/*
  * 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 "internal.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, void *data, int *got_frame,

                         AVPacket *avpkt)
 {

     FRWUContext *s = avctx->priv_data;

     int field, ret;

     AVFrame *pic = data;

     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;

     pic->pict_type = AV_PICTURE_TYPE_I;

     pic->key_frame = 1;
 
     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,
 };
 

 AVCodec ff_frwu_decoder = {

     .name           = "frwu",

     .long_name      = NULL_IF_CONFIG_SMALL("Forward Uncompressed"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_FRWU,

     .priv_data_size = sizeof(FRWUContext),

     .init           = decode_init,
     .decode         = decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

     .priv_class     = &frwu_class,

 };