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 "avcodec.h"
24 #include "bytestream.h"
25 #include "codec_internal.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 */
expand_rle_row8(SgiState *s, uint8_t *out_buf, int len, int pixelstride)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
expand_rle_row16(SgiState *s, uint16_t *out_buf, int len, int pixelstride)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 */
read_rle_sgi(uint8_t *out_buf, SgiState *s)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 */
read_uncompressed_sgi(unsigned char *out_buf, SgiState *s)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
decode_frame(AVCodecContext *avctx, AVFrame *p, int *got_frame, AVPacket *avpkt)202 static int decode_frame(AVCodecContext *avctx, AVFrame *p,
203 int *got_frame, AVPacket *avpkt)
204 {
205 SgiState *s = avctx->priv_data;
206 unsigned int dimension, rle;
207 int ret = 0;
208 uint8_t *out_buf, *out_end;
209
210 bytestream2_init(&s->g, avpkt->data, avpkt->size);
211 if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
212 av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
213 return AVERROR_INVALIDDATA;
214 }
215
216 /* Test for SGI magic. */
217 if (bytestream2_get_be16u(&s->g) != SGI_MAGIC) {
218 av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
219 return AVERROR_INVALIDDATA;
220 }
221
222 rle = bytestream2_get_byteu(&s->g);
223 s->bytes_per_channel = bytestream2_get_byteu(&s->g);
224 dimension = bytestream2_get_be16u(&s->g);
225 s->width = bytestream2_get_be16u(&s->g);
226 s->height = bytestream2_get_be16u(&s->g);
227 s->depth = bytestream2_get_be16u(&s->g);
228
229 if (s->bytes_per_channel != 1 && s->bytes_per_channel != 2) {
230 av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
231 return AVERROR_INVALIDDATA;
232 }
233
234 /* Check for supported image dimensions. */
235 if (dimension != 2 && dimension != 3) {
236 av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
237 return AVERROR_INVALIDDATA;
238 }
239
240 if (s->depth == SGI_GRAYSCALE) {
241 avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
242 } else if (s->depth == SGI_RGB) {
243 avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;
244 } else if (s->depth == SGI_RGBA) {
245 avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGBA64BE : AV_PIX_FMT_RGBA;
246 } else {
247 av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
248 return AVERROR_INVALIDDATA;
249 }
250
251 ret = ff_set_dimensions(avctx, s->width, s->height);
252 if (ret < 0)
253 return ret;
254
255 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
256 return ret;
257
258 p->pict_type = AV_PICTURE_TYPE_I;
259 p->key_frame = 1;
260 out_buf = p->data[0];
261
262 out_end = out_buf + p->linesize[0] * s->height;
263
264 s->linesize = p->linesize[0];
265
266 /* Skip header. */
267 bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
268 if (rle) {
269 ret = read_rle_sgi(out_end, s);
270 } else {
271 ret = read_uncompressed_sgi(out_buf, s);
272 }
273 if (ret)
274 return ret;
275
276 *got_frame = 1;
277 return avpkt->size;
278 }
279
sgi_decode_init(AVCodecContext *avctx)280 static av_cold int sgi_decode_init(AVCodecContext *avctx)
281 {
282 SgiState *s = avctx->priv_data;
283
284 s->avctx = avctx;
285
286 return 0;
287 }
288
289 const FFCodec ff_sgi_decoder = {
290 .p.name = "sgi",
291 .p.long_name = NULL_IF_CONFIG_SMALL("SGI image"),
292 .p.type = AVMEDIA_TYPE_VIDEO,
293 .p.id = AV_CODEC_ID_SGI,
294 .priv_data_size = sizeof(SgiState),
295 FF_CODEC_DECODE_CB(decode_frame),
296 .init = sgi_decode_init,
297 .p.capabilities = AV_CODEC_CAP_DR1,
298 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
299 };
300