diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-03-12-09-44-31.bpo-46993.-13hGo.rst b/Misc/NEWS.d/next/Core and Builtins/2022-03-12-09-44-31.bpo-46993.-13hGo.rst new file mode 100644 index 00000000000..b7f7078856b --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2022-03-12-09-44-31.bpo-46993.-13hGo.rst @@ -0,0 +1 @@ +Speed up :class:`bytearray` creation from :class:`list` and :class:`tuple` by 40%. Patch by Kumar Aditya. diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c index 0ebb2ece39d..3493ff046ae 100644 --- a/Objects/bytearrayobject.c +++ b/Objects/bytearrayobject.c @@ -844,8 +844,33 @@ bytearray___init___impl(PyByteArrayObject *self, PyObject *arg, return -1; } - /* XXX Optimize this if the arguments is a list, tuple */ - + if (PyList_CheckExact(arg) || PyTuple_CheckExact(arg)) { + Py_ssize_t size = PySequence_Fast_GET_SIZE(arg); + if (PyByteArray_Resize((PyObject *)self, size) < 0) { + return -1; + } + PyObject **items = PySequence_Fast_ITEMS(arg); + char *s = PyByteArray_AS_STRING(self); + for (Py_ssize_t i = 0; i < size; i++) { + int value; + if (!PyLong_CheckExact(items[i])) { + /* Resize to 0 and go through slowpath */ + if (Py_SIZE(self) != 0) { + if (PyByteArray_Resize((PyObject *)self, 0) < 0) { + return -1; + } + } + goto slowpath; + } + int rc = _getbytevalue(items[i], &value); + if (!rc) { + return -1; + } + s[i] = value; + } + return 0; + } +slowpath: /* Get the iterator */ it = PyObject_GetIter(arg); if (it == NULL) {