Fix undefined behaviour when left-shifting signed integers.

Found by -fsanitize=undefined.

diff --git a/src/hash.c b/src/hash.c
index 91fc3d6..50934d9 100644 (file)
--- a/src/hash.c
+++ b/src/hash.c
@@ -29,7 +29,7 @@ static uint32_t hash_function(const void *p, size_t len) {
        uint32_t hash = 0;
        while(true) {
                for(int i = len > 4 ? 4 : len; --i;)
-                       hash += q[len - i] << (8 * i);
+                       hash += (uint32_t)q[len - i] << (8 * i);
                hash *= 0x9e370001UL; // Golden ratio prime.
                if(len <= 4)
                        break;