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  1. /*
  2.  * PC Paintbrush PCX (.pcx) image decoder
  3.  * Copyright (c) 2007, 2008 Ivo van Poorten
  4.  *
  5.  * This decoder does not support CGA palettes. I am unable to find samples
  6.  * and Netpbm cannot generate them.
  7.  *
  8.  * This file is part of FFmpeg.
  9.  *
  10.  * FFmpeg is free software; you can redistribute it and/or
  11.  * modify it under the terms of the GNU Lesser General Public
  12.  * License as published by the Free Software Foundation; either
  13.  * version 2.1 of the License, or (at your option) any later version.
  14.  *
  15.  * FFmpeg is distributed in the hope that it will be useful,
  16.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18.  * Lesser General Public License for more details.
  19.  *
  20.  * You should have received a copy of the GNU Lesser General Public
  21.  * License along with FFmpeg; if not, write to the Free Software
  22.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23.  */
  24.  
  25. #include "libavutil/imgutils.h"
  26. #include "avcodec.h"
  27. #include "bytestream.h"
  28. #include "get_bits.h"
  29. #include "internal.h"
  30.  
  31. static void pcx_rle_decode(GetByteContext *gb,
  32.                            uint8_t *dst,
  33.                            unsigned int bytes_per_scanline,
  34.                            int compressed)
  35. {
  36.     unsigned int i = 0;
  37.     unsigned char run, value;
  38.  
  39.     if (compressed) {
  40.         while (i < bytes_per_scanline && bytestream2_get_bytes_left(gb)>0) {
  41.             run   = 1;
  42.             value = bytestream2_get_byte(gb);
  43.             if (value >= 0xc0 && bytestream2_get_bytes_left(gb)>0) {
  44.                 run   = value & 0x3f;
  45.                 value = bytestream2_get_byte(gb);
  46.             }
  47.             while (i < bytes_per_scanline && run--)
  48.                 dst[i++] = value;
  49.         }
  50.     } else {
  51.         bytestream2_get_buffer(gb, dst, bytes_per_scanline);
  52.     }
  53. }
  54.  
  55. static void pcx_palette(GetByteContext *gb, uint32_t *dst, int pallen)
  56. {
  57.     int i;
  58.  
  59.     pallen = FFMIN(pallen, bytestream2_get_bytes_left(gb) / 3);
  60.     for (i = 0; i < pallen; i++)
  61.         *dst++ = 0xFF000000 | bytestream2_get_be24u(gb);
  62.     if (pallen < 256)
  63.         memset(dst, 0, (256 - pallen) * sizeof(*dst));
  64. }
  65.  
  66. static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
  67.                             AVPacket *avpkt)
  68. {
  69.     GetByteContext gb;
  70.     AVFrame * const p  = data;
  71.     int compressed, xmin, ymin, xmax, ymax;
  72.     int ret;
  73.     unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
  74.                  bytes_per_scanline;
  75.     uint8_t *ptr, *scanline;
  76.  
  77.     if (avpkt->size < 128)
  78.         return AVERROR_INVALIDDATA;
  79.  
  80.     bytestream2_init(&gb, avpkt->data, avpkt->size);
  81.  
  82.     if (bytestream2_get_byteu(&gb) != 0x0a || bytestream2_get_byteu(&gb) > 5) {
  83.         av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
  84.         return AVERROR_INVALIDDATA;
  85.     }
  86.  
  87.     compressed                     = bytestream2_get_byteu(&gb);
  88.     bits_per_pixel                 = bytestream2_get_byteu(&gb);
  89.     xmin                           = bytestream2_get_le16u(&gb);
  90.     ymin                           = bytestream2_get_le16u(&gb);
  91.     xmax                           = bytestream2_get_le16u(&gb);
  92.     ymax                           = bytestream2_get_le16u(&gb);
  93.     avctx->sample_aspect_ratio.num = bytestream2_get_le16u(&gb);
  94.     avctx->sample_aspect_ratio.den = bytestream2_get_le16u(&gb);
  95.  
  96.     if (xmax < xmin || ymax < ymin) {
  97.         av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
  98.         return AVERROR_INVALIDDATA;
  99.     }
  100.  
  101.     w = xmax - xmin + 1;
  102.     h = ymax - ymin + 1;
  103.  
  104.     bytestream2_skipu(&gb, 49);
  105.     nplanes            = bytestream2_get_byteu(&gb);
  106.     bytes_per_line     = bytestream2_get_le16u(&gb);
  107.     bytes_per_scanline = nplanes * bytes_per_line;
  108.  
  109.     if (bytes_per_scanline < (w * bits_per_pixel * nplanes + 7) / 8 ||
  110.         (!compressed && bytes_per_scanline > bytestream2_get_bytes_left(&gb) / h)) {
  111.         av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
  112.         return AVERROR_INVALIDDATA;
  113.     }
  114.  
  115.     switch ((nplanes << 8) + bits_per_pixel) {
  116.     case 0x0308:
  117.         avctx->pix_fmt = AV_PIX_FMT_RGB24;
  118.         break;
  119.     case 0x0108:
  120.     case 0x0104:
  121.     case 0x0102:
  122.     case 0x0101:
  123.     case 0x0401:
  124.     case 0x0301:
  125.     case 0x0201:
  126.         avctx->pix_fmt = AV_PIX_FMT_PAL8;
  127.         break;
  128.     default:
  129.         av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
  130.         return AVERROR_INVALIDDATA;
  131.     }
  132.  
  133.     bytestream2_skipu(&gb, 60);
  134.  
  135.     if ((ret = ff_set_dimensions(avctx, w, h)) < 0)
  136.         return ret;
  137.  
  138.     if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
  139.         return ret;
  140.  
  141.     p->pict_type = AV_PICTURE_TYPE_I;
  142.  
  143.     ptr    = p->data[0];
  144.     stride = p->linesize[0];
  145.  
  146.     scanline = av_malloc(bytes_per_scanline + AV_INPUT_BUFFER_PADDING_SIZE);
  147.     if (!scanline)
  148.         return AVERROR(ENOMEM);
  149.  
  150.     if (nplanes == 3 && bits_per_pixel == 8) {
  151.         for (y = 0; y < h; y++) {
  152.             pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
  153.  
  154.             for (x = 0; x < w; x++) {
  155.                 ptr[3 * x]     = scanline[x];
  156.                 ptr[3 * x + 1] = scanline[x + bytes_per_line];
  157.                 ptr[3 * x + 2] = scanline[x + (bytes_per_line << 1)];
  158.             }
  159.  
  160.             ptr += stride;
  161.         }
  162.     } else if (nplanes == 1 && bits_per_pixel == 8) {
  163.         int palstart = avpkt->size - 769;
  164.  
  165.         if (avpkt->size < 769) {
  166.             av_log(avctx, AV_LOG_ERROR, "File is too short\n");
  167.             ret = avctx->err_recognition & AV_EF_EXPLODE ?
  168.                   AVERROR_INVALIDDATA : avpkt->size;
  169.             goto end;
  170.         }
  171.  
  172.         for (y = 0; y < h; y++, ptr += stride) {
  173.             pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
  174.             memcpy(ptr, scanline, w);
  175.         }
  176.  
  177.         if (bytestream2_tell(&gb) != palstart) {
  178.             av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
  179.             bytestream2_seek(&gb, palstart, SEEK_SET);
  180.         }
  181.         if (bytestream2_get_byte(&gb) != 12) {
  182.             av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
  183.             ret = avctx->err_recognition & AV_EF_EXPLODE ?
  184.                   AVERROR_INVALIDDATA : avpkt->size;
  185.             goto end;
  186.         }
  187.     } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
  188.         GetBitContext s;
  189.  
  190.         for (y = 0; y < h; y++) {
  191.             init_get_bits8(&s, scanline, bytes_per_scanline);
  192.  
  193.             pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
  194.  
  195.             for (x = 0; x < w; x++)
  196.                 ptr[x] = get_bits(&s, bits_per_pixel);
  197.             ptr += stride;
  198.         }
  199.     } else {    /* planar, 4, 8 or 16 colors */
  200.         int i;
  201.  
  202.         for (y = 0; y < h; y++) {
  203.             pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
  204.  
  205.             for (x = 0; x < w; x++) {
  206.                 int m = 0x80 >> (x & 7), v = 0;
  207.                 for (i = nplanes - 1; i >= 0; i--) {
  208.                     v <<= 1;
  209.                     v  += !!(scanline[i * bytes_per_line + (x >> 3)] & m);
  210.                 }
  211.                 ptr[x] = v;
  212.             }
  213.             ptr += stride;
  214.         }
  215.     }
  216.  
  217.     ret = bytestream2_tell(&gb);
  218.     if (nplanes == 1 && bits_per_pixel == 8) {
  219.         pcx_palette(&gb, (uint32_t *)p->data[1], 256);
  220.         ret += 256 * 3;
  221.     } else if (bits_per_pixel * nplanes == 1) {
  222.         AV_WN32A(p->data[1]  , 0xFF000000);
  223.         AV_WN32A(p->data[1]+4, 0xFFFFFFFF);
  224.     } else if (bits_per_pixel < 8) {
  225.         bytestream2_seek(&gb, 16, SEEK_SET);
  226.         pcx_palette(&gb, (uint32_t *)p->data[1], 16);
  227.     }
  228.  
  229.     *got_frame = 1;
  230.  
  231. end:
  232.     av_free(scanline);
  233.     return ret;
  234. }
  235.  
  236. AVCodec ff_pcx_decoder = {
  237.     .name         = "pcx",
  238.     .long_name    = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
  239.     .type         = AVMEDIA_TYPE_VIDEO,
  240.     .id           = AV_CODEC_ID_PCX,
  241.     .decode       = pcx_decode_frame,
  242.     .capabilities = AV_CODEC_CAP_DR1,
  243. };
  244.