gstreamer/gst-libs/gst/vaapi/gstvaapiminiobject.c

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/*
* gstvaapiminiobject.c - A lightweight reference counted object
*
* Copyright (C) 2012-2013 Intel Corporation
* Author: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
*
* 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 2.1
* 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
*/
#include <string.h>
#include "gstvaapiminiobject.h"
static void
gst_vaapi_mini_object_free(GstVaapiMiniObject *object)
{
const GstVaapiMiniObjectClass * const klass = object->object_class;
g_atomic_int_inc(&object->ref_count);
if (klass->finalize)
klass->finalize(object);
if (G_LIKELY(g_atomic_int_dec_and_test(&object->ref_count)))
g_slice_free1(klass->size, object);
}
/**
* gst_vaapi_mini_object_new:
* @object_class: (optional): The object class
*
* Creates a new #GstVaapiMiniObject. If @object_class is NULL, then the
* size of the allocated object is the same as sizeof(GstVaapiMiniObject).
* If @object_class is not NULL, typically when a sub-class is implemented,
* that pointer shall reference a statically allocated descriptor.
*
* This function does *not* zero-initialize the derived object data,
* use gst_vaapi_mini_object_new0() to fill this purpose.
*
* Returns: The newly allocated #GstVaapiMiniObject
*/
GstVaapiMiniObject *
gst_vaapi_mini_object_new(const GstVaapiMiniObjectClass *object_class)
{
GstVaapiMiniObject *object;
static const GstVaapiMiniObjectClass default_object_class = {
.size = sizeof(GstVaapiMiniObject),
};
if (G_UNLIKELY(!object_class))
object_class = &default_object_class;
g_return_val_if_fail(object_class->size >= sizeof(*object), NULL);
object = g_slice_alloc(object_class->size);
if (!object)
return NULL;
object->object_class = object_class;
object->ref_count = 1;
object->flags = 0;
return object;
}
/**
* gst_vaapi_mini_object_new0:
* @object_class: (optional): The object class
*
* Creates a new #GstVaapiMiniObject. This function is similar to
* gst_vaapi_mini_object_new() but derived object data is initialized
* to zeroes.
*
* Returns: The newly allocated #GstVaapiMiniObject
*/
GstVaapiMiniObject *
gst_vaapi_mini_object_new0(const GstVaapiMiniObjectClass *object_class)
{
GstVaapiMiniObject *object;
guint sub_size;
object = gst_vaapi_mini_object_new(object_class);
if (!object)
return NULL;
object_class = object->object_class;
sub_size = object_class->size - sizeof(*object);
if (sub_size > 0)
memset(((guchar *)object) + sizeof(*object), 0, sub_size);
return object;
}
/**
* gst_vaapi_mini_object_ref:
* @object: a #GstVaapiMiniObject
*
* Atomically increases the reference count of the given @object by one.
*
* Returns: The same @object argument
*/
GstVaapiMiniObject *
gst_vaapi_mini_object_ref(GstVaapiMiniObject *object)
{
g_return_val_if_fail(object != NULL, NULL);
g_atomic_int_inc(&object->ref_count);
return object;
}
/**
* gst_vaapi_mini_object_unref:
* @object: a #GstVaapiMiniObject
*
* Atomically decreases the reference count of the @object by one. If
* the reference count reaches zero, the object will be free'd.
*/
void
gst_vaapi_mini_object_unref(GstVaapiMiniObject *object)
{
g_return_if_fail(object != NULL);
g_return_if_fail(object->ref_count > 0);
if (g_atomic_int_dec_and_test(&object->ref_count))
gst_vaapi_mini_object_free(object);
}
/**
* gst_vaapi_mini_object_replace:
* @old_object_ptr: a pointer to a #GstVaapiMiniObject
* @new_object: a #GstVaapiMiniObject
*
* Atomically replaces the object held in @old_object_ptr with
* @new_object. This means that @old_object_ptr shall reference a
* valid object. However, @new_object can be NULL.
*/
void
gst_vaapi_mini_object_replace(GstVaapiMiniObject **old_object_ptr,
GstVaapiMiniObject *new_object)
{
GstVaapiMiniObject *old_object;
g_return_if_fail(old_object_ptr != NULL);
old_object = g_atomic_pointer_get((gpointer *)old_object_ptr);
if (old_object == new_object)
return;
if (new_object)
gst_vaapi_mini_object_ref(new_object);
while (!g_atomic_pointer_compare_and_exchange((gpointer *)old_object_ptr,
old_object, new_object))
old_object = g_atomic_pointer_get((gpointer *)old_object_ptr);
if (old_object)
gst_vaapi_mini_object_unref(old_object);
}