/*
  * Cinepak Video Decoder
  * Copyright (C) 2003 the ffmpeg project
  *

  * 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

  * Cinepak video decoder
  * by Ewald Snel <ewald@rambo.its.tudelft.nl>
  * For more information on the Cinepak algorithm, visit:
  *   http://www.csse.monash.edu.au/~timf/

  * For more information on the quirky data inside Sega FILM/CPK files, visit:
  *   http://wiki.multimedia.cx/index.php?title=Sega_FILM

  */
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 

 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"
 
 
 typedef struct {
     uint8_t  y0, y1, y2, y3;
     uint8_t  u, v;

 } cvid_codebook;

 
 #define MAX_STRIPS      32
 
 typedef struct {
     uint16_t          id;
     uint16_t          x1, y1;
     uint16_t          x2, y2;

     cvid_codebook     v4_codebook[256];
     cvid_codebook     v1_codebook[256];
 } cvid_strip;

 
 typedef struct CinepakContext {
 
     AVCodecContext *avctx;
     AVFrame frame;
 

     const unsigned char *data;

     int size;
 

     int width, height;
 

     int palette_video;

     cvid_strip strips[MAX_STRIPS];

     int sega_film_skip_bytes;
 

     uint32_t pal[256];

 } CinepakContext;
 

 static void cinepak_decode_codebook (cvid_codebook *codebook,

                                      int chunk_id, int size, const uint8_t *data)

 {

     const uint8_t *eod = (data + size);

     uint32_t flag, mask;
     int      i, n;
 
     /* check if this chunk contains 4- or 6-element vectors */

     n    = (chunk_id & 0x04) ? 4 : 6;

     flag = 0;
     mask = 0;
 
     for (i=0; i < 256; i++) {

         if ((chunk_id & 0x01) && !(mask >>= 1)) {

             if ((data + 4) > eod)
                 break;
 

             flag  = AV_RB32 (data);

             data += 4;
             mask  = 0x80000000;
         }
 

         if (!(chunk_id & 0x01) || (flag & mask)) {

             if ((data + n) > eod)
                 break;
 
             if (n == 6) {
                 codebook[i].y0 = *data++;
                 codebook[i].y1 = *data++;
                 codebook[i].y2 = *data++;
                 codebook[i].y3 = *data++;
                 codebook[i].u  = 128 + *data++;
                 codebook[i].v  = 128 + *data++;
             } else {

                 /* this codebook type indicates either greyscale or

                  * palettized video; if palettized, U & V components will
                  * not be used so it is safe to set them to 128 for the
                  * benefit of greyscale rendering in YUV420P */
                 codebook[i].y0 = *data++;
                 codebook[i].y1 = *data++;
                 codebook[i].y2 = *data++;
                 codebook[i].y3 = *data++;
                 codebook[i].u  = 128;
                 codebook[i].v  = 128;
             }
         }
     }
 }
 

 static int cinepak_decode_vectors (CinepakContext *s, cvid_strip *strip,

                                    int chunk_id, int size, const uint8_t *data)

 {

     const uint8_t   *eod = (data + size);

     uint32_t         flag, mask;

     cvid_codebook   *codebook;

     unsigned int     x, y;

     uint32_t         iy[4];
     uint32_t         iu[2];
     uint32_t         iv[2];
 
     flag = 0;
     mask = 0;
 
     for (y=strip->y1; y < strip->y2; y+=4) {
 
         iy[0] = strip->x1 + (y * s->frame.linesize[0]);
         iy[1] = iy[0] + s->frame.linesize[0];
         iy[2] = iy[1] + s->frame.linesize[0];
         iy[3] = iy[2] + s->frame.linesize[0];
         iu[0] = (strip->x1/2) + ((y/2) * s->frame.linesize[1]);
         iu[1] = iu[0] + s->frame.linesize[1];
         iv[0] = (strip->x1/2) + ((y/2) * s->frame.linesize[2]);
         iv[1] = iv[0] + s->frame.linesize[2];
 
         for (x=strip->x1; x < strip->x2; x+=4) {

             if ((chunk_id & 0x01) && !(mask >>= 1)) {

                 if ((data + 4) > eod)
                     return -1;
 

                 flag  = AV_RB32 (data);

                 data += 4;
                 mask  = 0x80000000;
             }
 

             if (!(chunk_id & 0x01) || (flag & mask)) {
                 if (!(chunk_id & 0x02) && !(mask >>= 1)) {

                     if ((data + 4) > eod)
                         return -1;
 

                     flag  = AV_RB32 (data);

                     data += 4;
                     mask  = 0x80000000;
                 }
 

                 if ((chunk_id & 0x02) || (~flag & mask)) {

                     if (data >= eod)
                         return -1;
 
                     codebook = &strip->v1_codebook[*data++];
                     s->frame.data[0][iy[0] + 0] = codebook->y0;
                     s->frame.data[0][iy[0] + 1] = codebook->y0;
                     s->frame.data[0][iy[1] + 0] = codebook->y0;
                     s->frame.data[0][iy[1] + 1] = codebook->y0;
                     if (!s->palette_video) {
                         s->frame.data[1][iu[0]] = codebook->u;
                         s->frame.data[2][iv[0]] = codebook->v;
                     }
 

                     s->frame.data[0][iy[0] + 2] = codebook->y1;
                     s->frame.data[0][iy[0] + 3] = codebook->y1;
                     s->frame.data[0][iy[1] + 2] = codebook->y1;
                     s->frame.data[0][iy[1] + 3] = codebook->y1;

                     if (!s->palette_video) {
                         s->frame.data[1][iu[0] + 1] = codebook->u;
                         s->frame.data[2][iv[0] + 1] = codebook->v;
                     }
 

                     s->frame.data[0][iy[2] + 0] = codebook->y2;
                     s->frame.data[0][iy[2] + 1] = codebook->y2;
                     s->frame.data[0][iy[3] + 0] = codebook->y2;
                     s->frame.data[0][iy[3] + 1] = codebook->y2;

                     if (!s->palette_video) {
                         s->frame.data[1][iu[1]] = codebook->u;
                         s->frame.data[2][iv[1]] = codebook->v;
                     }
 

                     s->frame.data[0][iy[2] + 2] = codebook->y3;
                     s->frame.data[0][iy[2] + 3] = codebook->y3;
                     s->frame.data[0][iy[3] + 2] = codebook->y3;
                     s->frame.data[0][iy[3] + 3] = codebook->y3;

                     if (!s->palette_video) {
                         s->frame.data[1][iu[1] + 1] = codebook->u;
                         s->frame.data[2][iv[1] + 1] = codebook->v;
                     }
 
                 } else if (flag & mask) {
                     if ((data + 4) > eod)
                         return -1;
 
                     codebook = &strip->v4_codebook[*data++];
                     s->frame.data[0][iy[0] + 0] = codebook->y0;
                     s->frame.data[0][iy[0] + 1] = codebook->y1;
                     s->frame.data[0][iy[1] + 0] = codebook->y2;
                     s->frame.data[0][iy[1] + 1] = codebook->y3;
                     if (!s->palette_video) {
                         s->frame.data[1][iu[0]] = codebook->u;
                         s->frame.data[2][iv[0]] = codebook->v;
                     }
 
                     codebook = &strip->v4_codebook[*data++];
                     s->frame.data[0][iy[0] + 2] = codebook->y0;
                     s->frame.data[0][iy[0] + 3] = codebook->y1;
                     s->frame.data[0][iy[1] + 2] = codebook->y2;
                     s->frame.data[0][iy[1] + 3] = codebook->y3;
                     if (!s->palette_video) {
                         s->frame.data[1][iu[0] + 1] = codebook->u;
                         s->frame.data[2][iv[0] + 1] = codebook->v;
                     }
 
                     codebook = &strip->v4_codebook[*data++];
                     s->frame.data[0][iy[2] + 0] = codebook->y0;
                     s->frame.data[0][iy[2] + 1] = codebook->y1;
                     s->frame.data[0][iy[3] + 0] = codebook->y2;
                     s->frame.data[0][iy[3] + 1] = codebook->y3;
                     if (!s->palette_video) {
                         s->frame.data[1][iu[1]] = codebook->u;
                         s->frame.data[2][iv[1]] = codebook->v;
                     }
 
                     codebook = &strip->v4_codebook[*data++];
                     s->frame.data[0][iy[2] + 2] = codebook->y0;
                     s->frame.data[0][iy[2] + 3] = codebook->y1;
                     s->frame.data[0][iy[3] + 2] = codebook->y2;
                     s->frame.data[0][iy[3] + 3] = codebook->y3;
                     if (!s->palette_video) {
                         s->frame.data[1][iu[1] + 1] = codebook->u;
                         s->frame.data[2][iv[1] + 1] = codebook->v;
                     }
 
                 }
             }
 
             iy[0] += 4;  iy[1] += 4;
             iy[2] += 4;  iy[3] += 4;
             iu[0] += 2;  iu[1] += 2;
             iv[0] += 2;  iv[1] += 2;
         }
     }
 
     return 0;
 }
 
 static int cinepak_decode_strip (CinepakContext *s,

                                  cvid_strip *strip, const uint8_t *data, int size)

 {

     const uint8_t *eod = (data + size);

     int      chunk_id, chunk_size;
 
     /* coordinate sanity checks */

     if (strip->x1 >= s->width  || strip->x2 > s->width  ||
         strip->y1 >= s->height || strip->y2 > s->height ||
         strip->x1 >= strip->x2 || strip->y1 >= strip->y2)

         return -1;
 
     while ((data + 4) <= eod) {

         chunk_id   = data[0];
         chunk_size = AV_RB24 (&data[1]) - 4;

         if(chunk_size < 0)
             return -1;
 

         data      += 4;
         chunk_size = ((data + chunk_size) > eod) ? (eod - data) : chunk_size;
 
         switch (chunk_id) {
 

         case 0x20:
         case 0x21:
         case 0x24:
         case 0x25:

             cinepak_decode_codebook (strip->v4_codebook, chunk_id,

                 chunk_size, data);
             break;
 

         case 0x22:
         case 0x23:
         case 0x26:
         case 0x27:

             cinepak_decode_codebook (strip->v1_codebook, chunk_id,

                 chunk_size, data);
             break;
 

         case 0x30:
         case 0x31:
         case 0x32:

             return cinepak_decode_vectors (s, strip, chunk_id,

                 chunk_size, data);
         }
 
         data += chunk_size;
     }
 
     return -1;
 }
 
 static int cinepak_decode (CinepakContext *s)
 {

     const uint8_t  *eod = (s->data + s->size);

     int           i, result, strip_size, frame_flags, num_strips;
     int           y0 = 0;

     int           encoded_buf_size;

 
     if (s->size < 10)
         return -1;
 
     frame_flags = s->data[0];

     num_strips  = AV_RB16 (&s->data[8]);
     encoded_buf_size = ((s->data[1] << 16) | AV_RB16 (&s->data[2]));

 
     /* if this is the first frame, check for deviant Sega FILM data */
     if (s->sega_film_skip_bytes == -1) {
         if (encoded_buf_size != s->size) {
             /* If the encoded frame size differs from the frame size as indicated
              * by the container file, this data likely comes from a Sega FILM/CPK file.
              * If the frame header is followed by the bytes FE 00 00 06 00 00 then
              * this is probably one of the two known files that have 6 extra bytes
              * after the frame header. Else, assume 2 extra bytes. */

             if (s->size >= 16 &&
                 (s->data[10] == 0xFE) &&

                 (s->data[11] == 0x00) &&
                 (s->data[12] == 0x00) &&
                 (s->data[13] == 0x06) &&
                 (s->data[14] == 0x00) &&
                 (s->data[15] == 0x00))
                 s->sega_film_skip_bytes = 6;
             else
                 s->sega_film_skip_bytes = 2;
         } else
             s->sega_film_skip_bytes = 0;
     }
 
     s->data += 10 + s->sega_film_skip_bytes;

 
     if (num_strips > MAX_STRIPS)
         num_strips = MAX_STRIPS;
 
     for (i=0; i < num_strips; i++) {
         if ((s->data + 12) > eod)
             return -1;
 

         s->strips[i].id = s->data[0];

         s->strips[i].y1 = y0;
         s->strips[i].x1 = 0;

         s->strips[i].y2 = y0 + AV_RB16 (&s->data[8]);

         s->strips[i].x2 = s->avctx->width;
 

         strip_size = AV_RB24 (&s->data[1]) - 12;

         if(strip_size < 0)
             return -1;

         s->data   += 12;
         strip_size = ((s->data + strip_size) > eod) ? (eod - s->data) : strip_size;
 
         if ((i > 0) && !(frame_flags & 0x01)) {
             memcpy (s->strips[i].v4_codebook, s->strips[i-1].v4_codebook,
                 sizeof(s->strips[i].v4_codebook));
             memcpy (s->strips[i].v1_codebook, s->strips[i-1].v1_codebook,
                 sizeof(s->strips[i].v1_codebook));
         }
 
         result = cinepak_decode_strip (s, &s->strips[i], s->data, strip_size);
 
         if (result != 0)
             return result;
 
         s->data += strip_size;
         y0    = s->strips[i].y2;
     }
     return 0;
 }
 

 static av_cold int cinepak_decode_init(AVCodecContext *avctx)

 {

     CinepakContext *s = avctx->priv_data;

 
     s->avctx = avctx;

     s->width = (avctx->width + 3) & ~3;
     s->height = (avctx->height + 3) & ~3;

     s->sega_film_skip_bytes = -1;  /* uninitialized state */

     // check for paletted data

     if (avctx->bits_per_coded_sample != 8) {

         s->palette_video = 0;
         avctx->pix_fmt = PIX_FMT_YUV420P;
     } else {
         s->palette_video = 1;
         avctx->pix_fmt = PIX_FMT_PAL8;
     }

     avcodec_get_frame_defaults(&s->frame);

     s->frame.data[0] = NULL;

 
     return 0;
 }
 
 static int cinepak_decode_frame(AVCodecContext *avctx,
                                 void *data, int *data_size,

                                 AVPacket *avpkt)

 {

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

     CinepakContext *s = avctx->priv_data;

 
     s->data = buf;
     s->size = buf_size;
 

     s->frame.reference = 1;
     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE |
                             FF_BUFFER_HINTS_REUSABLE;
     if (avctx->reget_buffer(avctx, &s->frame)) {
         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");

         return -1;
     }
 

     if (s->palette_video) {

         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
         if (pal) {

             s->frame.palette_has_changed = 1;

             memcpy(s->pal, pal, AVPALETTE_SIZE);
         }

     }
 

     cinepak_decode(s);
 
     if (s->palette_video)
         memcpy (s->frame.data[1], s->pal, AVPALETTE_SIZE);
 

     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = s->frame;
 
     /* report that the buffer was completely consumed */
     return buf_size;
 }
 

 static av_cold int cinepak_decode_end(AVCodecContext *avctx)

 {

     CinepakContext *s = avctx->priv_data;

     if (s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);

 
     return 0;
 }
 

 AVCodec ff_cinepak_decoder = {

     "cinepak",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_CINEPAK,
     sizeof(CinepakContext),
     cinepak_decode_init,
     NULL,
     cinepak_decode_end,
     cinepak_decode_frame,
     CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("Cinepak"),

 };