libavcodec/sgidec.c

   1 /*
   2  * SGI image decoder
   3  * Todd Kirby <doubleshot@pacbell.net>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/imgutils.h"
  23 #include "avcodec.h"
  24 #include "bytestream.h"
  25 #include "internal.h"
  26 #include "sgi.h"
  27
  28 typedef struct SgiState {
  29     AVFrame picture;
  30     unsigned int width;
  31     unsigned int height;
  32     unsigned int depth;
  33     unsigned int bytes_per_channel;
  34     int linesize;
  35     GetByteContext g;
  36 } SgiState;
  37
  38 /**
  39  * Expand an RLE row into a channel.
  40  * @param s the current image state
  41  * @param out_buf Points to one line after the output buffer.
  42  * @param out_end end of line in output buffer
  43  * @param pixelstride pixel stride of input buffer
  44  * @return size of output in bytes, -1 if buffer overflows
  45  */
  46 static int expand_rle_row(SgiState *s, uint8_t *out_buf,
  47                           uint8_t *out_end, int pixelstride)
  48 {
  49     unsigned char pixel, count;
  50     unsigned char *orig = out_buf;
  51
  52     while (1) {
  53         if (bytestream2_get_bytes_left(&s->g) < 1)
  54             return AVERROR_INVALIDDATA;
  55         pixel = bytestream2_get_byteu(&s->g);
  56         if (!(count = (pixel & 0x7f))) {
  57             return (out_buf - orig) / pixelstride;
  58         }
  59
  60         /* Check for buffer overflow. */
  61         if(out_buf + pixelstride * count >= out_end) return -1;
  62
  63         if (pixel & 0x80) {
  64             while (count--) {
  65                 *out_buf = bytestream2_get_byte(&s->g);
  66                 out_buf += pixelstride;
  67             }
  68         } else {
  69             pixel = bytestream2_get_byte(&s->g);
  70
  71             while (count--) {
  72                 *out_buf = pixel;
  73                 out_buf += pixelstride;
  74             }
  75         }
  76     }
  77 }
  78
  79 /**
  80  * Read a run length encoded SGI image.
  81  * @param out_buf output buffer
  82  * @param s the current image state
  83  * @return 0 if no error, else return error number.
  84  */
  85 static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
  86 {
  87     uint8_t *dest_row;
  88     unsigned int len = s->height * s->depth * 4;
  89     GetByteContext g_table = s->g;
  90     unsigned int y, z;
  91     unsigned int start_offset;
  92
  93     /* size of  RLE offset and length tables */
  94     if (len * 2  > bytestream2_get_bytes_left(&s->g)) {
  95         return AVERROR_INVALIDDATA;
  96     }
  97
  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 = bytestream2_get_be32(&g_table);
 103             bytestream2_seek(&s->g, start_offset, SEEK_SET);
 104             if (expand_rle_row(s, dest_row + z, dest_row + FFABS(s->linesize),
 105                                s->depth) != s->width) {
 106                 return AVERROR_INVALIDDATA;
 107             }
 108         }
 109     }
 110     return 0;
 111 }
 112
 113 /**
 114  * Read an uncompressed SGI image.
 115  * @param out_buf output buffer
 116  * @param out_end end ofoutput buffer
 117  * @param s the current image state
 118  * @return 0 if read success, otherwise return -1.
 119  */
 120 static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
 121                                  SgiState *s)
 122 {
 123     int x, y, z;
 124     unsigned int offset = s->height * s->width * s->bytes_per_channel;
 125     GetByteContext gp[4];
 126
 127     /* Test buffer size. */
 128     if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
 129         return AVERROR_INVALIDDATA;
 130
 131     /* Create a reader for each plane */
 132     for (z = 0; z < s->depth; z++) {
 133         gp[z] = s->g;
 134         bytestream2_skip(&gp[z], z * offset);
 135     }
 136
 137     for (y = s->height - 1; y >= 0; y--) {
 138         out_end = out_buf + (y * s->linesize);
 139         if (s->bytes_per_channel == 1) {
 140             for (x = s->width; x > 0; x--)
 141                 for (z = 0; z < s->depth; z++)
 142                     *out_end++ = bytestream2_get_byteu(&gp[z]);
 143         } else {
 144             uint16_t *out16 = (uint16_t *)out_end;
 145             for (x = s->width; x > 0; x--)
 146                 for (z = 0; z < s->depth; z++)
 147                     *out16++ = bytestream2_get_ne16u(&gp[z]);
 148         }
 149     }
 150     return 0;
 151 }
 152
 153 static int decode_frame(AVCodecContext *avctx,
 154                         void *data, int *got_frame,
 155                         AVPacket *avpkt)
 156 {
 157     SgiState *s = avctx->priv_data;
 158     AVFrame *picture = data;
 159     AVFrame *p = &s->picture;
 160     unsigned int dimension, rle;
 161     int ret = 0;
 162     uint8_t *out_buf, *out_end;
 163
 164     bytestream2_init(&s->g, avpkt->data, avpkt->size);
 165     if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
 166         av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
 167         return AVERROR_INVALIDDATA;
 168     }
 169
 170     /* Test for SGI magic. */
 171     if (bytestream2_get_be16(&s->g) != SGI_MAGIC) {
 172         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
 173         return AVERROR_INVALIDDATA;
 174     }
 175
 176     rle                  = bytestream2_get_byte(&s->g);
 177     s->bytes_per_channel = bytestream2_get_byte(&s->g);
 178     dimension            = bytestream2_get_be16(&s->g);
 179     s->width             = bytestream2_get_be16(&s->g);
 180     s->height            = bytestream2_get_be16(&s->g);
 181     s->depth             = bytestream2_get_be16(&s->g);
 182
 183     if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
 184         av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
 185         return -1;
 186     }
 187
 188     /* Check for supported image dimensions. */
 189     if (dimension != 2 && dimension != 3) {
 190         av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
 191         return -1;
 192     }
 193
 194     if (s->depth == SGI_GRAYSCALE) {
 195         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
 196     } else if (s->depth == SGI_RGB) {
 197         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;
 198     } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) {
 199         avctx->pix_fmt = AV_PIX_FMT_RGBA;
 200     } else {
 201         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
 202         return -1;
 203     }
 204
 205     if (av_image_check_size(s->width, s->height, 0, avctx))
 206         return -1;
 207     avcodec_set_dimensions(avctx, s->width, s->height);
 208
 209     if (p->data[0])
 210         avctx->release_buffer(avctx, p);
 211
 212     p->reference = 0;
 213     if (ff_get_buffer(avctx, p) < 0) {
 214         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
 215         return -1;
 216     }
 217
 218     p->pict_type = AV_PICTURE_TYPE_I;
 219     p->key_frame = 1;
 220     out_buf = p->data[0];
 221
 222     out_end = out_buf + p->linesize[0] * s->height;
 223
 224     s->linesize = p->linesize[0];
 225
 226     /* Skip header. */
 227     bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
 228     if (rle) {
 229         ret = read_rle_sgi(out_end, s);
 230     } else {
 231         ret = read_uncompressed_sgi(out_buf, out_end, s);
 232     }
 233
 234     if (ret == 0) {
 235         *picture   = s->picture;
 236         *got_frame = 1;
 237         return avpkt->size;
 238     } else {
 239         return ret;
 240     }
 241 }
 242
 243 static av_cold int sgi_init(AVCodecContext *avctx){
 244     SgiState *s = avctx->priv_data;
 245
 246     avcodec_get_frame_defaults(&s->picture);
 247     avctx->coded_frame = &s->picture;
 248
 249     return 0;
 250 }
 251
 252 static av_cold int sgi_end(AVCodecContext *avctx)
 253 {
 254     SgiState * const s = avctx->priv_data;
 255
 256     if (s->picture.data[0])
 257         avctx->release_buffer(avctx, &s->picture);
 258
 259     return 0;
 260 }
 261
 262 AVCodec ff_sgi_decoder = {
 263     .name           = "sgi",
 264     .type           = AVMEDIA_TYPE_VIDEO,
 265     .id             = AV_CODEC_ID_SGI,
 266     .priv_data_size = sizeof(SgiState),
 267     .init           = sgi_init,
 268     .close          = sgi_end,
 269     .decode         = decode_frame,
 270     .long_name      = NULL_IF_CONFIG_SMALL("SGI image"),
 271     .capabilities   = CODEC_CAP_DR1,
 272 };