Fix array bounds violation in the solver. Oops.

[originally from svn r6225]

diff --git a/inertia.c b/inertia.c
index a158363adb1807facbb80ef780b4362400cb948d..fc213da2deeeda860759002f885f72ee6f136136 100644 (file)
--- a/inertia.c
+++ b/inertia.c
@@ -370,7 +370,9 @@ static int find_gem_candidates(int w, int h, char *grid,
                    d2 = n;
                }
                i2 = (y2*w+x2)*DIRECTIONS+d2;
-               if (!reachable[i2]) {
+               if (x2 >= 0 && x2 < w &&
+                   y2 >= 0 && y2 < h &&
+                   !reachable[i2]) {
                    int ok;
 #ifdef SOLVER_DIAGNOSTICS
                    printf("  trying point %d,%d,%d", x2, y2, d2);