--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gstreamer_core/gst/gstbufferlist.c	Fri Apr 16 15:15:52 2010 +0300
@@ -0,0 +1,887 @@
+/* GStreamer
+ * Copyright (C) 2009 Axis Communications <dev-gstreamer at axis dot com>
+ * @author Jonas Holmberg <jonas dot holmberg at axis dot com>
+ *
+ * gstbufferlist.c: Buffer list
+ *
+ * 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:gstbufferlist
+ * @short_description: Grouped scatter data buffer type for data-passing
+ * @see_also: #GstPad, #GstMiniObject
+ *
+ * Buffer lists are units of grouped scatter/gather data transfer in
+ * GStreamer.
+ *
+ * Buffer lists are created with gst_buffer_list_new() and filled with data
+ * using a #GstBufferListIterator. The iterator has no current buffer; its
+ * cursor position lies between buffers, immediately before the buffer that
+ * would be returned by gst_buffer_list_iterator_next(). After iterating to the
+ * end of a group the iterator must be advanced to the next group by a call to
+ * gst_buffer_list_iterator_next_group() before any further calls to
+ * gst_buffer_list_iterator_next() can return buffers again. The cursor position
+ * of a newly created iterator lies before the first group; a call to
+ * gst_buffer_list_iterator_next_group() is necessary before calls to
+ * gst_buffer_list_iterator_next() can return buffers.
+ *
+ * <informalexample>
+ *   <programlisting>
+ *      +--- group0 ----------------------+--- group1 ------------+
+ *      |   buffer0   buffer1   buffer2   |   buffer3   buffer4   |
+ *    ^   ^         ^         ^         ^   ^         ^         ^
+ *    Iterator positions
+ *   </programlisting>
+ * </informalexample>
+ *
+ * The gst_buffer_list_iterator_remove(), gst_buffer_list_iterator_steal(),
+ * gst_buffer_list_iterator_take(), gst_buffer_list_iterator_do() and
+ * gst_buffer_list_iterator_do_data() functions are not defined in terms of the
+ * cursor position; they operate on the last element returned from
+ * gst_buffer_list_iterator_next().
+ *
+ * The basic use pattern of creating a buffer list with an iterator is as
+ * follows:
+ *
+ * <example>
+ * <title>Creating a buffer list</title>
+ *   <programlisting>
+ *    GstBufferList *list;
+ *    GstBufferListIterator *it;
+ *
+ *    list = gst_buffer_list_new ();
+ *    it = gst_buffer_list_iterate (list);
+ *    gst_buffer_list_iterator_add_group (it);
+ *    gst_buffer_list_iterator_add (it, header1);
+ *    gst_buffer_list_iterator_add (it, data1);
+ *    gst_buffer_list_iterator_add_group (it);
+ *    gst_buffer_list_iterator_add (it, header2);
+ *    gst_buffer_list_iterator_add (it, data2);
+ *    gst_buffer_list_iterator_add_group (it);
+ *    gst_buffer_list_iterator_add (it, header3);
+ *    gst_buffer_list_iterator_add (it, data3);
+ *    ...
+ *    gst_buffer_list_iterator_free (it);
+ *   </programlisting>
+ * </example>
+ *
+ * The basic use pattern of iterating over a buffer list is as follows:
+ *
+ * <example>
+ * <title>Iterating a buffer list</title>
+ *   <programlisting>
+ *    GstBufferListIterator *it;
+ *
+ *    it = gst_buffer_list_iterate (list);
+ *    while (gst_buffer_list_iterator_next_group (it)) {
+ *      while ((buffer = gst_buffer_list_iterator_next (it)) != NULL) {
+ *        do_something_with_buffer (buffer);
+ *      }
+ *    }
+ *    gst_buffer_list_iterator_free (it);
+ *   </programlisting>
+ * </example>
+ *
+ * The basic use pattern of modifying a buffer in a list is as follows:
+ *
+ * <example>
+ * <title>Modifying the data of the first buffer in a list</title>
+ *   <programlisting>
+ *    GstBufferListIterator *it;
+ *
+ *    list = gst_buffer_list_make_writable (list);
+ *    it = gst_buffer_list_iterate (list);
+ *    if (gst_buffer_list_iterator_next_group (it)) {
+ *      GstBuffer *buf
+ *
+ *      buf = gst_buffer_list_iterator_next (it);
+ *      if (buf != NULL) {
+ *        buf = gst_buffer_list_iterator_do (it,
+ *            (GstBufferListDoFunction) gst_mini_object_make_writable, NULL);
+ *        modify_data (GST_BUFFER_DATA (buf));
+ *      }
+ *    }
+ *    gst_buffer_list_iterator_free (it);
+ *   </programlisting>
+ * </example>
+ *
+ * Since: 0.10.24
+ */
+#include "gst_private.h"
+
+#include "gstbuffer.h"
+#include "gstbufferlist.h"
+#ifdef __SYMBIAN32__
+#include <glib_global.h>
+#endif
+
+#define GST_CAT_DEFAULT GST_CAT_BUFFER_LIST
+
+#define GROUP_START NULL
+static const gpointer STOLEN = "";
+
+/**
+ * GstBufferList:
+ * @mini_object: the parent structure
+ *
+ * Opaque list of grouped buffers.
+ */
+struct _GstBufferList
+{
+  GstMiniObject mini_object;
+
+  GList *buffers;
+};
+
+struct _GstBufferListClass
+{
+  GstMiniObjectClass mini_object_class;
+};
+
+/**
+ * GstBufferListIterator:
+ *
+ * Opaque iterator for a #GstBufferList.
+ */
+struct _GstBufferListIterator
+{
+  GstBufferList *list;
+  GList *next;
+  GList *last_returned;
+};
+
+static GType _gst_buffer_list_type = 0;
+static GstMiniObjectClass *parent_class = NULL;
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+
+void
+_gst_buffer_list_initialize (void)
+{
+  g_type_class_ref (gst_buffer_list_get_type ());
+}
+
+static void
+gst_buffer_list_init (GTypeInstance * instance, gpointer g_class)
+{
+  GstBufferList *list;
+
+  list = (GstBufferList *) instance;
+  list->buffers = NULL;
+
+  GST_LOG ("init %p", list);
+}
+
+static void
+gst_buffer_list_finalize (GstBufferList * list)
+{
+  GList *tmp;
+
+  g_return_if_fail (list != NULL);
+
+  GST_LOG ("finalize %p", list);
+
+  tmp = list->buffers;
+  while (tmp) {
+    if (tmp->data != GROUP_START && tmp->data != STOLEN) {
+      gst_buffer_unref (GST_BUFFER_CAST (tmp->data));
+    }
+    tmp = tmp->next;
+  }
+  g_list_free (list->buffers);
+
+  parent_class->finalize (GST_MINI_OBJECT_CAST (list));
+}
+
+static GstBufferList *
+_gst_buffer_list_copy (GstBufferList * list)
+{
+  GstBufferList *list_copy;
+  GList *tmp;
+
+  g_return_val_if_fail (list != NULL, NULL);
+
+  list_copy = gst_buffer_list_new ();
+
+  /* shallow copy of list and pointers */
+  list_copy->buffers = g_list_copy (list->buffers);
+
+  /* ref all buffers in the list */
+  tmp = list_copy->buffers;
+  while (tmp) {
+    if (tmp->data != GROUP_START && tmp->data != STOLEN) {
+      tmp->data = gst_buffer_ref (GST_BUFFER_CAST (tmp->data));
+    }
+    tmp = g_list_next (tmp);
+  }
+
+  return list_copy;
+}
+
+static void
+gst_buffer_list_class_init (gpointer g_class, gpointer class_data)
+{
+  GstBufferListClass *list_class = GST_BUFFER_LIST_CLASS (g_class);
+
+  parent_class = g_type_class_peek_parent (g_class);
+
+  list_class->mini_object_class.copy =
+      (GstMiniObjectCopyFunction) _gst_buffer_list_copy;
+  list_class->mini_object_class.finalize =
+      (GstMiniObjectFinalizeFunction) gst_buffer_list_finalize;
+}
+
+/**
+ * gst_buffer_list_new:
+ *
+ * Creates a new, empty #GstBufferList. The caller is responsible for unreffing
+ * the returned #GstBufferList.
+ *
+ * Returns: the new #GstBufferList. gst_buffer_list_unref() after usage.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstBufferList *
+gst_buffer_list_new (void)
+{
+  GstBufferList *list;
+
+  list = (GstBufferList *) gst_mini_object_new (_gst_buffer_list_type);
+
+  GST_LOG ("new %p", list);
+
+  return list;
+}
+
+/**
+ * gst_buffer_list_n_groups:
+ * @list: a #GstBufferList
+ *
+ * Returns the number of groups in @list.
+ *
+ * Returns: the number of groups in the buffer list
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+guint
+gst_buffer_list_n_groups (GstBufferList * list)
+{
+  GList *tmp;
+  guint n;
+
+  g_return_val_if_fail (list != NULL, 0);
+
+  tmp = list->buffers;
+  n = 0;
+  while (tmp) {
+    if (tmp->data == GROUP_START) {
+      n++;
+    }
+    tmp = g_list_next (tmp);
+  }
+
+  return n;
+}
+
+/**
+ * gst_buffer_list_foreach:
+ * @list: a #GstBufferList
+ * @func: a #GstBufferListFunc to call
+ * @user_data: user data passed to @func
+ *
+ * Call @func with @data for each buffer in @list.
+ *
+ * @func can modify the passed buffer pointer or its contents. The return value
+ * of @func define if this function returns or if the remaining buffers in a
+ * group should be skipped.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_buffer_list_foreach (GstBufferList * list, GstBufferListFunc func,
+    gpointer user_data)
+{
+  GList *tmp, *next;
+  guint group, idx;
+  GstBufferListItem res;
+
+  g_return_if_fail (list != NULL);
+  g_return_if_fail (func != NULL);
+
+  next = list->buffers;
+  group = idx = 0;
+  while (next) {
+    GstBuffer *buffer;
+
+    tmp = next;
+    next = g_list_next (tmp);
+
+    buffer = tmp->data;
+
+    if (buffer == GROUP_START) {
+      group++;
+      idx = 0;
+      continue;
+    } else if (buffer == STOLEN)
+      continue;
+    else
+      idx++;
+
+    /* need to decrement the indices */
+    res = func (&buffer, group - 1, idx - 1, user_data);
+
+    if (G_UNLIKELY (buffer != tmp->data)) {
+      /* the function changed the buffer */
+      if (buffer == NULL) {
+        /* we were asked to remove the item */
+        list->buffers = g_list_delete_link (list->buffers, tmp);
+        idx--;
+      } else {
+        /* change the buffer */
+        tmp->data = buffer;
+      }
+    }
+
+    switch (res) {
+      case GST_BUFFER_LIST_CONTINUE:
+        break;
+      case GST_BUFFER_LIST_SKIP_GROUP:
+        while (next && next->data != GROUP_START)
+          next = g_list_next (next);
+        break;
+      case GST_BUFFER_LIST_END:
+        return;
+    }
+  }
+}
+
+/**
+ * gst_buffer_list_get:
+ * @list: a #GstBufferList
+ * @group: the group
+ * @idx: the index in @group
+ *
+ * Get the buffer at @idx in @group.
+ *
+ * Note that this function is not efficient for iterating over the entire list.
+ * Use an iterator or gst_buffer_list_foreach() instead.
+ *
+ * Returns: the buffer at @idx in @group or NULL when there is no buffer. The
+ * buffer remains valid as long as @list is valid.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstBuffer *
+gst_buffer_list_get (GstBufferList * list, guint group, guint idx)
+{
+  GList *tmp;
+  guint cgroup, cidx;
+
+  g_return_val_if_fail (list != NULL, NULL);
+
+  tmp = list->buffers;
+  cgroup = 0;
+  while (tmp) {
+    if (tmp->data == GROUP_START) {
+      if (cgroup == group) {
+        /* we found the group */
+        tmp = g_list_next (tmp);
+        cidx = 0;
+        while (tmp && tmp->data != GROUP_START) {
+          if (tmp->data != STOLEN) {
+            if (cidx == idx)
+              return GST_BUFFER_CAST (tmp->data);
+            else
+              cidx++;
+          }
+          tmp = g_list_next (tmp);
+        }
+        break;
+      } else {
+        cgroup++;
+        if (cgroup > group)
+          break;
+      }
+    }
+    tmp = g_list_next (tmp);
+  }
+  return NULL;
+}
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+
+GType
+gst_buffer_list_get_type (void)
+{
+  if (G_UNLIKELY (_gst_buffer_list_type == 0)) {
+    static const GTypeInfo buffer_list_info = {
+      sizeof (GstBufferListClass),
+      NULL,
+      NULL,
+      gst_buffer_list_class_init,
+      NULL,
+      NULL,
+      sizeof (GstBufferList),
+      0,
+      gst_buffer_list_init,
+      NULL
+    };
+
+    _gst_buffer_list_type = g_type_register_static (GST_TYPE_MINI_OBJECT,
+        "GstBufferList", &buffer_list_info, 0);
+  }
+
+  return _gst_buffer_list_type;
+}
+
+/**
+ * gst_buffer_list_iterate:
+ * @list: a #GstBufferList
+ *
+ * Iterate the buffers in @list. The owner of the iterator must also be the
+ * owner of a reference to @list while the returned iterator is in use.
+ *
+ * Returns: a new #GstBufferListIterator of the buffers in @list.
+ * gst_buffer_list_iterator_free() after usage
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstBufferListIterator *
+gst_buffer_list_iterate (GstBufferList * list)
+{
+  GstBufferListIterator *it;
+
+  g_return_val_if_fail (list != NULL, NULL);
+
+  it = g_slice_new (GstBufferListIterator);
+  it->list = list;
+  it->next = list->buffers;
+  it->last_returned = NULL;
+
+  return it;
+}
+
+/**
+ * gst_buffer_list_iterator_free:
+ * @it: the #GstBufferListIterator to free
+ *
+ * Free the iterator.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_buffer_list_iterator_free (GstBufferListIterator * it)
+{
+  g_return_if_fail (it != NULL);
+
+  g_slice_free (GstBufferListIterator, it);
+}
+
+/**
+ * gst_buffer_list_iterator_n_buffers:
+ * @it: a #GstBufferListIterator
+ *
+ * Returns the number of buffers left to iterate in the current group. I.e. the
+ * number of calls that can be made to gst_buffer_list_iterator_next() before
+ * it returns NULL.
+ *
+ * This function will not move the implicit cursor or in any other way affect
+ * the state of the iterator @it.
+ *
+ * Returns: the number of buffers left to iterate in the current group
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+guint
+gst_buffer_list_iterator_n_buffers (const GstBufferListIterator * it)
+{
+  GList *tmp;
+  guint n;
+
+  g_return_val_if_fail (it != NULL, 0);
+
+  tmp = it->next;
+  n = 0;
+  while (tmp && tmp->data != GROUP_START) {
+    if (tmp->data != STOLEN) {
+      n++;
+    }
+    tmp = g_list_next (tmp);
+  }
+
+  return n;
+}
+
+/**
+ * gst_buffer_list_iterator_add:
+ * @it: a #GstBufferListIterator
+ * @buffer: a #GstBuffer
+ *
+ * Inserts @buffer into the #GstBufferList iterated with @it. The buffer is
+ * inserted into the current group, immediately before the buffer that would be
+ * returned by gst_buffer_list_iterator_next(). The buffer is inserted before
+ * the implicit cursor, a subsequent call to gst_buffer_list_iterator_next()
+ * will return the buffer after the inserted buffer, if any.
+ *
+ * This function takes ownership of @buffer.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_buffer_list_iterator_add (GstBufferListIterator * it, GstBuffer * buffer)
+{
+  g_return_if_fail (it != NULL);
+  g_return_if_fail (buffer != NULL);
+
+  /* adding before the first group start is not allowed */
+  g_return_if_fail (it->next != it->list->buffers);
+
+  /* cheap insert into the GList */
+  it->list->buffers = g_list_insert_before (it->list->buffers, it->next,
+      buffer);
+}
+
+/**
+ * gst_buffer_list_iterator_add_group:
+ * @it: a #GstBufferListIterator
+ *
+ * Inserts a new, empty group into the #GstBufferList iterated with @it. The
+ * group is inserted immediately before the group that would be returned by
+ * gst_buffer_list_iterator_next_group(). A subsequent call to
+ * gst_buffer_list_iterator_next_group() will advance the iterator to the group
+ * after the inserted group, if any.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_buffer_list_iterator_add_group (GstBufferListIterator * it)
+{
+  g_return_if_fail (it != NULL);
+
+  /* advance iterator to next group start */
+  while (it->next != NULL && it->next->data != GROUP_START) {
+    it->next = g_list_next (it->next);
+  }
+
+  /* cheap insert of a group start into the GList */
+  it->list->buffers = g_list_insert_before (it->list->buffers, it->next,
+      GROUP_START);
+}
+
+/**
+ * gst_buffer_list_iterator_next:
+ * @it: a #GstBufferListIterator
+ *
+ * Returns the next buffer in the list iterated with @it. If the iterator is at
+ * the end of a group, NULL will be returned. This function may be called
+ * repeatedly to iterate through the current group.
+ *
+ * The caller will not get a new ref to the returned #GstBuffer and must not
+ * unref it.
+ *
+ * Returns: the next buffer in the current group of the buffer list, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstBuffer *
+gst_buffer_list_iterator_next (GstBufferListIterator * it)
+{
+  GstBuffer *buffer;
+
+  g_return_val_if_fail (it != NULL, NULL);
+
+  while (it->next != NULL && it->next->data != GROUP_START &&
+      it->next->data == STOLEN) {
+    it->next = g_list_next (it->next);
+  }
+
+  if (it->next == NULL || it->next->data == GROUP_START) {
+    goto no_buffer;
+  }
+
+  buffer = GST_BUFFER_CAST (it->next->data);
+
+  it->last_returned = it->next;
+  it->next = g_list_next (it->next);
+
+  return buffer;
+
+no_buffer:
+  {
+    it->last_returned = NULL;
+    return NULL;
+  }
+}
+
+/**
+ * gst_buffer_list_iterator_next_group:
+ * @it: a #GstBufferListIterator
+ *
+ * Advance the iterator @it to the first buffer in the next group. If the
+ * iterator is at the last group, FALSE will be returned. This function may be
+ * called repeatedly to iterate through the groups in a buffer list.
+ *
+ * Returns: TRUE if the iterator could be advanced to the next group, FALSE if
+ * the iterator was already at the last group
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gboolean
+gst_buffer_list_iterator_next_group (GstBufferListIterator * it)
+{
+  g_return_val_if_fail (it != NULL, FALSE);
+
+  /* advance iterator to next group start */
+  while (it->next != NULL && it->next->data != GROUP_START) {
+    it->next = g_list_next (it->next);
+  }
+
+  if (it->next) {
+    /* move one step beyond the group start */
+    it->next = g_list_next (it->next);
+  }
+
+  it->last_returned = NULL;
+
+  return (it->next != NULL);
+}
+
+/**
+ * gst_buffer_list_iterator_remove:
+ * @it: a #GstBufferListIterator
+ *
+ * Removes the last buffer returned by gst_buffer_list_iterator_next() from
+ * the #GstBufferList iterated with @it. gst_buffer_list_iterator_next() must
+ * have been called on @it before this function is called. This function can
+ * only be called once per call to gst_buffer_list_iterator_next().
+ *
+ * The removed buffer is unreffed.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_buffer_list_iterator_remove (GstBufferListIterator * it)
+{
+  g_return_if_fail (it != NULL);
+  g_return_if_fail (it->last_returned != NULL);
+  g_assert (it->last_returned->data != GROUP_START);
+
+  if (it->last_returned->data != STOLEN) {
+    gst_buffer_unref (it->last_returned->data);
+  }
+  it->list->buffers = g_list_delete_link (it->list->buffers, it->last_returned);
+  it->last_returned = NULL;
+}
+
+/**
+ * gst_buffer_list_iterator_take:
+ * @it: a #GstBufferListIterator
+ * @buffer: a #GstBuffer
+ *
+ * Replaces the last buffer returned by gst_buffer_list_iterator_next() with
+ * @buffer in the #GstBufferList iterated with @it and takes ownership of
+ * @buffer. gst_buffer_list_iterator_next() must have been called on @it before
+ * this function is called. gst_buffer_list_iterator_remove() must not have been
+ * called since the last call to gst_buffer_list_iterator_next().
+ *
+ * This function unrefs the replaced buffer if it has not been stolen with
+ * gst_buffer_list_iterator_steal() and takes ownership of @buffer (i.e. the
+ * refcount of @buffer is not increased).
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_buffer_list_iterator_take (GstBufferListIterator * it, GstBuffer * buffer)
+{
+  g_return_if_fail (it != NULL);
+  g_return_if_fail (it->last_returned != NULL);
+  g_return_if_fail (buffer != NULL);
+  g_assert (it->last_returned->data != GROUP_START);
+
+  if (it->last_returned->data != STOLEN) {
+    gst_buffer_unref (it->last_returned->data);
+  }
+  it->last_returned->data = buffer;
+}
+
+/**
+ * gst_buffer_list_iterator_steal:
+ * @it: a #GstBufferListIterator
+ *
+ * Returns the last buffer returned by gst_buffer_list_iterator_next() without
+ * modifying the refcount of the buffer.
+ *
+ * Returns: the last buffer returned by gst_buffer_list_iterator_next()
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstBuffer *
+gst_buffer_list_iterator_steal (GstBufferListIterator * it)
+{
+  GstBuffer *buffer;
+
+  g_return_val_if_fail (it != NULL, NULL);
+  g_return_val_if_fail (it->last_returned != NULL, NULL);
+  g_return_val_if_fail (it->last_returned->data != STOLEN, NULL);
+  g_assert (it->last_returned->data != GROUP_START);
+
+  buffer = it->last_returned->data;
+  it->last_returned->data = STOLEN;
+
+  return buffer;
+}
+
+/**
+ * gst_buffer_list_iterator_do:
+ * @it: a #GstBufferListIterator
+ * @do_func: the function to be called
+ * @user_data: the gpointer to optional user data.
+ *
+ * Calls the given function for the last buffer returned by
+ * gst_buffer_list_iterator_next(). gst_buffer_list_iterator_next() must have
+ * been called on @it before this function is called.
+ * gst_buffer_list_iterator_remove() and gst_buffer_list_iterator_steal() must
+ * not have been called since the last call to gst_buffer_list_iterator_next().
+ *
+ * See #GstBufferListDoFunction for more details.
+ *
+ * Returns: the return value from @do_func
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstBuffer *
+gst_buffer_list_iterator_do (GstBufferListIterator * it,
+    GstBufferListDoFunction do_func, gpointer user_data)
+{
+  GstBuffer *buffer;
+
+  g_return_val_if_fail (it != NULL, NULL);
+  g_return_val_if_fail (it->last_returned != NULL, NULL);
+  g_return_val_if_fail (it->last_returned->data != STOLEN, NULL);
+  g_return_val_if_fail (do_func != NULL, NULL);
+  g_return_val_if_fail (gst_buffer_list_is_writable (it->list), NULL);
+  g_assert (it->last_returned->data != GROUP_START);
+
+  buffer = gst_buffer_list_iterator_steal (it);
+  buffer = do_func (buffer, user_data);
+  if (buffer == NULL) {
+    gst_buffer_list_iterator_remove (it);
+  } else {
+    gst_buffer_list_iterator_take (it, buffer);
+  }
+
+  return buffer;
+}
+
+/**
+ * gst_buffer_list_iterator_merge_group:
+ * @it: a #GstBufferListIterator
+ *
+ * Merge a buffer list group into a normal #GstBuffer by copying its metadata
+ * and memcpying its data into consecutive memory. All buffers in the current
+ * group after the implicit cursor will be merged into one new buffer. The
+ * metadata of the new buffer will be a copy of the metadata of the buffer that
+ * would be returned by gst_buffer_list_iterator_next(). If there is no buffer
+ * in the current group after the implicit cursor, NULL will be returned.
+ *
+ * This function will not move the implicit cursor or in any other way affect
+ * the state of the iterator @it or the list.
+ *
+ * Returns: a new #GstBuffer, gst_buffer_unref() after usage, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstBuffer *
+gst_buffer_list_iterator_merge_group (const GstBufferListIterator * it)
+{
+  GList *tmp;
+  guint size;
+  GstBuffer *buf;
+  guint8 *ptr;
+
+  g_return_val_if_fail (it != NULL, NULL);
+
+  /* calculate size of merged buffer */
+  size = 0;
+  tmp = it->next;
+  while (tmp && tmp->data != GROUP_START) {
+    if (tmp->data != STOLEN) {
+      size += GST_BUFFER_SIZE (tmp->data);
+    }
+    tmp = g_list_next (tmp);
+  }
+
+  if (size == 0) {
+    return NULL;
+  }
+
+  /* allocate a new buffer */
+  buf = gst_buffer_new_and_alloc (size);
+
+  /* copy metadata from the next buffer after the implicit cursor */
+  gst_buffer_copy_metadata (buf, GST_BUFFER_CAST (it->next->data),
+      GST_BUFFER_COPY_ALL);
+
+  /* copy data of all buffers before the next group start into the new buffer */
+  ptr = GST_BUFFER_DATA (buf);
+  tmp = it->next;
+  do {
+    if (tmp->data != STOLEN) {
+      memcpy (ptr, GST_BUFFER_DATA (tmp->data), GST_BUFFER_SIZE (tmp->data));
+      ptr += GST_BUFFER_SIZE (tmp->data);
+    }
+    tmp = g_list_next (tmp);
+  } while (tmp && tmp->data != GROUP_START);
+
+  return buf;
+}