bpo-38629: implement __floor__ and __ceil__ for float

Author: isidentical

Lib/test/test_float.py

@@ -312,6 +312,34 @@ def assertEqualAndEqualSign(self, a, b):
         # distinguishes -0.0 and 0.0.
         self.assertEqual((a, copysign(1.0, a)), (b, copysign(1.0, b)))
 
+    def test_float_floor(self):
+        self.assertIsInstance(float(0.5).__floor__(), int)
+        self.assertEqual(float(0.5).__floor__(), 0)
+        self.assertEqual(float(1.0).__floor__(), 1)
+        self.assertEqual(float(1.5).__floor__(), 1)
+        self.assertEqual(float(-0.5).__floor__(), -1)
+        self.assertEqual(float(-1.0).__floor__(), -1)
+        self.assertEqual(float(-1.5).__floor__(), -2)
+        self.assertEqual(float(1.23e167).__floor__(), 1.23e167)
+        self.assertEqual(float(-1.23e167).__floor__(), -1.23e167)
+        self.assertRaises(ValueError, float("nan").__floor__)
+        self.assertRaises(OverflowError, float("inf").__floor__)
+        self.assertRaises(OverflowError, float("-inf").__floor__)
+
+    def test_float_ceil(self):
+        self.assertIsInstance(float(0.5).__ceil__(), int)
+        self.assertEqual(float(0.5).__ceil__(), 1)
+        self.assertEqual(float(1.0).__ceil__(), 1)
+        self.assertEqual(float(1.5).__ceil__(), 2)
+        self.assertEqual(float(-0.5).__ceil__(), 0)
+        self.assertEqual(float(-1.0).__ceil__(), -1)
+        self.assertEqual(float(-1.5).__ceil__(), -1)
+        self.assertEqual(float(1.23e167).__ceil__(), 1.23e167)
+        self.assertEqual(float(-1.23e167).__ceil__(), -1.23e167)
+        self.assertRaises(ValueError, float("nan").__ceil__)
+        self.assertRaises(OverflowError, float("inf").__ceil__)
+        self.assertRaises(OverflowError, float("-inf").__ceil__)
+
     @support.requires_IEEE_754
     def test_float_mod(self):
         # Check behaviour of % operator for IEEE 754 special cases.

Misc/NEWS.d/next/Core and Builtins/2019-10-29-17-11-15.bpo-38629.3qinhF.rst

@@ -0,0 +1,2 @@
+Implementation of missing floor and ceil methods to float object -- by
+Batuhan Taskaya.

Objects/clinic/floatobject.c.h

@@ -923,6 +923,34 @@ float___trunc___impl(PyObject *self)
     return PyLong_FromDouble(wholepart);
 }
 
+/*[clinic input]
+float.__floor__
+
+Return the floor as an Integral.
+[clinic start generated code]*/
+
+static PyObject *
+float___floor___impl(PyObject *self)
+/*[clinic end generated code: output=e0551dbaea8c01d1 input=38c8fb1dd0b579b4]*/
+{
+    double x = PyFloat_AsDouble(self);
+    return PyLong_FromDouble(floor(x));
+}
+
+/*[clinic input]
+float.__ceil__
+
+Return the ceiling as an Integral.
+[clinic start generated code]*/
+
+static PyObject *
+float___ceil___impl(PyObject *self)
+/*[clinic end generated code: output=a2fd8858f73736f9 input=e3d4c94c2b8c8675]*/
+{
+    double x = PyFloat_AsDouble(self);
+    return PyLong_FromDouble(ceil(x));
+}
+
 /* double_round: rounds a finite double to the closest multiple of
    10**-ndigits; here ndigits is within reasonable bounds (typically, -308 <=
    ndigits <= 323).  Returns a Python float, or sets a Python error and
@@ -1847,6 +1875,8 @@ float___format___impl(PyObject *self, PyObject *format_spec)
 static PyMethodDef float_methods[] = {
     FLOAT_CONJUGATE_METHODDEF
     FLOAT___TRUNC___METHODDEF
+    FLOAT___FLOOR___METHODDEF
+    FLOAT___CEIL___METHODDEF
     FLOAT___ROUND___METHODDEF
     FLOAT_AS_INTEGER_RATIO_METHODDEF
     FLOAT_FROMHEX_METHODDEF