/* GStreamer Opus Encoder

 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>

 * Copyright (C) <2008> Sebastian Dröge <sebastian.droege@collabora.co.uk>

 * Copyright (C) <2011> Vincent Penquerc'h <vincent.penquerch@collabora.co.uk>

 *

 * 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.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <gst/tag/tag.h>

#include <gst/base/gstbytewriter.h>

#include "gstopusheader.h"

gboolean

gst_opus_header_is_header (GstBuffer * buf, const char *magic, guint magic_size)

{

  return (gst_buffer_get_size (buf) >= magic_size

      && !gst_buffer_memcmp (buf, 0, magic, magic_size));

}

gboolean

gst_opus_header_is_id_header (GstBuffer * buf)

{

  gsize size = gst_buffer_get_size (buf);

  guint8 *data = NULL;

  guint8 version, channels, channel_mapping_family, n_streams, n_stereo_streams;

  gboolean ret = FALSE;

  GstMapInfo map;

  if (size < 19)

    goto beach;

  if (!gst_opus_header_is_header (buf, "OpusHead", 8))

    goto beach;

  gst_buffer_map (buf, &map, GST_MAP_READ);

  data = map.data;

  size = map.size;

  version = data[8];

  if (version >= 0x0f)          /* major version >=0 is what we grok */

    goto beach;

  channels = data[9];

  if (channels == 0)

    goto beach;

  channel_mapping_family = data[18];

  if (channel_mapping_family == 0) {

    if (channels > 2)

      goto beach;

  } else {

    channels = data[9];

    if (size < 21 + channels)

      goto beach;

    n_streams = data[19];

    n_stereo_streams = data[20];

    if (n_streams == 0)

      goto beach;

    if (n_stereo_streams > n_streams)

      goto beach;

    if (n_streams + n_stereo_streams > 255)

      goto beach;

  }

  ret = TRUE;

beach:

  if (data)

    gst_buffer_unmap (buf, &map);

  return ret;

}

gboolean

gst_opus_header_is_comment_header (GstBuffer * buf)

{

  return gst_opus_header_is_header (buf, "OpusTags", 8);

}