gstreamer/gst/gstquery.h

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wim.taymans@chello.be>
 *                    2005 Wim Taymans <wim@fluendo.com>
 *
 * gstquery.h: GstQuery API declaration
 *
 * 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_QUERY_H__
#define __GST_QUERY_H__

#include <glib.h>

#include <gst/gstiterator.h>
#include <gst/gstdata.h>
#include <gst/gststructure.h>

G_BEGIN_DECLS

typedef enum {
  GST_QUERY_NONE = 0,
  GST_QUERY_TOTAL, /* deprecated, use POSITION */
  GST_QUERY_POSITION,
  GST_QUERY_LATENCY,
  GST_QUERY_JITTER, /* not in draft-query, necessary? */
  GST_QUERY_START, /* deprecated, use SEEKING */
  GST_QUERY_SEGMENT_END, /* deprecated, use SEEKING */
  GST_QUERY_RATE, /* not in draft-query, necessary? */
  GST_QUERY_SEEKING,
  GST_QUERY_CONVERT,
  GST_QUERY_FORMATS
} GstQueryType;

/* rate is relative to 1000000  */
#define GST_QUERY_TYPE_RATE_DEN          G_GINT64_CONSTANT (1000000)

typedef struct _GstQueryTypeDefinition GstQueryTypeDefinition;
typedef struct _GstQuery GstQuery;

struct _GstQueryTypeDefinition
{
  GstQueryType   value;
  gchar     	*nick;
  gchar     	*description;
};

#ifdef G_HAVE_ISO_VARARGS
#define GST_QUERY_TYPE_FUNCTION(type, functionname, ...)  	\
static const GstQueryType*                           	\
functionname (type object)                         	\
{                                                       \
  static const GstQueryType types[] = {              	\
    __VA_ARGS__,                                        \
    0                                              	\
  };                                                    \
  return types;                                         \
}
#elif defined(G_HAVE_GNUC_VARARGS)
#define GST_QUERY_TYPE_FUNCTION(type, functionname, a...) 	\
static const GstQueryType*                           	\
functionname (type object)                          	\
{                                                       \
  static const GstQueryType types[] = {              	\
    a,                                                  \
    0                                              	\
  };                                                    \
  return types;                                         \
}
#endif

GST_EXPORT GType _gst_query_type;

#define GST_TYPE_QUERY	(_gst_query_type)
#define GST_QUERY(query)	((GstQuery*)(query))
#define GST_IS_QUERY(query)	(GST_DATA_TYPE(query) == GST_TYPE_QUERY)
#define GST_QUERY_TYPE(query)	(((GstQuery*)(query))->type)

struct _GstQuery
{
  GstData data;

  /*< public > */
  GstQueryType type;

  GstStructure *structure;
  
  /*< private > */
  gpointer _gst_reserved[GST_PADDING];
};

void            _gst_query_initialize          (void);
GType		gst_query_get_type             (void);

/* register a new query */
GstQueryType    gst_query_type_register        (const gchar *nick, 
                                                const gchar *description);
GstQueryType    gst_query_type_get_by_nick     (const gchar *nick);

/* check if a query is in an array of querys */
gboolean        gst_query_types_contains       (const GstQueryType *types,
                                                GstQueryType type);

/* query for query details */
G_CONST_RETURN GstQueryTypeDefinition*      
                gst_query_type_get_details         (GstQueryType type);
GstIterator*    gst_query_type_iterate_definitions (void);

/* refcounting */
#define         gst_query_ref(msg)		GST_QUERY (gst_data_ref (GST_DATA (msg)))
#define         gst_query_ref_by_count(msg,c)	GST_QUERY (gst_data_ref_by_count (GST_DATA (msg), (c)))
#define         gst_query_unref(msg)		gst_data_unref (GST_DATA (msg))
/* copy query */
#define         gst_query_copy(msg)		GST_QUERY (gst_data_copy (GST_DATA (msg)))
#define         gst_query_copy_on_write(msg)	GST_QUERY (gst_data_copy_on_write (GST_DATA (msg)))

GstQuery *	gst_query_new_application 	(GstQueryType type,
                                                 GstStructure *structure);

GstStructure *  gst_query_get_structure		(GstQuery *query);

/* hmm */
#define GST_QUERY_POSITION_GET_FORMAT(q) \
    (gst_structure_get_int ((q)->structure, "format"))

G_END_DECLS

#endif /* __GST_QUERY_H__ */