https://github.com/python/cpython/commit/9274d969f3b8d66a01ae704cac866ceb9e207d0e
commit: 9274d969f3b8d66a01ae704cac866ceb9e207d0e
branch: main
author: Victor Stinner <[email protected]>
committer: encukou <[email protected]>
date: 2026-05-06T16:28:11+02:00
summary:
gh-148675: Optimize arraydescr structure: use char[3] (GH-149455)
Replace "const char *typecode;" with "char typecode[3];" to make the
arraydescr structure smaller and avoids an indirection.
files:
M Modules/arraymodule.c
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index a8347123e6496a..472c59ea8c9882 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -33,7 +33,7 @@ static struct PyModuleDef arraymodule;
* functions aren't visible yet.
*/
struct arraydescr {
- const char *typecode;
+ char typecode[3]; // big enough to store "Zd\0"
int itemsize;
PyObject * (*getitem)(struct arrayobject *, Py_ssize_t);
int (*setitem)(struct arrayobject *, Py_ssize_t, PyObject *);
@@ -784,7 +784,7 @@ static const struct arraydescr descriptors[] = {
{"d", sizeof(double), d_getitem, d_setitem, NULL, 0, 0},
{"Zf", 2*sizeof(float), cf_getitem, cf_setitem, NULL, 0, 0},
{"Zd", 2*sizeof(double), cd_getitem, cd_setitem, NULL, 0, 0},
- {NULL, 0, 0, 0, 0, 0, 0} /* Sentinel */
+ {"", 0, 0, 0, 0, 0, 0} /* Sentinel */
};
/****************************************************************************
@@ -2298,12 +2298,12 @@ array__array_reconstructor_impl(PyObject *module,
PyTypeObject *arraytype,
arraytype->tp_name, state->ArrayType->tp_name);
return NULL;
}
- for (descr = descriptors; descr->typecode != NULL; descr++) {
+ for (descr = descriptors; descr->typecode[0] != 0; descr++) {
if (strcmp(descr->typecode, typecode) == 0) {
break;
}
}
- if (descr->typecode == NULL) {
+ if (descr->typecode[0] == 0) {
PyErr_SetString(PyExc_ValueError,
"second argument must be a valid type code");
return NULL;
@@ -2500,7 +2500,7 @@ array__array_reconstructor_impl(PyObject *module,
PyTypeObject *arraytype,
*
* XXX: Is it possible to write a unit test for this?
*/
- for (descr = descriptors; descr->typecode != NULL; descr++) {
+ for (descr = descriptors; descr->typecode[0] != 0; descr++) {
if (descr->is_integer_type &&
(size_t)descr->itemsize == mf_descr.size &&
descr->is_signed == mf_descr.is_signed)
@@ -3047,7 +3047,7 @@ array_new(PyTypeObject *type, PyObject *args, PyObject
*kwds)
*/
initial = NULL;
}
- for (descr = descriptors; descr->typecode != NULL; descr++) {
+ for (descr = descriptors; descr->typecode[0] != 0; descr++) {
if (strcmp(descr->typecode, s) == 0) {
PyObject *a;
Py_ssize_t len;
@@ -3531,7 +3531,7 @@ array_modexec(PyObject *m)
if (typecodes == NULL) {
return -1;
}
- for (descr = descriptors; descr->typecode != NULL; descr++) {
+ for (descr = descriptors; descr->typecode[0] != 0; descr++) {
PyObject *typecode = PyUnicode_DecodeASCII(descr->typecode,
strlen(descr->typecode), NULL);
if (typecode == NULL) {
Py_DECREF(typecodes);
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