/*
  * Winnov WNV1 codec
  * Copyright (c) 2005 Konstantin Shishkov
  *

  * 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

  * Winnov WNV1 codec.
  */

 #include "avcodec.h"

 #include "get_bits.h"

 #include "libavutil/common.h"

 
 
 typedef struct WNV1Context{
     AVCodecContext *avctx;
     AVFrame pic;
 
     int shift;

     GetBitContext gb;

 } WNV1Context;
 

 static const uint16_t code_tab[16][2]={

 {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},

 {0x000,1},

 {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
 };
 
 #define CODE_VLC_BITS 9
 static VLC code_vlc;
 

 /* returns modified base_value */
 static inline int wnv1_get_code(WNV1Context *w, int base_value)
 {

     int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);

     if(v==15)

         return av_reverse[ get_bits(&w->gb, 8 - w->shift) ];

     else
         return base_value + ((v - 7)<<w->shift);

 }
 

 static int decode_frame(AVCodecContext *avctx,

                         void *data, int *data_size,

                         AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     WNV1Context * const l = avctx->priv_data;

     AVFrame * const p = &l->pic;

     unsigned char *Y,*U,*V;
     int i, j;
     int prev_y = 0, prev_u = 0, prev_v = 0;

     uint8_t *rbuf;
 
     rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
     if(!rbuf){
         av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
         return -1;
     }

 
     if(p->data[0])
         avctx->release_buffer(avctx, p);
 
     p->reference = 0;
     if(avctx->get_buffer(avctx, p) < 0){
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

         av_free(rbuf);

         return -1;
     }
     p->key_frame = 1;

 
     for(i=8; i<buf_size; i++)

         rbuf[i]= av_reverse[ buf[i] ];

     init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8);

     if (buf[2] >> 4 == 6)
         l->shift = 2;
     else {
         l->shift = 8 - (buf[2] >> 4);
         if (l->shift > 4) {

             av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
                                   buf[2] >> 4);

             l->shift = 4;
         }
         if (l->shift < 1) {

             av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
                                   buf[2] >> 4);

             l->shift = 1;
         }
     }

     Y = p->data[0];
     U = p->data[1];
     V = p->data[2];
     for (j = 0; j < avctx->height; j++) {
         for (i = 0; i < avctx->width / 2; i++) {
             Y[i * 2] = wnv1_get_code(l, prev_y);
             prev_u = U[i] = wnv1_get_code(l, prev_u);
             prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
             prev_v = V[i] = wnv1_get_code(l, prev_v);
         }
         Y += p->linesize[0];
         U += p->linesize[1];
         V += p->linesize[2];
     }
 

     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = l->pic;

     av_free(rbuf);

     return buf_size;
 }
 

 static av_cold int decode_init(AVCodecContext *avctx){

     WNV1Context * const l = avctx->priv_data;

     static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];

 
     l->avctx = avctx;
     avctx->pix_fmt = PIX_FMT_YUV422P;

     avcodec_get_frame_defaults(&l->pic);

     code_vlc.table = code_table;
     code_vlc.table_allocated = 1 << CODE_VLC_BITS;

     init_vlc(&code_vlc, CODE_VLC_BITS, 16,
              &code_tab[0][1], 4, 2,
              &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);

     return 0;
 }
 

 static av_cold int decode_end(AVCodecContext *avctx){
     WNV1Context * const l = avctx->priv_data;
     AVFrame *pic = &l->pic;
 
     if (pic->data[0])
         avctx->release_buffer(avctx, pic);
 
     return 0;
 }
 

 AVCodec ff_wnv1_decoder = {

     .name           = "wnv1",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_WNV1,
     .priv_data_size = sizeof(WNV1Context),
     .init           = decode_init,
     .close          = decode_end,
     .decode         = decode_frame,
     .capabilities   = CODEC_CAP_DR1,

     .long_name      = NULL_IF_CONFIG_SMALL("Winnov WNV1"),

 };