gstreamer/ext/dash/gstplugin.c
2014-04-10 17:52:02 +01:00

105 lines
3.1 KiB
C

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <string.h>
#include <gst/gst.h>
#include "gstdashdemux.h"
#define XML_BUFFER_SIZE 16
#define XML_INC_BUFFER { \
pos++; \
if (pos == XML_BUFFER_SIZE) { \
pos = 0; \
offset += XML_BUFFER_SIZE; \
data = gst_type_find_peek (tf, offset, XML_BUFFER_SIZE); \
if (data == NULL) return FALSE; \
} else { \
data++; \
} \
}
static gboolean
xml_check_first_element (GstTypeFind * tf, const gchar * element, guint elen,
gboolean strict)
{
gboolean got_xmldec;
const guint8 *data;
guint offset = 0;
guint pos = 0;
data = gst_type_find_peek (tf, 0, XML_BUFFER_SIZE);
if (!data)
return FALSE;
/* look for the XMLDec
* see XML spec 2.8, Prolog and Document Type Declaration
* http://www.w3.org/TR/2004/REC-xml-20040204/#sec-prolog-dtd */
got_xmldec = (memcmp (data, "<?xml", 5) == 0);
if (strict && !got_xmldec)
return FALSE;
/* skip XMLDec in any case if we've got one */
if (got_xmldec) {
pos += 5;
data += 5;
}
/* look for the first element, it has to be the requested element. Bail
* out if it is not within the first 4kB. */
while (data && (offset + pos) < 4096) {
while (*data != '<' && (offset + pos) < 4096) {
XML_INC_BUFFER;
}
XML_INC_BUFFER;
if (!g_ascii_isalpha (*data)) {
/* if not alphabetic, it's a PI or an element / attribute declaration
* like <?xxx or <!xxx */
XML_INC_BUFFER;
continue;
}
/* the first normal element, check if it's the one asked for */
data = gst_type_find_peek (tf, offset + pos, elen + 1);
return (data && element && strncmp ((char *) data, element, elen) == 0);
}
return FALSE;
}
/*** application/dash+xml typefind helper ***/
static GstStaticCaps dash_caps = GST_STATIC_CAPS ("application/dash+xml");
#define DASH_CAPS gst_static_caps_get (&dash_caps)
static void
dash_type_find (GstTypeFind * tf, gpointer unused)
{
if (xml_check_first_element (tf, "MPD", 3, FALSE) ||
xml_check_first_element (tf, "mpd", 3, FALSE)) {
gst_type_find_suggest (tf, GST_TYPE_FIND_MAXIMUM, DASH_CAPS);
}
}
static gboolean
fragmented_init (GstPlugin * plugin)
{
if (!gst_element_register (plugin, "dashdemux", GST_RANK_PRIMARY,
GST_TYPE_DASH_DEMUX) || FALSE)
return FALSE;
if (!gst_type_find_register (plugin, "application/dash+xml",
GST_RANK_SECONDARY, dash_type_find, NULL, DASH_CAPS, NULL, NULL))
return FALSE;
return TRUE;
}
GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
GST_VERSION_MINOR,
dashdemux,
"DASH demuxer plugin",
fragmented_init, VERSION, "LGPL", PACKAGE_NAME, "http://www.gstreamer.org/")