text: /*
   * PC Paintbrush PCX (.pcx) image decoder
   * Copyright (c) 2007, 2008 Ivo van Poorten
   *
   * This decoder does not support CGA palettes. I am unable to find samples
   * and Netpbm cannot generate them.
   *
   * 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
   */
  
  #include "libavutil/imgutils.h"
  #include "avcodec.h"
  #include "bytestream.h"
  #include "get_bits.h"
  #include "internal.h"
  
  static void pcx_rle_decode(GetByteContext *gb,
                             uint8_t *dst,
                             unsigned int bytes_per_scanline,
                             int compressed)
  {
      unsigned int i = 0;
      unsigned char run, value;
  
      if (compressed) {
          while (i < bytes_per_scanline && bytestream2_get_bytes_left(gb)>0) {
              run   = 1;
              value = bytestream2_get_byte(gb);
              if (value >= 0xc0 && bytestream2_get_bytes_left(gb)>0) {
                  run   = value & 0x3f;
                  value = bytestream2_get_byte(gb);
              }
              while (i < bytes_per_scanline && run--)
                  dst[i++] = value;
          }
      } else {
          bytestream2_get_buffer(gb, dst, bytes_per_scanline);
      }
  }
  
  static void pcx_palette(GetByteContext *gb, uint32_t *dst, int pallen)
  {
      int i;
  
      pallen = FFMIN(pallen, bytestream2_get_bytes_left(gb) / 3);
      for (i = 0; i < pallen; i++)
          *dst++ = 0xFF000000 | bytestream2_get_be24u(gb);
      if (pallen < 256)
          memset(dst, 0, (256 - pallen) * sizeof(*dst));
  }
  
  static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                              AVPacket *avpkt)
  {
      GetByteContext gb;
      AVFrame * const p  = data;
      int compressed, xmin, ymin, xmax, ymax;
      int ret;
      unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
                   bytes_per_scanline;
      uint8_t *ptr, *scanline;
  
      if (avpkt->size < 128)
          return AVERROR_INVALIDDATA;
  
      bytestream2_init(&gb, avpkt->data, avpkt->size);
  
      if (bytestream2_get_byteu(&gb) != 0x0a || bytestream2_get_byteu(&gb) > 5) {
          av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
          return AVERROR_INVALIDDATA;
      }
  
      compressed                     = bytestream2_get_byteu(&gb);
      bits_per_pixel                 = bytestream2_get_byteu(&gb);
      xmin                           = bytestream2_get_le16u(&gb);
      ymin                           = bytestream2_get_le16u(&gb);
      xmax                           = bytestream2_get_le16u(&gb);
      ymax                           = bytestream2_get_le16u(&gb);
      avctx->sample_aspect_ratio.num = bytestream2_get_le16u(&gb);
      avctx->sample_aspect_ratio.den = bytestream2_get_le16u(&gb);
  
      if (xmax < xmin || ymax < ymin) {
          av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
          return AVERROR_INVALIDDATA;
      }
  
      w = xmax - xmin + 1;
      h = ymax - ymin + 1;
  
      bytestream2_skipu(&gb, 49);
      nplanes            = bytestream2_get_byteu(&gb);
      bytes_per_line     = bytestream2_get_le16u(&gb);
      bytes_per_scanline = nplanes * bytes_per_line;
  
      if (bytes_per_scanline < (w * bits_per_pixel * nplanes + 7) / 8 ||
          (!compressed && bytes_per_scanline > bytestream2_get_bytes_left(&gb) / h)) {
          av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
          return AVERROR_INVALIDDATA;
      }
  
      switch ((nplanes << 8) + bits_per_pixel) {
      case 0x0308:
          avctx->pix_fmt = AV_PIX_FMT_RGB24;
          break;
      case 0x0108:
      case 0x0104:
      case 0x0102:
      case 0x0101:
      case 0x0401:
      case 0x0301:
      case 0x0201:
          avctx->pix_fmt = AV_PIX_FMT_PAL8;
          break;
      default:
          av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
          return AVERROR_INVALIDDATA;
      }
  
      bytestream2_skipu(&gb, 60);
  
      if ((ret = av_image_check_size(w, h, 0, avctx)) < 0)
          return ret;
      if (w != avctx->width || h != avctx->height)
          avcodec_set_dimensions(avctx, w, h);
      if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
          return ret;
  
      p->pict_type = AV_PICTURE_TYPE_I;
  
      ptr    = p->data[0];
      stride = p->linesize[0];
  
      scanline = av_malloc(bytes_per_scanline + FF_INPUT_BUFFER_PADDING_SIZE);
      if (!scanline)
          return AVERROR(ENOMEM);
  
      if (nplanes == 3 && bits_per_pixel == 8) {
          for (y = 0; y < h; y++) {
              pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
  
              for (x = 0; x < w; x++) {
                  ptr[3 * x]     = scanline[x];
                  ptr[3 * x + 1] = scanline[x + bytes_per_line];
                  ptr[3 * x + 2] = scanline[x + (bytes_per_line << 1)];
              }
  
              ptr += stride;
          }
      } else if (nplanes == 1 && bits_per_pixel == 8) {
          int palstart = avpkt->size - 769;
  
          if (avpkt->size < 769) {
              av_log(avctx, AV_LOG_ERROR, "File is too short\n");
              ret = avctx->err_recognition & AV_EF_EXPLODE ?
                    AVERROR_INVALIDDATA : avpkt->size;
              goto end;
          }
  
          for (y = 0; y < h; y++, ptr += stride) {
              pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
              memcpy(ptr, scanline, w);
          }
  
          if (bytestream2_tell(&gb) != palstart) {
              av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
              bytestream2_seek(&gb, palstart, SEEK_SET);
          }
          if (bytestream2_get_byte(&gb) != 12) {
              av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
              ret = avctx->err_recognition & AV_EF_EXPLODE ?
                    AVERROR_INVALIDDATA : avpkt->size;
              goto end;
          }
      } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
          GetBitContext s;
  
          for (y = 0; y < h; y++) {
              init_get_bits8(&s, scanline, bytes_per_scanline);
  
              pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
  
              for (x = 0; x < w; x++)
                  ptr[x] = get_bits(&s, bits_per_pixel);
              ptr += stride;
          }
      } else {    /* planar, 4, 8 or 16 colors */
          int i;
  
          for (y = 0; y < h; y++) {
              pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
  
              for (x = 0; x < w; x++) {
                  int m = 0x80 >> (x & 7), v = 0;
                  for (i = nplanes - 1; i >= 0; i--) {
                      v <<= 1;
                      v  += !!(scanline[i * bytes_per_line + (x >> 3)] & m);
                  }
                  ptr[x] = v;
              }
              ptr += stride;
          }
      }
  
      ret = bytestream2_tell(&gb);
      if (nplanes == 1 && bits_per_pixel == 8) {
          pcx_palette(&gb, (uint32_t *)p->data[1], 256);
          ret += 256 * 3;
      } else if (bits_per_pixel * nplanes == 1) {
          AV_WN32A(p->data[1]  , 0xFF000000);
          AV_WN32A(p->data[1]+4, 0xFFFFFFFF);
      } else if (bits_per_pixel < 8) {
          bytestream2_seek(&gb, 16, SEEK_SET);
          pcx_palette(&gb, (uint32_t *)p->data[1], 16);
      }
  
      *got_frame = 1;
  
  end:
      av_free(scanline);
      return ret;
  }
  
  AVCodec ff_pcx_decoder = {
      .name         = "pcx",
      .long_name    = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
      .type         = AVMEDIA_TYPE_VIDEO,
      .id           = AV_CODEC_ID_PCX,
      .decode       = pcx_decode_frame,
      .capabilities = CODEC_CAP_DR1,
  };
  