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+/* $OpenBSD: hash_func.c,v 1.11 2016/05/29 20:47:49 guenther Exp $ */
+
+/*-
+ * Copyright (c) 1990, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Margo Seltzer.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+
+#include <db.h>
+
+/* Chris Torek's hash function. */
+u_int32_t
+__default_hash(const void *key, size_t len)
+{
+ u_int32_t h, loop;
+ u_int8_t *k;
+
+#define HASH4a h = (h << 5) - h + *k++;
+#define HASH4b h = (h << 5) + h + *k++;
+#define HASH4 HASH4b
+
+ h = 0;
+ k = (u_int8_t *)key;
+ if (len > 0) {
+ loop = (len + 8 - 1) >> 3;
+
+ switch (len & (8 - 1)) {
+ case 0:
+ do { /* All fall throughs */
+ HASH4;
+ case 7:
+ HASH4;
+ case 6:
+ HASH4;
+ case 5:
+ HASH4;
+ case 4:
+ HASH4;
+ case 3:
+ HASH4;
+ case 2:
+ HASH4;
+ case 1:
+ HASH4;
+ } while (--loop);
+ }
+
+ }
+ return (h);
+}