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116 lines
3.4 KiB
C
116 lines
3.4 KiB
C
/* GStreamer
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* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
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* 2000,2005 Wim Taymans <wim@fluendo.com>
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*
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* gstpushsrc.c:
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/**
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* SECTION:gstpushsrc
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* @short_description: Base class for push based source elements
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* @see_also: #GstBaseSrc
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*
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* This class is mostly useful for elements that cannot do
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* random access, or at least very slowly. The source usually
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* prefers to push out a fixed size buffer.
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*
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* Subclasses usually operate in a format that is different from the
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* default GST_FORMAT_BYTES format of #GstBaseSrc.
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*
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* Classes extending this base class will usually be scheduled
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* in a push based mode. If the peer accepts to operate without
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* offsets and within the limits of the allowed block size, this
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* class can operate in getrange based mode automatically. To make
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* this possible, the subclass should override the ::check_get_range
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* method.
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*
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* The subclass should extend the methods from the baseclass in
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* addition to the ::create method.
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*
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* Seeking, flushing, scheduling and sync is all handled by this
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* base class.
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*
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* Last reviewed on 2006-07-04 (0.10.9)
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include "gstpushsrc.h"
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#include "gsttypefindhelper.h"
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#include <gst/gstmarshal.h>
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GST_DEBUG_CATEGORY_STATIC (gst_push_src_debug);
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#define GST_CAT_DEFAULT gst_push_src_debug
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#define _do_init \
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GST_DEBUG_CATEGORY_INIT (gst_push_src_debug, "pushsrc", 0, \
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"pushsrc element");
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#define gst_push_src_parent_class parent_class
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G_DEFINE_TYPE_WITH_CODE (GstPushSrc, gst_push_src, GST_TYPE_BASE_SRC, _do_init);
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static gboolean gst_push_src_check_get_range (GstBaseSrc * src);
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static GstFlowReturn gst_push_src_create (GstBaseSrc * bsrc, guint64 offset,
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guint length, GstBuffer ** ret);
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static void
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gst_push_src_class_init (GstPushSrcClass * klass)
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{
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GstBaseSrcClass *gstbasesrc_class = (GstBaseSrcClass *) klass;
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gstbasesrc_class->create = GST_DEBUG_FUNCPTR (gst_push_src_create);
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gstbasesrc_class->check_get_range =
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GST_DEBUG_FUNCPTR (gst_push_src_check_get_range);
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}
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static void
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gst_push_src_init (GstPushSrc * pushsrc)
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{
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/* nop */
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}
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static gboolean
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gst_push_src_check_get_range (GstBaseSrc * src)
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{
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/* a pushsrc can by default never operate in pull mode override
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* if you want something different. */
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return FALSE;
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}
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static GstFlowReturn
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gst_push_src_create (GstBaseSrc * bsrc, guint64 offset, guint length,
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GstBuffer ** ret)
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{
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GstFlowReturn fret;
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GstPushSrc *src;
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GstPushSrcClass *pclass;
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src = GST_PUSH_SRC (bsrc);
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pclass = GST_PUSH_SRC_GET_CLASS (src);
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if (pclass->create)
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fret = pclass->create (src, ret);
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else
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fret = GST_FLOW_ERROR;
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return fret;
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}
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