bpo-38639: Optimize floor(), ceil() and trunc() for floats. (GH-16991)
diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py
index c237bc1..f832246 100644
--- a/Lib/test/test_math.py
+++ b/Lib/test/test_math.py
@@ -240,6 +240,13 @@
else:
return None
+class FloatLike:
+ def __init__(self, value):
+ self.value = value
+
+ def __float__(self):
+ return self.value
+
class IntSubclass(int):
pass
@@ -397,12 +404,14 @@
def testCeil(self):
self.assertRaises(TypeError, math.ceil)
self.assertEqual(int, type(math.ceil(0.5)))
- self.ftest('ceil(0.5)', math.ceil(0.5), 1)
- self.ftest('ceil(1.0)', math.ceil(1.0), 1)
- self.ftest('ceil(1.5)', math.ceil(1.5), 2)
- self.ftest('ceil(-0.5)', math.ceil(-0.5), 0)
- self.ftest('ceil(-1.0)', math.ceil(-1.0), -1)
- self.ftest('ceil(-1.5)', math.ceil(-1.5), -1)
+ self.assertEqual(math.ceil(0.5), 1)
+ self.assertEqual(math.ceil(1.0), 1)
+ self.assertEqual(math.ceil(1.5), 2)
+ self.assertEqual(math.ceil(-0.5), 0)
+ self.assertEqual(math.ceil(-1.0), -1)
+ self.assertEqual(math.ceil(-1.5), -1)
+ self.assertEqual(math.ceil(0.0), 0)
+ self.assertEqual(math.ceil(-0.0), 0)
#self.assertEqual(math.ceil(INF), INF)
#self.assertEqual(math.ceil(NINF), NINF)
#self.assertTrue(math.isnan(math.ceil(NAN)))
@@ -410,9 +419,14 @@
class TestCeil:
def __ceil__(self):
return 42
+ class FloatCeil(float):
+ def __ceil__(self):
+ return 42
class TestNoCeil:
pass
- self.ftest('ceil(TestCeil())', math.ceil(TestCeil()), 42)
+ self.assertEqual(math.ceil(TestCeil()), 42)
+ self.assertEqual(math.ceil(FloatCeil()), 42)
+ self.assertEqual(math.ceil(FloatLike(42.5)), 43)
self.assertRaises(TypeError, math.ceil, TestNoCeil())
t = TestNoCeil()
@@ -536,16 +550,12 @@
def testFloor(self):
self.assertRaises(TypeError, math.floor)
self.assertEqual(int, type(math.floor(0.5)))
- self.ftest('floor(0.5)', math.floor(0.5), 0)
- self.ftest('floor(1.0)', math.floor(1.0), 1)
- self.ftest('floor(1.5)', math.floor(1.5), 1)
- self.ftest('floor(-0.5)', math.floor(-0.5), -1)
- self.ftest('floor(-1.0)', math.floor(-1.0), -1)
- self.ftest('floor(-1.5)', math.floor(-1.5), -2)
- # pow() relies on floor() to check for integers
- # This fails on some platforms - so check it here
- self.ftest('floor(1.23e167)', math.floor(1.23e167), 1.23e167)
- self.ftest('floor(-1.23e167)', math.floor(-1.23e167), -1.23e167)
+ self.assertEqual(math.floor(0.5), 0)
+ self.assertEqual(math.floor(1.0), 1)
+ self.assertEqual(math.floor(1.5), 1)
+ self.assertEqual(math.floor(-0.5), -1)
+ self.assertEqual(math.floor(-1.0), -1)
+ self.assertEqual(math.floor(-1.5), -2)
#self.assertEqual(math.ceil(INF), INF)
#self.assertEqual(math.ceil(NINF), NINF)
#self.assertTrue(math.isnan(math.floor(NAN)))
@@ -553,9 +563,14 @@
class TestFloor:
def __floor__(self):
return 42
+ class FloatFloor(float):
+ def __floor__(self):
+ return 42
class TestNoFloor:
pass
- self.ftest('floor(TestFloor())', math.floor(TestFloor()), 42)
+ self.assertEqual(math.floor(TestFloor()), 42)
+ self.assertEqual(math.floor(FloatFloor()), 42)
+ self.assertEqual(math.floor(FloatLike(41.9)), 41)
self.assertRaises(TypeError, math.floor, TestNoFloor())
t = TestNoFloor()
@@ -1448,17 +1463,21 @@
self.assertEqual(math.trunc(-0.999999), -0)
self.assertEqual(math.trunc(-100.999), -100)
- class TestTrunc(object):
+ class TestTrunc:
def __trunc__(self):
return 23
-
- class TestNoTrunc(object):
+ class FloatTrunc(float):
+ def __trunc__(self):
+ return 23
+ class TestNoTrunc:
pass
self.assertEqual(math.trunc(TestTrunc()), 23)
+ self.assertEqual(math.trunc(FloatTrunc()), 23)
self.assertRaises(TypeError, math.trunc)
self.assertRaises(TypeError, math.trunc, 1, 2)
+ self.assertRaises(TypeError, math.trunc, FloatLike(23.5))
self.assertRaises(TypeError, math.trunc, TestNoTrunc())
def testIsfinite(self):
diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-10-30-11-31-47.bpo-38639.9-vKtO.rst b/Misc/NEWS.d/next/Core and Builtins/2019-10-30-11-31-47.bpo-38639.9-vKtO.rst
new file mode 100644
index 0000000..4432afd
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-10-30-11-31-47.bpo-38639.9-vKtO.rst
@@ -0,0 +1,2 @@
+Optimized :func:`math.floor()`, :func:`math.ceil()` and :func:`math.trunc()`
+for floats.
diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index e1b46ec..eaaeedb 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -1014,12 +1014,6 @@
}
static PyObject *
-math_1_to_int(PyObject *arg, double (*func) (double), int can_overflow)
-{
- return math_1_to_whatever(arg, func, PyLong_FromDouble, can_overflow);
-}
-
-static PyObject *
math_2(PyObject *const *args, Py_ssize_t nargs,
double (*func) (double, double), const char *funcname)
{
@@ -1112,17 +1106,22 @@
/*[clinic end generated code: output=6c3b8a78bc201c67 input=2725352806399cab]*/
{
_Py_IDENTIFIER(__ceil__);
- PyObject *method, *result;
- method = _PyObject_LookupSpecial(number, &PyId___ceil__);
- if (method == NULL) {
+ if (!PyFloat_CheckExact(number)) {
+ PyObject *method = _PyObject_LookupSpecial(number, &PyId___ceil__);
+ if (method != NULL) {
+ PyObject *result = _PyObject_CallNoArg(method);
+ Py_DECREF(method);
+ return result;
+ }
if (PyErr_Occurred())
return NULL;
- return math_1_to_int(number, ceil, 0);
}
- result = _PyObject_CallNoArg(method);
- Py_DECREF(method);
- return result;
+ double x = PyFloat_AsDouble(number);
+ if (x == -1.0 && PyErr_Occurred())
+ return NULL;
+
+ return PyLong_FromDouble(ceil(x));
}
FUNC2(copysign, copysign,
@@ -1170,17 +1169,22 @@
/*[clinic end generated code: output=c6a65c4884884b8a input=63af6b5d7ebcc3d6]*/
{
_Py_IDENTIFIER(__floor__);
- PyObject *method, *result;
- method = _PyObject_LookupSpecial(number, &PyId___floor__);
- if (method == NULL) {
+ if (!PyFloat_CheckExact(number)) {
+ PyObject *method = _PyObject_LookupSpecial(number, &PyId___floor__);
+ if (method != NULL) {
+ PyObject *result = _PyObject_CallNoArg(method);
+ Py_DECREF(method);
+ return result;
+ }
if (PyErr_Occurred())
return NULL;
- return math_1_to_int(number, floor, 0);
}
- result = _PyObject_CallNoArg(method);
- Py_DECREF(method);
- return result;
+ double x = PyFloat_AsDouble(number);
+ if (x == -1.0 && PyErr_Occurred())
+ return NULL;
+
+ return PyLong_FromDouble(floor(x));
}
FUNC1A(gamma, m_tgamma,
@@ -2061,6 +2065,10 @@
_Py_IDENTIFIER(__trunc__);
PyObject *trunc, *result;
+ if (PyFloat_CheckExact(x)) {
+ return PyFloat_Type.tp_as_number->nb_int(x);
+ }
+
if (Py_TYPE(x)->tp_dict == NULL) {
if (PyType_Ready(Py_TYPE(x)) < 0)
return NULL;