gst-libs/gst/tag/: API: add GstTagDemux base class for simple tag demuxers.

Original commit message from CVS:
* gst-libs/gst/tag/Makefile.am:
* gst-libs/gst/tag/gsttagdemux.c:
* gst-libs/gst/tag/gsttagdemux.h:
API: add GstTagDemux base class for simple tag demuxers.
* docs/libs/gst-plugins-base-libs-docs.sgml:
* docs/libs/gst-plugins-base-libs-sections.txt:
Add GstTagDemux to docs.

ChangeLog

@@ -1,3 +1,14 @@
+2007-10-06  Tim-Philipp Müller  <tim at centricular dot net>
+
+	* gst-libs/gst/tag/Makefile.am:
+	* gst-libs/gst/tag/gsttagdemux.c:
+	* gst-libs/gst/tag/gsttagdemux.h:
+	  API: add GstTagDemux base class for simple tag demuxers.
+
+	* docs/libs/gst-plugins-base-libs-docs.sgml:
+	* docs/libs/gst-plugins-base-libs-sections.txt:
+	  Add GstTagDemux to docs.
+
 2007-10-05  Sebastian Dröge  <slomo@circular-chaos.org>
 
 	* gst-libs/gst/rtp/gstrtpbuffer.c:

docs/libs/gst-plugins-base-libs-docs.sgml

@@ -64,6 +64,7 @@
 <!ENTITY GstTag SYSTEM "xml/gsttag.xml">
 <!ENTITY GstTagVorbis SYSTEM "xml/gsttagvorbis.xml">
 <!ENTITY GstTagID3 SYSTEM "xml/gsttagid3.xml">
+<!ENTITY GstTagDemux SYSTEM "xml/gsttagdemux.xml">
 <!-- utils -->
 <!ENTITY GstPBUtils SYSTEM "xml/gstpbutils.xml">
 <!ENTITY GstPBUtilsDescriptions SYSTEM "xml/gstpbutilsdescriptions.xml">
@@ -240,6 +241,7 @@
       &GstTag;
       &GstTagVorbis;
       &GstTagID3;
+      &GstTagDemux;
     </chapter>
 
     <chapter id="gstreamer-base-utils">

docs/libs/gst-plugins-base-libs-sections.txt

@@ -1348,6 +1348,14 @@ gst_tag_from_id3_user_tag
 gst_tag_to_id3_tag
 </SECTION>
 
+<SECTION>
+<FILE>gsttagdemux</FILE>
+<INCLUDE>gst/tag/gsttagdemux.h</INCLUDE>
+GstTagDemux
+GstTagDemuxClass
+GstTagDemuxResult
+</SECTION>
+
 # base utils
 
 <SECTION>

gst-libs/gst/tag/Makefile.am

@@ -2,13 +2,13 @@ libgsttagincludedir = \
 	$(includedir)/gstreamer-@GST_MAJORMINOR@/gst/tag
 
 libgsttaginclude_HEADERS = \
-	tag.h
+	tag.h gsttagdemux.h
 
 lib_LTLIBRARIES = libgsttag-@GST_MAJORMINOR@.la
 
-libgsttag_@GST_MAJORMINOR@_la_SOURCES = gstvorbistag.c gstid3tag.c tags.c
+libgsttag_@GST_MAJORMINOR@_la_SOURCES = gstvorbistag.c gstid3tag.c tags.c gsttagdemux.c
-libgsttag_@GST_MAJORMINOR@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS)
+libgsttag_@GST_MAJORMINOR@_la_CFLAGS = $(GST_BASE_CFLAGS) $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS)
-libgsttag_@GST_MAJORMINOR@_la_LIBADD = $(GST_LIBS) 
+libgsttag_@GST_MAJORMINOR@_la_LIBADD = $(GST_BASE_LIBS) $(GST_LIBS) 
 libgsttag_@GST_MAJORMINOR@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)
 
 noinst_HEADERS = gsttageditingprivate.h

gst-libs/gst/tag/gsttagdemux.h

@@ -0,0 +1,140 @@
+/* GStreamer Base Class for Tag Demuxing
+ * Copyright (C) 2005  Jan Schmidt <thaytan@mad.scientist.com>
+ * Copyright (C) 2006  Tim-Philipp Müller <tim centricular net>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GST_TAG_DEMUX_H__
+#define __GST_TAG_DEMUX_H__
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_TAG_DEMUX            (gst_tag_demux_get_type())
+#define GST_TAG_DEMUX(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_TAG_DEMUX,GstTagDemux))
+#define GST_TAG_DEMUX_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_TAG_DEMUX,GstTagDemuxClass))
+#define GST_IS_TAG_DEMUX(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_TAG_DEMUX))
+#define GST_IS_TAG_DEMUX_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_TAG_DEMUX))
+
+typedef struct _GstTagDemux        GstTagDemux;
+typedef struct _GstTagDemuxClass   GstTagDemuxClass;
+typedef struct _GstTagDemuxPrivate GstTagDemuxPrivate;
+
+/**
+ * GstTagDemuxResult:
+ * @GST_TAG_DEMUX_RESULT_BROKEN_TAG: cannot parse tag, just skip it
+ * @GST_TAG_DEMUX_RESULT_AGAIN     : call again with less or more data
+ * @GST_TAG_DEMUX_RESULT_OK	   : parsed tag successfully
+ *
+ * Result values from the parse_tag virtual function.
+ *
+ * Since: 0.10.15
+ */
+typedef enum {
+  GST_TAG_DEMUX_RESULT_BROKEN_TAG,
+  GST_TAG_DEMUX_RESULT_AGAIN,
+  GST_TAG_DEMUX_RESULT_OK
+} GstTagDemuxResult;
+
+/**
+ * GstTagDemux:
+ *
+ * Opaque #GstTagDemux structure.
+ *
+ * Since: 0.10.15
+ */
+struct _GstTagDemux
+{
+  GstElement element;
+
+  /*< private >*/
+  GstTagDemuxPrivate  *priv;
+
+  gpointer             reserved[GST_PADDING];
+};
+
+/**
+ * GstTagDemuxClass:
+ * @parent_class: the parent class.
+ * @min_start_size: minimum size required to identify a tag at the start and
+ * determine its total size. Set to 0 if not interested in start tags.
+ * Subclasses should set this in their class_init function.
+ * @min_end_size: minimum size required to identify a tag at the end and
+ * determine its total size. Set to 0 if not interested in end tags.
+ * Subclasses should set this in their class_init function.
+ * @identify_tag: identify tag and determine the size required to parse the
+ * tag. Buffer may be larger than the specified minimum size.
+ * Subclassed MUST override this vfunc in their class_init function.
+ * @parse_tag: parse the tag. Buffer will be exactly of the size determined by
+ * the identify_tag vfunc before. The parse_tag vfunc may change the size
+ * stored in *tag_size and return GST_TAG_DEMUX_RESULT_AGAIN to request a
+ * larger or smaller buffer. It is also permitted to adjust the tag_size to a
+ * smaller value and then return GST_TAG_DEMUX_RESULT_OK in one go.
+ * Subclassed MUST override the parse_tag vfunc in their class_init function.
+ * @merge_tags: merge start and end tags. Subclasses may want to override this
+ * vfunc to allow prioritising of start or end tag according to user
+ * preference.  Note that both start_tags and end_tags may be NULL. By default
+ * start tags are prefered over end tags.
+ *
+ * The #GstTagDemuxClass structure.  See documentation at beginning of section
+ * for details about what subclasses need to override and do.
+ *
+ * Since: 0.10.15
+ */
+struct _GstTagDemuxClass
+{
+  GstElementClass parent_class;
+
+  /* minimum size required to identify a tag at the start and determine
+   * its total size */
+  guint                  min_start_size;
+
+  /* minimum size required to identify a tag at the end and determine
+   * its total size */
+  guint                  min_end_size;
+
+  /* vtable */
+
+  /* identify tag and determine the size required to parse the tag */
+  gboolean               (*identify_tag)  (GstTagDemux * demux,
+                                           GstBuffer   * buffer,
+                                           gboolean      start_tag,
+                                           guint       * tag_size);
+
+  /* parse the tag once it is identified and its size is known */
+  GstTagDemuxResult      (*parse_tag)     (GstTagDemux * demux,
+                                           GstBuffer   * buffer,
+                                           gboolean      start_tag,
+                                           guint       * tag_size,
+                                           GstTagList ** tags);
+
+  /* merge start and end tags (optional) */
+  GstTagList *           (*merge_tags)    (GstTagDemux      * demux,
+                                           const GstTagList * start_tags,
+                                           const GstTagList * end_tags);
+
+  /*< private >*/
+  gpointer               reserved[GST_PADDING];
+};
+
+GType     gst_tag_demux_get_type (void);
+
+G_END_DECLS
+
+#endif /* __GST_TAG_DEMUX_H__ */
+