mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-11-25 04:34:37 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 11

Make int, long and float subclassable.

Browse source 
This uses a slightly wimpy and wasteful approach, but it works. :-)
This commit is contained in:
Guido van Rossum 2001-08-29 15:47:46 +00:00
parent e705ef1bce
commit bef1417f9f
3 changed files with 111 additions and 14 deletions
Download patch file Download diff file Expand all files Collapse all files

40
Objects/floatobject.c
View file

@ -626,13 +626,17 @@ float_float(PyObject *v)
}
staticforward PyObject *
float_subtype_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
static PyObject *
float_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
PyObject *x = Py_False; /* Integer zero */
static char *kwlist[] = {"x", 0};
assert(type == &PyFloat_Type);
if (type != &PyFloat_Type)
return float_subtype_new(type, args, kwds); /* Wimp out */
if (!PyArg_ParseTupleAndKeywords(args, kwds, "|O:float", kwlist, &x))
return NULL;
if (PyString_Check(x))
@ -640,6 +644,29 @@ float_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
return PyNumber_Float(x);
}
/* Wimpy, slow approach to tp_new calls for subtypes of float:
first create a regular float from whatever arguments we got,
then allocate a subtype instance and initialize its ob_fval
from the regular float. The regular float is then thrown away.
*/
static PyObject *
float_subtype_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
PyObject *tmp, *new;
assert(PyType_IsSubtype(type, &PyFloat_Type));
tmp = float_new(&PyFloat_Type, args, kwds);
if (tmp == NULL)
return NULL;
assert(PyFloat_Check(tmp));
new = type->tp_alloc(type, 0);;
if (new == NULL)
return NULL;
((PyFloatObject *)new)->ob_fval = ((PyFloatObject *)tmp)->ob_fval;
Py_DECREF(tmp);
return new;
}
static char float_doc[] =
"float(x) -> floating point number\n\
\n\
@ -708,7 +735,8 @@ PyTypeObject PyFloat_Type = {
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES, /* tp_flags */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES |
Py_TPFLAGS_BASETYPE, /* tp_flags */
float_doc, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
@ -750,7 +778,7 @@ PyFloat_Fini(void)
for (i = 0, p = &list->objects[0];
i < N_FLOATOBJECTS;
i++, p++) {
if (PyFloat_Check(p) && p->ob_refcnt != 0)
if (p->ob_type == &PyFloat_Type && p->ob_refcnt != 0)
frem++;
}
next = list->next;
@ -760,7 +788,8 @@ PyFloat_Fini(void)
for (i = 0, p = &list->objects[0];
i < N_FLOATOBJECTS;
i++, p++) {
if (!PyFloat_Check(p) || p->ob_refcnt == 0) {
if (p->ob_type != &PyFloat_Type ||
p->ob_refcnt == 0) {
p->ob_type = (struct _typeobject *)
free_list;
free_list = p;
@ -792,7 +821,8 @@ PyFloat_Fini(void)
for (i = 0, p = &list->objects[0];
i < N_FLOATOBJECTS;
i++, p++) {
if (PyFloat_Check(p) && p->ob_refcnt != 0) {
if (p->ob_type == &PyFloat_Type &&
p->ob_refcnt != 0) {
char buf[100];
PyFloat_AsString(buf, p);
fprintf(stderr,