diff options
Diffstat (limited to 'usr/src/common/ctf/ctf_hash.c')
| -rw-r--r-- | usr/src/common/ctf/ctf_hash.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/usr/src/common/ctf/ctf_hash.c b/usr/src/common/ctf/ctf_hash.c new file mode 100644 index 0000000000..ff2ba61352 --- /dev/null +++ b/usr/src/common/ctf/ctf_hash.c @@ -0,0 +1,159 @@ +/* + * 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 2004 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); +} + +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; + } +} |