text: /*
   * 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
   * @author Ewald Snel <ewald@rambo.its.tudelft.nl>
   *
   * @see For more information on the Cinepak algorithm, visit:
   *   http://www.csse.monash.edu.au/~timf/
   * @see For more information on the quirky data inside Sega FILM/CPK files, visit:
   *   http://wiki.multimedia.cx/index.php?title=Sega_FILM
   *
   * Cinepak colorspace support (c) 2013 Rl, Aetey Global Technologies AB
   * @author Cinepak colorspace, Rl, Aetey Global Technologies AB
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "libavutil/common.h"
  #include "libavutil/intreadwrite.h"
  #include "avcodec.h"
  #include "internal.h"
  
  
  typedef uint8_t cvid_codebook[12];
  
  #define MAX_STRIPS      32
  
  typedef struct cvid_strip {
      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;
      uint8_t *p;
  
      /* check if this chunk contains 4- or 6-element vectors */
      n    = (chunk_id & 0x04) ? 4 : 6;
      flag = 0;
      mask = 0;
  
      p = codebook[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)) {
              int k, kk;
  
              if ((data + n) > eod)
                  break;
  
              for (k = 0; k < 4; ++k) {
                  int r = *data++;
                  for (kk = 0; kk < 3; ++kk)
                      *p++ = r;
              }
              if (n == 6) {
                  int r, g, b, u, v;
                  u = *(int8_t *)data++;
                  v = *(int8_t *)data++;
                  p -= 12;
                  for(k=0; k<4; ++k) {
                      r = *p++ + v*2;
                      g = *p++ - (u/2) - v;
                      b = *p   + u*2;
                      p -= 2;
                      *p++ = av_clip_uint8(r);
                      *p++ = av_clip_uint8(g);
                      *p++ = av_clip_uint8(b);
                  }
              }
          } else {
              p += 12;
          }
      }
  }
  
  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;
      uint8_t         *cb0, *cb1, *cb2, *cb3;
      int             x, y;
      char            *ip0, *ip1, *ip2, *ip3;
  
      flag = 0;
      mask = 0;
  
      for (y=strip->y1; y < strip->y2; y+=4) {
  
  /* take care of y dimension not being multiple of 4, such streams exist */
          ip0 = ip1 = ip2 = ip3 = s->frame->data[0] +
            (s->palette_video?strip->x1:strip->x1*3) + (y * s->frame->linesize[0]);
          if(s->avctx->height - y > 1) {
              ip1 = ip0 + s->frame->linesize[0];
              if(s->avctx->height - y > 2) {
                  ip2 = ip1 + s->frame->linesize[0];
                  if(s->avctx->height - y > 3) {
                      ip3 = ip2 + s->frame->linesize[0];
                  }
              }
          }
  /* to get the correct picture for not-multiple-of-4 cases let us fill
   * each block from the bottom up, thus possibly overwriting the top line
   * more than once but ending with the correct data in place
   * (instead of in-loop checking) */
  
          for (x=strip->x1; x < strip->x2; x+=4) {
              if ((chunk_id & 0x01) && !(mask >>= 1)) {
                  if ((data + 4) > eod)
                      return AVERROR_INVALIDDATA;
  
                  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 AVERROR_INVALIDDATA;
  
                      flag  = AV_RB32 (data);
                      data += 4;
                      mask  = 0x80000000;
                  }
  
                  if ((chunk_id & 0x02) || (~flag & mask)) {
                      uint8_t *p;
                      if (data >= eod)
                          return AVERROR_INVALIDDATA;
  
                      p = strip->v1_codebook[*data++];
                      if (s->palette_video) {
                          ip3[0] = ip3[1] = ip2[0] = ip2[1] = p[6];
                          ip3[2] = ip3[3] = ip2[2] = ip2[3] = p[9];
                          ip1[0] = ip1[1] = ip0[0] = ip0[1] = p[0];
                          ip1[2] = ip1[3] = ip0[2] = ip0[3] = p[3];
                      } else {
                          p += 6;
                          memcpy(ip3 + 0, p, 3); memcpy(ip3 + 3, p, 3);
                          memcpy(ip2 + 0, p, 3); memcpy(ip2 + 3, p, 3);
                          p += 3; /* ... + 9 */
                          memcpy(ip3 + 6, p, 3); memcpy(ip3 + 9, p, 3);
                          memcpy(ip2 + 6, p, 3); memcpy(ip2 + 9, p, 3);
                          p -= 9; /* ... + 0 */
                          memcpy(ip1 + 0, p, 3); memcpy(ip1 + 3, p, 3);
                          memcpy(ip0 + 0, p, 3); memcpy(ip0 + 3, p, 3);
                          p += 3; /* ... + 3 */
                          memcpy(ip1 + 6, p, 3); memcpy(ip1 + 9, p, 3);
                          memcpy(ip0 + 6, p, 3); memcpy(ip0 + 9, p, 3);
                      }
  
                  } else if (flag & mask) {
                      if ((data + 4) > eod)
                          return AVERROR_INVALIDDATA;
  
                      cb0 = strip->v4_codebook[*data++];
                      cb1 = strip->v4_codebook[*data++];
                      cb2 = strip->v4_codebook[*data++];
                      cb3 = strip->v4_codebook[*data++];
                      if (s->palette_video) {
                          uint8_t *p;
                          p = ip3;
                          *p++ = cb2[6];
                          *p++ = cb2[9];
                          *p++ = cb3[6];
                          *p   = cb3[9];
                          p = ip2;
                          *p++ = cb2[0];
                          *p++ = cb2[3];
                          *p++ = cb3[0];
                          *p   = cb3[3];
                          p = ip1;
                          *p++ = cb0[6];
                          *p++ = cb0[9];
                          *p++ = cb1[6];
                          *p   = cb1[9];
                          p = ip0;
                          *p++ = cb0[0];
                          *p++ = cb0[3];
                          *p++ = cb1[0];
                          *p   = cb1[3];
                      } else {
                          memcpy(ip3 + 0, cb2 + 6, 6);
                          memcpy(ip3 + 6, cb3 + 6, 6);
                          memcpy(ip2 + 0, cb2 + 0, 6);
                          memcpy(ip2 + 6, cb3 + 0, 6);
                          memcpy(ip1 + 0, cb0 + 6, 6);
                          memcpy(ip1 + 6, cb1 + 6, 6);
                          memcpy(ip0 + 0, cb0 + 0, 6);
                          memcpy(ip0 + 6, cb1 + 0, 6);
                      }
  
                  }
              }
  
              if (s->palette_video) {
                  ip0 += 4;  ip1 += 4;
                  ip2 += 4;  ip3 += 4;
              } else {
                  ip0 += 12;  ip1 += 12;
                  ip2 += 12;  ip3 += 12;
              }
          }
      }
  
      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->x2 > s->width   ||
          strip->y2 > s->height  ||
          strip->x1 >= strip->x2 || strip->y1 >= strip->y2)
          return AVERROR_INVALIDDATA;
  
      while ((data + 4) <= eod) {
          chunk_id   = data[0];
          chunk_size = AV_RB24 (&data[1]) - 4;
          if(chunk_size < 0)
              return AVERROR_INVALIDDATA;
  
          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 AVERROR_INVALIDDATA;
  }
  
  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 AVERROR_INVALIDDATA;
  
      frame_flags = s->data[0];
      num_strips  = AV_RB16 (&s->data[8]);
      encoded_buf_size = AV_RB24(&s->data[1]);
  
      /* if this is the first frame, check for deviant Sega FILM data */
      if (s->sega_film_skip_bytes == -1) {
          if (!encoded_buf_size) {
              avpriv_request_sample(s->avctx, "encoded_buf_size 0");
              return AVERROR_PATCHWELCOME;
          }
          if (encoded_buf_size != s->size && (s->size % encoded_buf_size) != 0) {
              /* 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. The container
               * size also cannot be a multiple of the encoded size. */
              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;
  
      num_strips = FFMIN(num_strips, MAX_STRIPS);
  
      s->frame->key_frame = 0;
  
      for (i=0; i < num_strips; i++) {
          if ((s->data + 12) > eod)
              return AVERROR_INVALIDDATA;
  
          s->strips[i].id = s->data[0];
  /* zero y1 means "relative to the previous stripe" */
          if (!(s->strips[i].y1 = AV_RB16 (&s->data[4])))
              s->strips[i].y2 = (s->strips[i].y1 = y0) + AV_RB16 (&s->data[8]);
          else
              s->strips[i].y2 = AV_RB16 (&s->data[8]);
          s->strips[i].x1 = AV_RB16 (&s->data[6]);
          s->strips[i].x2 = AV_RB16 (&s->data[10]);
  
          if (s->strips[i].id == 0x10)
              s->frame->key_frame = 1;
  
          strip_size = AV_RB24 (&s->data[1]) - 12;
          if (strip_size < 0)
              return AVERROR_INVALIDDATA;
          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 = AV_PIX_FMT_RGB24;
      } else {
          s->palette_video = 1;
          avctx->pix_fmt = AV_PIX_FMT_PAL8;
      }
  
      s->frame = av_frame_alloc();
      if (!s->frame)
          return AVERROR(ENOMEM);
  
      return 0;
  }
  
  static int cinepak_decode_frame(AVCodecContext *avctx,
                                  void *data, int *got_frame,
                                  AVPacket *avpkt)
  {
      const uint8_t *buf = avpkt->data;
      int ret = 0, buf_size = avpkt->size;
      CinepakContext *s = avctx->priv_data;
  
      s->data = buf;
      s->size = buf_size;
  
      if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
          return ret;
  
      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);
          }
      }
  
      if ((ret = cinepak_decode(s)) < 0) {
          av_log(avctx, AV_LOG_ERROR, "cinepak_decode failed\n");
      }
  
      if (s->palette_video)
          memcpy (s->frame->data[1], s->pal, AVPALETTE_SIZE);
  
      if ((ret = av_frame_ref(data, s->frame)) < 0)
          return ret;
  
      *got_frame = 1;
  
      /* report that the buffer was completely consumed */
      return buf_size;
  }
  
  static av_cold int cinepak_decode_end(AVCodecContext *avctx)
  {
      CinepakContext *s = avctx->priv_data;
  
      av_frame_free(&s->frame);
  
      return 0;
  }
  
  AVCodec ff_cinepak_decoder = {
      .name           = "cinepak",
      .long_name      = NULL_IF_CONFIG_SMALL("Cinepak"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_CINEPAK,
      .priv_data_size = sizeof(CinepakContext),
      .init           = cinepak_decode_init,
      .close          = cinepak_decode_end,
      .decode         = cinepak_decode_frame,
      .capabilities   = CODEC_CAP_DR1,
  };
  