MDEV-18477: add generic_hash_fnv1abb-10.4-MDEV-18477

2 files changed, 20 insertions, 0 deletions

diff --git a/include/hash.h b/include/hash.h
index fd64bf4c5df..4c5b5a186c9 100644
--- a/include/hash.h
+++ b/include/hash.h
@@ -41,13 +41,22 @@ extern "C" {
 #define HASH_UNIQUE     1       /* hash_insert fails on duplicate key */
 #define HASH_THREAD_SPECIFIC 2  /* Mark allocated memory THREAD_SPECIFIC */
 
+
 typedef uint32 my_hash_value_type;
 typedef uchar *(*my_hash_get_key)(const uchar *,size_t*,my_bool);
 typedef my_hash_value_type (*my_hash_function)(CHARSET_INFO *,
                                                const uchar *, size_t);
+/**
+ * @param ci - not used, for my_hash_function signature compatibility
+ * @param p  - data
+ * @param sz - bytes count
+ */
+my_hash_value_type generic_hash_fnv1a(CHARSET_INFO *ci, const uchar *p, size_t sz);
+
 typedef void (*my_hash_free_key)(void *);
 typedef my_bool (*my_hash_walk_action)(void *,void *);
 
+
 typedef struct st_hash {
   size_t key_offset,key_length;		/* Length of key if const length */
   size_t blength;
diff --git a/mysys/hash.cc b/mysys/hash.cc
index d29297a5233..0ea8a802ef0 100644
--- a/mysys/hash.cc
+++ b/mysys/hash.cc
@@ -41,6 +41,17 @@ static void movelink(HASH_LINK *array,uint pos,uint next_link,uint newlink);
 static int hashcmp(const HASH *hash, HASH_LINK *pos, const uchar *key,
                    size_t length);
 
+my_hash_value_type generic_hash_fnv1a(CHARSET_INFO *, const uchar *p, size_t sz)
+{
+  size_t result= static_cast<size_t>(14695981039346656037ULL);
+  for (; sz--; )
+  {
+    result ^= static_cast<size_t>(*p++);
+    result *= static_cast<size_t>(1099511628211ULL);
+  }
+  return static_cast<my_hash_value_type>(result);
+}
+
 my_hash_value_type my_hash_sort(CHARSET_INFO *cs, const uchar *key,
                                 size_t length)
 {