pool.c

/*
 * Copyright (c) 2003, 2004 Niels Provos <provos@citi.umich.edu>
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <sys/types.h>
#include <sys/param.h>

#include "config.h"

#include <sys/queue.h>

#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>

#include "pool.h"

struct pool*
pool_init(size_t size)
{
	struct pool *pool;

	if (POOL_PAGE_SIZE / (sizeof(struct pool_entry) + size) < 1)
	{
		syslog(LOG_ERR, "%s: object size too large for pool", __func__);
		exit(EXIT_FAILURE);
	}

	if ((pool = calloc(1, sizeof(struct pool))) == NULL)
	{
		syslog(LOG_ERR, "%s: calloc", __func__);
		exit(EXIT_FAILURE);
	}

	SLIST_INIT(&pool->entries);
	pool->size = size;

	return (pool);
}

void *
pool_alloc_size(struct pool *pool, size_t size)
{
	struct pool_entry *entry = NULL;

	if (size) {
		entry = malloc(size + sizeof(struct pool_entry));
		if (entry == NULL)
		{
			syslog(LOG_ERR, "%s: malloc", __func__);
			exit(EXIT_FAILURE);
		}
		
		entry->data = (void *)entry + sizeof(struct pool_entry);;
		entry->size = size;
		pool->nalloc++;
	} else {
		void *p = malloc(POOL_PAGE_SIZE);
		int i, max;

		if (p == NULL)
		{
			syslog(LOG_ERR, "%s: malloc", __func__);
			exit(EXIT_FAILURE);
		}

		size = pool->size;
		max = POOL_PAGE_SIZE / (sizeof(struct pool_entry) + size);
		pool->nalloc += max;
		for (i = 0; i < max; i++) {
			entry = p;
			entry->data = (void *)entry+ sizeof(struct pool_entry);
			entry->size = size;

			/* We want to use the last one as return */
			if (i < max - 1) {
				SLIST_INSERT_HEAD(&pool->entries, entry, next);
				p += sizeof(struct pool_entry) + size;
			}
		}
	}

	return (entry->data);
}