/*
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Side data bitstream filter -- remove side data from packets and from the
 * stream, or select packets by their side data.
 */

#include "libavcodec/bsf.h"
#include "libavcodec/bsf_internal.h"
#include "libavcodec/packet_internal.h"

#include "libavutil/opt.h"

typedef struct SideDataContext {
    const AVClass *class;

    int *remove;
    unsigned nb_remove;
    int *select;
    unsigned nb_select;
} SideDataContext;

static int side_data_init(AVBSFContext *ctx)
{
    SideDataContext *s = ctx->priv_data;

    for (unsigned i = 0; i < s->nb_remove; i++)
        av_packet_side_data_remove(ctx->par_out->coded_side_data,
                                   &ctx->par_out->nb_coded_side_data,
                                   s->remove[i]);

    return 0;
}

static int is_selected(const SideDataContext *s, const AVPacket *pkt)
{
    if (!s->nb_select)
        return 1;

    for (unsigned i = 0; i < s->nb_select; i++)
        if (av_packet_side_data_get(pkt->side_data, pkt->side_data_elems,
                                    s->select[i]))
            return 1;

    return 0;
}

static int side_data_filter(AVBSFContext *ctx, AVPacket *pkt)
{
    SideDataContext *s = ctx->priv_data;
    int ret = ff_bsf_get_packet_ref(ctx, pkt);

    if (ret < 0)
        return ret;

    if (!is_selected(s, pkt)) {
        av_packet_unref(pkt);
        return AVERROR(EAGAIN);
    }

    for (unsigned i = 0; i < s->nb_remove; i++)
        av_packet_side_data_remove(pkt->side_data, &pkt->side_data_elems,
                                   s->remove[i]);

    return 0;
}

static const AVOptionArrayDef types_def = { .sep = '+' };

#define OFFSET(x) offsetof(SideDataContext, x)
#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_BSF_PARAM)
#define TYPE_CONST(type, handle) \
    { handle, NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_PKT_DATA_ ## type }, .flags = FLAGS, .unit = "type" },
static const AVOption options[] = {
    { "remove", "side data types to remove, joined with '+'", OFFSET(remove), AV_OPT_TYPE_INT | AV_OPT_TYPE_FLAG_ARRAY, { .arr = &types_def }, 0, AV_PKT_DATA_NB - 1, FLAGS, .unit = "type" },
    { "select", "side data types of the packets to keep, joined with '+'", OFFSET(select), AV_OPT_TYPE_INT | AV_OPT_TYPE_FLAG_ARRAY, { .arr = &types_def }, 0, AV_PKT_DATA_NB - 1, FLAGS, .unit = "type" },
    FF_PACKET_SIDE_DATA_HANDLES(TYPE_CONST)
    { NULL },
};

static const AVClass side_data_class = {
    .class_name = "side_data bsf",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

const FFBitStreamFilter ff_side_data_bsf = {
    .p.name         = "side_data",
    .p.priv_class   = &side_data_class,
    .priv_data_size = sizeof(SideDataContext),
    .init           = side_data_init,
    .filter         = side_data_filter,
};