gstreamer/gst/gstutils.h

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/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstutils.h: Header for various utility functions
*
* 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.
*/
#ifndef __GST_UTILS_H__
#define __GST_UTILS_H__
#include <glib.h>
#include <gst/gstelement.h>
G_BEGIN_DECLS
void gst_util_set_value_from_string (GValue *value, const gchar *value_str);
void gst_util_set_object_arg (GObject *object, const gchar *name, const gchar *value);
void gst_util_dump_mem (const guchar *mem, guint size);
void gst_print_pad_caps (GString *buf, gint indent, GstPad *pad);
void gst_print_element_args (GString *buf, gint indent, GstElement *element);
/* Macros for defining classes. Ideas taken from Bonobo, which took theirs
from Nautilus and GOB. */
/* Define the boilerplate type stuff to reduce typos and code size. Defines
the get_type method and the parent_class static variable.
void additional_initializations (GType type) is for initializing interfaces
and stuff like that */
#define GST_BOILERPLATE_FULL(type, type_as_function, parent_type, \
parent_type_macro, additional_initializations) \
\
static void type_as_function ## _base_init (gpointer g_class); \
static void type_as_function ## _class_init (type ## Class *g_class); \
static void type_as_function ## _init (type *object); \
static parent_type ## Class *parent_class = NULL; \
static void \
type_as_function ## _class_init_trampoline (gpointer g_class, \
gpointer data) \
{ \
parent_class = (parent_type ## Class *) g_type_class_peek_parent (g_class); \
type_as_function ## _class_init ((type ## Class *)g_class); \
} \
\
GType \
type_as_function ## _get_type (void) \
{ \
static GType object_type = 0; \
if (object_type == 0) { \
static const GTypeInfo object_info = { \
sizeof (type ## Class), \
type_as_function ## _base_init, \
NULL, /* base_finalize */ \
type_as_function ## _class_init_trampoline, \
NULL, /* class_finalize */ \
NULL, /* class_data */ \
sizeof (type), \
0, /* n_preallocs */ \
(GInstanceInitFunc) type_as_function ## _init \
}; \
object_type = g_type_register_static (parent_type_macro, #type, \
&object_info, 0); \
additional_initializations (object_type); \
} \
return object_type; \
}
#define __GST_DO_NOTHING(type) /* NOP */
#define GST_BOILERPLATE(type,type_as_function,parent_type,parent_type_macro) \
GST_BOILERPLATE_FULL (type, type_as_function, parent_type, parent_type_macro, \
__GST_DO_NOTHING)
/* Just call the parent handler. This assumes that there is a variable
* named parent_class that points to the (duh!) parent class. Note that
* this macro is not to be used with things that return something, use
* the _WITH_DEFAULT version for that */
#define GST_CALL_PARENT(parent_class_cast, name, args) \
((parent_class_cast(parent_class)->name != NULL) ? \
parent_class_cast(parent_class)->name args : (void) 0)
/* Same as above, but in case there is no implementation, it evaluates
* to def_return */
#define GST_CALL_PARENT_WITH_DEFAULT(parent_class_cast, name, args, def_return) \
((parent_class_cast(parent_class)->name != NULL) ? \
parent_class_cast(parent_class)->name args : def_return)
G_END_DECLS
#endif /* __GST_UTILS_H__ */