gstreamer/gst/gstdata.c

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/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstdata.c: Data operations
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/* this file makes too much noise for most debugging sessions */
#define GST_DEBUG_FORCE_DISABLE
#include "gst_private.h"
#include "gstatomic_impl.h"
#include "gstdata.h"
#include "gstdata_private.h"
#include "gstlog.h"
/**
* gst_data_init:
* @data: a #GstData to initialize
* @type: the type of this data
* @flags: flags for this data
* @free: a free function
* @copy: a copy function
*
* Initialize the given data structure with the given parameters. The free and copy
* function will be called when this data is freed or copied respectively.
*/
void
gst_data_init (GstData *data, GType type, guint16 flags, GstDataFreeFunction free, GstDataCopyFunction copy)
{
g_return_if_fail (data != NULL);
_GST_DATA_INIT (data, type, flags, free, copy);
}
/**
* gst_data_copy_into:
* @data: a #GstData to copy
* @target: the target #GstData to copy into
*
* Copy the GstData into the specified target GstData structure.
* Thos method is mainly used by subclasses when they want to copy
* the relevant GstData info.
*/
void
gst_data_copy_into (const GstData *data, GstData *target)
{
g_return_if_fail (data != NULL);
}
/**
* gst_data_dispose:
* @data: a #GstData to dispose
*
* Free all the resources allocated in the gst_data_init() function,
* mainly used by subclass implementors.
*/
void
gst_data_dispose (GstData *data)
{
g_return_if_fail (data != NULL);
_GST_DATA_DISPOSE (data);
}
/**
* gst_data_copy:
* @data: a #GstData to copy
*
* Copies the given #GstData. This function will call the custom subclass
* copy function or return NULL if no function was provided by the subclass.
*
* Returns: a copy of the data or NULL if the data cannot be copied. The refcount
* of the original buffer is not changed so you should unref it when you don't
* need it anymore.
*/
GstData*
gst_data_copy (const GstData *data)
{
g_return_val_if_fail (data != NULL, NULL);
if (data->copy)
return data->copy (data);
return NULL;
}
/**
* gst_data_is_writable:
* @data: a #GstData to copy
*
* Query if the gstdata needs to be copied before it can safely be modified.
*
* Returns: FALSE if the given #GstData is potentially shared and needs to
* be copied before it can be modified safely.
*/
gboolean
gst_data_is_writable (GstData *data)
{
gint refcount;
g_return_val_if_fail (data != NULL, FALSE);
refcount = gst_atomic_int_read (&data->refcount);
if (refcount == 1 && !GST_DATA_FLAG_IS_SET (data, GST_DATA_READONLY))
return FALSE;
return TRUE;
}
/**
* gst_data_copy_on_write:
* @data: a #GstData to copy
*
* Copies the given #GstData if the refcount is greater than 1 so that the
* #GstData object can be written to safely.
*
* Returns: a copy of the data if the refcount is > 1 or the buffer is
* marked READONLY, data if the refcount == 1,
* or NULL if the data could not be copied. The refcount of the original buffer
* is decreased when a copy is made, so you are not supposed to use it after a
* call to this function.
*/
GstData*
gst_data_copy_on_write (GstData *data)
{
gint refcount;
g_return_val_if_fail (data != NULL, NULL);
refcount = gst_atomic_int_read (&data->refcount);
if (refcount == 1 && !GST_DATA_FLAG_IS_SET (data, GST_DATA_READONLY))
return GST_DATA (data);
if (data->copy) {
GstData *copy = data->copy (data);
gst_data_unref (data);
return copy;
}
return NULL;
}
/**
* gst_data_free:
* @data: a #GstData to free
*
* Frees the given #GstData. This function will call the custom free function
* provided by the subclass.
*/
void
gst_data_free (GstData *data)
{
if (!data)
return;
if (data->free)
data->free (data);
}
/**
* gst_data_ref:
* @data: a #GstData to reference
*
* Increments the reference count of this data.
*
* Returns: the data
*/
GstData*
gst_data_ref (GstData *data)
{
g_return_val_if_fail (data != NULL, NULL);
g_return_val_if_fail (GST_DATA_REFCOUNT_VALUE(data) > 0, NULL);
gst_atomic_int_inc (&data->refcount);
return data;
}
/**
* gst_data_ref_by_count:
* @data: a #GstData to reference
* @count: the number to increment the reference count by
*
* Increments the reference count of this data by the given number.
*
* Returns: the data
*/
GstData*
gst_data_ref_by_count (GstData *data, gint count)
{
g_return_val_if_fail (data != NULL, NULL);
g_return_val_if_fail (count >= 0, NULL);
g_return_val_if_fail (GST_DATA_REFCOUNT_VALUE(data) > 0, NULL);
gst_atomic_int_add (&data->refcount, count);
return data;
}
/**
* gst_data_unref:
* @data: a #GstData to unreference
*
* Decrements the refcount of this data. If the refcount is
* zero, the data will be freed.
*
* When you add data to a pipeline, the pipeline takes ownership of the
* data. When the data has been used by some plugin, it must unref()s it.
* Applications usually don't need to unref() anything.
*/
void
gst_data_unref (GstData *data)
{
gint zero;
g_return_if_fail (data != NULL);
GST_INFO (GST_CAT_BUFFER, "unref data %p, count before unref is %d",
data, GST_DATA_REFCOUNT_VALUE (data));
g_return_if_fail (GST_DATA_REFCOUNT_VALUE (data) > 0);
zero = gst_atomic_int_dec_and_test (&data->refcount);
/* if we ended up with the refcount at zero, free the data */
if (zero) {
if (data->free)
data->free (data);
}
}