FFmpeg: libavcodec/sgidec.c Source File

FFmpeg
sgidec.c
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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 
29  typedef 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  */
47  static 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 
85  static 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 (out_end - out_buf <= pixelstride * (count - 1)) {
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  */
131  static 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;
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  */
169  static 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 
202  static 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 
282  static 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 
291  AVCodec 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 };
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