From be3d1d588f8c53cb94ae5c723da1f7a11baf8e19 Mon Sep 17 00:00:00 2001
From: Tobias Scharnowski <sceptic-ctf@web.de>
Date: Mon, 4 Jul 2022 16:37:36 +0200
Subject: [PATCH] Make ByteNegMutator negate, not flip (#675)

Change the ByteNegMutator to negate a byte, not flip it. Flipping a byte is already implemented in ByteFlipMutator.

See issue: https://github.com/AFLplusplus/LibAFL/issues/674
---
 libafl/src/mutators/mutations.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libafl/src/mutators/mutations.rs b/libafl/src/mutators/mutations.rs
index 8b63e8f4d9..cf3a9c04c3 100644
--- a/libafl/src/mutators/mutations.rs
+++ b/libafl/src/mutators/mutations.rs
@@ -271,7 +271,7 @@ where
             Ok(MutationResult::Skipped)
         } else {
             let byte = state.rand_mut().choose(input.bytes_mut());
-            *byte = !*byte;
+            *byte = (-(*byte as i16)) as u8;
             Ok(MutationResult::Mutated)
         }
     }