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       1                 :            : /* GStreamer
       2                 :            :  * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
       3                 :            :  *               2000,2005 Wim Taymans <wim@fluendo.com>
       4                 :            :  *
       5                 :            :  * gstpushsrc.c:
       6                 :            :  *
       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.
      11                 :            :  *
      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.
      16                 :            :  *
      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., 59 Temple Place - Suite 330,
      20                 :            :  * Boston, MA 02111-1307, USA.
      21                 :            :  */
      22                 :            : 
      23                 :            : /**
      24                 :            :  * SECTION:gstpushsrc
      25                 :            :  * @short_description: Base class for push based source elements
      26                 :            :  * @see_also: #GstBaseSrc
      27                 :            :  *
      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.
      31                 :            :  *
      32                 :            :  * Subclasses usually operate in a format that is different from the
      33                 :            :  * default GST_FORMAT_BYTES format of #GstBaseSrc.
      34                 :            :  *
      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 override the ::check_get_range
      40                 :            :  * method.
      41                 :            :  *
      42                 :            :  * The subclass should extend the methods from the baseclass in
      43                 :            :  * addition to the ::create method.
      44                 :            :  *
      45                 :            :  * Seeking, flushing, scheduling and sync is all handled by this
      46                 :            :  * base class.
      47                 :            :  *
      48                 :            :  * Last reviewed on 2006-07-04 (0.10.9)
      49                 :            :  */
      50                 :            : 
      51                 :            : #ifdef HAVE_CONFIG_H
      52                 :            : #  include "config.h"
      53                 :            : #endif
      54                 :            : 
      55                 :            : #include <stdlib.h>
      56                 :            : #include <string.h>
      57                 :            : 
      58                 :            : #include "gstpushsrc.h"
      59                 :            : #include "gsttypefindhelper.h"
      60                 :            : #include <gst/gstmarshal.h>
      61                 :            : 
      62                 :            : GST_DEBUG_CATEGORY_STATIC (gst_push_src_debug);
      63                 :            : #define GST_CAT_DEFAULT gst_push_src_debug
      64                 :            : 
      65                 :            : #define _do_init(type) \
      66                 :            :     GST_DEBUG_CATEGORY_INIT (gst_push_src_debug, "pushsrc", 0, \
      67                 :            :         "pushsrc element");
      68                 :            : 
      69 [ +  + ][ +  - ]:     147510 : GST_BOILERPLATE_FULL (GstPushSrc, gst_push_src, GstBaseSrc, GST_TYPE_BASE_SRC,
      70                 :     147510 :     _do_init);
      71                 :            : 
      72                 :            : static gboolean gst_push_src_check_get_range (GstBaseSrc * src);
      73                 :            : static GstFlowReturn gst_push_src_create (GstBaseSrc * bsrc, guint64 offset,
      74                 :            :     guint length, GstBuffer ** ret);
      75                 :            : 
      76                 :            : static void
      77                 :         24 : gst_push_src_base_init (gpointer g_class)
      78                 :            : {
      79                 :            :   /* nop */
      80                 :         24 : }
      81                 :            : 
      82                 :            : static void
      83                 :         12 : gst_push_src_class_init (GstPushSrcClass * klass)
      84                 :            : {
      85                 :         12 :   GstBaseSrcClass *gstbasesrc_class = (GstBaseSrcClass *) klass;
      86                 :            : 
      87                 :         12 :   gstbasesrc_class->create = GST_DEBUG_FUNCPTR (gst_push_src_create);
      88                 :         12 :   gstbasesrc_class->check_get_range =
      89                 :         12 :       GST_DEBUG_FUNCPTR (gst_push_src_check_get_range);
      90                 :         12 : }
      91                 :            : 
      92                 :            : static void
      93                 :         16 : gst_push_src_init (GstPushSrc * pushsrc, GstPushSrcClass * klass)
      94                 :            : {
      95                 :            :   /* nop */
      96                 :         16 : }
      97                 :            : 
      98                 :            : static gboolean
      99                 :          0 : gst_push_src_check_get_range (GstBaseSrc * src)
     100                 :            : {
     101                 :            :   /* a pushsrc can by default never operate in pull mode override
     102                 :            :    * if you want something different. */
     103                 :          0 :   return FALSE;
     104                 :            : }
     105                 :            : 
     106                 :            : static GstFlowReturn
     107                 :     147330 : gst_push_src_create (GstBaseSrc * bsrc, guint64 offset, guint length,
     108                 :            :     GstBuffer ** ret)
     109                 :            : {
     110                 :            :   GstFlowReturn fret;
     111                 :            :   GstPushSrc *src;
     112                 :            :   GstPushSrcClass *pclass;
     113                 :            : 
     114                 :     147330 :   src = GST_PUSH_SRC (bsrc);
     115                 :     147338 :   pclass = GST_PUSH_SRC_GET_CLASS (src);
     116         [ +  - ]:     147338 :   if (pclass->create)
     117                 :     147338 :     fret = pclass->create (src, ret);
     118                 :            :   else
     119                 :          0 :     fret = GST_FLOW_ERROR;
     120                 :            : 
     121                 :     147338 :   return fret;
     122                 :            : }