libavcodec/sgidec.c
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00001 /*
00002  * SGI image decoder
00003  * Todd Kirby <doubleshot@pacbell.net>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "libavutil/imgutils.h"
00023 #include "libavutil/avassert.h"
00024 #include "avcodec.h"
00025 #include "bytestream.h"
00026 #include "sgi.h"
00027 
00028 typedef struct SgiState {
00029     AVFrame picture;
00030     unsigned int width;
00031     unsigned int height;
00032     unsigned int depth;
00033     unsigned int bytes_per_channel;
00034     int linesize;
00035     GetByteContext g;
00036 } SgiState;
00037 
00046 static int expand_rle_row(SgiState *s, uint8_t *out_buf,
00047                           uint8_t *out_end, int pixelstride)
00048 {
00049     unsigned char pixel, count;
00050     unsigned char *orig = out_buf;
00051 
00052     while (1) {
00053         if (bytestream2_get_bytes_left(&s->g) < 1)
00054             return AVERROR_INVALIDDATA;
00055         pixel = bytestream2_get_byteu(&s->g);
00056         if (!(count = (pixel & 0x7f))) {
00057             return (out_buf - orig) / pixelstride;
00058         }
00059 
00060         /* Check for buffer overflow. */
00061         if(out_buf + pixelstride * count >= out_end) return -1;
00062 
00063         if (pixel & 0x80) {
00064             while (count--) {
00065                 *out_buf = bytestream2_get_byte(&s->g);
00066                 out_buf += pixelstride;
00067             }
00068         } else {
00069             pixel = bytestream2_get_byte(&s->g);
00070 
00071             while (count--) {
00072                 *out_buf = pixel;
00073                 out_buf += pixelstride;
00074             }
00075         }
00076     }
00077 }
00078 
00085 static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
00086 {
00087     uint8_t *dest_row;
00088     unsigned int len = s->height * s->depth * 4;
00089     GetByteContext g_table = s->g;
00090     unsigned int y, z;
00091     unsigned int start_offset;
00092 
00093     /* size of  RLE offset and length tables */
00094     if (len * 2  > bytestream2_get_bytes_left(&s->g)) {
00095         return AVERROR_INVALIDDATA;
00096     }
00097 
00098     for (z = 0; z < s->depth; z++) {
00099         dest_row = out_buf;
00100         for (y = 0; y < s->height; y++) {
00101             dest_row -= s->linesize;
00102             start_offset = bytestream2_get_be32(&g_table);
00103             bytestream2_seek(&s->g, start_offset, SEEK_SET);
00104             if (expand_rle_row(s, dest_row + z, dest_row + FFABS(s->linesize),
00105                                s->depth) != s->width) {
00106                 return AVERROR_INVALIDDATA;
00107             }
00108         }
00109     }
00110     return 0;
00111 }
00112 
00120 static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
00121                                  SgiState *s)
00122 {
00123     int x, y, z;
00124     unsigned int offset = s->height * s->width * s->bytes_per_channel;
00125     GetByteContext gp[4];
00126 
00127     /* Test buffer size. */
00128     if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
00129         return AVERROR_INVALIDDATA;
00130 
00131     /* Create a reader for each plane */
00132     for (z = 0; z < s->depth; z++) {
00133         gp[z] = s->g;
00134         bytestream2_skip(&gp[z], z * offset);
00135     }
00136 
00137     for (y = s->height - 1; y >= 0; y--) {
00138         out_end = out_buf + (y * s->linesize);
00139         if (s->bytes_per_channel == 1) {
00140             for (x = s->width; x > 0; x--)
00141                 for (z = 0; z < s->depth; z++)
00142                     *out_end++ = bytestream2_get_byteu(&gp[z]);
00143         } else {
00144             uint16_t *out16 = (uint16_t *)out_end;
00145             for (x = s->width; x > 0; x--)
00146                 for (z = 0; z < s->depth; z++)
00147                     *out16++ = bytestream2_get_ne16u(&gp[z]);
00148         }
00149     }
00150     return 0;
00151 }
00152 
00153 static int decode_frame(AVCodecContext *avctx,
00154                         void *data, int *data_size,
00155                         AVPacket *avpkt)
00156 {
00157     SgiState *s = avctx->priv_data;
00158     AVFrame *picture = data;
00159     AVFrame *p = &s->picture;
00160     unsigned int dimension, rle;
00161     int ret = 0;
00162     uint8_t *out_buf, *out_end;
00163 
00164     bytestream2_init(&s->g, avpkt->data, avpkt->size);
00165     if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
00166         av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
00167         return AVERROR_INVALIDDATA;
00168     }
00169 
00170     /* Test for SGI magic. */
00171     if (bytestream2_get_be16(&s->g) != SGI_MAGIC) {
00172         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
00173         return AVERROR_INVALIDDATA;
00174     }
00175 
00176     rle                  = bytestream2_get_byte(&s->g);
00177     s->bytes_per_channel = bytestream2_get_byte(&s->g);
00178     dimension            = bytestream2_get_be16(&s->g);
00179     s->width             = bytestream2_get_be16(&s->g);
00180     s->height            = bytestream2_get_be16(&s->g);
00181     s->depth             = bytestream2_get_be16(&s->g);
00182 
00183     if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
00184         av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
00185         return -1;
00186     }
00187 
00188     /* Check for supported image dimensions. */
00189     if (dimension != 2 && dimension != 3) {
00190         av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
00191         return -1;
00192     }
00193 
00194     if (s->depth == SGI_GRAYSCALE) {
00195         avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_GRAY16BE : PIX_FMT_GRAY8;
00196     } else if (s->depth == SGI_RGB) {
00197         avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGB48BE : PIX_FMT_RGB24;
00198     } else if (s->depth == SGI_RGBA) {
00199         avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGBA64BE : PIX_FMT_RGBA;
00200     } else {
00201         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
00202         return -1;
00203     }
00204 
00205     if (av_image_check_size(s->width, s->height, 0, avctx))
00206         return -1;
00207     avcodec_set_dimensions(avctx, s->width, s->height);
00208 
00209     if (p->data[0])
00210         avctx->release_buffer(avctx, p);
00211 
00212     p->reference = 0;
00213     if (avctx->get_buffer(avctx, p) < 0) {
00214         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
00215         return -1;
00216     }
00217 
00218     p->pict_type = AV_PICTURE_TYPE_I;
00219     p->key_frame = 1;
00220     out_buf = p->data[0];
00221 
00222     out_end = out_buf + p->linesize[0] * s->height;
00223 
00224     s->linesize = p->linesize[0];
00225 
00226     /* Skip header. */
00227     bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
00228     if (rle) {
00229         ret = read_rle_sgi(out_end, s);
00230     } else {
00231         ret = read_uncompressed_sgi(out_buf, out_end, s);
00232     }
00233 
00234     if (ret == 0) {
00235         *picture   = s->picture;
00236         *data_size = sizeof(AVPicture);
00237         return avpkt->size;
00238     } else {
00239         return ret;
00240     }
00241 }
00242 
00243 static av_cold int sgi_init(AVCodecContext *avctx){
00244     SgiState *s = avctx->priv_data;
00245 
00246     avcodec_get_frame_defaults(&s->picture);
00247     avctx->coded_frame = &s->picture;
00248 
00249     return 0;
00250 }
00251 
00252 static av_cold int sgi_end(AVCodecContext *avctx)
00253 {
00254     SgiState * const s = avctx->priv_data;
00255 
00256     if (s->picture.data[0])
00257         avctx->release_buffer(avctx, &s->picture);
00258 
00259     return 0;
00260 }
00261 
00262 AVCodec ff_sgi_decoder = {
00263     .name           = "sgi",
00264     .type           = AVMEDIA_TYPE_VIDEO,
00265     .id             = CODEC_ID_SGI,
00266     .priv_data_size = sizeof(SgiState),
00267     .init           = sgi_init,
00268     .close          = sgi_end,
00269     .decode         = decode_frame,
00270     .long_name = NULL_IF_CONFIG_SMALL("SGI image"),
00271 };
00272