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"
static GMemChunk *_gst_caps_chunk;
static GMutex *_gst_caps_chunk_lock;
void
_gst_caps_initialize (void)
{
_gst_caps_chunk = g_mem_chunk_new ("GstCaps",
sizeof (GstCaps), sizeof (GstCaps) * 256,
G_ALLOC_AND_FREE);
_gst_caps_chunk_lock = g_mutex_new ();
}
static guint16
get_type_for_mime (const 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
* @props: the properties to add to this capability
*
* Create a new capability with the given mime typei and properties.
*
* Returns: a new capability
*/
GstCaps*
gst_caps_new (const gchar *name, const gchar *mime, GstProps *props)
{
GstCaps *caps;
g_return_val_if_fail (mime != NULL, NULL);
g_mutex_lock (_gst_caps_chunk_lock);
caps = g_mem_chunk_alloc (_gst_caps_chunk);
g_mutex_unlock (_gst_caps_chunk_lock);
caps->name = g_strdup (name);
caps->id = get_type_for_mime (mime);
caps->properties = props;
caps->next = NULL;
caps->refcount = 1;
caps->lock = g_mutex_new ();
return caps;
}
/**
* gst_caps_destroy:
* @caps: the caps to destroy
*
* Frees the memory used by this caps structure and all
* the chained caps and properties.
*/
void
gst_caps_destroy (GstCaps *caps)
{
GstCaps *next;
g_return_if_fail (caps != NULL);
GST_CAPS_LOCK (caps);
next = caps->next;
g_free (caps->name);
g_free (caps);
GST_CAPS_UNLOCK (caps);
if (next)
gst_caps_unref (next);
}
/**
* gst_caps_unref:
* @caps: the caps to unref
*
* Decrease the refcount of this caps structure,
* destroying it when the refcount is 0
*
* Returns: caps or NULL if the refcount reached 0
*/
GstCaps*
gst_caps_unref (GstCaps *caps)
{
gboolean zero;
GstCaps **next;
g_return_val_if_fail (caps != NULL, NULL);
g_return_val_if_fail (caps->refcount > 0, NULL);
GST_CAPS_LOCK (caps);
caps->refcount--;
zero = (caps->refcount == 0);
next = &caps->next;
GST_CAPS_UNLOCK (caps);
if (*next)
*next = gst_caps_unref (*next);
if (zero) {
gst_caps_destroy (caps);
caps = NULL;
}
return caps;
}
/**
* gst_caps_ref:
* @caps: the caps to ref
*
* Increase the refcount of this caps structure
*
* Returns: the caps with the refcount incremented
*/
GstCaps*
gst_caps_ref (GstCaps *caps)
{
g_return_val_if_fail (caps != NULL, NULL);
GST_CAPS_LOCK (caps);
caps->refcount++;
GST_CAPS_UNLOCK (caps);
return caps;
}
/**
* gst_caps_copy:
* @caps: the caps to copy
*
* Copies the caps.
*
* Returns: a copy of the GstCaps structure.
*/
GstCaps*
gst_caps_copy (GstCaps *caps)
{
GstCaps *new = caps;;
g_return_val_if_fail (caps != NULL, NULL);
GST_CAPS_LOCK (caps);
new = gst_caps_new (
caps->name,
(gst_type_find_by_id (caps->id))->mime,
gst_props_copy (caps->properties));
GST_CAPS_UNLOCK (caps);
return new;
}
/**
* gst_caps_copy_on_write:
* @caps: the caps to copy
*
* Copies the caps if the refcount is greater than 1
*
* Returns: a pointer to a GstCaps strcuture that can
* be safely written to
*/
GstCaps*
gst_caps_copy_on_write (GstCaps *caps)
{
GstCaps *new = caps;
gboolean needcopy;
g_return_val_if_fail (caps != NULL, NULL);
GST_CAPS_LOCK (caps);
needcopy = (caps->refcount > 1);
GST_CAPS_UNLOCK (caps);
if (needcopy) {
new = gst_caps_copy (caps);
gst_caps_unref (caps);
}
return new;
}
/**
* gst_caps_get_name:
* @caps: the caps to get the name from
*
* Get the name of a GstCaps structure.
*
* Returns: the name of the caps
*/
const gchar*
gst_caps_get_name (GstCaps *caps)
{
g_return_val_if_fail (caps != NULL, NULL);
return (const gchar *)caps->name;
}
/**
* gst_caps_set_name:
* @caps: the caps to set the name to
* @name: the name to set
*
* Set the name of a caps.
*/
void
gst_caps_set_name (GstCaps *caps, const gchar *name)
{
g_return_if_fail (caps != NULL);
if (caps->name)
g_free (caps->name);
caps->name = g_strdup (name);
}
/**
* gst_caps_get_mime:
* @caps: the caps to get the mime type from
*
* Get the mime type of the caps as a string.
*
* Returns: the mime type of the caps
*/
const gchar*
gst_caps_get_mime (GstCaps *caps)
{
GstType *type;
g_return_val_if_fail (caps != NULL, NULL);
type = gst_type_find_by_id (caps->id);
if (type)
return type->mime;
else
return "unknown/unknown";
}
/**
* gst_caps_set_mime:
* @caps: the caps to set the mime type to
* @mime: the mime type to attach to the caps
*
* Set the mime type of the caps as a string.
*/
void
gst_caps_set_mime (GstCaps *caps, const gchar *mime)
{
g_return_if_fail (caps != NULL);
g_return_if_fail (mime != NULL);
caps->id = get_type_for_mime (mime);
}
/**
* gst_caps_get_type_id:
* @caps: the caps to get the type id from
*
* Get the type id of the caps.
*
* Returns: the type id of the caps
*/
guint16
gst_caps_get_type_id (GstCaps *caps)
{
g_return_val_if_fail (caps != NULL, 0);
return caps->id;
}
/**
* gst_caps_set_type_id:
* @caps: the caps to set the type id to
* @type_id: the type id to set
*
* Set the type id of the caps.
*/
void
gst_caps_set_type_id (GstCaps *caps, guint16 type_id)
{
g_return_if_fail (caps != NULL);
caps->id = type_id;
}
/**
* 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_chain:
* @caps: a capabilty
* @...: more capabilities
*
* chains the given capabilities
*
* Returns: the new capability
*/
GstCaps*
gst_caps_chain (GstCaps *caps, ...)
{
GstCaps *orig = caps;
va_list var_args;
va_start (var_args, caps);
while (caps) {
GstCaps *toadd;
toadd = va_arg (var_args, GstCaps*);
gst_caps_append (caps, toadd);
caps = toadd;
}
va_end (var_args);
return orig;
}
/**
* gst_caps_append:
* @caps: a capabilty
* @capstoadd: the capability to append
*
* Appends a capability to the existing capability.
*
* Returns: the new capability
*/
GstCaps*
gst_caps_append (GstCaps *caps, GstCaps *capstoadd)
{
GstCaps *orig = caps;
g_return_val_if_fail (caps != capstoadd, caps);
if (caps == NULL)
return capstoadd;
while (caps->next) {
caps = caps->next;
}
caps->next = capstoadd;
return orig;
}
/**
* gst_caps_prepend:
* @caps: a capabilty
* @capstoadd: a capabilty to prepend
*
* prepend the capability to the list of capabilities
*
* Returns: the new capability
*/
GstCaps*
gst_caps_prepend (GstCaps *caps, GstCaps *capstoadd)
{
GstCaps *orig = capstoadd;
g_return_val_if_fail (caps != capstoadd, caps);
if (capstoadd == NULL)
return caps;
while (capstoadd->next) {
capstoadd = capstoadd->next;
}
capstoadd->next = caps;
return orig;
}
/**
* gst_caps_get_by_name:
* @caps: a capabilty
* @name: the name of the capability to get
*
* Get the capability with the given name from this
* chain of capabilities.
*
* Returns: the first capability in the chain with the
* given name
*/
GstCaps*
gst_caps_get_by_name (GstCaps *caps, const gchar *name)
{
g_return_val_if_fail (caps != NULL, NULL);
g_return_val_if_fail (name != NULL, NULL);
while (caps) {
if (!strcmp (caps->name, name))
return caps;
caps = caps->next;
}
return NULL;
}
static gboolean
gst_caps_check_compatibility_func (GstCaps *fromcaps, GstCaps *tocaps)
{
if (fromcaps->id != tocaps->id) {
GST_DEBUG (0,"gstcaps: mime types differ (%s to %s)\n",
gst_type_find_by_id (fromcaps->id)->mime,
gst_type_find_by_id (tocaps->id)->mime);
return FALSE;
}
if (tocaps->properties) {
if (fromcaps->properties) {
return gst_props_check_compatibility (fromcaps->properties, tocaps->properties);
}
else {
GST_DEBUG (0,"gstcaps: no source caps\n");
return FALSE;
}
}
else {
// assume it accepts everything
GST_DEBUG (0,"gstcaps: no caps\n");
return TRUE;
}
}
/**
* 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)
{
if (fromcaps == NULL) {
if (tocaps == NULL) {
GST_DEBUG (0,"gstcaps: no caps\n");
return TRUE;
}
else {
GST_DEBUG (0,"gstcaps: no src but destination caps\n");
return FALSE;
}
}
else {
if (tocaps == NULL) {
GST_DEBUG (0,"gstcaps: src caps and no dest caps\n");
return TRUE;
}
}
while (fromcaps) {
GstCaps *destcaps = tocaps;
while (destcaps) {
if (gst_caps_check_compatibility_func (fromcaps, destcaps))
return TRUE;
destcaps = destcaps->next;
}
fromcaps = fromcaps->next;
}
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;
xmlNodePtr subsubtree;
while (caps) {
subtree = xmlNewChild (parent, NULL, "capscomp", NULL);
xmlNewChild (subtree, NULL, "name", caps->name);
xmlNewChild (subtree, NULL, "type", gst_type_find_by_id (caps->id)->mime);
if (caps->properties) {
subsubtree = xmlNewChild (subtree, NULL, "properties", NULL);
gst_props_save_thyself (caps->properties, subsubtree);
}
caps = caps->next;
}
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 *result = NULL;
xmlNodePtr field = parent->xmlChildrenNode;
while (field) {
if (!strcmp (field->name, "capscomp")) {
xmlNodePtr subfield = field->xmlChildrenNode;
GstCaps *caps;
gchar *content;
g_mutex_lock (_gst_caps_chunk_lock);
caps = g_mem_chunk_alloc0 (_gst_caps_chunk);
g_mutex_unlock (_gst_caps_chunk_lock);
caps->refcount = 1;
caps->lock = g_mutex_new ();
caps->next = NULL;
while (subfield) {
if (!strcmp (subfield->name, "name")) {
caps->name = xmlNodeGetContent (subfield);
}
if (!strcmp (subfield->name, "type")) {
content = xmlNodeGetContent (subfield);
caps->id = get_type_for_mime (content);
g_free (content);
}
else if (!strcmp (subfield->name, "properties")) {
caps->properties = gst_props_load_thyself (subfield);
}
subfield = subfield->next;
}
result = gst_caps_append (result, caps);
}
field = field->next;
}
return result;
}