179 lines
4.3 KiB
C
179 lines
4.3 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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#pragma ident "%Z%%M% %I% %E% SMI"
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#include <ctf_impl.h>
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static const ushort_t _CTF_EMPTY[1] = { 0 };
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int
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ctf_hash_create(ctf_hash_t *hp, ulong_t nelems)
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{
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if (nelems > USHRT_MAX)
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return (EOVERFLOW);
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/*
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* If the hash table is going to be empty, don't bother allocating any
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* memory and make the only bucket point to a zero so lookups fail.
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*/
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if (nelems == 0) {
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bzero(hp, sizeof (ctf_hash_t));
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hp->h_buckets = (ushort_t *)_CTF_EMPTY;
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hp->h_nbuckets = 1;
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return (0);
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}
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hp->h_nbuckets = 211; /* use a prime number of hash buckets */
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hp->h_nelems = nelems + 1; /* we use index zero as a sentinel */
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hp->h_free = 1; /* first free element is index 1 */
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hp->h_buckets = ctf_alloc(sizeof (ushort_t) * hp->h_nbuckets);
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hp->h_chains = ctf_alloc(sizeof (ctf_helem_t) * hp->h_nelems);
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if (hp->h_buckets == NULL || hp->h_chains == NULL) {
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ctf_hash_destroy(hp);
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return (EAGAIN);
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}
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bzero(hp->h_buckets, sizeof (ushort_t) * hp->h_nbuckets);
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bzero(hp->h_chains, sizeof (ctf_helem_t) * hp->h_nelems);
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return (0);
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}
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uint_t
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ctf_hash_size(const ctf_hash_t *hp)
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{
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return (hp->h_nelems ? hp->h_nelems - 1 : 0);
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}
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static ulong_t
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ctf_hash_compute(const char *key, size_t len)
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{
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ulong_t g, h = 0;
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const char *p, *q = key + len;
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size_t n = 0;
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for (p = key; p < q; p++, n++) {
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h = (h << 4) + *p;
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if ((g = (h & 0xf0000000)) != 0) {
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h ^= (g >> 24);
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h ^= g;
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}
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}
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return (h);
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}
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int
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ctf_hash_insert(ctf_hash_t *hp, ctf_file_t *fp, ushort_t type, uint_t name)
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{
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ctf_strs_t *ctsp = &fp->ctf_str[CTF_NAME_STID(name)];
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const char *str = ctsp->cts_strs + CTF_NAME_OFFSET(name);
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ctf_helem_t *hep = &hp->h_chains[hp->h_free];
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ulong_t h;
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if (type == 0)
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return (EINVAL);
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if (hp->h_free >= hp->h_nelems)
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return (EOVERFLOW);
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if (ctsp->cts_strs == NULL)
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return (ECTF_STRTAB);
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if (ctsp->cts_len <= CTF_NAME_OFFSET(name))
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return (ECTF_BADNAME);
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if (str[0] == '\0')
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return (0); /* just ignore empty strings on behalf of caller */
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hep->h_name = name;
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hep->h_type = type;
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h = ctf_hash_compute(str, strlen(str)) % hp->h_nbuckets;
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hep->h_next = hp->h_buckets[h];
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hp->h_buckets[h] = hp->h_free++;
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return (0);
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}
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/*
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* Wrapper for ctf_hash_lookup/ctf_hash_insert: if the key is already in the
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* hash, override the previous definition with this new official definition.
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* If the key is not present, then call ctf_hash_insert() and hash it in.
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*/
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int
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ctf_hash_define(ctf_hash_t *hp, ctf_file_t *fp, ushort_t type, uint_t name)
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{
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const char *str = ctf_strptr(fp, name);
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ctf_helem_t *hep = ctf_hash_lookup(hp, fp, str, strlen(str));
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if (hep == NULL)
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return (ctf_hash_insert(hp, fp, type, name));
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hep->h_type = type;
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return (0);
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}
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ctf_helem_t *
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ctf_hash_lookup(ctf_hash_t *hp, ctf_file_t *fp, const char *key, size_t len)
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{
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ctf_helem_t *hep;
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ctf_strs_t *ctsp;
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const char *str;
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ushort_t i;
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ulong_t h = ctf_hash_compute(key, len) % hp->h_nbuckets;
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for (i = hp->h_buckets[h]; i != 0; i = hep->h_next) {
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hep = &hp->h_chains[i];
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ctsp = &fp->ctf_str[CTF_NAME_STID(hep->h_name)];
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str = ctsp->cts_strs + CTF_NAME_OFFSET(hep->h_name);
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if (strncmp(key, str, len) == 0 && str[len] == '\0')
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return (hep);
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}
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return (NULL);
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}
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void
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ctf_hash_destroy(ctf_hash_t *hp)
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{
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if (hp->h_buckets != NULL && hp->h_nbuckets != 1) {
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ctf_free(hp->h_buckets, sizeof (ushort_t) * hp->h_nbuckets);
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hp->h_buckets = NULL;
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}
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if (hp->h_chains != NULL) {
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ctf_free(hp->h_chains, sizeof (ctf_helem_t) * hp->h_nelems);
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hp->h_chains = NULL;
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}
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}
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