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| author | Massimo Valentini <mvalentini@src.gnome.org> | 2014-09-23 12:37:26 +0200 |
|---|---|---|
| committer | Bryce Harrington <bryce@osg.samsung.com> | 2015-06-04 15:01:57 -0700 |
| commit | 63f59ea89625bc2f445c5ab342c0f1c3971aabea (patch) | |
| tree | c43da4fed8bfa0dd4cf2512b1da1089ab5859925 | |
| parent | a3c022bb98d716bd4e3f9ce50095a72e25605fe8 (diff) | |
| download | cairo-63f59ea89625bc2f445c5ab342c0f1c3971aabea.tar.gz | |
polygon-intersection: Try not to invoke undefined behaviour
Optimizing compilers aggressively remove code that is executed only
after an undefined behaviour occurred.
Also, the difference of two (non char) pointers hides an integer
division that, because the divisor is known at compile time, is
transformed into a multiplication by a pseudo-reciprocal, and in this
case the difference is not always a multiple of the divisor, resulting
in an invalid comparison predicate.
Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=74779
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>
| -rw-r--r-- | src/cairo-polygon-intersect.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/cairo-polygon-intersect.c b/src/cairo-polygon-intersect.c index 02ef3b5e2..52e67752e 100644 --- a/src/cairo-polygon-intersect.c +++ b/src/cairo-polygon-intersect.c @@ -76,7 +76,7 @@ struct _cairo_bo_edge { #define PQ_LEFT_CHILD_INDEX(i) ((i) << 1) typedef enum { - CAIRO_BO_EVENT_TYPE_STOP, + CAIRO_BO_EVENT_TYPE_STOP = -1, CAIRO_BO_EVENT_TYPE_INTERSECTION, CAIRO_BO_EVENT_TYPE_START } cairo_bo_event_type_t; @@ -783,7 +783,7 @@ cairo_bo_event_compare (const cairo_bo_event_t *a, if (cmp) return cmp; - return a - b; + return a < b ? -1 : a == b ? 0 : 1; } static inline void |