Author: mladen.turk(a)jboss.com Date: 2007-09-08 12:43:04 -0400 (Sat, 08 Sep 2007) New Revision: 989 Added: trunk/sight/native/share/cache.c Log: Add cache.c for list based hash Added: trunk/sight/native/share/cache.c =================================================================== --- trunk/sight/native/share/cache.c (rev 0) +++ trunk/sight/native/share/cache.c 2007-09-08 16:43:04 UTC (rev 989) @@ -0,0 +1,147 @@ +/* + * SIGHT - System information gathering hybrid tool + * + * Copyright(c) 2007 Red Hat Middleware, LLC, + * and individual contributors as indicated by the @authors tag. + * See the copyright.txt in the distribution for a + * full listing of individual contributors. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library in the file COPYING.LIB; + * if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + * + * @author Mladen Turk + * + */ + +#include "sight.h" +#include "sight_local.h" +#include "sight_types.h" + +static unsigned int times33hash(const char *key) +{ + const char *p; + unsigned int hash = 0; + for (p = key; *p; p++) { + hash = hash * 33 + *p; + } + return hash & CACHE_HASH_MASK; +} + +cache_table_t *cache_new(size_t init) +{ + cache_table_t *t = (cache_table_t *)malloc(sizeof(cache_table_t)); + if (!t) + return NULL; + t->siz = 0; + t->len = init; + if (!(t->list = (cache_entry_t **)malloc(init * sizeof(cache_entry_t *)))) { + int saved = errno; + free(t); + t = NULL; + errno = saved; + } + return t; +} + +cache_entry_t *cache_add(cache_table_t *t, const char *key) +{ + cache_entry_t *e; + unsigned int hash; + + if (!key || !*key) { + errno = EINVAL; + return NULL; /* Skip empty and null strings */ + } + hash = times33hash(key); + + if (t->hash[hash]) { + /* + * This spot in the table is already in use. See if the current string + * has already been inserted, and if so, increment its count. + */ + for (e = t->hash[hash]; e; e = e->next) { + if (!strcmp(key, e->key)) + return e; + } + } + if (!(e = (cache_entry_t *)malloc(sizeof(cache_entry_t )))) + return NULL; + e->data = NULL; + /* Insert new bucket into the list */ + if (t->siz < t->len) { + t->list[t->siz++] = e; + } + else { + cache_entry_t **nl; + size_t len = t->len << 2; + if (!(nl = (cache_entry_t **)malloc(len * sizeof(cache_entry_t *)))) + return NULL; + memcpy(nl, t->list, t->siz * sizeof(cache_entry_t *)); + free(t->list); + t->len = len; + t->list = nl; + t->list[t->siz++] = e; + } + if (!(e->key = strdup(key))) + return NULL; + e->next = t->hash[hash]; + t->hash[hash] = e; + return e; +} + +cache_entry_t *cache_find(cache_table_t *t, const char *key) +{ + cache_entry_t *e; + unsigned int hash; + + if (!key || !*key) { + return NULL; /* Skip empty and null strings */ + } + hash = times33hash(key); + + if (t->hash[hash]) { + /* + * This spot in the table is already in use. See if the current string + * has already been inserted, and if so, return existing entry. + */ + for (e = t->hash[hash]; e; e = e->next) { + if (!strcmp(key, e->key)) + return e; + } + } + return NULL; +} + +void cache_free(cache_table_t *t, void (*destroy)(const char *, void *)) +{ + size_t i; + + if (!t) + return; + for (i = 0; i < t->siz; i++) { + if (t->list[i]) { + if (t->list[i]->data) { + if (destroy) + (*destroy)(t->list[i]->key, t->list[i]->data); + else + free(t->list[i]->data); + } + if (t->list[i]->key) + free(t->list[i]->key); + } + } + free(t->list); + free(t); +} Property changes on: trunk/sight/native/share/cache.c ___________________________________________________________________ Name: svn:eol-style + native