FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/sgidec.c
Date: 2026-05-03 13:33:45
Exec Total Coverage
Lines: 99 123 80.5%
Functions: 5 5 100.0%
Branches: 62 80 77.5%
Line Branch Exec Source
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 "codec_internal.h"
25 #include "decode.h"
26 #include "libavutil/attributes.h"
27 #include "sgi.h"
28
29 /**
30 * Expand an RLE row into a channel.
31 * @param logctx a logcontext
32 * @param out_buf Points to one line after the output buffer.
33 * @param g GetByteContext used to read input from
34 * @param width length of out_buf in nb of elements
35 * @return nb of elements written, else return error code.
36 */
37 21152 static int expand_rle_row8(void *logctx, uint8_t *out_buf,
38 GetByteContext *g, unsigned width)
39 {
40 unsigned char pixel, count;
41 21152 unsigned char *orig = out_buf;
42 21152 uint8_t *out_end = out_buf + width;
43
44
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 546421 while (out_buf < out_end) {
45
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 525269 if (bytestream2_get_bytes_left(g) < 1)
46 ✗ return AVERROR_INVALIDDATA;
47 525269 pixel = bytestream2_get_byteu(g);
48
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 525269 if (!(count = (pixel & 0x7f))) {
49 ✗ break;
50 }
51
52 /* Check for buffer overflow. */
53
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 525269 if (out_end - out_buf < count) {
54 ✗ av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
55 ✗ return AVERROR_INVALIDDATA;
56 }
57
58
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 525269 if (pixel & 0x80) {
59
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 4926830 while (count--)
60 4780725 *out_buf++ = bytestream2_get_byte(g);
61 } else {
62 379164 pixel = bytestream2_get_byte(g);
63
64
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 4354663 while (count--)
65 3975499 *out_buf++ = pixel;
66 }
67 }
68 21152 return out_buf - orig;
69 }
70
71 4096 static int expand_rle_row16(void *logctx, uint16_t *out_buf,
72 GetByteContext *g, unsigned width)
73 {
74 unsigned short pixel;
75 unsigned char count;
76 4096 unsigned short *orig = out_buf;
77 4096 uint16_t *out_end = out_buf + width;
78
79
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 148976 while (out_buf < out_end) {
80
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 144880 if (bytestream2_get_bytes_left(g) < 2)
81 ✗ return AVERROR_INVALIDDATA;
82 144880 pixel = bytestream2_get_be16u(g);
83
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 144880 if (!(count = (pixel & 0x7f)))
84 ✗ break;
85
86 /* Check for buffer overflow. */
87
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 144880 if (out_end - out_buf < count) {
88 ✗ av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
89 ✗ return AVERROR_INVALIDDATA;
90 }
91
92
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 144880 if (pixel & 0x80) {
93
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 308360 while (count--) {
94 289372 pixel = bytestream2_get_ne16(g);
95 289372 AV_WN16A(out_buf, pixel);
96 289372 out_buf++;
97 }
98 } else {
99 125892 pixel = bytestream2_get_ne16(g);
100
101
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 1933672 while (count--) {
102 1807780 AV_WN16A(out_buf, pixel);
103 1807780 out_buf++;
104 }
105 }
106 }
107 4096 return out_buf - orig;
108 }
109
110
111 /**
112 * Read a run length encoded SGI image.
113 * @param out_buf output buffer
114 * @param s the current image state
115 * @return 0 if no error, else return error code.
116 */
117 33 static int read_rle_sgi(void *logctx, uint8_t *out[4], ptrdiff_t stride[4],
118 GetByteContext *g, unsigned width, int height,
119 unsigned nb_components, unsigned bytes_per_channel)
120 {
121 33 unsigned int len = height * nb_components * 4;
122 33 GetByteContext g_table = *g;
123 unsigned int start_offset;
124 int ret;
125
126 /* size of RLE offset and length tables */
127
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 33 if (len * 2 > bytestream2_get_bytes_left(g)) {
128 ✗ return AVERROR_INVALIDDATA;
129 }
130
131
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 126 for (unsigned z = 0; z < nb_components; z++) {
132 93 uint8_t *dest_row = out[z] + (height - 1) * stride[z];
133 while (1) {
134 25248 start_offset = bytestream2_get_be32(&g_table);
135 25248 bytestream2_seek(g, start_offset, SEEK_SET);
136
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 25248 if (bytes_per_channel == 1)
137 21152 ret = expand_rle_row8(logctx, dest_row, g, width);
138 else
139 4096 ret = expand_rle_row16(logctx, (uint16_t *)dest_row, g, width);
140
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 25248 if (ret != width)
141 ✗ return AVERROR_INVALIDDATA;
142
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 25248 if (dest_row == out[z])
143 93 break;
144 25155 dest_row -= stride[z];
145 }
146 }
147 33 return 0;
148 }
149
150 /**
151 * Read an uncompressed SGI image.
152 * @param out_buf output buffer
153 * @param s the current image state
154 * @return 0 if read success, else return error code.
155 */
156 6 static int read_uncompressed_sgi(uint8_t *const out[4], const ptrdiff_t stride[4],
157 GetByteContext *g, unsigned width, int height,
158 unsigned nb_components, unsigned bytes_per_channel)
159 {
160 6 unsigned rowsize = width * bytes_per_channel;
161
162 /* Test buffer size. */
163
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 6 if (rowsize * (int64_t)height * nb_components > bytestream2_get_bytes_left(g))
164 ✗ return AVERROR_INVALIDDATA;
165
166
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 22 for (unsigned z = 0; z < nb_components; z++) {
167 16 uint8_t *cur_row = out[z] + (height - 1) * stride[z];
168 while (1) {
169 4096 bytestream2_get_bufferu(g, cur_row, rowsize);
170
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 4096 if (cur_row == out[z])
171 16 break;
172 4080 cur_row -= stride[z];
173 }
174 }
175 6 return 0;
176 }
177
178 39 static int decode_frame(AVCodecContext *avctx, AVFrame *p,
179 int *got_frame, AVPacket *avpkt)
180 {
181 GetByteContext g;
182 unsigned int bytes_per_channel, nb_components, dimension, rle, width;
183 uint8_t *out[4];
184 ptrdiff_t linesize[4];
185 int height;
186 39 int ret = 0;
187
188 39 bytestream2_init(&g, avpkt->data, avpkt->size);
189
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 39 if (bytestream2_get_bytes_left(&g) < SGI_HEADER_SIZE) {
190 ✗ av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
191 ✗ return AVERROR_INVALIDDATA;
192 }
193
194 /* Test for SGI magic. */
195
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 39 if (bytestream2_get_be16u(&g) != SGI_MAGIC) {
196 ✗ av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
197 ✗ return AVERROR_INVALIDDATA;
198 }
199
200 39 rle = bytestream2_get_byteu(&g);
201 39 bytes_per_channel = bytestream2_get_byteu(&g);
202 39 dimension = bytestream2_get_be16u(&g);
203 39 width = bytestream2_get_be16u(&g);
204 39 height = bytestream2_get_be16u(&g);
205 39 nb_components = bytestream2_get_be16u(&g);
206
207
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 39 if (bytes_per_channel != 1 && bytes_per_channel != 2) {
208 ✗ av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
209 ✗ return AVERROR_INVALIDDATA;
210 }
211
212 /* Check for supported image dimensions. */
213
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 39 if (dimension != 2 && dimension != 3) {
214 ✗ av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
215 ✗ return AVERROR_INVALIDDATA;
216 }
217
218
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 39 if (nb_components == SGI_GRAYSCALE) {
219
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 8 avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
220
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 31 } else if (nb_components == SGI_RGB) {
221
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 23 avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRP16BE : AV_PIX_FMT_GBRP;
222
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 8 } else if (nb_components == SGI_RGBA) {
223
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 8 avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRAP16BE : AV_PIX_FMT_GBRAP;
224 } else {
225 ✗ av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
226 ✗ return AVERROR_INVALIDDATA;
227 }
228
229 39 ret = ff_set_dimensions(avctx, width, height);
230
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 39 if (ret < 0)
231 ✗ return ret;
232
233
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 39 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
234 ✗ return ret;
235
236
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 39 switch (nb_components) {
237 #define MAP(in_idx, out_idx) \
238 out[(in_idx)] = p->data[(out_idx)]; \
239 linesize[(in_idx)] = p->linesize[(out_idx)]
240 8 case SGI_GRAYSCALE:
241 8 MAP(0, 0);
242 8 break;
243 8 case SGI_RGBA:
244 8 MAP(3, 3);
245 av_fallthrough;
246 31 case SGI_RGB:
247 31 MAP(0, 2);
248 31 MAP(1, 0);
249 31 MAP(2, 1);
250 31 break;
251 }
252
253 /* Skip header. */
254 39 bytestream2_seek(&g, SGI_HEADER_SIZE, SEEK_SET);
255
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 39 if (rle) {
256 33 ret = read_rle_sgi(avctx, out, linesize, &g,
257 width, height, nb_components, bytes_per_channel);
258 } else {
259 6 ret = read_uncompressed_sgi(out, linesize, &g,
260 width, height, nb_components, bytes_per_channel);
261 }
262
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 39 if (ret)
263 ✗ return ret;
264
265 39 *got_frame = 1;
266 39 return avpkt->size;
267 }
268
269 const FFCodec ff_sgi_decoder = {
270 .p.name = "sgi",
271 CODEC_LONG_NAME("SGI image"),
272 .p.type = AVMEDIA_TYPE_VIDEO,
273 .p.id = AV_CODEC_ID_SGI,
274 FF_CODEC_DECODE_CB(decode_frame),
275 .p.capabilities = AV_CODEC_CAP_DR1,
276 };
277