1/* 2 * SGI image decoder 3 * Todd Kirby <doubleshot@pacbell.net> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg 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 * FFmpeg 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 FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "avcodec.h" 23#include "bytestream.h" 24#include "sgi.h" 25 26typedef struct SgiState { 27 AVFrame picture; 28 unsigned int width; 29 unsigned int height; 30 unsigned int depth; 31 unsigned int bytes_per_channel; 32 int linesize; 33} SgiState; 34 35/** 36 * Expand an RLE row into a channel. 37 * @param in_buf input buffer 38 * @param in_end end of input buffer 39 * @param out_buf Points to one line after the output buffer. 40 * @param out_end end of line in output buffer 41 * @param pixelstride pixel stride of input buffer 42 * @return size of output in bytes, -1 if buffer overflows 43 */ 44static int expand_rle_row(const uint8_t *in_buf, const uint8_t* in_end, 45 unsigned char *out_buf, uint8_t* out_end, int pixelstride) 46{ 47 unsigned char pixel, count; 48 unsigned char *orig = out_buf; 49 50 while (1) { 51 if(in_buf + 1 > in_end) return -1; 52 pixel = bytestream_get_byte(&in_buf); 53 if (!(count = (pixel & 0x7f))) { 54 return (out_buf - orig) / pixelstride; 55 } 56 57 /* Check for buffer overflow. */ 58 if(out_buf + pixelstride * count >= out_end) return -1; 59 60 if (pixel & 0x80) { 61 while (count--) { 62 *out_buf = bytestream_get_byte(&in_buf); 63 out_buf += pixelstride; 64 } 65 } else { 66 pixel = bytestream_get_byte(&in_buf); 67 68 while (count--) { 69 *out_buf = pixel; 70 out_buf += pixelstride; 71 } 72 } 73 } 74} 75 76/** 77 * Read a run length encoded SGI image. 78 * @param out_buf output buffer 79 * @param in_buf input buffer 80 * @param in_end end of input buffer 81 * @param s the current image state 82 * @return 0 if no error, else return error number. 83 */ 84static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf, 85 const uint8_t *in_end, SgiState* s) 86{ 87 uint8_t *dest_row; 88 unsigned int len = s->height * s->depth * 4; 89 const uint8_t *start_table = in_buf; 90 unsigned int y, z; 91 unsigned int start_offset; 92 93 /* size of RLE offset and length tables */ 94 if(len * 2 > in_end - in_buf) { 95 return AVERROR_INVALIDDATA; 96 } 97 98 in_buf -= SGI_HEADER_SIZE; 99 for (z = 0; z < s->depth; z++) { 100 dest_row = out_buf; 101 for (y = 0; y < s->height; y++) { 102 dest_row -= s->linesize; 103 start_offset = bytestream_get_be32(&start_table); 104 if(start_offset > in_end - in_buf) { 105 return AVERROR_INVALIDDATA; 106 } 107 if (expand_rle_row(in_buf + start_offset, in_end, dest_row + z, 108 dest_row + FFABS(s->linesize), s->depth) != s->width) 109 return AVERROR_INVALIDDATA; 110 } 111 } 112 return 0; 113} 114 115/** 116 * Read an uncompressed SGI image. 117 * @param out_buf output buffer 118 * @param out_end end ofoutput buffer 119 * @param in_buf input buffer 120 * @param in_end end of input buffer 121 * @param s the current image state 122 * @return 0 if read success, otherwise return -1. 123 */ 124static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end, 125 const uint8_t *in_buf, const uint8_t *in_end, SgiState* s) 126{ 127 int x, y, z; 128 const uint8_t *ptr; 129 unsigned int offset = s->height * s->width * s->bytes_per_channel; 130 131 /* Test buffer size. */ 132 if (offset * s->depth > in_end - in_buf) { 133 return -1; 134 } 135 136 for (y = s->height - 1; y >= 0; y--) { 137 out_end = out_buf + (y * s->linesize); 138 for (x = s->width; x > 0; x--) { 139 ptr = in_buf += s->bytes_per_channel; 140 for(z = 0; z < s->depth; z ++) { 141 memcpy(out_end, ptr, s->bytes_per_channel); 142 out_end += s->bytes_per_channel; 143 ptr += offset; 144 } 145 } 146 } 147 return 0; 148} 149 150static int decode_frame(AVCodecContext *avctx, 151 void *data, int *data_size, 152 AVPacket *avpkt) 153{ 154 const uint8_t *in_buf = avpkt->data; 155 int buf_size = avpkt->size; 156 SgiState *s = avctx->priv_data; 157 AVFrame *picture = data; 158 AVFrame *p = &s->picture; 159 const uint8_t *in_end = in_buf + buf_size; 160 unsigned int dimension, rle; 161 int ret = 0; 162 uint8_t *out_buf, *out_end; 163 164 if (buf_size < SGI_HEADER_SIZE){ 165 av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size); 166 return -1; 167 } 168 169 /* Test for SGI magic. */ 170 if (bytestream_get_be16(&in_buf) != SGI_MAGIC) { 171 av_log(avctx, AV_LOG_ERROR, "bad magic number\n"); 172 return -1; 173 } 174 175 rle = bytestream_get_byte(&in_buf); 176 s->bytes_per_channel = bytestream_get_byte(&in_buf); 177 dimension = bytestream_get_be16(&in_buf); 178 s->width = bytestream_get_be16(&in_buf); 179 s->height = bytestream_get_be16(&in_buf); 180 s->depth = bytestream_get_be16(&in_buf); 181 182 if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) { 183 av_log(avctx, AV_LOG_ERROR, "wrong channel number\n"); 184 return -1; 185 } 186 187 /* Check for supported image dimensions. */ 188 if (dimension != 2 && dimension != 3) { 189 av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n"); 190 return -1; 191 } 192 193 if (s->depth == SGI_GRAYSCALE) { 194 avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_GRAY16BE : PIX_FMT_GRAY8; 195 } else if (s->depth == SGI_RGB) { 196 avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGB48BE : PIX_FMT_RGB24; 197 } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) { 198 avctx->pix_fmt = PIX_FMT_RGBA; 199 } else { 200 av_log(avctx, AV_LOG_ERROR, "wrong picture format\n"); 201 return -1; 202 } 203 204 if (avcodec_check_dimensions(avctx, s->width, s->height)) 205 return -1; 206 avcodec_set_dimensions(avctx, s->width, s->height); 207 208 if (p->data[0]) 209 avctx->release_buffer(avctx, p); 210 211 p->reference = 0; 212 if (avctx->get_buffer(avctx, p) < 0) { 213 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n"); 214 return -1; 215 } 216 217 p->pict_type = FF_I_TYPE; 218 p->key_frame = 1; 219 out_buf = p->data[0]; 220 221 out_end = out_buf + p->linesize[0] * s->height; 222 223 s->linesize = p->linesize[0]; 224 225 /* Skip header. */ 226 in_buf += SGI_HEADER_SIZE - 12; 227 if (rle) { 228 ret = read_rle_sgi(out_end, in_buf, in_end, s); 229 } else { 230 ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s); 231 } 232 233 if (ret == 0) { 234 *picture = s->picture; 235 *data_size = sizeof(AVPicture); 236 return buf_size; 237 } else { 238 return -1; 239 } 240} 241 242static av_cold int sgi_init(AVCodecContext *avctx){ 243 SgiState *s = avctx->priv_data; 244 245 avcodec_get_frame_defaults(&s->picture); 246 avctx->coded_frame = &s->picture; 247 248 return 0; 249} 250 251static av_cold int sgi_end(AVCodecContext *avctx) 252{ 253 SgiState * const s = avctx->priv_data; 254 255 if (s->picture.data[0]) 256 avctx->release_buffer(avctx, &s->picture); 257 258 return 0; 259} 260 261AVCodec sgi_decoder = { 262 "sgi", 263 AVMEDIA_TYPE_VIDEO, 264 CODEC_ID_SGI, 265 sizeof(SgiState), 266 sgi_init, 267 NULL, 268 sgi_end, 269 decode_frame, 270 .long_name = NULL_IF_CONFIG_SMALL("SGI image"), 271}; 272 273