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