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 int linesize; 32} SgiState; 33 34/** 35 * Expand an RLE row into a channel. 36 * @param in_buf input buffer 37 * @param in_end end of input buffer 38 * @param out_buf Points to one line after the output buffer. 39 * @param out_end end of line in output buffer 40 * @param pixelstride pixel stride of input buffer 41 * @return size of output in bytes, -1 if buffer overflows 42 */ 43static int expand_rle_row(const uint8_t *in_buf, const uint8_t* in_end, 44 unsigned char *out_buf, uint8_t* out_end, int pixelstride) 45{ 46 unsigned char pixel, count; 47 unsigned char *orig = out_buf; 48 49 while (1) { 50 if(in_buf + 1 > in_end) return -1; 51 pixel = bytestream_get_byte(&in_buf); 52 if (!(count = (pixel & 0x7f))) { 53 return (out_buf - orig) / pixelstride; 54 } 55 56 /* Check for buffer overflow. */ 57 if(out_buf + pixelstride * count >= out_end) return -1; 58 59 if (pixel & 0x80) { 60 while (count--) { 61 *out_buf = bytestream_get_byte(&in_buf); 62 out_buf += pixelstride; 63 } 64 } else { 65 pixel = bytestream_get_byte(&in_buf); 66 67 while (count--) { 68 *out_buf = pixel; 69 out_buf += pixelstride; 70 } 71 } 72 } 73} 74 75/** 76 * Read a run length encoded SGI image. 77 * @param out_buf output buffer 78 * @param in_buf input buffer 79 * @param in_end end of input buffer 80 * @param s the current image state 81 * @return 0 if no error, else return error number. 82 */ 83static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf, 84 const uint8_t *in_end, SgiState* s) 85{ 86 uint8_t *dest_row; 87 unsigned int len = s->height * s->depth * 4; 88 const uint8_t *start_table = in_buf; 89 unsigned int y, z; 90 unsigned int start_offset; 91 92 /* size of RLE offset and length tables */ 93 if(len * 2 > in_end - in_buf) { 94 return AVERROR_INVALIDDATA; 95 } 96 97 in_buf -= SGI_HEADER_SIZE; 98 for (z = 0; z < s->depth; z++) { 99 dest_row = out_buf; 100 for (y = 0; y < s->height; y++) { 101 dest_row -= s->linesize; 102 start_offset = bytestream_get_be32(&start_table); 103 if(start_offset > in_end - in_buf) { 104 return AVERROR_INVALIDDATA; 105 } 106 if (expand_rle_row(in_buf + start_offset, in_end, dest_row + z, 107 dest_row + FFABS(s->linesize), s->depth) != s->width) 108 return AVERROR_INVALIDDATA; 109 } 110 } 111 return 0; 112} 113 114/** 115 * Read an uncompressed SGI image. 116 * @param out_buf output buffer 117 * @param out_end end ofoutput buffer 118 * @param in_buf input buffer 119 * @param in_end end of input buffer 120 * @param s the current image state 121 * @return 0 if read success, otherwise return -1. 122 */ 123static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end, 124 const uint8_t *in_buf, const uint8_t *in_end, SgiState* s) 125{ 126 int x, y, z; 127 const uint8_t *ptr; 128 unsigned int offset = s->height * s->width; 129 130 /* Test buffer size. */ 131 if (offset * s->depth > in_end - in_buf) { 132 return -1; 133 } 134 135 for (y = s->height - 1; y >= 0; y--) { 136 out_end = out_buf + (y * s->linesize); 137 for (x = s->width; x > 0; x--) { 138 ptr = in_buf++; 139 for(z = 0; z < s->depth; z ++) { 140 bytestream_put_byte(&out_end, *ptr); 141 ptr += offset; 142 } 143 } 144 } 145 return 0; 146} 147 148static int decode_frame(AVCodecContext *avctx, 149 void *data, int *data_size, 150 const uint8_t *in_buf, int buf_size) 151{ 152 SgiState *s = avctx->priv_data; 153 AVFrame *picture = data; 154 AVFrame *p = &s->picture; 155 const uint8_t *in_end = in_buf + buf_size; 156 unsigned int dimension, bytes_per_channel, rle; 157 int ret = 0; 158 uint8_t *out_buf, *out_end; 159 160 if (buf_size < SGI_HEADER_SIZE){ 161 av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size); 162 return -1; 163 } 164 165 /* Test for SGI magic. */ 166 if (bytestream_get_be16(&in_buf) != SGI_MAGIC) { 167 av_log(avctx, AV_LOG_ERROR, "bad magic number\n"); 168 return -1; 169 } 170 171 rle = bytestream_get_byte(&in_buf); 172 bytes_per_channel = bytestream_get_byte(&in_buf); 173 dimension = bytestream_get_be16(&in_buf); 174 s->width = bytestream_get_be16(&in_buf); 175 s->height = bytestream_get_be16(&in_buf); 176 s->depth = bytestream_get_be16(&in_buf); 177 178 if (bytes_per_channel != 1) { 179 av_log(avctx, AV_LOG_ERROR, "wrong channel number\n"); 180 return -1; 181 } 182 183 /* Check for supported image dimensions. */ 184 if (dimension != 2 && dimension != 3) { 185 av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n"); 186 return -1; 187 } 188 189 if (s->depth == SGI_GRAYSCALE) { 190 avctx->pix_fmt = PIX_FMT_GRAY8; 191 } else if (s->depth == SGI_RGB) { 192 avctx->pix_fmt = PIX_FMT_RGB24; 193 } else if (s->depth == SGI_RGBA) { 194 avctx->pix_fmt = PIX_FMT_RGBA; 195 } else { 196 av_log(avctx, AV_LOG_ERROR, "wrong picture format\n"); 197 return -1; 198 } 199 200 if (avcodec_check_dimensions(avctx, s->width, s->height)) 201 return -1; 202 avcodec_set_dimensions(avctx, s->width, s->height); 203 204 if (p->data[0]) 205 avctx->release_buffer(avctx, p); 206 207 p->reference = 0; 208 if (avctx->get_buffer(avctx, p) < 0) { 209 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n"); 210 return -1; 211 } 212 213 p->pict_type = FF_I_TYPE; 214 p->key_frame = 1; 215 out_buf = p->data[0]; 216 217 out_end = out_buf + p->linesize[0] * s->height; 218 219 s->linesize = p->linesize[0]; 220 221 /* Skip header. */ 222 in_buf += SGI_HEADER_SIZE - 12; 223 if (rle) { 224 ret = read_rle_sgi(out_end, in_buf, in_end, s); 225 } else { 226 ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s); 227 } 228 229 if (ret == 0) { 230 *picture = s->picture; 231 *data_size = sizeof(AVPicture); 232 return buf_size; 233 } else { 234 return -1; 235 } 236} 237 238static av_cold int sgi_init(AVCodecContext *avctx){ 239 SgiState *s = avctx->priv_data; 240 241 avcodec_get_frame_defaults(&s->picture); 242 avctx->coded_frame = &s->picture; 243 244 return 0; 245} 246 247static av_cold int sgi_end(AVCodecContext *avctx) 248{ 249 SgiState * const s = avctx->priv_data; 250 251 if (s->picture.data[0]) 252 avctx->release_buffer(avctx, &s->picture); 253 254 return 0; 255} 256 257AVCodec sgi_decoder = { 258 "sgi", 259 CODEC_TYPE_VIDEO, 260 CODEC_ID_SGI, 261 sizeof(SgiState), 262 sgi_init, 263 NULL, 264 sgi_end, 265 decode_frame, 266 .long_name = NULL_IF_CONFIG_SMALL("SGI image"), 267}; 268 269