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float_int(): Some systems raise an exception if a double is cast to

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long but the double is too big to fit in a long.  Prevent that.  This
closes some recent bug or patch on SF, but SF is down now so I can't
say which.

Bugfix candidate.
This commit is contained in:
Tim Peters 2002-11-21 22:26:37 +00:00
parent d899605e30
commit 7d791240c0
1 changed files with 16 additions and 14 deletions
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30
Objects/floatobject.c
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@ -653,23 +653,25 @@ float_int(PyObject *v)
{
double x = PyFloat_AsDouble(v);
double wholepart; /* integral portion of x, rounded toward 0 */
long aslong; /* (long)wholepart */
(void)modf(x, &wholepart);
#ifdef RISCOS
/* conversion from floating to integral type would raise exception */
if (wholepart>LONG_MAX || wholepart<LONG_MIN) {
return float_long(v);
}
#endif
/* doubles may have more bits than longs, or vice versa; and casting
to long may yield gibberish in either case. What really matters
is whether converting back to double again reproduces what we
started with. */
aslong = (long)wholepart;
if ((double)aslong == wholepart)
/* Try to get out cheap if this fits in a Python int. The attempt
* to cast to long must be protected, as C doesn't define what
* happens if the double is too big to fit in a long. Some rare
* systems raise an exception then (RISCOS was mentioned as one,
* and someone using a non-default option on Sun also bumped into
* that). Note that checking for >= and <= LONG_{MIN,MAX} would
* still be vulnerable: if a long has more bits of precision than
* a double, casting MIN/MAX to double may yield an approximation,
* and if that's rounded up, then, e.g., wholepart=LONG_MAX+1 would
* yield true from the C expression wholepart<=LONG_MAX, despite
* that wholepart is actually greater than LONG_MAX.
*/
if (LONG_MIN < wholepart && wholepart < LONG_MAX) {
const long aslong = (long)wholepart;
return PyInt_FromLong(aslong);
return float_long(v);
}
return PyLong_FromDouble(wholepart);
}
static PyObject *