libgrapheme

commit 195946ab880bddbf6296fe47da5152163a126022
parent e57131a3dfd4e73747538a27ec472f9803e09803
Author: Laslo Hunhold <dev@frign.de>
Date:   Tue, 14 Dec 2021 13:45:02 +0100

Avoid undefined signed integer overflow in heisenstate_set()

Instead, specify explicitly that we're working with unsigned (at least)
64 bit integers.

This was found using clang's UB-sanitizer and (interestingly) leads
to another speedup of around 3-5%. On my machine, it's now at roughly
4 million CP/s.

Signed-off-by: Laslo Hunhold <dev@frign.de>

Diffstat:
M
src/util.c
 | 
6
+++---

1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/src/util.c b/src/util.c
@@ -27,11 +27,11 @@ heisenstate_set(struct lg_internal_heisenstate *h, int slot, int state)
 		/* no state given or slot out of range */
 		return 1;
 	} else {
-		h->determined |= (1 << slot);
+		h->determined |= (UINT64_C(1) << slot);
 		if (state) {
-			h->state |= (1 << slot);
+			h->state |= (UINT64_C(1) << slot);
 		} else {
-			h->state &= ~(1 << slot);
+			h->state &= ~(UINT64_C(1) << slot);
 		}
 	}