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author | ed <ed@FreeBSD.org> | 2010-02-21 19:53:33 +0000 |
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committer | ed <ed@FreeBSD.org> | 2010-02-21 19:53:33 +0000 |
commit | 6c820f64790683ade031ffe5af60a265fdbf2e82 (patch) | |
tree | b9ea7de0e2f7c93861f534a07f4c8c30cddb3021 /sys/kern/subr_hash.c | |
parent | 05c4bc6f8b3d998d311e288eb6671e9389625504 (diff) | |
download | FreeBSD-src-6c820f64790683ade031ffe5af60a265fdbf2e82.zip FreeBSD-src-6c820f64790683ade031ffe5af60a265fdbf2e82.tar.gz |
Decompose the most lousy named file in sys/kern; kern_subr.c.
Although this file has historically been used as a dumping ground for
random functions, nowadays it only contains functions related to copying
bits {from,to} userspace and hash table utility functions.
Behold, subr_uio.c and subr_hash.c.
Diffstat (limited to 'sys/kern/subr_hash.c')
-rw-r--r-- | sys/kern/subr_hash.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/sys/kern/subr_hash.c b/sys/kern/subr_hash.c new file mode 100644 index 0000000..8ffbc9c --- /dev/null +++ b/sys/kern/subr_hash.c @@ -0,0 +1,132 @@ +/*- + * Copyright (c) 1982, 1986, 1991, 1993 + * The Regents of the University of California. All rights reserved. + * (c) UNIX System Laboratories, Inc. + * All or some portions of this file are derived from material licensed + * to the University of California by American Telephone and Telegraph + * Co. or Unix System Laboratories, Inc. and are reproduced herein with + * the permission of UNIX System Laboratories, Inc. + * + * 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. + * 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. + * + * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94 + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/malloc.h> + +/* + * General routine to allocate a hash table with control of memory flags. + */ +void * +hashinit_flags(int elements, struct malloc_type *type, u_long *hashmask, + int flags) +{ + long hashsize; + LIST_HEAD(generic, generic) *hashtbl; + int i; + + if (elements <= 0) + panic("hashinit: bad elements"); + + /* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */ + KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT), + ("Bad flags (0x%x) passed to hashinit_flags", flags)); + + for (hashsize = 1; hashsize <= elements; hashsize <<= 1) + continue; + hashsize >>= 1; + + if (flags & HASH_NOWAIT) + hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), + type, M_NOWAIT); + else + hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), + type, M_WAITOK); + + if (hashtbl != NULL) { + for (i = 0; i < hashsize; i++) + LIST_INIT(&hashtbl[i]); + *hashmask = hashsize - 1; + } + return (hashtbl); +} + +/* + * Allocate and initialize a hash table with default flag: may sleep. + */ +void * +hashinit(int elements, struct malloc_type *type, u_long *hashmask) +{ + + return (hashinit_flags(elements, type, hashmask, HASH_WAITOK)); +} + +void +hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask) +{ + LIST_HEAD(generic, generic) *hashtbl, *hp; + + hashtbl = vhashtbl; + for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++) + if (!LIST_EMPTY(hp)) + panic("hashdestroy: hash not empty"); + free(hashtbl, type); +} + +static const int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, + 2039, 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, + 6653, 7159, 7673, 8191, 12281, 16381, 24571, 32749 }; +#define NPRIMES (sizeof(primes) / sizeof(primes[0])) + +/* + * General routine to allocate a prime number sized hash table. + */ +void * +phashinit(int elements, struct malloc_type *type, u_long *nentries) +{ + long hashsize; + LIST_HEAD(generic, generic) *hashtbl; + int i; + + if (elements <= 0) + panic("phashinit: bad elements"); + for (i = 1, hashsize = primes[1]; hashsize <= elements;) { + i++; + if (i == NPRIMES) + break; + hashsize = primes[i]; + } + hashsize = primes[i - 1]; + hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK); + for (i = 0; i < hashsize; i++) + LIST_INIT(&hashtbl[i]); + *nentries = hashsize; + return (hashtbl); +} |