Libav
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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 "avcodec.h" 00023 #include "bytestream.h" 00024 #include "sgi.h" 00025 00026 typedef struct SgiState { 00027 AVFrame picture; 00028 unsigned int width; 00029 unsigned int height; 00030 unsigned int depth; 00031 unsigned int bytes_per_channel; 00032 int linesize; 00033 } SgiState; 00034 00044 static int expand_rle_row(const uint8_t *in_buf, const uint8_t* in_end, 00045 unsigned char *out_buf, uint8_t* out_end, int pixelstride) 00046 { 00047 unsigned char pixel, count; 00048 unsigned char *orig = out_buf; 00049 00050 while (1) { 00051 if(in_buf + 1 > in_end) return -1; 00052 pixel = bytestream_get_byte(&in_buf); 00053 if (!(count = (pixel & 0x7f))) { 00054 return (out_buf - orig) / pixelstride; 00055 } 00056 00057 /* Check for buffer overflow. */ 00058 if(out_buf + pixelstride * count >= out_end) return -1; 00059 00060 if (pixel & 0x80) { 00061 while (count--) { 00062 *out_buf = bytestream_get_byte(&in_buf); 00063 out_buf += pixelstride; 00064 } 00065 } else { 00066 pixel = bytestream_get_byte(&in_buf); 00067 00068 while (count--) { 00069 *out_buf = pixel; 00070 out_buf += pixelstride; 00071 } 00072 } 00073 } 00074 } 00075 00084 static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf, 00085 const uint8_t *in_end, SgiState* s) 00086 { 00087 uint8_t *dest_row; 00088 unsigned int len = s->height * s->depth * 4; 00089 const uint8_t *start_table = in_buf; 00090 unsigned int y, z; 00091 unsigned int start_offset; 00092 00093 /* size of RLE offset and length tables */ 00094 if(len * 2 > in_end - in_buf) { 00095 return AVERROR_INVALIDDATA; 00096 } 00097 00098 in_buf -= SGI_HEADER_SIZE; 00099 for (z = 0; z < s->depth; z++) { 00100 dest_row = out_buf; 00101 for (y = 0; y < s->height; y++) { 00102 dest_row -= s->linesize; 00103 start_offset = bytestream_get_be32(&start_table); 00104 if(start_offset > in_end - in_buf) { 00105 return AVERROR_INVALIDDATA; 00106 } 00107 if (expand_rle_row(in_buf + start_offset, in_end, dest_row + z, 00108 dest_row + FFABS(s->linesize), s->depth) != s->width) 00109 return AVERROR_INVALIDDATA; 00110 } 00111 } 00112 return 0; 00113 } 00114 00124 static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end, 00125 const uint8_t *in_buf, const uint8_t *in_end, SgiState* s) 00126 { 00127 int x, y, z; 00128 const uint8_t *ptr; 00129 unsigned int offset = s->height * s->width * s->bytes_per_channel; 00130 00131 /* Test buffer size. */ 00132 if (offset * s->depth > in_end - in_buf) { 00133 return -1; 00134 } 00135 00136 for (y = s->height - 1; y >= 0; y--) { 00137 out_end = out_buf + (y * s->linesize); 00138 for (x = s->width; x > 0; x--) { 00139 ptr = in_buf += s->bytes_per_channel; 00140 for(z = 0; z < s->depth; z ++) { 00141 memcpy(out_end, ptr, s->bytes_per_channel); 00142 out_end += s->bytes_per_channel; 00143 ptr += offset; 00144 } 00145 } 00146 } 00147 return 0; 00148 } 00149 00150 static int decode_frame(AVCodecContext *avctx, 00151 void *data, int *data_size, 00152 AVPacket *avpkt) 00153 { 00154 const uint8_t *in_buf = avpkt->data; 00155 int buf_size = avpkt->size; 00156 SgiState *s = avctx->priv_data; 00157 AVFrame *picture = data; 00158 AVFrame *p = &s->picture; 00159 const uint8_t *in_end = in_buf + buf_size; 00160 unsigned int dimension, rle; 00161 int ret = 0; 00162 uint8_t *out_buf, *out_end; 00163 00164 if (buf_size < SGI_HEADER_SIZE){ 00165 av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size); 00166 return -1; 00167 } 00168 00169 /* Test for SGI magic. */ 00170 if (bytestream_get_be16(&in_buf) != SGI_MAGIC) { 00171 av_log(avctx, AV_LOG_ERROR, "bad magic number\n"); 00172 return -1; 00173 } 00174 00175 rle = bytestream_get_byte(&in_buf); 00176 s->bytes_per_channel = bytestream_get_byte(&in_buf); 00177 dimension = bytestream_get_be16(&in_buf); 00178 s->width = bytestream_get_be16(&in_buf); 00179 s->height = bytestream_get_be16(&in_buf); 00180 s->depth = bytestream_get_be16(&in_buf); 00181 00182 if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) { 00183 av_log(avctx, AV_LOG_ERROR, "wrong channel number\n"); 00184 return -1; 00185 } 00186 00187 /* Check for supported image dimensions. */ 00188 if (dimension != 2 && dimension != 3) { 00189 av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n"); 00190 return -1; 00191 } 00192 00193 if (s->depth == SGI_GRAYSCALE) { 00194 avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_GRAY16BE : PIX_FMT_GRAY8; 00195 } else if (s->depth == SGI_RGB) { 00196 avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGB48BE : PIX_FMT_RGB24; 00197 } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) { 00198 avctx->pix_fmt = PIX_FMT_RGBA; 00199 } else { 00200 av_log(avctx, AV_LOG_ERROR, "wrong picture format\n"); 00201 return -1; 00202 } 00203 00204 if (avcodec_check_dimensions(avctx, s->width, s->height)) 00205 return -1; 00206 avcodec_set_dimensions(avctx, s->width, s->height); 00207 00208 if (p->data[0]) 00209 avctx->release_buffer(avctx, p); 00210 00211 p->reference = 0; 00212 if (avctx->get_buffer(avctx, p) < 0) { 00213 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n"); 00214 return -1; 00215 } 00216 00217 p->pict_type = FF_I_TYPE; 00218 p->key_frame = 1; 00219 out_buf = p->data[0]; 00220 00221 out_end = out_buf + p->linesize[0] * s->height; 00222 00223 s->linesize = p->linesize[0]; 00224 00225 /* Skip header. */ 00226 in_buf += SGI_HEADER_SIZE - 12; 00227 if (rle) { 00228 ret = read_rle_sgi(out_end, in_buf, in_end, s); 00229 } else { 00230 ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s); 00231 } 00232 00233 if (ret == 0) { 00234 *picture = s->picture; 00235 *data_size = sizeof(AVPicture); 00236 return buf_size; 00237 } else { 00238 return -1; 00239 } 00240 } 00241 00242 static av_cold int sgi_init(AVCodecContext *avctx){ 00243 SgiState *s = avctx->priv_data; 00244 00245 avcodec_get_frame_defaults(&s->picture); 00246 avctx->coded_frame = &s->picture; 00247 00248 return 0; 00249 } 00250 00251 static av_cold int sgi_end(AVCodecContext *avctx) 00252 { 00253 SgiState * const s = avctx->priv_data; 00254 00255 if (s->picture.data[0]) 00256 avctx->release_buffer(avctx, &s->picture); 00257 00258 return 0; 00259 } 00260 00261 AVCodec sgi_decoder = { 00262 "sgi", 00263 AVMEDIA_TYPE_VIDEO, 00264 CODEC_ID_SGI, 00265 sizeof(SgiState), 00266 sgi_init, 00267 NULL, 00268 sgi_end, 00269 decode_frame, 00270 .long_name = NULL_IF_CONFIG_SMALL("SGI image"), 00271 }; 00272