text: /*
   * Packed Animation File video decoder
   * Copyright (c) 2012 Paul B Mahol
   *
   * This file is part of Libav.
   *
   * Libav 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.
   *
   * Libav 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 Libav; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "libavutil/imgutils.h"
  
  #include "avcodec.h"
  #include "bytestream.h"
  #include "copy_block.h"
  #include "internal.h"
  
  static const uint8_t block_sequences[16][8] = {
      { 0, 0, 0, 0, 0, 0, 0, 0 }, { 2, 0, 0, 0, 0, 0, 0, 0 },
      { 5, 7, 0, 0, 0, 0, 0, 0 }, { 5, 0, 0, 0, 0, 0, 0, 0 },
      { 6, 0, 0, 0, 0, 0, 0, 0 }, { 5, 7, 5, 7, 0, 0, 0, 0 },
      { 5, 7, 5, 0, 0, 0, 0, 0 }, { 5, 7, 6, 0, 0, 0, 0, 0 },
      { 5, 5, 0, 0, 0, 0, 0, 0 }, { 3, 0, 0, 0, 0, 0, 0, 0 },
      { 6, 6, 0, 0, 0, 0, 0, 0 }, { 2, 4, 0, 0, 0, 0, 0, 0 },
      { 2, 4, 5, 7, 0, 0, 0, 0 }, { 2, 4, 5, 0, 0, 0, 0, 0 },
      { 2, 4, 6, 0, 0, 0, 0, 0 }, { 2, 4, 5, 7, 5, 7, 0, 0 },
  };
  
  typedef struct PAFVideoDecContext {
      AVFrame  *pic;
      GetByteContext gb;
  
      int width;
      int height;
  
      int current_frame;
      uint8_t *frame[4];
      int frame_size;
      int video_size;
  
      uint8_t *opcodes;
  } PAFVideoDecContext;
  
  static av_cold int paf_video_close(AVCodecContext *avctx)
  {
      PAFVideoDecContext *c = avctx->priv_data;
      int i;
  
      av_frame_free(&c->pic);
  
      for (i = 0; i < 4; i++)
          av_freep(&c->frame[i]);
  
      return 0;
  }
  
  static av_cold int paf_video_init(AVCodecContext *avctx)
  {
      PAFVideoDecContext *c = avctx->priv_data;
      int i;
  
      c->width  = avctx->width;
      c->height = avctx->height;
  
      if (avctx->height & 3 || avctx->width & 3) {
          av_log(avctx, AV_LOG_ERROR,
                 "width %d and height %d must be multiplie of 4.\n",
                 avctx->width, avctx->height);
          return AVERROR_INVALIDDATA;
      }
  
      avctx->pix_fmt = AV_PIX_FMT_PAL8;
  
      c->pic = av_frame_alloc();
      if (!c->pic)
          return AVERROR(ENOMEM);
  
      c->frame_size = avctx->width * FFALIGN(avctx->height, 256);
      c->video_size = avctx->width * avctx->height;
      for (i = 0; i < 4; i++) {
          c->frame[i] = av_mallocz(c->frame_size);
          if (!c->frame[i]) {
              paf_video_close(avctx);
              return AVERROR(ENOMEM);
          }
      }
  
      return 0;
  }
  
  static void read4x4block(PAFVideoDecContext *c, uint8_t *dst, int width)
  {
      int i;
  
      for (i = 0; i < 4; i++) {
          bytestream2_get_buffer(&c->gb, dst, 4);
          dst += width;
      }
  }
  
  static void copy_color_mask(uint8_t *dst, int width, uint8_t mask, uint8_t color)
  {
      int i;
  
      for (i = 0; i < 4; i++) {
          if (mask & (1 << 7 - i))
              dst[i] = color;
          if (mask & (1 << 3 - i))
              dst[width + i] = color;
      }
  }
  
  static void copy_src_mask(uint8_t *dst, int width, uint8_t mask, const uint8_t *src)
  {
      int i;
  
      for (i = 0; i < 4; i++) {
          if (mask & (1 << 7 - i))
              dst[i] = src[i];
          if (mask & (1 << 3 - i))
              dst[width + i] = src[width + i];
      }
  }
  
  static void set_src_position(PAFVideoDecContext *c,
                               const uint8_t **p,
                               const uint8_t **pend)
  {
      int val  = bytestream2_get_be16(&c->gb);
      int page = val >> 14;
      int x    = (val & 0x7F);
      int y    = ((val >> 7) & 0x7F);
  
      *p    = c->frame[page] + x * 2 + y * 2 * c->width;
      *pend = c->frame[page] + c->frame_size;
  }
  
  static int decode_0(PAFVideoDecContext *c, uint8_t *pkt, uint8_t code)
  {
      uint32_t opcode_size, offset;
      uint8_t *dst, *dend, mask = 0, color = 0;
      const uint8_t *src, *send, *opcodes;
      int i, j, op = 0;
  
      i = bytestream2_get_byte(&c->gb);
      if (i) {
          if (code & 0x10) {
              int pos = bytestream2_tell(&c->gb) & 3;
              if (pos)
                  bytestream2_skip(&c->gb, 4 - pos);
          }
          do {
              int page, val, x, y;
              val    = bytestream2_get_be16(&c->gb);
              page   = val >> 14;
              x      = (val & 0x7F) * 2;
              y      = ((val >> 7) & 0x7F) * 2;
              dst    = c->frame[page] + x + y * c->width;
              dend   = c->frame[page] + c->frame_size;
              offset = (x & 0x7F) * 2;
              j      = bytestream2_get_le16(&c->gb) + offset;
              do {
                  offset++;
                  if (dst + 3 * c->width + 4 > dend)
                      return AVERROR_INVALIDDATA;
                  read4x4block(c, dst, c->width);
                  if ((offset & 0x3F) == 0)
                      dst += c->width * 3;
                  dst += 4;
              } while (offset < j);
          } while (--i);
      }
  
      dst  = c->frame[c->current_frame];
      dend = c->frame[c->current_frame] + c->frame_size;
      do {
          set_src_position(c, &src, &send);
          if ((src + 3 * c->width + 4 > send) ||
              (dst + 3 * c->width + 4 > dend))
              return AVERROR_INVALIDDATA;
          copy_block4(dst, src, c->width, c->width, 4);
          i++;
          if ((i & 0x3F) == 0)
              dst += c->width * 3;
          dst += 4;
      } while (i < c->video_size / 16);
  
      opcode_size = bytestream2_get_le16(&c->gb);
      bytestream2_skip(&c->gb, 2);
  
      if (bytestream2_get_bytes_left(&c->gb) < opcode_size)
          return AVERROR_INVALIDDATA;
  
      opcodes = pkt + bytestream2_tell(&c->gb);
      bytestream2_skipu(&c->gb, opcode_size);
  
      dst = c->frame[c->current_frame];
  
      for (i = 0; i < c->height; i += 4, dst += c->width * 3)
          for (j = 0; j < c->width; j += 4, dst += 4) {
              int opcode, k = 0;
              if (op > opcode_size)
                  return AVERROR_INVALIDDATA;
              if (j & 4) {
                  opcode = opcodes[op] & 15;
                  op++;
              } else {
                  opcode = opcodes[op] >> 4;
              }
  
              while (block_sequences[opcode][k]) {
                  offset = c->width * 2;
                  code   = block_sequences[opcode][k++];
  
                  switch (code) {
                  case 2:
                      offset = 0;
                  case 3:
                      color = bytestream2_get_byte(&c->gb);
                  case 4:
                      mask = bytestream2_get_byte(&c->gb);
                      copy_color_mask(dst + offset, c->width, mask, color);
                      break;
                  case 5:
                      offset = 0;
                  case 6:
                      set_src_position(c, &src, &send);
                  case 7:
                      if (src + offset + c->width + 4 > send)
                          return AVERROR_INVALIDDATA;
                      mask = bytestream2_get_byte(&c->gb);
                      copy_src_mask(dst + offset, c->width, mask, src + offset);
                      break;
                  }
              }
          }
  
      return 0;
  }
  
  static int paf_video_decode(AVCodecContext *avctx, void *data,
                              int *got_frame, AVPacket *pkt)
  {
      PAFVideoDecContext *c = avctx->priv_data;
      uint8_t code, *dst, *end;
      int i, frame, ret;
  
      if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)
          return ret;
  
      bytestream2_init(&c->gb, pkt->data, pkt->size);
  
      code = bytestream2_get_byte(&c->gb);
      if (code & 0x20) {  // frame is keyframe
          for (i = 0; i < 4; i++)
              memset(c->frame[i], 0, c->frame_size);
  
          memset(c->pic->data[1], 0, AVPALETTE_SIZE);
          c->current_frame  = 0;
          c->pic->key_frame = 1;
          c->pic->pict_type = AV_PICTURE_TYPE_I;
      } else {
          c->pic->key_frame = 0;
          c->pic->pict_type = AV_PICTURE_TYPE_P;
      }
  
      if (code & 0x40) {  // palette update
          uint32_t *out = (uint32_t *)c->pic->data[1];
          int index, count;
  
          index = bytestream2_get_byte(&c->gb);
          count = bytestream2_get_byte(&c->gb) + 1;
  
          if (index + count > 256)
              return AVERROR_INVALIDDATA;
          if (bytestream2_get_bytes_left(&c->gb) < 3 * count)
              return AVERROR_INVALIDDATA;
  
          out += index;
          for (i = 0; i < count; i++) {
              unsigned r, g, b;
  
              r = bytestream2_get_byteu(&c->gb);
              r = r << 2 | r >> 4;
              g = bytestream2_get_byteu(&c->gb);
              g = g << 2 | g >> 4;
              b = bytestream2_get_byteu(&c->gb);
              b = b << 2 | b >> 4;
              *out++ = (0xFFU << 24) | (r << 16) | (g << 8) | b;
          }
          c->pic->palette_has_changed = 1;
      }
  
      switch (code & 0x0F) {
      case 0:
          /* Block-based motion compensation using 4x4 blocks with either
           * horizontal or vertical vectors; might incorporate VQ as well. */
          if ((ret = decode_0(c, pkt->data, code)) < 0)
              return ret;
          break;
      case 1:
          /* Uncompressed data. This mode specifies that (width * height) bytes
           * should be copied directly from the encoded buffer into the output. */
          dst = c->frame[c->current_frame];
          // possibly chunk length data
          bytestream2_skip(&c->gb, 2);
          if (bytestream2_get_bytes_left(&c->gb) < c->video_size)
              return AVERROR_INVALIDDATA;
          bytestream2_get_bufferu(&c->gb, dst, c->video_size);
          break;
      case 2:
          /* Copy reference frame: Consume the next byte in the stream as the
           * reference frame (which should be 0, 1, 2, or 3, and should not be
           * the same as the current frame number). */
          frame = bytestream2_get_byte(&c->gb);
          if (frame > 3)
              return AVERROR_INVALIDDATA;
          if (frame != c->current_frame)
              memcpy(c->frame[c->current_frame], c->frame[frame], c->frame_size);
          break;
      case 4:
          /* Run length encoding.*/
          dst = c->frame[c->current_frame];
          end = dst + c->video_size;
  
          bytestream2_skip(&c->gb, 2);
  
          while (dst < end) {
              int8_t code;
              int count;
  
              if (bytestream2_get_bytes_left(&c->gb) < 2)
                  return AVERROR_INVALIDDATA;
  
              code  = bytestream2_get_byteu(&c->gb);
              count = FFABS(code) + 1;
  
              if (dst + count > end)
                  return AVERROR_INVALIDDATA;
              if (code < 0)
                  memset(dst, bytestream2_get_byteu(&c->gb), count);
              else
                  bytestream2_get_buffer(&c->gb, dst, count);
              dst += count;
          }
          break;
      default:
          avpriv_request_sample(avctx, "unknown/invalid code");
          return AVERROR_INVALIDDATA;
      }
  
      av_image_copy_plane(c->pic->data[0], c->pic->linesize[0],
                          c->frame[c->current_frame], c->width,
                          c->width, c->height);
  
      c->current_frame = (c->current_frame + 1) & 3;
      if ((ret = av_frame_ref(data, c->pic)) < 0)
          return ret;
  
      *got_frame = 1;
  
      return pkt->size;
  }
  
  AVCodec ff_paf_video_decoder = {
      .name           = "paf_video",
      .long_name      = NULL_IF_CONFIG_SMALL("Amazing Studio Packed Animation File Video"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_PAF_VIDEO,
      .priv_data_size = sizeof(PAFVideoDecContext),
      .init           = paf_video_init,
      .close          = paf_video_close,
      .decode         = paf_video_decode,
      .capabilities   = AV_CODEC_CAP_DR1,
  };
  