libavcodec/pcx.c

   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 Libav.
   9  *
  10  * Libav 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  * Libav 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 Libav; 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
  30 typedef struct PCXContext {
  31     AVFrame picture;
  32 } PCXContext;
  33
  34 static av_cold int pcx_init(AVCodecContext *avctx) {
  35     PCXContext *s = avctx->priv_data;
  36
  37     avcodec_get_frame_defaults(&s->picture);
  38     avctx->coded_frame= &s->picture;
  39
  40     return 0;
  41 }
  42
  43 /**
  44  * @return advanced src pointer
  45  */
  46 static const uint8_t *pcx_rle_decode(const uint8_t *src, uint8_t *dst,
  47                             unsigned int bytes_per_scanline, int compressed) {
  48     unsigned int i = 0;
  49     unsigned char run, value;
  50
  51     if (compressed) {
  52         while (i<bytes_per_scanline) {
  53             run = 1;
  54             value = *src++;
  55             if (value >= 0xc0) {
  56                 run = value & 0x3f;
  57                 value = *src++;
  58             }
  59             while (i<bytes_per_scanline && run--)
  60                 dst[i++] = value;
  61         }
  62     } else {
  63         memcpy(dst, src, bytes_per_scanline);
  64         src += bytes_per_scanline;
  65     }
  66
  67     return src;
  68 }
  69
  70 static void pcx_palette(const uint8_t **src, uint32_t *dst, unsigned int pallen) {
  71     unsigned int i;
  72
  73     for (i=0; i<pallen; i++)
  74         *dst++ = bytestream_get_be24(src);
  75     if (pallen < 256)
  76         memset(dst, 0, (256 - pallen) * sizeof(*dst));
  77 }
  78
  79 static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
  80                             AVPacket *avpkt) {
  81     const uint8_t *buf = avpkt->data;
  82     int buf_size = avpkt->size;
  83     PCXContext * const s = avctx->priv_data;
  84     AVFrame *picture = data;
  85     AVFrame * const p = &s->picture;
  86     int compressed, xmin, ymin, xmax, ymax;
  87     unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
  88                  bytes_per_scanline;
  89     uint8_t *ptr;
  90     uint8_t const *bufstart = buf;
  91     uint8_t *scanline;
  92     int ret = -1;
  93
  94     if (buf[0] != 0x0a || buf[1] > 5) {
  95         av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
  96         return -1;
  97     }
  98
  99     compressed = buf[2];
 100     xmin = AV_RL16(buf+ 4);
 101     ymin = AV_RL16(buf+ 6);
 102     xmax = AV_RL16(buf+ 8);
 103     ymax = AV_RL16(buf+10);
 104
 105     if (xmax < xmin || ymax < ymin) {
 106         av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
 107         return -1;
 108     }
 109
 110     w = xmax - xmin + 1;
 111     h = ymax - ymin + 1;
 112
 113     bits_per_pixel     = buf[3];
 114     bytes_per_line     = AV_RL16(buf+66);
 115     nplanes            = buf[65];
 116     bytes_per_scanline = nplanes * bytes_per_line;
 117
 118     if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
 119         av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
 120         return -1;
 121     }
 122
 123     switch ((nplanes<<8) + bits_per_pixel) {
 124         case 0x0308:
 125             avctx->pix_fmt = AV_PIX_FMT_RGB24;
 126             break;
 127         case 0x0108:
 128         case 0x0104:
 129         case 0x0102:
 130         case 0x0101:
 131         case 0x0401:
 132         case 0x0301:
 133         case 0x0201:
 134             avctx->pix_fmt = AV_PIX_FMT_PAL8;
 135             break;
 136         default:
 137             av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
 138             return -1;
 139     }
 140
 141     buf += 128;
 142
 143     if (p->data[0])
 144         avctx->release_buffer(avctx, p);
 145
 146     if (av_image_check_size(w, h, 0, avctx))
 147         return -1;
 148     if (w != avctx->width || h != avctx->height)
 149         avcodec_set_dimensions(avctx, w, h);
 150     if (avctx->get_buffer(avctx, p) < 0) {
 151         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 152         return -1;
 153     }
 154
 155     p->pict_type = AV_PICTURE_TYPE_I;
 156
 157     ptr    = p->data[0];
 158     stride = p->linesize[0];
 159
 160     scanline = av_malloc(bytes_per_scanline);
 161     if (!scanline)
 162         return AVERROR(ENOMEM);
 163
 164     if (nplanes == 3 && bits_per_pixel == 8) {
 165         for (y=0; y<h; y++) {
 166             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
 167
 168             for (x=0; x<w; x++) {
 169                 ptr[3*x  ] = scanline[x                    ];
 170                 ptr[3*x+1] = scanline[x+ bytes_per_line    ];
 171                 ptr[3*x+2] = scanline[x+(bytes_per_line<<1)];
 172             }
 173
 174             ptr += stride;
 175         }
 176
 177     } else if (nplanes == 1 && bits_per_pixel == 8) {
 178         const uint8_t *palstart = bufstart + buf_size - 769;
 179
 180         for (y=0; y<h; y++, ptr+=stride) {
 181             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
 182             memcpy(ptr, scanline, w);
 183         }
 184
 185         if (buf != palstart) {
 186             av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
 187             buf = palstart;
 188         }
 189         if (*buf++ != 12) {
 190             av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
 191             goto end;
 192         }
 193
 194     } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
 195         GetBitContext s;
 196
 197         for (y=0; y<h; y++) {
 198             init_get_bits(&s, scanline, bytes_per_scanline<<3);
 199
 200             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
 201
 202             for (x=0; x<w; x++)
 203                 ptr[x] = get_bits(&s, bits_per_pixel);
 204             ptr += stride;
 205         }
 206
 207     } else {    /* planar, 4, 8 or 16 colors */
 208         int i;
 209
 210         for (y=0; y<h; y++) {
 211             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
 212
 213             for (x=0; x<w; x++) {
 214                 int m = 0x80 >> (x&7), v = 0;
 215                 for (i=nplanes - 1; i>=0; i--) {
 216                     v <<= 1;
 217                     v  += !!(scanline[i*bytes_per_line + (x>>3)] & m);
 218                 }
 219                 ptr[x] = v;
 220             }
 221             ptr += stride;
 222         }
 223     }
 224
 225     if (nplanes == 1 && bits_per_pixel == 8) {
 226         pcx_palette(&buf, (uint32_t *) p->data[1], 256);
 227     } else if (bits_per_pixel < 8) {
 228         const uint8_t *palette = bufstart+16;
 229         pcx_palette(&palette, (uint32_t *) p->data[1], 16);
 230     }
 231
 232     *picture = s->picture;
 233     *data_size = sizeof(AVFrame);
 234
 235     ret = buf - bufstart;
 236 end:
 237     av_free(scanline);
 238     return ret;
 239 }
 240
 241 static av_cold int pcx_end(AVCodecContext *avctx) {
 242     PCXContext *s = avctx->priv_data;
 243
 244     if(s->picture.data[0])
 245         avctx->release_buffer(avctx, &s->picture);
 246
 247     return 0;
 248 }
 249
 250 AVCodec ff_pcx_decoder = {
 251     .name           = "pcx",
 252     .type           = AVMEDIA_TYPE_VIDEO,
 253     .id             = AV_CODEC_ID_PCX,
 254     .priv_data_size = sizeof(PCXContext),
 255     .init           = pcx_init,
 256     .close          = pcx_end,
 257     .decode         = pcx_decode_frame,
 258     .capabilities   = CODEC_CAP_DR1,
 259     .long_name      = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
 260 };