/*
 * Copyright (C) 2023 Barry
 *
 * This file is part of Barry's Little Objects in C Library (libBLOC).
 *
 * libBLOC 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 3 of the License, or (at your option) any later
 * version.
 *
 * libBLOC is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTIBILITY 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
 * libBLOC.  If not, see <https://www.gnu.org/licenses/>.
 */

/*
 * This file contains the core of the object library.  It implements the basic
 * operations each object needs and leaves the rest up to the respective
 * program that implements the object.  The object library is a resource
 * manager which should help improve memory safety within a program.  It
 * reference counts each object and controls their instantiation and deletion.
 */

#include <string.h>
#include <BLOC/object.h>
#include "../assert.h"
#include "object.h"

/* Obtain a reference to an object */
void *
obj_get(void *addr)
{
	struct ObjectHeader *obj = object_header(addr);
	ASSERT(obj->magic == OBJECT_MAGIC);
	__atomic_add_fetch(&obj->type->usage, 1, __ATOMIC_RELAXED);
	__atomic_add_fetch(&obj->usage, 1, __ATOMIC_RELAXED);
	return addr;
}

/* Release a reference to an object */
void
obj_put(void *addr)
{
	struct ObjectHeader *obj = object_header(addr);
	ASSERT(obj->magic == OBJECT_MAGIC);
	__atomic_sub_fetch(&obj->type->usage, 1, __ATOMIC_RELAXED);
	if (__atomic_sub_fetch(&obj->usage, 1, __ATOMIC_RELAXED))
		return;

	/* Free object */
	obj_lock(addr);
	if (obj->type->delete)
		obj->type->delete(addr);
	obj_unlock(addr);
	obj->magic = 0;
	free(obj);
}

/* Create a new instance of an object type */
void *
obj_new(struct ObjectType *type)
{
	void *body;
	struct ObjectHeader *obj;
	obj = malloc(sizeof(struct ObjectType) + type->size);
	body = (void *) (obj + 1);
	memset(body, 0, type->size);

	obj->magic = OBJECT_MAGIC;
	obj->type = type;
	if (type->new)
		type->new(body);

	return obj_get(body);
}