/**
* gst_buffer_is_span_fast:
* @buf1: the first #GstBuffer.
* @buf2: the second #GstBuffer.
*
* Determines whether a gst_buffer_span() can be done without copying
* the contents, that is, whether the data areas are contiguous sub-buffers of
* the same buffer.
*
* MT safe.
* Returns: TRUE if the buffers are contiguous,
* FALSE if a copy would be required.
*/
gboolean
gst_buffer_is_span_fast (GstBuffer * buf1, GstBuffer * buf2)
{
g_return_val_if_fail (buf1 != NULL && buf2 != NULL, FALSE);
g_return_val_if_fail (buf1->mini_object.refcount > 0, FALSE);
g_return_val_if_fail (buf2->mini_object.refcount > 0, FALSE);
/* it's only fast if we have subbuffers of the same parent */
return (GST_IS_SUBBUFFER (buf1) &&
GST_IS_SUBBUFFER (buf2) && (buf1->parent == buf2->parent)
&& ((buf1->data + buf1->size) == buf2->data));
}
/**
* gst_buffer_create_sub:
* @parent: a #GstBuffer.
* @offset: the offset into parent #GstBuffer at which the new sub-buffer
* begins.
* @size: the size of the new #GstBuffer sub-buffer, in bytes.
*
* Creates a sub-buffer from @parent at @offset and @size.
* This sub-buffer uses the actual memory space of the parent buffer.
* This function will copy the offset and timestamp fields when the
* offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
* #GST_BUFFER_OFFSET_NONE.
* If @offset equals 0 and @size equals the total size of @buffer, the
* duration and offset end fields are also copied. If not they will be set
* to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
*
* MT safe.
* Returns: the new #GstBuffer.
* Returns NULL if the arguments were invalid.
*/
GstBuffer *
gst_buffer_create_sub (GstBuffer * buffer, guint offset, guint size)
{
GstSubBuffer *subbuffer;
GstBuffer *parent;
gboolean complete;
g_return_val_if_fail (buffer != NULL, NULL);
g_return_val_if_fail (buffer->mini_object.refcount > 0, NULL);
g_return_val_if_fail (buffer->size >= offset + size, NULL);
/* find real parent */
if (GST_IS_SUBBUFFER (buffer)) {
parent = GST_SUBBUFFER_CAST (buffer)->parent;
} else {
parent = buffer;
}
gst_buffer_ref (parent);
/* create the new buffer */
subbuffer = (GstSubBuffer *) gst_mini_object_new (_gst_subbuffer_type);
subbuffer->parent = parent;
GST_CAT_LOG (GST_CAT_BUFFER, "new subbuffer %p (parent %p)", subbuffer,
parent);
/* set the right values in the child */
GST_BUFFER_DATA (GST_BUFFER_CAST (subbuffer)) = buffer->data + offset;
GST_BUFFER_SIZE (GST_BUFFER_CAST (subbuffer)) = size;
if ((offset == 0) && (size == GST_BUFFER_SIZE (buffer))) {
/* copy all the flags except IN_CAPS */
GST_BUFFER_FLAG_SET (subbuffer, GST_BUFFER_FLAGS (buffer));
GST_BUFFER_FLAG_UNSET (subbuffer, GST_BUFFER_FLAG_IN_CAPS);
} else {
/* copy only PREROLL & GAP flags */
GST_BUFFER_FLAG_SET (subbuffer, (GST_BUFFER_FLAGS (buffer) &
(GST_BUFFER_FLAG_PREROLL | GST_BUFFER_FLAG_GAP)));
}
/* we can copy the timestamp and offset if the new buffer starts at
* offset 0 */
if (offset == 0) {
GST_BUFFER_TIMESTAMP (subbuffer) = GST_BUFFER_TIMESTAMP (buffer);
GST_BUFFER_OFFSET (subbuffer) = GST_BUFFER_OFFSET (buffer);
complete = (buffer->size == size);
} else {
GST_BUFFER_TIMESTAMP (subbuffer) = GST_CLOCK_TIME_NONE;
GST_BUFFER_OFFSET (subbuffer) = GST_BUFFER_OFFSET_NONE;
complete = FALSE;
}
if (complete) {
GstCaps *caps;
/* if we copied the complete buffer we can copy the duration,
* offset_end and caps as well */
GST_BUFFER_DURATION (subbuffer) = GST_BUFFER_DURATION (buffer);
GST_BUFFER_OFFSET_END (subbuffer) = GST_BUFFER_OFFSET_END (buffer);
if ((caps = GST_BUFFER_CAPS (buffer)))
gst_caps_ref (caps);
GST_BUFFER_CAPS (subbuffer) = caps;
} else {
GST_BUFFER_DURATION (subbuffer) = GST_CLOCK_TIME_NONE;
GST_BUFFER_OFFSET_END (subbuffer) = GST_BUFFER_OFFSET_NONE;
GST_BUFFER_CAPS (subbuffer) = NULL;
}
return GST_BUFFER_CAST (subbuffer);
}
