FNV128: fix shift UB and ensure that the test vector match

The test vectors are `golden128` from https://github.com/golang/go/blob/master/src/hash/fnv/fnv_test.go FNV128("") = 6c62272e07bb014262b821756295c58d FNV128("a") = d228cb69101a8caf78912b704e4a141e FNV128("ab") = 0880945aeeab1be95aa073305526c088 FNV128("abc") = a68bb2a4348b5822836dbc78c6aee73b
rurban · Sep 28, 2024 · 5a4db55 · 5a4db55
1 parent 2e07153
commit 5a4db55
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/Hashes.cpp b/Hashes.cpp
@@ -388,7 +388,7 @@ FNV128(uint64_t buf[2], const char *key, int len, uint64_t seed)
     uint64_t s0 = multhi;                 // high
     uint64_t s1 = prime128Lower * buf[1]; // low
 
-    s0 += buf[1] << (prime128Shift + prime128Lower * buf[0]);
+    s0 += (buf[1] << prime128Shift) + prime128Lower * buf[0];
 
     // Update the values
     buf[1] = s1;

diff --git a/main.cpp b/main.cpp
@@ -276,7 +276,7 @@ HashInfo g_hashes[] =
   {0x811c9dc5, 0x23d4a49d} /* !! */ },
 { FNV64a_test,          64, 0x103455FC, "FNV64",       "Fowler-Noll-Vo hash, 64-bit", POOR,
   {0x811c9dc5, 0xcbf29ce4, 0x84222325, 0xcbf29ce484222325} /* TODO */},
-{ FNV128_test,         128, 0xBCAA1426, "FNV128",      "Go variant of FNV, 128-bit", POOR, {} },
+{ FNV128_test,         128, 0xC6FF4526, "FNV128",      "Go variant of FNV, 128-bit", POOR, {} },
 #endif
 { FNV2_test,    __WORDSIZE, FNV2_VERIF, "FNV2",        "wordwise FNV", POOR, {} },
 { fletcher2_test,       64, 0x890767C0, "fletcher2",   "fletcher2 ZFS", POOR, {0UL} /* !! */ },