 +531,7 @@ PyLong_Fini(); PyFloat_Fini(); PyDict_Fini(); + PySlice_Fini(); /* Cleanup Unicode implementation */ _PyUnicode_Fini();