/*
  * Brute Force & Ignorance (BFI) video decoder
  * Copyright (c) 2008 Sisir Koppaka
  *
  * 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

  * @brief Brute Force & Ignorance (.bfi) video decoder
  * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )

  * @see http://wiki.multimedia.cx/index.php?title=BFI

  */
 

 #include "libavutil/common.h"

 #include "avcodec.h"
 #include "bytestream.h"

 #include "internal.h"

 
 typedef struct BFIContext {
     AVCodecContext *avctx;
     uint8_t *dst;

     uint32_t pal[256];

 } BFIContext;
 

 static av_cold int bfi_decode_init(AVCodecContext *avctx)

 {
     BFIContext *bfi = avctx->priv_data;

     avctx->pix_fmt  = AV_PIX_FMT_PAL8;

     bfi->dst        = av_mallocz(avctx->width * avctx->height);

     if (!bfi->dst)
         return AVERROR(ENOMEM);

     return 0;
 }
 

 static int bfi_decode_frame(AVCodecContext *avctx, void *data,

                             int *got_frame, AVPacket *avpkt)

 {

     AVFrame *frame = data;

     GetByteContext g;

     int buf_size    = avpkt->size;

     BFIContext *bfi = avctx->priv_data;

     uint8_t *dst    = bfi->dst;

     uint8_t *src, *dst_offset, colour1, colour2;
     uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;
     uint32_t *pal;

     int i, j, ret, height = avctx->height;

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

         return ret;

     bytestream2_init(&g, avpkt->data, buf_size);
 

     /* Set frame parameters and palette, if necessary */
     if (!avctx->frame_number) {

         frame->pict_type = AV_PICTURE_TYPE_I;
         frame->key_frame = 1;

         /* Setting the palette */

         if (avctx->extradata_size > 768) {

             av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");

             return AVERROR_INVALIDDATA;

         }

         pal = (uint32_t *)frame->data[1];

         for (i = 0; i < avctx->extradata_size / 3; i++) {
             int shift = 16;

             *pal = 0xFFU << 24;

             for (j = 0; j < 3; j++, shift -= 8)

                 *pal += ((avctx->extradata[i * 3 + j] << 2) |
                          (avctx->extradata[i * 3 + j] >> 4)) << shift;

             pal++;
         }

         memcpy(bfi->pal, frame->data[1], sizeof(bfi->pal));

         frame->palette_has_changed = 1;

     } else {

         frame->pict_type = AV_PICTURE_TYPE_P;
         frame->key_frame = 0;

         frame->palette_has_changed = 0;
         memcpy(frame->data[1], bfi->pal, sizeof(bfi->pal));

     }
 

     bytestream2_skip(&g, 4); // Unpacked size, not required.

 
     while (dst != frame_end) {

         static const uint8_t lentab[4] = { 0, 2, 0, 1 };

         unsigned int byte   = bytestream2_get_byte(&g), av_uninit(offset);

         unsigned int code   = byte >> 6;

         unsigned int length = byte & ~0xC0;
 

         if (!bytestream2_get_bytes_left(&g)) {

             av_log(avctx, AV_LOG_ERROR,
                    "Input resolution larger than actual frame.\n");

             return AVERROR_INVALIDDATA;

         }
 

         /* Get length and offset (if required) */

         if (length == 0) {
             if (code == 1) {

                 length = bytestream2_get_byte(&g);
                 offset = bytestream2_get_le16(&g);

             } else {

                 length = bytestream2_get_le16(&g);

                 if (code == 2 && length == 0)
                     break;
             }
         } else {
             if (code == 1)

                 offset = bytestream2_get_byte(&g);

         }
 
         /* Do boundary check */

         if (dst + (length << lentab[code]) > frame_end)

             break;
 
         switch (code) {

         case 0:                // normal chain

             if (length >= bytestream2_get_bytes_left(&g)) {

                 av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");

                 return AVERROR_INVALIDDATA;

             }

             bytestream2_get_buffer(&g, dst, length);

             dst += length;
             break;

         case 1:                // back chain

             dst_offset = dst - offset;

             length    *= 4;     // Convert dwords to bytes.

             if (dst_offset < bfi->dst)
                 break;
             while (length--)
                 *dst++ = *dst_offset++;
             break;

         case 2:                // skip chain

             dst += length;
             break;

         case 3:                // fill chain

             colour1 = bytestream2_get_byte(&g);
             colour2 = bytestream2_get_byte(&g);

             while (length--) {
                 *dst++ = colour1;
                 *dst++ = colour2;
             }
             break;
         }
     }
 
     src = bfi->dst;

     dst = frame->data[0];

     while (height--) {
         memcpy(dst, src, avctx->width);
         src += avctx->width;

         dst += frame->linesize[0];

     }

     *got_frame = 1;

     return buf_size;
 }
 

 static av_cold int bfi_decode_close(AVCodecContext *avctx)

 {
     BFIContext *bfi = avctx->priv_data;
     av_free(bfi->dst);
     return 0;
 }
 

 AVCodec ff_bfi_decoder = {

     .name           = "bfi",

     .long_name      = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_BFI,

     .priv_data_size = sizeof(BFIContext),

     .init           = bfi_decode_init,
     .close          = bfi_decode_close,
     .decode         = bfi_decode_frame,
     .capabilities   = CODEC_CAP_DR1,

 };