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 "sgi.h" 26 27typedef struct SgiState { 28 AVFrame picture; 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 */ 45static 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 */ 84static 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 */ 119static 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 152static int decode_frame(AVCodecContext *avctx, 153 void *data, int *data_size, 154 AVPacket *avpkt) 155{ 156 SgiState *s = avctx->priv_data; 157 AVFrame *picture = data; 158 AVFrame *p = &s->picture; 159 unsigned int dimension, rle; 160 int ret = 0; 161 uint8_t *out_buf, *out_end; 162 163 bytestream2_init(&s->g, avpkt->data, avpkt->size); 164 if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) { 165 av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size); 166 return AVERROR_INVALIDDATA; 167 } 168 169 /* Test for SGI magic. */ 170 if (bytestream2_get_be16(&s->g) != SGI_MAGIC) { 171 av_log(avctx, AV_LOG_ERROR, "bad magic number\n"); 172 return AVERROR_INVALIDDATA; 173 } 174 175 rle = bytestream2_get_byte(&s->g); 176 s->bytes_per_channel = bytestream2_get_byte(&s->g); 177 dimension = bytestream2_get_be16(&s->g); 178 s->width = bytestream2_get_be16(&s->g); 179 s->height = bytestream2_get_be16(&s->g); 180 s->depth = bytestream2_get_be16(&s->g); 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 (av_image_check_size(s->width, s->height, 0, avctx)) 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 = AV_PICTURE_TYPE_I; 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 bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET); 227 if (rle) { 228 ret = read_rle_sgi(out_end, s); 229 } else { 230 ret = read_uncompressed_sgi(out_buf, out_end, s); 231 } 232 233 if (ret == 0) { 234 *picture = s->picture; 235 *data_size = sizeof(AVPicture); 236 return avpkt->size; 237 } else { 238 return ret; 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 ff_sgi_decoder = { 262 .name = "sgi", 263 .type = AVMEDIA_TYPE_VIDEO, 264 .id = CODEC_ID_SGI, 265 .priv_data_size = sizeof(SgiState), 266 .init = sgi_init, 267 .close = sgi_end, 268 .decode = decode_frame, 269 .long_name = NULL_IF_CONFIG_SMALL("SGI image"), 270}; 271 272