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Diffstat (limited to 'db/hash/hash_func.c')
| -rw-r--r-- | db/hash/hash_func.c | 212 |
1 files changed, 0 insertions, 212 deletions
diff --git a/db/hash/hash_func.c b/db/hash/hash_func.c deleted file mode 100644 index a5ec434ee9..0000000000 --- a/db/hash/hash_func.c +++ /dev/null @@ -1,212 +0,0 @@ -/*- - * 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. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. 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. - */ - -#if defined(LIBC_SCCS) && !defined(lint) -static char sccsid[] = "@(#)hash_func.c 8.2 (Berkeley) 2/21/94"; -#endif /* LIBC_SCCS and not lint */ - -#include <sys/types.h> - -#include <db.h> -#include "hash.h" -#include "page.h" -#include "extern.h" - -static u_int32_t hash1 __P((const void *, size_t)); -static u_int32_t hash2 __P((const void *, size_t)); -static u_int32_t hash3 __P((const void *, size_t)); -static u_int32_t hash4 __P((const void *, size_t)); - -/* Global default hash function */ -u_int32_t (*__default_hash) __P((const void *, size_t)) = hash4; - -/* - * HASH FUNCTIONS - * - * Assume that we've already split the bucket to which this key hashes, - * calculate that bucket, and check that in fact we did already split it. - * - * This came from ejb's hsearch. - */ - -#define PRIME1 37 -#define PRIME2 1048583 - -static u_int32_t -hash1(keyarg, len) - const void *keyarg; - register size_t len; -{ - register const u_char *key; - register u_int32_t h; - - /* Convert string to integer */ - for (key = keyarg, h = 0; len--;) - h = h * PRIME1 ^ (*key++ - ' '); - h %= PRIME2; - return (h); -} - -/* - * Phong's linear congruential hash - */ -#define dcharhash(h, c) ((h) = 0x63c63cd9*(h) + 0x9c39c33d + (c)) - -static u_int32_t -hash2(keyarg, len) - const void *keyarg; - size_t len; -{ - register const u_char *e, *key; - register u_int32_t h; - register u_char c; - - key = keyarg; - e = key + len; - for (h = 0; key != e;) { - c = *key++; - if (!c && key > e) - break; - dcharhash(h, c); - } - return (h); -} - -/* - * This is INCREDIBLY ugly, but fast. We break the string up into 8 byte - * units. On the first time through the loop we get the "leftover bytes" - * (strlen % 8). On every other iteration, we perform 8 HASHC's so we handle - * all 8 bytes. Essentially, this saves us 7 cmp & branch instructions. If - * this routine is heavily used enough, it's worth the ugly coding. - * - * OZ's original sdbm hash - */ -static u_int32_t -hash3(keyarg, len) - const void *keyarg; - register size_t len; -{ - register const u_char *key; - register size_t loop; - register u_int32_t h; - -#define HASHC h = *key++ + 65599 * h - - h = 0; - key = keyarg; - if (len > 0) { - loop = (len + 8 - 1) >> 3; - - switch (len & (8 - 1)) { - case 0: - do { - HASHC; - /* FALLTHROUGH */ - case 7: - HASHC; - /* FALLTHROUGH */ - case 6: - HASHC; - /* FALLTHROUGH */ - case 5: - HASHC; - /* FALLTHROUGH */ - case 4: - HASHC; - /* FALLTHROUGH */ - case 3: - HASHC; - /* FALLTHROUGH */ - case 2: - HASHC; - /* FALLTHROUGH */ - case 1: - HASHC; - } while (--loop); - } - } - return (h); -} - -/* Hash function from Chris Torek. */ -static u_int32_t -hash4(keyarg, len) - const void *keyarg; - register size_t len; -{ - register const u_char *key; - register size_t loop; - register u_int32_t h; - -#define HASH4a h = (h << 5) - h + *key++; -#define HASH4b h = (h << 5) + h + *key++; -#define HASH4 HASH4b - - h = 0; - key = keyarg; - if (len > 0) { - loop = (len + 8 - 1) >> 3; - - switch (len & (8 - 1)) { - case 0: - do { - HASH4; - /* FALLTHROUGH */ - case 7: - HASH4; - /* FALLTHROUGH */ - case 6: - HASH4; - /* FALLTHROUGH */ - case 5: - HASH4; - /* FALLTHROUGH */ - case 4: - HASH4; - /* FALLTHROUGH */ - case 3: - HASH4; - /* FALLTHROUGH */ - case 2: - HASH4; - /* FALLTHROUGH */ - case 1: - HASH4; - } while (--loop); - } - } - return (h); -} |