Use FNV hash function

git-svn-id: file:///svn/tokudb@117 c7de825b-a66e-492c-adef-691d508d4ae1

newbrt/cachetable.c

@@ -7,6 +7,7 @@
 #include <errno.h>
 #include <sys/stat.h>
 #include <string.h>
+#include "hashfun.h"
 
 //#define TRACE_CACHETABLE
 #ifdef TRACE_CACHETABLE
@@ -164,27 +165,14 @@ int cachefile_count_pinned (CACHEFILE cf, int print_them) {
     return n_pinned;
 }
 
-static unsigned int hash_key (const char *key, int keylen) {
-    /* From Sedgewick.  There are probably better hash functions. */
-    unsigned int b    = 378551;
-    unsigned int a    = 63689;
-    unsigned int hash = 0;
-    int i;
-    for (i = 0; i < keylen; i++ ) {
-	hash = hash * a + key[i];
-	a *= b;
-    }
-    return hash;
-}
-
 unsigned int ct_hash_longlong (unsigned long long l) {
-    unsigned int r = hash_key((char*)&l, 8);
+    unsigned int r = hash_key((unsigned char*)&l, 8);
     printf("%lld --> %d --> %d\n", l, r, r%64);
     return  r;
 }
 
 static unsigned int hashit (CACHETABLE t, CACHEKEY key) {
-    return hash_key((char*)&key, sizeof(key))%t->table_size;
+    return hash_key((unsigned char*)&key, sizeof(key))%t->table_size;
 }
 
 

newbrt/hashtable.c

@@ -9,6 +9,7 @@
 
 #include "key.h"
 #include "yerror.h"
+#include "hashfun.h"
 
 int toku_hashtable_create (HASHTABLE *h) {
     HASHTABLE MALLOC(tab);
@@ -23,33 +24,6 @@ int toku_hashtable_create (HASHTABLE *h) {
     return 0;
 }
 
-// FNV Hash: From an idea sent by Glenn Fowler and Phong Vo to the IEEE POSIX 1003.2 committee.  Landon Curt Noll improved it.
-// See: http://isthe.com/chongo/tech/comp/fnv/
-static unsigned int hash_key (const char *key, ITEMLEN keylen) {
-    ITEMLEN i;
-    unsigned int hash=0;
-    for (i=0; i<keylen; i++, key++) {
-	hash *= 16777619;
-	hash ^= *(unsigned char*)key;
-    }
-    return hash;
-}
-
-#if 0
-static unsigned int hash_key (const char *key, ITEMLEN keylen) {
-    /* From Sedgewick.  There are probably better hash functions. */
-    unsigned int b    = 378551;
-    unsigned int a    = 63689;
-    unsigned int hash = 0;
-    ITEMLEN i;
-    for (i = 0; i < keylen; i++ ) {
-	hash = hash * a + key[i];
-	a *= b;
-    }
-    return hash;
-}
-#endif
-
 static void hash_find_internal (HASHTABLE tab, const char *key, ITEMLEN keylen, HASHELT *hashelt, HASHELT **prev_ptr) {
     unsigned int h = hash_key (key, keylen) % tab->arraysize;
     HASHELT he;