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     unsigned int bytes_per_channel;
  32     int linesize;
  33 } SgiState;
  34
  35 /**
  36  * Expand an RLE row into a channel.
  37  * @param in_buf input buffer
  38  * @param in_end end of input buffer
  39  * @param out_buf Points to one line after the output buffer.
  40  * @param out_end end of line in output buffer
  41  * @param pixelstride pixel stride of input buffer
  42  * @return size of output in bytes, -1 if buffer overflows
  43  */
  44 static int expand_rle_row(const uint8_t *in_buf, const uint8_t* in_end,
  45             unsigned char *out_buf, uint8_t* out_end, int pixelstride)
  46 {
  47     unsigned char pixel, count;
  48     unsigned char *orig = out_buf;
  49
  50     while (1) {
  51         if(in_buf + 1 > in_end) return -1;
  52         pixel = bytestream_get_byte(&in_buf);
  53         if (!(count = (pixel & 0x7f))) {
  54             return (out_buf - orig) / pixelstride;
  55         }
  56
  57         /* Check for buffer overflow. */
  58         if(out_buf + pixelstride * count >= out_end) return -1;
  59
  60         if (pixel & 0x80) {
  61             while (count--) {
  62                 *out_buf = bytestream_get_byte(&in_buf);
  63                 out_buf += pixelstride;
  64             }
  65         } else {
  66             pixel = bytestream_get_byte(&in_buf);
  67
  68             while (count--) {
  69                 *out_buf = pixel;
  70                 out_buf += pixelstride;
  71             }
  72         }
  73     }
  74 }
  75
  76 /**
  77  * Read a run length encoded SGI image.
  78  * @param out_buf output buffer
  79  * @param in_buf input buffer
  80  * @param in_end end of input buffer
  81  * @param s the current image state
  82  * @return 0 if no error, else return error number.
  83  */
  84 static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf,
  85                         const uint8_t *in_end, SgiState* s)
  86 {
  87     uint8_t *dest_row;
  88     unsigned int len = s->height * s->depth * 4;
  89     const uint8_t *start_table = in_buf;
  90     unsigned int y, z;
  91     unsigned int start_offset;
  92
  93     /* size of  RLE offset and length tables */
  94     if(len * 2  > in_end - in_buf) {
  95         return AVERROR_INVALIDDATA;
  96     }
  97
  98     in_buf -= SGI_HEADER_SIZE;
  99     for (z = 0; z < s->depth; z++) {
 100         dest_row = out_buf;
 101         for (y = 0; y < s->height; y++) {
 102             dest_row -= s->linesize;
 103             start_offset = bytestream_get_be32(&start_table);
 104             if(start_offset > in_end - in_buf) {
 105                 return AVERROR_INVALIDDATA;
 106             }
 107             if (expand_rle_row(in_buf + start_offset, in_end, dest_row + z,
 108                 dest_row + FFABS(s->linesize), s->depth) != s->width)
 109                 return AVERROR_INVALIDDATA;
 110         }
 111     }
 112     return 0;
 113 }
 114
 115 /**
 116  * Read an uncompressed SGI image.
 117  * @param out_buf output buffer
 118  * @param out_end end ofoutput buffer
 119  * @param in_buf input buffer
 120  * @param in_end end of input buffer
 121  * @param s the current image state
 122  * @return 0 if read success, otherwise return -1.
 123  */
 124 static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
 125                 const uint8_t *in_buf, const uint8_t *in_end, SgiState* s)
 126 {
 127     int x, y, z;
 128     const uint8_t *ptr;
 129     unsigned int offset = s->height * s->width * s->bytes_per_channel;
 130
 131     /* Test buffer size. */
 132     if (offset * s->depth > in_end - in_buf) {
 133        return -1;
 134     }
 135
 136     for (y = s->height - 1; y >= 0; y--) {
 137         out_end = out_buf + (y * s->linesize);
 138         for (x = s->width; x > 0; x--) {
 139             ptr = in_buf += s->bytes_per_channel;
 140             for(z = 0; z < s->depth; z ++) {
 141                 memcpy(out_end, ptr, s->bytes_per_channel);
 142                 out_end += s->bytes_per_channel;
 143                 ptr += offset;
 144             }
 145         }
 146     }
 147     return 0;
 148 }
 149
 150 static int decode_frame(AVCodecContext *avctx,
 151                         void *data, int *data_size,
 152                         AVPacket *avpkt)
 153 {
 154     const uint8_t *in_buf = avpkt->data;
 155     int buf_size = avpkt->size;
 156     SgiState *s = avctx->priv_data;
 157     AVFrame *picture = data;
 158     AVFrame *p = &s->picture;
 159     const uint8_t *in_end = in_buf + buf_size;
 160     unsigned int dimension, rle;
 161     int ret = 0;
 162     uint8_t *out_buf, *out_end;
 163
 164     if (buf_size < SGI_HEADER_SIZE){
 165         av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size);
 166         return -1;
 167     }
 168
 169     /* Test for SGI magic. */
 170     if (bytestream_get_be16(&in_buf) != SGI_MAGIC) {
 171         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
 172         return -1;
 173     }
 174
 175     rle = bytestream_get_byte(&in_buf);
 176     s->bytes_per_channel = bytestream_get_byte(&in_buf);
 177     dimension = bytestream_get_be16(&in_buf);
 178     s->width  = bytestream_get_be16(&in_buf);
 179     s->height = bytestream_get_be16(&in_buf);
 180     s->depth  = bytestream_get_be16(&in_buf);
 181
 182     if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
 183         av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
 184         return -1;
 185     }
 186
 187     /* Check for supported image dimensions. */
 188     if (dimension != 2 && dimension != 3) {
 189         av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
 190         return -1;
 191     }
 192
 193     if (s->depth == SGI_GRAYSCALE) {
 194         avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_GRAY16BE : PIX_FMT_GRAY8;
 195     } else if (s->depth == SGI_RGB) {
 196         avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGB48BE : PIX_FMT_RGB24;
 197     } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) {
 198         avctx->pix_fmt = PIX_FMT_RGBA;
 199     } else {
 200         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
 201         return -1;
 202     }
 203
 204     if (avcodec_check_dimensions(avctx, s->width, s->height))
 205         return -1;
 206     avcodec_set_dimensions(avctx, s->width, s->height);
 207
 208     if (p->data[0])
 209         avctx->release_buffer(avctx, p);
 210
 211     p->reference = 0;
 212     if (avctx->get_buffer(avctx, p) < 0) {
 213         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
 214         return -1;
 215     }
 216
 217     p->pict_type = FF_I_TYPE;
 218     p->key_frame = 1;
 219     out_buf = p->data[0];
 220
 221     out_end = out_buf + p->linesize[0] * s->height;
 222
 223     s->linesize = p->linesize[0];
 224
 225     /* Skip header. */
 226     in_buf += SGI_HEADER_SIZE - 12;
 227     if (rle) {
 228         ret = read_rle_sgi(out_end, in_buf, in_end, s);
 229     } else {
 230         ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s);
 231     }
 232
 233     if (ret == 0) {
 234         *picture   = s->picture;
 235         *data_size = sizeof(AVPicture);
 236         return buf_size;
 237     } else {
 238         return -1;
 239     }
 240 }
 241
 242 static av_cold int sgi_init(AVCodecContext *avctx){
 243     SgiState *s = avctx->priv_data;
 244
 245     avcodec_get_frame_defaults(&s->picture);
 246     avctx->coded_frame = &s->picture;
 247
 248     return 0;
 249 }
 250
 251 static av_cold int sgi_end(AVCodecContext *avctx)
 252 {
 253     SgiState * const s = avctx->priv_data;
 254
 255     if (s->picture.data[0])
 256         avctx->release_buffer(avctx, &s->picture);
 257
 258     return 0;
 259 }
 260
 261 AVCodec sgi_decoder = {
 262     "sgi",
 263     CODEC_TYPE_VIDEO,
 264     CODEC_ID_SGI,
 265     sizeof(SgiState),
 266     sgi_init,
 267     NULL,
 268     sgi_end,
 269     decode_frame,
 270     .long_name = NULL_IF_CONFIG_SMALL("SGI image"),
 271 };
 272