From: Dmitriy Nester <dmitriynester@gmail.com>
Date: Thu, 27 Feb 2020 13:17:45 +0000 (+0200)
Subject: util/hash_table: replace fnv1a hash function with xxhash
X-Git-Url: https://git.libre-soc.org/?p=mesa.git;a=commitdiff_plain;h=387176829bcef7058ff2be8f175295e9f80008e5

util/hash_table: replace fnv1a hash function with xxhash

xxhash is faster than fnv1a in almost all circumstances, so we're
switching to it globally.

Signed-off-by: Dmytro Nester <dmytro.nester@globallogic.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4020>
---

diff --git a/src/util/hash_table.c b/src/util/hash_table.c
index 0b0077cc7f3..7b2b7eb0d6a 100644
--- a/src/util/hash_table.c
+++ b/src/util/hash_table.c
@@ -597,14 +597,14 @@ _mesa_hash_u32(const void *key)
 uint32_t
 _mesa_hash_string(const void *_key)
 {
-   uint32_t hash = _mesa_fnv32_1a_offset_bias;
+   uint32_t hash = 0;
    const char *key = _key;
-
-   while (*key != 0) {
-      hash = _mesa_fnv32_1a_accumulate(hash, *key);
-      key++;
-   }
-
+   size_t len = strlen(key);
+#if defined(_WIN64) || defined(__x86_64__)
+   hash = (uint32_t)XXH64(key, len, hash);
+#else
+   hash = XXH32(key, len, hash);
+#endif
    return hash;
 }