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 "libavutil/imgutils.h" 23#include "libavutil/avassert.h" 24#include "avcodec.h" 25#include "bytestream.h" 26#include "internal.h" 27#include "sgi.h" 28 29typedef struct SgiState { 30 AVCodecContext *avctx; 31 unsigned int width; 32 unsigned int height; 33 unsigned int depth; 34 unsigned int bytes_per_channel; 35 int linesize; 36 GetByteContext g; 37} SgiState; 38 39/** 40 * Expand an RLE row into a channel. 41 * @param s the current image state 42 * @param out_buf Points to one line after the output buffer. 43 * @param len length of out_buf in bytes 44 * @param pixelstride pixel stride of input buffer 45 * @return size of output in bytes, else return error code. 46 */ 47static int expand_rle_row8(SgiState *s, uint8_t *out_buf, 48 int len, int pixelstride) 49{ 50 unsigned char pixel, count; 51 unsigned char *orig = out_buf; 52 uint8_t *out_end = out_buf + len; 53 54 while (out_buf < out_end) { 55 if (bytestream2_get_bytes_left(&s->g) < 1) 56 return AVERROR_INVALIDDATA; 57 pixel = bytestream2_get_byteu(&s->g); 58 if (!(count = (pixel & 0x7f))) { 59 break; 60 } 61 62 /* Check for buffer overflow. */ 63 if (out_end - out_buf <= pixelstride * (count - 1)) { 64 av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n"); 65 return AVERROR_INVALIDDATA; 66 } 67 68 if (pixel & 0x80) { 69 while (count--) { 70 *out_buf = bytestream2_get_byte(&s->g); 71 out_buf += pixelstride; 72 } 73 } else { 74 pixel = bytestream2_get_byte(&s->g); 75 76 while (count--) { 77 *out_buf = pixel; 78 out_buf += pixelstride; 79 } 80 } 81 } 82 return (out_buf - orig) / pixelstride; 83} 84 85static int expand_rle_row16(SgiState *s, uint16_t *out_buf, 86 int len, int pixelstride) 87{ 88 unsigned short pixel; 89 unsigned char count; 90 unsigned short *orig = out_buf; 91 uint16_t *out_end = out_buf + len; 92 93 while (out_buf < out_end) { 94 if (bytestream2_get_bytes_left(&s->g) < 2) 95 return AVERROR_INVALIDDATA; 96 pixel = bytestream2_get_be16u(&s->g); 97 if (!(count = (pixel & 0x7f))) 98 break; 99 100 /* Check for buffer overflow. */ 101 if (pixelstride * (count - 1) >= len) { 102 av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n"); 103 return AVERROR_INVALIDDATA; 104 } 105 106 if (pixel & 0x80) { 107 while (count--) { 108 pixel = bytestream2_get_ne16(&s->g); 109 AV_WN16A(out_buf, pixel); 110 out_buf += pixelstride; 111 } 112 } else { 113 pixel = bytestream2_get_ne16(&s->g); 114 115 while (count--) { 116 AV_WN16A(out_buf, pixel); 117 out_buf += pixelstride; 118 } 119 } 120 } 121 return (out_buf - orig) / pixelstride; 122} 123 124 125/** 126 * Read a run length encoded SGI image. 127 * @param out_buf output buffer 128 * @param s the current image state 129 * @return 0 if no error, else return error code. 130 */ 131static int read_rle_sgi(uint8_t *out_buf, SgiState *s) 132{ 133 uint8_t *dest_row; 134 unsigned int len = s->height * s->depth * 4; 135 GetByteContext g_table = s->g; 136 unsigned int y, z; 137 unsigned int start_offset; 138 int linesize, ret; 139 140 /* size of RLE offset and length tables */ 141 if (len * 2 > bytestream2_get_bytes_left(&s->g)) { 142 return AVERROR_INVALIDDATA; 143 } 144 145 for (z = 0; z < s->depth; z++) { 146 dest_row = out_buf; 147 for (y = 0; y < s->height; y++) { 148 linesize = s->width * s->depth * s->bytes_per_channel; 149 dest_row -= s->linesize; 150 start_offset = bytestream2_get_be32(&g_table); 151 bytestream2_seek(&s->g, start_offset, SEEK_SET); 152 if (s->bytes_per_channel == 1) 153 ret = expand_rle_row8(s, dest_row + z, linesize, s->depth); 154 else 155 ret = expand_rle_row16(s, (uint16_t *)dest_row + z, linesize, s->depth); 156 if (ret != s->width) 157 return AVERROR_INVALIDDATA; 158 } 159 } 160 return 0; 161} 162 163/** 164 * Read an uncompressed SGI image. 165 * @param out_buf output buffer 166 * @param s the current image state 167 * @return 0 if read success, else return error code. 168 */ 169static int read_uncompressed_sgi(unsigned char *out_buf, SgiState *s) 170{ 171 int x, y, z; 172 unsigned int offset = s->height * s->width * s->bytes_per_channel; 173 GetByteContext gp[4]; 174 uint8_t *out_end; 175 176 /* Test buffer size. */ 177 if (offset * s->depth > bytestream2_get_bytes_left(&s->g)) 178 return AVERROR_INVALIDDATA; 179 180 /* Create a reader for each plane */ 181 for (z = 0; z < s->depth; z++) { 182 gp[z] = s->g; 183 bytestream2_skip(&gp[z], z * offset); 184 } 185 186 for (y = s->height - 1; y >= 0; y--) { 187 out_end = out_buf + (y * s->linesize); 188 if (s->bytes_per_channel == 1) { 189 for (x = s->width; x > 0; x--) 190 for (z = 0; z < s->depth; z++) 191 *out_end++ = bytestream2_get_byteu(&gp[z]); 192 } else { 193 uint16_t *out16 = (uint16_t *)out_end; 194 for (x = s->width; x > 0; x--) 195 for (z = 0; z < s->depth; z++) 196 *out16++ = bytestream2_get_ne16u(&gp[z]); 197 } 198 } 199 return 0; 200} 201 202static int decode_frame(AVCodecContext *avctx, 203 void *data, int *got_frame, 204 AVPacket *avpkt) 205{ 206 SgiState *s = avctx->priv_data; 207 AVFrame *p = data; 208 unsigned int dimension, rle; 209 int ret = 0; 210 uint8_t *out_buf, *out_end; 211 212 bytestream2_init(&s->g, avpkt->data, avpkt->size); 213 if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) { 214 av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size); 215 return AVERROR_INVALIDDATA; 216 } 217 218 /* Test for SGI magic. */ 219 if (bytestream2_get_be16u(&s->g) != SGI_MAGIC) { 220 av_log(avctx, AV_LOG_ERROR, "bad magic number\n"); 221 return AVERROR_INVALIDDATA; 222 } 223 224 rle = bytestream2_get_byteu(&s->g); 225 s->bytes_per_channel = bytestream2_get_byteu(&s->g); 226 dimension = bytestream2_get_be16u(&s->g); 227 s->width = bytestream2_get_be16u(&s->g); 228 s->height = bytestream2_get_be16u(&s->g); 229 s->depth = bytestream2_get_be16u(&s->g); 230 231 if (s->bytes_per_channel != 1 && s->bytes_per_channel != 2) { 232 av_log(avctx, AV_LOG_ERROR, "wrong channel number\n"); 233 return AVERROR_INVALIDDATA; 234 } 235 236 /* Check for supported image dimensions. */ 237 if (dimension != 2 && dimension != 3) { 238 av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n"); 239 return AVERROR_INVALIDDATA; 240 } 241 242 if (s->depth == SGI_GRAYSCALE) { 243 avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8; 244 } else if (s->depth == SGI_RGB) { 245 avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24; 246 } else if (s->depth == SGI_RGBA) { 247 avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGBA64BE : AV_PIX_FMT_RGBA; 248 } else { 249 av_log(avctx, AV_LOG_ERROR, "wrong picture format\n"); 250 return AVERROR_INVALIDDATA; 251 } 252 253 ret = ff_set_dimensions(avctx, s->width, s->height); 254 if (ret < 0) 255 return ret; 256 257 if ((ret = ff_get_buffer(avctx, p, 0)) < 0) 258 return ret; 259 260 p->pict_type = AV_PICTURE_TYPE_I; 261 p->key_frame = 1; 262 out_buf = p->data[0]; 263 264 out_end = out_buf + p->linesize[0] * s->height; 265 266 s->linesize = p->linesize[0]; 267 268 /* Skip header. */ 269 bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET); 270 if (rle) { 271 ret = read_rle_sgi(out_end, s); 272 } else { 273 ret = read_uncompressed_sgi(out_buf, s); 274 } 275 if (ret) 276 return ret; 277 278 *got_frame = 1; 279 return avpkt->size; 280} 281 282static av_cold int sgi_decode_init(AVCodecContext *avctx) 283{ 284 SgiState *s = avctx->priv_data; 285 286 s->avctx = avctx; 287 288 return 0; 289} 290 291AVCodec ff_sgi_decoder = { 292 .name = "sgi", 293 .long_name = NULL_IF_CONFIG_SMALL("SGI image"), 294 .type = AVMEDIA_TYPE_VIDEO, 295 .id = AV_CODEC_ID_SGI, 296 .priv_data_size = sizeof(SgiState), 297 .decode = decode_frame, 298 .init = sgi_decode_init, 299 .capabilities = CODEC_CAP_DR1, 300}; 301