libavcodec/sgidec.c

   1 /*
   2  * SGI image decoder
   3  * Todd Kirby <doubleshot@pacbell.net>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "avcodec.h"
  23 #include "bytestream.h"
  24 #include "sgi.h"
  25
  26 typedef struct SgiState {
  27     AVFrame picture;
  28     unsigned int width;
  29     unsigned int height;
  30     unsigned int depth;
  31     int linesize;
  32 } SgiState;
  33
  34 /**
  35  * Expand an RLE row into a channel.
  36  * @param in_buf input buffer
  37  * @param in_end end of input buffer
  38  * @param out_buf Points to one line after the output buffer.
  39  * @param out_end end of line in output buffer
  40  * @param pixelstride pixel stride of input buffer
  41  * @return size of output in bytes, -1 if buffer overflows
  42  */
  43 static int expand_rle_row(const uint8_t *in_buf, const uint8_t* in_end,
  44             unsigned char *out_buf, uint8_t* out_end, int pixelstride)
  45 {
  46     unsigned char pixel, count;
  47     unsigned char *orig = out_buf;
  48
  49     while (1) {
  50         if(in_buf + 1 > in_end) return -1;
  51         pixel = bytestream_get_byte(&in_buf);
  52         if (!(count = (pixel & 0x7f))) {
  53             return (out_buf - orig) / pixelstride;
  54         }
  55
  56         /* Check for buffer overflow. */
  57         if(out_buf + pixelstride * count >= out_end) return -1;
  58
  59         if (pixel & 0x80) {
  60             while (count--) {
  61                 *out_buf = bytestream_get_byte(&in_buf);
  62                 out_buf += pixelstride;
  63             }
  64         } else {
  65             pixel = bytestream_get_byte(&in_buf);
  66
  67             while (count--) {
  68                 *out_buf = pixel;
  69                 out_buf += pixelstride;
  70             }
  71         }
  72     }
  73 }
  74
  75 /**
  76  * Read a run length encoded SGI image.
  77  * @param out_buf output buffer
  78  * @param in_buf input buffer
  79  * @param in_end end of input buffer
  80  * @param s the current image state
  81  * @return 0 if no error, else return error number.
  82  */
  83 static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf,
  84                         const uint8_t *in_end, SgiState* s)
  85 {
  86     uint8_t *dest_row;
  87     unsigned int len = s->height * s->depth * 4;
  88     const uint8_t *start_table = in_buf;
  89     unsigned int y, z;
  90     unsigned int start_offset;
  91
  92     /* size of  RLE offset and length tables */
  93     if(len * 2  > in_end - in_buf) {
  94         return AVERROR_INVALIDDATA;
  95     }
  96
  97     in_buf -= SGI_HEADER_SIZE;
  98     for (z = 0; z < s->depth; z++) {
  99         dest_row = out_buf;
 100         for (y = 0; y < s->height; y++) {
 101             dest_row -= s->linesize;
 102             start_offset = bytestream_get_be32(&start_table);
 103             if(start_offset > in_end - in_buf) {
 104                 return AVERROR_INVALIDDATA;
 105             }
 106             if (expand_rle_row(in_buf + start_offset, in_end, dest_row + z,
 107                 dest_row + FFABS(s->linesize), s->depth) != s->width)
 108                 return AVERROR_INVALIDDATA;
 109         }
 110     }
 111     return 0;
 112 }
 113
 114 /**
 115  * Read an uncompressed SGI image.
 116  * @param out_buf output buffer
 117  * @param out_end end ofoutput buffer
 118  * @param in_buf input buffer
 119  * @param in_end end of input buffer
 120  * @param s the current image state
 121  * @return 0 if read success, otherwise return -1.
 122  */
 123 static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
 124                 const uint8_t *in_buf, const uint8_t *in_end, SgiState* s)
 125 {
 126     int x, y, z;
 127     const uint8_t *ptr;
 128     unsigned int offset = s->height * s->width;
 129
 130     /* Test buffer size. */
 131     if (offset * s->depth > in_end - in_buf) {
 132        return -1;
 133     }
 134
 135     for (y = s->height - 1; y >= 0; y--) {
 136         out_end = out_buf + (y * s->linesize);
 137         for (x = s->width; x > 0; x--) {
 138             ptr = in_buf++;
 139             for(z = 0; z < s->depth; z ++) {
 140                 bytestream_put_byte(&out_end, *ptr);
 141                 ptr += offset;
 142             }
 143         }
 144     }
 145     return 0;
 146 }
 147
 148 static int decode_frame(AVCodecContext *avctx,
 149                         void *data, int *data_size,
 150                         const uint8_t *in_buf, int buf_size)
 151 {
 152     SgiState *s = avctx->priv_data;
 153     AVFrame *picture = data;
 154     AVFrame *p = &s->picture;
 155     const uint8_t *in_end = in_buf + buf_size;
 156     unsigned int dimension, bytes_per_channel, rle;
 157     int ret = 0;
 158     uint8_t *out_buf, *out_end;
 159
 160     if (buf_size < SGI_HEADER_SIZE){
 161         av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size);
 162         return -1;
 163     }
 164
 165     /* Test for SGI magic. */
 166     if (bytestream_get_be16(&in_buf) != SGI_MAGIC) {
 167         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
 168         return -1;
 169     }
 170
 171     rle = bytestream_get_byte(&in_buf);
 172     bytes_per_channel = bytestream_get_byte(&in_buf);
 173     dimension = bytestream_get_be16(&in_buf);
 174     s->width  = bytestream_get_be16(&in_buf);
 175     s->height = bytestream_get_be16(&in_buf);
 176     s->depth  = bytestream_get_be16(&in_buf);
 177
 178     if (bytes_per_channel != 1) {
 179         av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
 180         return -1;
 181     }
 182
 183     /* Check for supported image dimensions. */
 184     if (dimension != 2 && dimension != 3) {
 185         av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
 186         return -1;
 187     }
 188
 189     if (s->depth == SGI_GRAYSCALE) {
 190         avctx->pix_fmt = PIX_FMT_GRAY8;
 191     } else if (s->depth == SGI_RGB) {
 192         avctx->pix_fmt = PIX_FMT_RGB24;
 193     } else if (s->depth == SGI_RGBA) {
 194         avctx->pix_fmt = PIX_FMT_RGBA;
 195     } else {
 196         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
 197         return -1;
 198     }
 199
 200     if (avcodec_check_dimensions(avctx, s->width, s->height))
 201         return -1;
 202     avcodec_set_dimensions(avctx, s->width, s->height);
 203
 204     if (p->data[0])
 205         avctx->release_buffer(avctx, p);
 206
 207     p->reference = 0;
 208     if (avctx->get_buffer(avctx, p) < 0) {
 209         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
 210         return -1;
 211     }
 212
 213     p->pict_type = FF_I_TYPE;
 214     p->key_frame = 1;
 215     out_buf = p->data[0];
 216
 217     out_end = out_buf + p->linesize[0] * s->height;
 218
 219     s->linesize = p->linesize[0];
 220
 221     /* Skip header. */
 222     in_buf += SGI_HEADER_SIZE - 12;
 223     if (rle) {
 224         ret = read_rle_sgi(out_end, in_buf, in_end, s);
 225     } else {
 226         ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s);
 227     }
 228
 229     if (ret == 0) {
 230         *picture   = s->picture;
 231         *data_size = sizeof(AVPicture);
 232         return buf_size;
 233     } else {
 234         return -1;
 235     }
 236 }
 237
 238 static av_cold int sgi_init(AVCodecContext *avctx){
 239     SgiState *s = avctx->priv_data;
 240
 241     avcodec_get_frame_defaults(&s->picture);
 242     avctx->coded_frame = &s->picture;
 243
 244     return 0;
 245 }
 246
 247 static av_cold int sgi_end(AVCodecContext *avctx)
 248 {
 249     SgiState * const s = avctx->priv_data;
 250
 251     if (s->picture.data[0])
 252         avctx->release_buffer(avctx, &s->picture);
 253
 254     return 0;
 255 }
 256
 257 AVCodec sgi_decoder = {
 258     "sgi",
 259     CODEC_TYPE_VIDEO,
 260     CODEC_ID_SGI,
 261     sizeof(SgiState),
 262     sgi_init,
 263     NULL,
 264     sgi_end,
 265     decode_frame,
 266     .long_name = "SGI image",
 267 };
 268