gstreamer/gst/gstcaps.c

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/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstcaps.c: Element capabilities subsystem
*
* 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.
*/
//#define GST_DEBUG_ENABLED
#include "gst_private.h"
#include "gstcaps.h"
#include "gsttype.h"
#include "gstpropsprivate.h"
void
_gst_caps_initialize (void)
{
}
static guint16
get_type_for_mime (gchar *mime)
{
guint16 typeid;
typeid = gst_type_find_by_mime (mime);
if (typeid == 0) {
GstTypeFactory *factory = g_new0 (GstTypeFactory, 1);
factory->mime = g_strdup (mime);
factory->exts = NULL;
factory->typefindfunc = NULL;
typeid = gst_type_register (factory);
}
return typeid;
}
/**
* gst_caps_new:
* @name: the name of this capability
* @mime: the mime type to attach to the capability
*
* create a new capability with the given mime type
*
* Returns: a new capability
*/
GstCaps*
gst_caps_new (gchar *name, gchar *mime)
{
GstCaps *caps;
g_return_val_if_fail (mime != NULL, NULL);
caps = g_new0 (GstCaps, 1);
caps->name = g_strdup (name);
caps->id = get_type_for_mime (mime);
caps->properties = NULL;
return caps;
}
/**
* gst_caps_new_with_props:
* @name: the name of this capability
* @mime: the mime type to attach to the capability
* @props: the properties for this capability
*
* create a new capability with the given mime type
* and the given properties
*
* Returns: a new capability
*/
GstCaps*
gst_caps_new_with_props (gchar *name, gchar *mime, GstProps *props)
{
GstCaps *caps;
caps = gst_caps_new (name, mime);
caps->properties = props;
return caps;
}
/**
* gst_caps_register:
* @factory: the factory to register
*
* Register the factory.
*
* Returns: The registered capability
*/
GstCaps*
gst_caps_register (GstCapsFactory *factory)
{
guint dummy;
return gst_caps_register_count (factory, &dummy);
}
/**
* gst_caps_register_count:
* @factory: the factory to register
* @counter: count how many entries were consumed
*
* Register the factory.
*
* Returns: The registered capability
*/
GstCaps*
gst_caps_register_count (GstCapsFactory *factory, guint *counter)
{
GstCapsFactoryEntry tag;
gint i = 0;
guint16 typeid;
gchar *name;
GstCaps *caps;
g_return_val_if_fail (factory != NULL, NULL);
tag = (*factory)[i++];
g_return_val_if_fail (tag != NULL, NULL);
name = tag;
tag = (*factory)[i++];
g_return_val_if_fail (tag != NULL, NULL);
typeid = get_type_for_mime ((gchar *)tag);
caps = g_new0 (GstCaps, 1);
g_return_val_if_fail (caps != NULL, NULL);
caps->name = g_strdup (name);
caps->id = typeid;
caps->properties = gst_props_register_count (&(*factory)[i], counter);
*counter += 2;
return caps;
}
/**
* gst_caps_set_props:
* @caps: the caps to attach the properties to
* @props: the properties to attach
*
* set the properties to the given caps
*
* Returns: The new caps structure
*/
GstCaps*
gst_caps_set_props (GstCaps *caps, GstProps *props)
{
g_return_val_if_fail (caps != NULL, caps);
g_return_val_if_fail (props != NULL, caps);
g_return_val_if_fail (caps->properties == NULL, caps);
caps->properties = props;
return caps;
}
/**
* gst_caps_get_props:
* @caps: the caps to get the properties from
*
* get the properties of the given caps
*
* Returns: The properties of the caps
*/
GstProps*
gst_caps_get_props (GstCaps *caps)
{
g_return_val_if_fail (caps != NULL, NULL);
return caps->properties;
}
/**
* gst_caps_check_compatibility:
* @fromcaps: a capabilty
* @tocaps: a capabilty
*
* Checks whether two capabilities are compatible
*
* Returns: true if compatible, false otherwise
*/
gboolean
gst_caps_check_compatibility (GstCaps *fromcaps, GstCaps *tocaps)
{
g_return_val_if_fail (fromcaps != NULL, FALSE);
g_return_val_if_fail (tocaps != NULL, FALSE);
if (fromcaps->id != tocaps->id) {
DEBUG ("gstcaps: mime types wrong\n");
return FALSE;
}
if (tocaps->properties) {
if (fromcaps->properties) {
return gst_props_check_compatibility (fromcaps->properties, tocaps->properties);
}
else {
DEBUG ("gstcaps: no source caps\n");
return FALSE;
}
}
else {
// assume it accepts everything
DEBUG ("gstcaps: no caps\n");
return TRUE;
}
}
/**
* gst_caps_list_check_compatibility:
* @fromcaps: a capabilty
* @tocaps: a capabilty
*
* Checks whether two capability lists are compatible
*
* Returns: true if compatible, false otherwise
*/
gboolean
gst_caps_list_check_compatibility (GList *fromcaps, GList *tocaps)
{
while (fromcaps) {
GstCaps *fromcap = (GstCaps *)fromcaps->data;
GList *destcaps = tocaps;
while (destcaps) {
GstCaps *destcap = (GstCaps *)destcaps->data;
if (gst_caps_check_compatibility (fromcap, destcap))
return TRUE;
destcaps = g_list_next (destcaps);
}
fromcaps = g_list_next (fromcaps);
}
return FALSE;
}
/**
* gst_caps_save_thyself:
* @caps: a capabilty to save
* @parent: the parent XML node pointer
*
* save the capability into an XML representation
*
* Returns: a new XML node pointer
*/
xmlNodePtr
gst_caps_save_thyself (GstCaps *caps, xmlNodePtr parent)
{
xmlNodePtr subtree;
g_return_val_if_fail (caps != NULL, NULL);
xmlNewChild (parent, NULL, "name", caps->name);
xmlNewChild (parent, NULL, "type", gst_type_find_by_id (caps->id)->mime);
if (caps->properties) {
subtree = xmlNewChild (parent, NULL, "properties", NULL);
gst_props_save_thyself (caps->properties, subtree);
}
return parent;
}
/**
* gst_caps_load_thyself:
* @parent: the parent XML node pointer
*
* load a new caps from the XML representation
*
* Returns: a new capability
*/
GstCaps*
gst_caps_load_thyself (xmlNodePtr parent)
{
GstCaps *caps = g_new0 (GstCaps, 1);
xmlNodePtr field = parent->childs;
while (field) {
if (!strcmp (field->name, "name")) {
caps->name = g_strdup (xmlNodeGetContent (field));
}
if (!strcmp (field->name, "type")) {
caps->id = get_type_for_mime (xmlNodeGetContent (field));
}
else if (!strcmp (field->name, "properties")) {
caps->properties = gst_props_load_thyself (field);
}
field = field->next;
}
return caps;
}