/*
  * 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 "internal.h"

 #include "mathops.h"

 typedef struct WNV1Context {

     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 ff_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 *got_frame,

                         AVPacket *avpkt)

 {
     WNV1Context * const l = avctx->priv_data;

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

     AVFrame * const p     = data;

     unsigned char *Y,*U,*V;

     int i, j, ret;

     int prev_y = 0, prev_u = 0, prev_v = 0;

     uint8_t *rbuf;
 

     if (buf_size <= 8) {
         av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size);

         return AVERROR_INVALIDDATA;
     }
 

     rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);

     if (!rbuf) {

         av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");

         return AVERROR(ENOMEM);

     }

     memset(rbuf + buf_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);

     if ((ret = ff_get_buffer(avctx, p, 0)) < 0) {

         av_free(rbuf);

         return ret;

     }
     p->key_frame = 1;

     for (i = 8; i < buf_size; i++)
         rbuf[i] = ff_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) {

             avpriv_request_sample(avctx,
                                   "Unknown WNV1 frame header value %i",

                                   buf[2] >> 4);

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

             avpriv_request_sample(avctx,
                                   "Unknown WNV1 frame header value %i",

                                   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];
     }
 

     *got_frame      = 1;

     av_free(rbuf);

     return buf_size;
 }
 

 static av_cold int decode_init(AVCodecContext *avctx)
 {

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

     avctx->pix_fmt = AV_PIX_FMT_YUV422P;

     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;
 }
 

 AVCodec ff_wnv1_decoder = {

     .name           = "wnv1",

     .long_name      = NULL_IF_CONFIG_SMALL("Winnov WNV1"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_WNV1,

     .priv_data_size = sizeof(WNV1Context),
     .init           = decode_init,
     .decode         = decode_frame,
     .capabilities   = CODEC_CAP_DR1,

 };