1 /* GStreamer Base Class for Tag Demuxing 2 * Copyright (C) 2005 Jan Schmidt <thaytan@mad.scientist.com> 3 * Copyright (C) 2006 Tim-Philipp Müller <tim centricular net> 4 * 5 * This library is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU Library General Public 7 * License as published by the Free Software Foundation; either 8 * version 2 of the License, or (at your option) any later version. 9 * 10 * This library is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 * Library General Public License for more details. 14 * 15 * You should have received a copy of the GNU Library General Public 16 * License along with this library; if not, write to the 17 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, 18 * Boston, MA 02110-1301, USA. 19 */ 20 21 #ifndef __GST_TAG_DEMUX_H__ 22 #define __GST_TAG_DEMUX_H__ 23 24 #include <gst/gst.h> 25 #include <gst/tag/tag-enumtypes.h> 26 27 G_BEGIN_DECLS 28 29 #define GST_TYPE_TAG_DEMUX (gst_tag_demux_get_type()) 30 #define GST_TAG_DEMUX(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_TAG_DEMUX,GstTagDemux)) 31 #define GST_TAG_DEMUX_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_TAG_DEMUX,GstTagDemuxClass)) 32 #define GST_IS_TAG_DEMUX(obj) (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_TAG_DEMUX)) 33 #define GST_IS_TAG_DEMUX_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_TAG_DEMUX)) 34 35 typedef struct _GstTagDemux GstTagDemux; 36 typedef struct _GstTagDemuxClass GstTagDemuxClass; 37 typedef struct _GstTagDemuxPrivate GstTagDemuxPrivate; 38 39 /** 40 * GstTagDemuxResult: 41 * @GST_TAG_DEMUX_RESULT_BROKEN_TAG: cannot parse tag, just skip it 42 * @GST_TAG_DEMUX_RESULT_AGAIN : call again with less or more data 43 * @GST_TAG_DEMUX_RESULT_OK : parsed tag successfully 44 * 45 * Result values from the parse_tag virtual function. 46 */ 47 typedef enum { 48 GST_TAG_DEMUX_RESULT_BROKEN_TAG, 49 GST_TAG_DEMUX_RESULT_AGAIN, 50 GST_TAG_DEMUX_RESULT_OK 51 } GstTagDemuxResult; 52 53 /** 54 * GstTagDemux: 55 * @element: parent element 56 * 57 * Opaque #GstTagDemux structure. 58 */ 59 struct _GstTagDemux 60 { 61 GstElement element; 62 63 /*< private >*/ 64 GstTagDemuxPrivate *priv; 65 66 gpointer reserved[GST_PADDING]; 67 }; 68 69 /** 70 * GstTagDemuxClass: 71 * @parent_class: the parent class. 72 * @min_start_size: minimum size required to identify a tag at the start and 73 * determine its total size. Set to 0 if not interested in start tags. 74 * Subclasses should set this in their class_init function. 75 * @min_end_size: minimum size required to identify a tag at the end and 76 * determine its total size. Set to 0 if not interested in end tags. 77 * Subclasses should set this in their class_init function. 78 * @identify_tag: identify tag and determine the size required to parse the 79 * tag. Buffer may be larger than the specified minimum size. 80 * Subclassed MUST override this vfunc in their class_init function. 81 * @parse_tag: parse the tag. Buffer will be exactly of the size determined by 82 * the identify_tag vfunc before. The parse_tag vfunc may change the size 83 * stored in *tag_size and return GST_TAG_DEMUX_RESULT_AGAIN to request a 84 * larger or smaller buffer. It is also permitted to adjust the tag_size to a 85 * smaller value and then return GST_TAG_DEMUX_RESULT_OK in one go. 86 * Subclassed MUST override the parse_tag vfunc in their class_init function. 87 * @merge_tags: merge start and end tags. Subclasses may want to override this 88 * vfunc to allow prioritising of start or end tag according to user 89 * preference. Note that both start_tags and end_tags may be NULL. By default 90 * start tags are prefered over end tags. 91 * 92 * The #GstTagDemuxClass structure. See documentation at beginning of section 93 * for details about what subclasses need to override and do. 94 */ 95 struct _GstTagDemuxClass 96 { 97 GstElementClass parent_class; 98 99 /* minimum size required to identify a tag at the start and determine 100 * its total size */ 101 guint min_start_size; 102 103 /* minimum size required to identify a tag at the end and determine 104 * its total size */ 105 guint min_end_size; 106 107 /* vtable */ 108 109 /* identify tag and determine the size required to parse the tag */ 110 gboolean (*identify_tag) (GstTagDemux * demux, 111 GstBuffer * buffer, 112 gboolean start_tag, 113 guint * tag_size); 114 115 /* parse the tag once it is identified and its size is known */ 116 GstTagDemuxResult (*parse_tag) (GstTagDemux * demux, 117 GstBuffer * buffer, 118 gboolean start_tag, 119 guint * tag_size, 120 GstTagList ** tags); 121 122 /* merge start and end tags (optional) */ 123 GstTagList * (*merge_tags) (GstTagDemux * demux, 124 const GstTagList * start_tags, 125 const GstTagList * end_tags); 126 127 /*< private >*/ 128 gpointer reserved[GST_PADDING]; 129 }; 130 131 GST_TAG_API 132 GType gst_tag_demux_get_type (void); 133 134 #ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC 135 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstTagDemux, gst_object_unref) 136 #endif 137 138 G_END_DECLS 139 140 #endif /* __GST_TAG_DEMUX_H__ */ 141 142