Stowage/cpython
2
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-10-30 21:21:22 +00:00
Code Issues Projects Releases Packages Wiki Activity

bpo-31373: remove overly strict float range checks (#3486)

Browse source 
This undoes a853a8ba78 except for the pytime.c
parts. We want to continue to allow IEEE 754 doubles larger than FLT_MAX to be
rounded into finite floats. Tests were added to very this behavior.
This commit is contained in:
Benjamin Peterson 2017-09-10 23:50:46 -07:00 • committed by GitHub
parent 252033d50e
commit 2bb69a5b4e
4 changed files with 14 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

6
Lib/test/test_float.py
View file

@ -617,6 +617,12 @@ def test_float_specials_do_unpack(self):
('<f', LE_FLOAT_NAN)]:
struct.unpack(fmt, data)
@support.requires_IEEE_754
def test_serialized_float_rounding(self):
from _testcapi import FLT_MAX
self.assertEqual(struct.pack("<f", 3.40282356e38), struct.pack("<f", FLT_MAX))
self.assertEqual(struct.pack("<f", -3.40282356e38), struct.pack("<f", -FLT_MAX))
class FormatTestCase(unittest.TestCase):
def test_format(self):

6
Lib/test/test_getargs2.py
View file

@ -377,6 +377,12 @@ def test_f(self):
r = getargs_f(NAN)
self.assertNotEqual(r, r)
@support.requires_IEEE_754
def test_f_rounding(self):
from _testcapi import getargs_f
self.assertEqual(getargs_f(3.40282356e38), FLT_MAX)
self.assertEqual(getargs_f(-3.40282356e38), -FLT_MAX)
def test_d(self):
from _testcapi import getargs_d
self.assertEqual(getargs_d(4.25), 4.25)

4
Objects/floatobject.c
View file

@ -2233,13 +2233,13 @@ _PyFloat_Pack4(double x, unsigned char *p, int le)
}
else {
float y = (float)x;
int i, incr = 1;
if (fabs(x) > FLT_MAX && !Py_IS_INFINITY(x))
if (Py_IS_INFINITY(y) && !Py_IS_INFINITY(x))
goto Overflow;
unsigned char s[sizeof(float)];
float y = (float)x;
memcpy(s, &y, sizeof(float));
if ((float_format == ieee_little_endian_format && !le)

4
Python/getargs.c
View file

@ -859,10 +859,6 @@ convertsimple(PyObject *arg, const char **p_format, va_list *p_va, int flags,
double dval = PyFloat_AsDouble(arg);
if (PyErr_Occurred())
RETURN_ERR_OCCURRED;
else if (dval > FLT_MAX)
*p = (float)INFINITY;
else if (dval < -FLT_MAX)
*p = (float)-INFINITY;
else
*p = (float) dval;
break;