Attachment 14774 Details for Bug 13748 – Patch: use a wrapper function to limit the returned value

[patch] Patch: use a wrapper function to limit the returned value

cmp.diff (text/plain), 1.70 KB, created by Adam Sampson on 2019-01-16 11:33:25 UTC

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Creator: Adam Sampson

Created: 2019-01-16 11:33:25 UTC

Size: 1.70 KB

patch

obsolete

>Python tp_compare functions must return -1, 0 or 1.
>
>In addition, the original code assumes that the difference of two
>pointers fits into an int, which isn't true on all platforms.
>
>diff -x config.log -x config.status -ru tmp/talloc-2.1.6/pytalloc.c work/talloc-2.1.6/pytalloc.c
>--- tmp/talloc-2.1.6/pytalloc.c	2016-03-08 13:37:39.000000000 +0000
>+++ work/talloc-2.1.6/pytalloc.c	2016-03-09 13:18:36.382047572 +0000
>@@ -17,6 +17,7 @@
>    along with this program.  If not, see <http://www.gnu.org/licenses/>.
> */
> 
>+#include <stddef.h>
> #include <Python.h>
> #include <talloc.h>
> #include <pytalloc.h>
>@@ -133,14 +134,23 @@
> 	return Py_NotImplemented;
> }
> #else
>+static int signof(ptrdiff_t val)
>+{
>+	if (val == 0)
>+		return 0;
>+	else if (val < 0)
>+		return -1;
>+	else
>+		return 1;
>+}
> static int pytalloc_default_cmp(PyObject *_obj1, PyObject *_obj2)
> {
> 	pytalloc_Object *obj1 = (pytalloc_Object *)_obj1,
> 					 *obj2 = (pytalloc_Object *)_obj2;
> 	if (obj1->ob_type != obj2->ob_type)
>-		return ((char *)obj1->ob_type - (char *)obj2->ob_type);
>+		return signof((char *)obj1->ob_type - (char *)obj2->ob_type);
> 
>-	return ((char *)pytalloc_get_ptr(obj1) - (char *)pytalloc_get_ptr(obj2));
>+	return signof((char *)pytalloc_get_ptr(obj1) - (char *)pytalloc_get_ptr(obj2));
> }
> #endif
> 
>@@ -218,9 +228,9 @@
> 	pytalloc_BaseObject *obj1 = (pytalloc_BaseObject *)_obj1,
> 					 *obj2 = (pytalloc_BaseObject *)_obj2;
> 	if (obj1->ob_type != obj2->ob_type)
>-		return ((char *)obj1->ob_type - (char *)obj2->ob_type);
>+		return signof((char *)obj1->ob_type - (char *)obj2->ob_type);
> 
>-	return ((char *)pytalloc_get_ptr(obj1) - (char *)pytalloc_get_ptr(obj2));
>+	return signof((char *)pytalloc_get_ptr(obj1) - (char *)pytalloc_get_ptr(obj2));
> }
> #endif
>

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