mpatch: introduce a safesub() helper as well
Same reason as safeadd().
--- a/mercurial/mpatch.c Mon Apr 30 22:13:42 2018 -0400
+++ b/mercurial/mpatch.c Thu May 03 12:54:20 2018 -0400
@@ -88,6 +88,17 @@
return true;
}
+/* subtract src from dest and store result in dest */
+static inline bool safesub(int src, int *dest)
+{
+ if (((src > 0) && (*dest < INT_MIN + src)) ||
+ ((src < 0) && (*dest > INT_MAX + src))) {
+ return false;
+ }
+ *dest -= src;
+ return true;
+}
+
/* move hunks in source that are less cut to dest, compensating
for changes in offset. the last hunk may be split if necessary.
*/