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     unsigned int width;
  30     unsigned int height;
  31     unsigned int depth;
  32     unsigned int bytes_per_channel;
  33     int linesize;
  34     GetByteContext g;
  35 } SgiState;
  36
  37 /**
  38  * Expand an RLE row into a channel.
  39  * @param s the current image state
  40  * @param out_buf Points to one line after the output buffer.
  41  * @param out_end end of line in output buffer
  42  * @param pixelstride pixel stride of input buffer
  43  * @return size of output in bytes, -1 if buffer overflows
  44  */
  45 static int expand_rle_row(SgiState *s, uint8_t *out_buf,
  46                           uint8_t *out_end, int pixelstride)
  47 {
  48     unsigned char pixel, count;
  49     unsigned char *orig = out_buf;
  50
  51     while (1) {
  52         if (bytestream2_get_bytes_left(&s->g) < 1)
  53             return AVERROR_INVALIDDATA;
  54         pixel = bytestream2_get_byteu(&s->g);
  55         if (!(count = (pixel & 0x7f))) {
  56             return (out_buf - orig) / pixelstride;
  57         }
  58
  59         /* Check for buffer overflow. */
  60         if(out_buf + pixelstride * count >= out_end) return -1;
  61
  62         if (pixel & 0x80) {
  63             while (count--) {
  64                 *out_buf = bytestream2_get_byte(&s->g);
  65                 out_buf += pixelstride;
  66             }
  67         } else {
  68             pixel = bytestream2_get_byte(&s->g);
  69
  70             while (count--) {
  71                 *out_buf = pixel;
  72                 out_buf += pixelstride;
  73             }
  74         }
  75     }
  76 }
  77
  78 /**
  79  * Read a run length encoded SGI image.
  80  * @param out_buf output 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(uint8_t *out_buf, SgiState *s)
  85 {
  86     uint8_t *dest_row;
  87     unsigned int len = s->height * s->depth * 4;
  88     GetByteContext g_table = s->g;
  89     unsigned int y, z;
  90     unsigned int start_offset;
  91
  92     /* size of  RLE offset and length tables */
  93     if (len * 2  > bytestream2_get_bytes_left(&s->g)) {
  94         return AVERROR_INVALIDDATA;
  95     }
  96
  97     for (z = 0; z < s->depth; z++) {
  98         dest_row = out_buf;
  99         for (y = 0; y < s->height; y++) {
 100             dest_row -= s->linesize;
 101             start_offset = bytestream2_get_be32(&g_table);
 102             bytestream2_seek(&s->g, start_offset, SEEK_SET);
 103             if (expand_rle_row(s, dest_row + z, dest_row + FFABS(s->linesize),
 104                                s->depth) != s->width) {
 105                 return AVERROR_INVALIDDATA;
 106             }
 107         }
 108     }
 109     return 0;
 110 }
 111
 112 /**
 113  * Read an uncompressed SGI image.
 114  * @param out_buf output buffer
 115  * @param out_end end ofoutput buffer
 116  * @param s the current image state
 117  * @return 0 if read success, otherwise return -1.
 118  */
 119 static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
 120                                  SgiState *s)
 121 {
 122     int x, y, z;
 123     unsigned int offset = s->height * s->width * s->bytes_per_channel;
 124     GetByteContext gp[4];
 125
 126     /* Test buffer size. */
 127     if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
 128         return AVERROR_INVALIDDATA;
 129
 130     /* Create a reader for each plane */
 131     for (z = 0; z < s->depth; z++) {
 132         gp[z] = s->g;
 133         bytestream2_skip(&gp[z], z * offset);
 134     }
 135
 136     for (y = s->height - 1; y >= 0; y--) {
 137         out_end = out_buf + (y * s->linesize);
 138         if (s->bytes_per_channel == 1) {
 139             for (x = s->width; x > 0; x--)
 140                 for (z = 0; z < s->depth; z++)
 141                     *out_end++ = bytestream2_get_byteu(&gp[z]);
 142         } else {
 143             uint16_t *out16 = (uint16_t *)out_end;
 144             for (x = s->width; x > 0; x--)
 145                 for (z = 0; z < s->depth; z++)
 146                     *out16++ = bytestream2_get_ne16u(&gp[z]);
 147         }
 148     }
 149     return 0;
 150 }
 151
 152 static int decode_frame(AVCodecContext *avctx,
 153                         void *data, int *got_frame,
 154                         AVPacket *avpkt)
 155 {
 156     SgiState *s = avctx->priv_data;
 157     AVFrame *p = data;
 158     unsigned int dimension, rle;
 159     int ret = 0;
 160     uint8_t *out_buf, *out_end;
 161
 162     bytestream2_init(&s->g, avpkt->data, avpkt->size);
 163     if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
 164         av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
 165         return AVERROR_INVALIDDATA;
 166     }
 167
 168     /* Test for SGI magic. */
 169     if (bytestream2_get_be16(&s->g) != SGI_MAGIC) {
 170         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
 171         return AVERROR_INVALIDDATA;
 172     }
 173
 174     rle                  = bytestream2_get_byte(&s->g);
 175     s->bytes_per_channel = bytestream2_get_byte(&s->g);
 176     dimension            = bytestream2_get_be16(&s->g);
 177     s->width             = bytestream2_get_be16(&s->g);
 178     s->height            = bytestream2_get_be16(&s->g);
 179     s->depth             = bytestream2_get_be16(&s->g);
 180
 181     if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
 182         av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
 183         return -1;
 184     }
 185
 186     /* Check for supported image dimensions. */
 187     if (dimension != 2 && dimension != 3) {
 188         av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
 189         return -1;
 190     }
 191
 192     if (s->depth == SGI_GRAYSCALE) {
 193         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
 194     } else if (s->depth == SGI_RGB) {
 195         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;
 196     } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) {
 197         avctx->pix_fmt = AV_PIX_FMT_RGBA;
 198     } else {
 199         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
 200         return -1;
 201     }
 202
 203     if (av_image_check_size(s->width, s->height, 0, avctx))
 204         return -1;
 205     avcodec_set_dimensions(avctx, s->width, s->height);
 206
 207     if (ff_get_buffer(avctx, p, 0) < 0) {
 208         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
 209         return -1;
 210     }
 211
 212     p->pict_type = AV_PICTURE_TYPE_I;
 213     p->key_frame = 1;
 214     out_buf = p->data[0];
 215
 216     out_end = out_buf + p->linesize[0] * s->height;
 217
 218     s->linesize = p->linesize[0];
 219
 220     /* Skip header. */
 221     bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
 222     if (rle) {
 223         ret = read_rle_sgi(out_end, s);
 224     } else {
 225         ret = read_uncompressed_sgi(out_buf, out_end, s);
 226     }
 227
 228     if (ret == 0) {
 229         *got_frame = 1;
 230         return avpkt->size;
 231     } else {
 232         return ret;
 233     }
 234 }
 235
 236 AVCodec ff_sgi_decoder = {
 237     .name           = "sgi",
 238     .type           = AVMEDIA_TYPE_VIDEO,
 239     .id             = AV_CODEC_ID_SGI,
 240     .priv_data_size = sizeof(SgiState),
 241     .decode         = decode_frame,
 242     .long_name      = NULL_IF_CONFIG_SMALL("SGI image"),
 243     .capabilities   = CODEC_CAP_DR1,
 244 };