sgidec.c
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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 
27 typedef struct SgiState {
29  unsigned int width;
30  unsigned int height;
31  unsigned int depth;
32  unsigned int bytes_per_channel;
33  int linesize;
35 } SgiState;
36 
45 static 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 
84 static 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 
119 static 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 
152 static 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);
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) {
195  } else if (s->depth == SGI_RGB) {
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 
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 
242 static av_cold int sgi_init(AVCodecContext *avctx){
243  SgiState *s = avctx->priv_data;
244 
246  avctx->coded_frame = &s->picture;
247 
248  return 0;
249 }
250 
251 static 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 
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