/*

 * Forward Uncompressed

 *

 * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>

 *

 * 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

 */

#include "avcodec.h"

#include "bytestream.h"

#include "codec_internal.h"

#include "decode.h"

#include "libavutil/opt.h"

typedef struct {

    AVClass *av_class;

    int change_field_order;

} FRWUContext;

static av_cold int decode_init(AVCodecContext *avctx)

{

    if (avctx->width & 1) {

        av_log(avctx, AV_LOG_ERROR, "frwu needs even width\n");

        return AVERROR(EINVAL);

    }

    avctx->pix_fmt = AV_PIX_FMT_UYVY422;

    return 0;

}

static int decode_frame(AVCodecContext *avctx, AVFrame *pic,

                        int *got_frame, AVPacket *avpkt)

{

    FRWUContext *s = avctx->priv_data;

    int field, ret;

    const uint8_t *buf = avpkt->data;

    const uint8_t *buf_end = buf + avpkt->size;

    if (avpkt->size < avctx->width * 2 * avctx->height + 4 + 2*8) {

        av_log(avctx, AV_LOG_ERROR, "Packet is too small.\n");

        return AVERROR_INVALIDDATA;

    }

    if (bytestream_get_le32(&buf) != MKTAG('F', 'R', 'W', '1')) {

        av_log(avctx, AV_LOG_ERROR, "incorrect marker\n");

        return AVERROR_INVALIDDATA;

    }

    if ((ret = ff_get_buffer(avctx, pic, 0)) < 0)

        return ret;

    for (field = 0; field < 2; field++) {

        int i;

        int field_h = (avctx->height + !field) >> 1;

        int field_size, min_field_size = avctx->width * 2 * field_h;

        uint8_t *dst = pic->data[0];

        if (buf_end - buf < 8)

            return AVERROR_INVALIDDATA;

        buf += 4; // flags? 0x80 == bottom field maybe?

        field_size = bytestream_get_le32(&buf);

        if (field_size < min_field_size) {

            av_log(avctx, AV_LOG_ERROR, "Field size %i is too small (required %i)\n", field_size, min_field_size);

            return AVERROR_INVALIDDATA;

        }

        if (buf_end - buf < field_size) {

            av_log(avctx, AV_LOG_ERROR, "Packet is too small, need %i, have %i\n", field_size, (int)(buf_end - buf));

            return AVERROR_INVALIDDATA;

        }

        if (field ^ s->change_field_order) {

            dst += pic->linesize[0];

        } else if (s->change_field_order) {

            dst += 2 * pic->linesize[0];

        }

        for (i = 0; i < field_h; i++) {

            if (s->change_field_order && field && i == field_h - 1)

                dst = pic->data[0];

            memcpy(dst, buf, avctx->width * 2);

            buf += avctx->width * 2;

            dst += pic->linesize[0] << 1;

        }

        buf += field_size - min_field_size;

    }

    *got_frame = 1;

    return avpkt->size;

}

static const AVOption frwu_options[] = {

    {"change_field_order", "Change field order", offsetof(FRWUContext, change_field_order), AV_OPT_TYPE_BOOL,

     {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM},

    {NULL}

};

static const AVClass frwu_class = {

    .class_name = "frwu Decoder",

    .item_name  = av_default_item_name,

    .option     = frwu_options,

    .version    = LIBAVUTIL_VERSION_INT,

};

const FFCodec ff_frwu_decoder = {

    .p.name         = "frwu",

    CODEC_LONG_NAME("Forward Uncompressed"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_FRWU,

    .priv_data_size = sizeof(FRWUContext),

    .init           = decode_init,

    FF_CODEC_DECODE_CB(decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

    .p.priv_class   = &frwu_class,

};