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     AVCodecContext *avctx;
  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 len length of out_buf in bytes
  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                           int len, 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 (pixelstride * (count - 1) >= len) {
  62             av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n");
  63             return AVERROR_INVALIDDATA;
  64         }
  65
  66         if (pixel & 0x80) {
  67             while (count--) {
  68                 *out_buf = bytestream2_get_byte(&s->g);
  69                 out_buf += pixelstride;
  70             }
  71         } else {
  72             pixel = bytestream2_get_byte(&s->g);
  73
  74             while (count--) {
  75                 *out_buf = pixel;
  76                 out_buf += pixelstride;
  77             }
  78         }
  79     }
  80 }
  81
  82 /**
  83  * Read a run length encoded SGI image.
  84  * @param out_buf output buffer
  85  * @param s the current image state
  86  * @return 0 if no error, else return error number.
  87  */
  88 static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
  89 {
  90     uint8_t *dest_row;
  91     unsigned int len = s->height * s->depth * 4;
  92     GetByteContext g_table = s->g;
  93     unsigned int y, z;
  94     unsigned int start_offset;
  95
  96     /* size of  RLE offset and length tables */
  97     if (len * 2  > bytestream2_get_bytes_left(&s->g)) {
  98         return AVERROR_INVALIDDATA;
  99     }
 100
 101     for (z = 0; z < s->depth; z++) {
 102         dest_row = out_buf;
 103         for (y = 0; y < s->height; y++) {
 104             dest_row -= s->linesize;
 105             start_offset = bytestream2_get_be32(&g_table);
 106             bytestream2_seek(&s->g, start_offset, SEEK_SET);
 107             if (expand_rle_row(s, dest_row + z, FFABS(s->linesize) - z,
 108                                s->depth) != s->width) {
 109                 return AVERROR_INVALIDDATA;
 110             }
 111         }
 112     }
 113     return 0;
 114 }
 115
 116 /**
 117  * Read an uncompressed SGI image.
 118  * @param out_buf output buffer
 119  * @param out_end end ofoutput 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                                  SgiState *s)
 125 {
 126     int x, y, z;
 127     unsigned int offset = s->height * s->width * s->bytes_per_channel;
 128     GetByteContext gp[4];
 129
 130     /* Test buffer size. */
 131     if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
 132         return AVERROR_INVALIDDATA;
 133
 134     /* Create a reader for each plane */
 135     for (z = 0; z < s->depth; z++) {
 136         gp[z] = s->g;
 137         bytestream2_skip(&gp[z], z * offset);
 138     }
 139
 140     for (y = s->height - 1; y >= 0; y--) {
 141         out_end = out_buf + (y * s->linesize);
 142         if (s->bytes_per_channel == 1) {
 143             for (x = s->width; x > 0; x--)
 144                 for (z = 0; z < s->depth; z++)
 145                     *out_end++ = bytestream2_get_byteu(&gp[z]);
 146         } else {
 147             uint16_t *out16 = (uint16_t *)out_end;
 148             for (x = s->width; x > 0; x--)
 149                 for (z = 0; z < s->depth; z++)
 150                     *out16++ = bytestream2_get_ne16u(&gp[z]);
 151         }
 152     }
 153     return 0;
 154 }
 155
 156 static int decode_frame(AVCodecContext *avctx,
 157                         void *data, int *got_frame,
 158                         AVPacket *avpkt)
 159 {
 160     SgiState *s = avctx->priv_data;
 161     AVFrame *p = data;
 162     unsigned int dimension, rle;
 163     int ret = 0;
 164     uint8_t *out_buf, *out_end;
 165
 166     bytestream2_init(&s->g, avpkt->data, avpkt->size);
 167     if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
 168         av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
 169         return AVERROR_INVALIDDATA;
 170     }
 171
 172     /* Test for SGI magic. */
 173     if (bytestream2_get_be16(&s->g) != SGI_MAGIC) {
 174         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
 175         return AVERROR_INVALIDDATA;
 176     }
 177
 178     rle                  = bytestream2_get_byte(&s->g);
 179     s->bytes_per_channel = bytestream2_get_byte(&s->g);
 180     dimension            = bytestream2_get_be16(&s->g);
 181     s->width             = bytestream2_get_be16(&s->g);
 182     s->height            = bytestream2_get_be16(&s->g);
 183     s->depth             = bytestream2_get_be16(&s->g);
 184
 185     if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
 186         av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
 187         return -1;
 188     }
 189
 190     /* Check for supported image dimensions. */
 191     if (dimension != 2 && dimension != 3) {
 192         av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
 193         return -1;
 194     }
 195
 196     if (s->depth == SGI_GRAYSCALE) {
 197         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
 198     } else if (s->depth == SGI_RGB) {
 199         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;
 200     } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) {
 201         avctx->pix_fmt = AV_PIX_FMT_RGBA;
 202     } else {
 203         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
 204         return -1;
 205     }
 206
 207     ret = ff_set_dimensions(avctx, s->width, s->height);
 208     if (ret < 0)
 209         return ret;
 210
 211     if (ff_get_buffer(avctx, p, 0) < 0) {
 212         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
 213         return -1;
 214     }
 215
 216     p->pict_type = AV_PICTURE_TYPE_I;
 217     p->key_frame = 1;
 218     out_buf = p->data[0];
 219
 220     out_end = out_buf + p->linesize[0] * s->height;
 221
 222     s->linesize = p->linesize[0];
 223
 224     /* Skip header. */
 225     bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
 226     if (rle) {
 227         ret = read_rle_sgi(out_end, s);
 228     } else {
 229         ret = read_uncompressed_sgi(out_buf, out_end, s);
 230     }
 231
 232     if (ret == 0) {
 233         *got_frame = 1;
 234         return avpkt->size;
 235     } else {
 236         return ret;
 237     }
 238 }
 239
 240 static av_cold int sgi_decode_init(AVCodecContext *avctx)
 241 {
 242     SgiState *s = avctx->priv_data;
 243
 244     s->avctx = avctx;
 245
 246     return 0;
 247 }
 248
 249 AVCodec ff_sgi_decoder = {
 250     .name           = "sgi",
 251     .long_name      = NULL_IF_CONFIG_SMALL("SGI image"),
 252     .type           = AVMEDIA_TYPE_VIDEO,
 253     .id             = AV_CODEC_ID_SGI,
 254     .priv_data_size = sizeof(SgiState),
 255     .decode         = decode_frame,
 256     .init           = sgi_decode_init,
 257     .capabilities   = CODEC_CAP_DR1,
 258 };