1 files changed, 142 insertions, 0 deletions
diff --git a/gst/gstcontrolsource.c b/gst/gstcontrolsource.c
new file mode 100644
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--- /dev/null
+++ b/gst/gstcontrolsource.c
@@ -0,0 +1,142 @@
+/* GStreamer
+ *
+ * Copyright (C) 2007 Sebastian Dröge <slomo@circular-chaos.org>
+ *
+ * gstcontrolsource.c: Interface declaration for control sources
+ *
+ * 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.
+ */
+
+/**
+ * SECTION:gstcontrolsource
+ * @short_description: base class for control source sources
+ *
+ * The #GstControlSource is a base class for control value sources that could
+ * be used by #GstController to get timestamp-value pairs.
+ *
+ * A #GstControlSource is used by first getting an instance, binding it to a
+ * #GParamSpec (for example by using gst_controller_set_control_source()) and
+ * then by having it used by the #GstController or calling
+ * gst_control_source_get_value() or gst_control_source_get_value_array().
+ *
+ * For implementing a new #GstControlSource one has to implement a
+ * #GstControlSourceBind method, which will depending on the #GParamSpec set up
+ * the control source for use and sets the #GstControlSourceGetValue and
+ * #GstControlSourceGetValueArray functions. These are then used by
+ * gst_control_source_get_value() or gst_control_source_get_value_array()
+ * to get values for specific timestamps.
+ *
+ */
+
+#include "gst_private.h"
+
+#include <glib-object.h>
+#include <gst/gst.h>
+
+#include "gstcontrolsource.h"
+
+#define GST_CAT_DEFAULT control_source_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define _do_init \
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "gstcontrolsource", 0, \
+      "dynamic parameter control sources");
+
+G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GstControlSource, gst_control_source,
+    GST_TYPE_OBJECT, _do_init);
+
+static GObject *gst_control_source_constructor (GType type,
+    guint n_construct_params, GObjectConstructParam * construct_params);
+
+static void
+gst_control_source_class_init (GstControlSourceClass * klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  gobject_class->constructor = gst_control_source_constructor;
+}
+
+static void
+gst_control_source_init (GstControlSource * self)
+{
+  self->get_value = NULL;
+  self->get_value_array = NULL;
+}
+
+static GObject *
+gst_control_source_constructor (GType type, guint n_construct_params,
+    GObjectConstructParam * construct_params)
+{
+  GObject *self;
+
+  self =
+      G_OBJECT_CLASS (gst_control_source_parent_class)->constructor (type,
+      n_construct_params, construct_params);
+  gst_object_ref_sink (self);
+
+  return self;
+}
+
+/**
+ * gst_control_source_get_value:
+ * @self: the #GstControlSource object
+ * @timestamp: the time for which the value should be returned
+ * @value: the value
+ *
+ * Gets the value for this #GstControlSource at a given timestamp.
+ *
+ * Returns: FALSE if the value couldn't be returned, TRUE otherwise.
+ */
+gboolean
+gst_control_source_get_value (GstControlSource * self, GstClockTime timestamp,
+    gdouble * value)
+{
+  g_return_val_if_fail (GST_IS_CONTROL_SOURCE (self), FALSE);
+
+  if (G_LIKELY (self->get_value)) {
+    return self->get_value (self, timestamp, value);
+  } else {
+    GST_ERROR ("Not bound to a specific property yet!");
+    return FALSE;
+  }
+}
+
+/**
+ * gst_control_source_get_value_array:
+ * @self: the #GstControlSource object
+ * @timestamp: the first timestamp
+ * @interval: the time steps
+ * @n_values: the number of values to fetch
+ * @value_array: array to put control-values in
+ *
+ * Gets an array of values for for this #GstControlSource.
+ *
+ * Returns: %TRUE if the given array could be filled, %FALSE otherwise
+ */
+gboolean
+gst_control_source_get_value_array (GstControlSource * self,
+    GstClockTime timestamp, GstClockTime interval, guint n_values,
+    gdouble * values)
+{
+  g_return_val_if_fail (GST_IS_CONTROL_SOURCE (self), FALSE);
+
+  if (G_LIKELY (self->get_value_array)) {
+    return self->get_value_array (self, timestamp, interval, n_values, values);
+  } else {
+    GST_ERROR ("Not bound to a specific property yet!");
+    return FALSE;
+  }
+}