gstreamer/gst/mpegtsdemux/gstmpegdesc.c

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/*
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
* The Original Code is Fluendo MPEG Demuxer plugin.
*
* The Initial Developer of the Original Code is Fluendo, S.L.
* Portions created by Fluendo, S.L. are Copyright (C) 2005
* Fluendo, S.L. All Rights Reserved.
*
* Contributor(s): Wim Taymans <wim@fluendo.com>
*
*/
#include <string.h>
#include <gst/gst.h>
#include "gstmpegdesc.h"
GST_DEBUG_CATEGORY (gstmpegtsdesc_debug);
#define GST_CAT_DEFAULT (gstmpegtsdesc_debug)
static guint
gst_mpeg_descriptor_parse_1 (guint8 * data, guint size)
{
guint8 tag;
guint8 length;
/* need at least 2 bytes for tag and length */
if (size < 2)
return 0;
tag = *data++;
length = *data++;
size -= 2;
GST_DEBUG ("tag: 0x%02x, length: %d", tag, length);
if (length > size)
return 0;
GST_MEMDUMP ("tag contents:", data, length);
return length + 2;
}
gboolean
gst_mpeg_descriptor_parse (GstMPEGDescriptor * result, guint8 * data,
guint size)
{
guint8 *current;
guint consumed, total, n_desc;
g_return_val_if_fail (data != NULL, FALSE);
current = data;
total = 0;
n_desc = 0;
result->n_desc = 0;
do {
consumed = gst_mpeg_descriptor_parse_1 (current, size);
if (consumed > 0) {
current += consumed;
total += consumed;
size -= consumed;
n_desc++;
}
}
while (consumed > 0);
GST_DEBUG ("parsed %d descriptors", n_desc);
if (total == 0)
return FALSE;
result->n_desc = n_desc;
result->data_length = total;
result->data = data;
return TRUE;
}
guint
gst_mpeg_descriptor_n_desc (GstMPEGDescriptor * desc)
{
g_return_val_if_fail (desc != NULL, 0);
return desc->n_desc;
}
guint8 *
gst_mpeg_descriptor_find (GstMPEGDescriptor * desc, gint tag)
{
guint8 length;
guint8 *current;
guint size;
g_return_val_if_fail (desc != NULL, NULL);
current = desc->data;
length = desc->data_length;
while (length > 0) {
if (DESC_TAG (current) == tag)
return current;
size = DESC_LENGTH (current) + 2;
current += size;
length -= size;
}
return NULL;
}
/* array needs freeing afterwards */
GArray *
gst_mpeg_descriptor_find_all (GstMPEGDescriptor * desc, gint tag)
{
GArray *all;
guint8 length;
guint8 *current;
guint size;
g_return_val_if_fail (desc != NULL, NULL);
all = g_array_new (TRUE, TRUE, sizeof (guint8 *));
current = desc->data;
length = desc->data_length;
while (length > 0) {
if (DESC_TAG (current) == tag)
g_array_append_val (all, current);
size = DESC_LENGTH (current) + 2;
current += size;
length -= size;
}
GST_DEBUG ("found tag 0x%02x %d times", tag, all->len);
return all;
}
guint8 *
gst_mpeg_descriptor_nth (GstMPEGDescriptor * desc, guint i)
{
guint8 length;
guint8 *current;
guint size;
g_return_val_if_fail (desc != NULL, NULL);
if (i > desc->n_desc)
return NULL;
current = desc->data;
length = desc->data_length;
while (length > 0) {
if (i == 0)
return current;
size = DESC_LENGTH (current) + 2;
current += size;
length -= size;
i--;
}
return NULL;
}
void
gst_mpegtsdesc_init_debug (void)
{
GST_DEBUG_CATEGORY_INIT (gstmpegtsdesc_debug, "mpegtsdesc", 0,
"MPEG transport stream parser (descriptor)");
}