#include "bcache.h"
#include "gdb_string.h" /* For memcpy declaration */
-
+/* The old hash function was stolen from SDBM. This is what DB 3.0 uses now,
+ * and is better than the old one.
+ */
\f
-/* The hash function. */
-
unsigned long
-hash (void *addr, int length)
+hash(void *addr, int length)
{
- /* If it's a short string, hash on every character. Otherwise, sample
- characters from throughout the string. */
- if (length <= 64)
- {
- char *byte = addr;
- unsigned long h = 0;
- int i;
-
- for (i = 0; i < length; i++)
- h = h * 65793 ^ (h >> (sizeof (h) * 8 - 6)) ^ byte[i];
-
- return h;
- }
- else
- {
- char *byte = addr;
- int n, i;
- unsigned long h = 0;
-
- for (n = i = 0; n < 64; n++)
- {
- h = h * 65793 + (h >> (sizeof (h) * 8 - 6)) + byte[i];
- i = h % length;
- }
-
- return h;
- }
+ const unsigned char *k, *e;
+ unsigned long h;
+
+ k = (const unsigned char *)addr;
+ e = k+length;
+ for (h=0; k< e;++k)
+ {
+ h *=16777619;
+ h ^= *k;
+ }
+ return (h);
}
-
\f
/* Growing the bcache's hash table. */