2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000,2005 Wim Taymans <wim@fluendo.com>
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
25 * @short_description: Base class for push based source elements
26 * @see_also: #GstBaseSrc
28 * This class is mostly useful for elements that cannot do
29 * random access, or at least very slowly. The source usually
30 * prefers to push out a fixed size buffer.
32 * Subclasses usually operate in a format that is different from the
33 * default GST_FORMAT_BYTES format of #GstBaseSrc.
35 * Classes extending this base class will usually be scheduled
36 * in a push based mode. If the peer accepts to operate without
37 * offsets and within the limits of the allowed block size, this
38 * class can operate in getrange based mode automatically. To make
39 * this possible, the subclass should implement and override the
42 * The subclass should extend the methods from the baseclass in
43 * addition to the ::create method.
45 * Seeking, flushing, scheduling and sync is all handled by this
48 * Last reviewed on 2006-07-04 (0.10.9)
58 #include "gstpushsrc.h"
59 #include "gsttypefindhelper.h"
61 GST_DEBUG_CATEGORY_STATIC (gst_push_src_debug);
62 #define GST_CAT_DEFAULT gst_push_src_debug
65 GST_DEBUG_CATEGORY_INIT (gst_push_src_debug, "pushsrc", 0, \
68 #define gst_push_src_parent_class parent_class
69 G_DEFINE_TYPE_WITH_CODE (GstPushSrc, gst_push_src, GST_TYPE_BASE_SRC, _do_init);
71 static gboolean gst_push_src_query (GstBaseSrc * src, GstQuery * query);
72 static GstFlowReturn gst_push_src_create (GstBaseSrc * bsrc, guint64 offset,
73 guint length, GstBuffer ** ret);
74 static GstFlowReturn gst_push_src_alloc (GstBaseSrc * bsrc, guint64 offset,
75 guint length, GstBuffer ** ret);
76 static GstFlowReturn gst_push_src_fill (GstBaseSrc * bsrc, guint64 offset,
77 guint length, GstBuffer * ret);
80 gst_push_src_class_init (GstPushSrcClass * klass)
82 GstBaseSrcClass *gstbasesrc_class = (GstBaseSrcClass *) klass;
84 gstbasesrc_class->create = GST_DEBUG_FUNCPTR (gst_push_src_create);
85 gstbasesrc_class->alloc = GST_DEBUG_FUNCPTR (gst_push_src_alloc);
86 gstbasesrc_class->fill = GST_DEBUG_FUNCPTR (gst_push_src_fill);
87 gstbasesrc_class->query = GST_DEBUG_FUNCPTR (gst_push_src_query);
91 gst_push_src_init (GstPushSrc * pushsrc)
97 gst_push_src_query (GstBaseSrc * src, GstQuery * query)
101 switch (GST_QUERY_TYPE (query)) {
102 case GST_QUERY_SCHEDULING:
104 /* a pushsrc can by default never operate in pull mode override
105 * if you want something different. */
106 gst_query_set_scheduling (query, GST_SCHEDULING_FLAG_SEQUENTIAL, 1, -1,
108 gst_query_add_scheduling_mode (query, GST_PAD_MODE_PUSH);
114 ret = GST_BASE_SRC_CLASS (parent_class)->query (src, query);
122 gst_push_src_create (GstBaseSrc * bsrc, guint64 offset, guint length,
127 GstPushSrcClass *pclass;
129 src = GST_PUSH_SRC (bsrc);
130 pclass = GST_PUSH_SRC_GET_CLASS (src);
132 fret = pclass->create (src, ret);
135 GST_BASE_SRC_CLASS (parent_class)->create (bsrc, offset, length, ret);
141 gst_push_src_alloc (GstBaseSrc * bsrc, guint64 offset, guint length,
146 GstPushSrcClass *pclass;
148 src = GST_PUSH_SRC (bsrc);
149 pclass = GST_PUSH_SRC_GET_CLASS (src);
151 fret = pclass->alloc (src, ret);
153 fret = GST_BASE_SRC_CLASS (parent_class)->alloc (bsrc, offset, length, ret);
159 gst_push_src_fill (GstBaseSrc * bsrc, guint64 offset, guint length,
164 GstPushSrcClass *pclass;
166 src = GST_PUSH_SRC (bsrc);
167 pclass = GST_PUSH_SRC_GET_CLASS (src);
169 fret = pclass->fill (src, ret);
171 fret = GST_BASE_SRC_CLASS (parent_class)->fill (bsrc, offset, length, ret);