/*
* Gegl id-pool
*
* 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; if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
* GeglIDPool: pool of reusable integer ids associated with pointers.
*
* Copyright (C) 2008 OpenedHand
* Author: Øyvind Kolås <pippin@o-hand-com>
*
*/
#define DEBUG_POOL
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gegl-id-pool.h"
struct _GeglIDPool
{
GArray *array; /* Array of pointers */
GSList *free_ids; /* A stack of freed ids */
};
GeglIDPool *
gegl_id_pool_new (guint initial_size)
{
GeglIDPool *self;
self = g_slice_new (GeglIDPool);
self->array = g_array_sized_new (FALSE, FALSE,
sizeof (gpointer), initial_size);
self->free_ids = NULL;
return self;
}
void
gegl_id_pool_free (GeglIDPool *id_pool)
{
g_return_if_fail (id_pool != NULL);
g_array_free (id_pool->array, TRUE);
g_slist_free (id_pool->free_ids);
g_slice_free (GeglIDPool, id_pool);
}
guint32
gegl_id_pool_add (GeglIDPool *id_pool,
gpointer ptr)
{
gpointer *array;
guint32 id;
g_return_val_if_fail (id_pool != NULL, 0);
if (id_pool->free_ids) /* There are items on our freelist, reuse one */
{
array = (void*) id_pool->array->data;
id = GPOINTER_TO_UINT (id_pool->free_ids->data);
id_pool->free_ids = g_slist_remove (id_pool->free_ids,
id_pool->free_ids->data);
array[id] = ptr;
return id;
}
/* Allocate new id */
id = id_pool->array->len;
g_array_append_val (id_pool->array, ptr);
return id;
}
void
gegl_id_pool_remove (GeglIDPool *id_pool,
guint32 id)
{
gpointer *array;
#ifdef DEBUG_POOL
return;
#endif
g_return_if_fail (id_pool != NULL);
array = (void*) id_pool->array->data;
array[id] = (void*)0xdecafbad; /* set pointer to a recognizably voided
value */
id_pool->free_ids = g_slist_prepend (id_pool->free_ids,
GUINT_TO_POINTER (id));
}
gpointer
gegl_id_pool_lookup (GeglIDPool *id_pool,
guint32 id)
{
gpointer *array;
g_return_val_if_fail (id_pool != NULL, NULL);
g_return_val_if_fail (id_pool->array != NULL, NULL);
g_return_val_if_fail (id < id_pool->array->len, NULL);
array = (void*) id_pool->array->data;
return array[id];
}