1 /*
2 * FITS demuxer
3 * Copyright (c) 2017 Paras Chadha
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 /**
23 * @file
24 * FITS demuxer.
25 */
26
27 #include "libavutil/avassert.h"
28 #include "libavutil/intreadwrite.h"
29 #include "internal.h"
30 #include "libavutil/opt.h"
31 #include "libavcodec/fits.h"
32 #include "libavutil/bprint.h"
33
34 #define FITS_BLOCK_SIZE 2880
35
36 typedef struct FITSContext {
37 const AVClass *class;
38 AVRational framerate;
39 int first_image;
40 int64_t pts;
41 } FITSContext;
42
fits_probe(const AVProbeData * p)43 static int fits_probe(const AVProbeData *p)
44 {
45 const uint8_t *b = p->buf;
46 if (!memcmp(b, "SIMPLE = T", 30))
47 return AVPROBE_SCORE_MAX - 1;
48 return 0;
49 }
50
fits_read_header(AVFormatContext * s)51 static int fits_read_header(AVFormatContext *s)
52 {
53 AVStream *st;
54 FITSContext * fits = s->priv_data;
55
56 st = avformat_new_stream(s, NULL);
57 if (!st)
58 return AVERROR(ENOMEM);
59
60 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
61 st->codecpar->codec_id = AV_CODEC_ID_FITS;
62
63 avpriv_set_pts_info(st, 64, fits->framerate.den, fits->framerate.num);
64 fits->pts = 0;
65 fits->first_image = 1;
66 return 0;
67 }
68
69 /**
70 * Parses header and checks that the current HDU contains image or not
71 * It also stores the header in the avbuf and stores the size of data part in data_size
72 * @param s pointer to AVFormat Context
73 * @param fits pointer to FITSContext
74 * @param header pointer to FITSHeader
75 * @param avbuf pointer to AVBPrint to store the header
76 * @param data_size to store the size of data part
77 * @return 1 if image found, 0 if any other extension and AVERROR_INVALIDDATA otherwise
78 */
is_image(AVFormatContext * s,FITSContext * fits,FITSHeader * header,AVBPrint * avbuf,uint64_t * data_size)79 static int64_t is_image(AVFormatContext *s, FITSContext *fits, FITSHeader *header,
80 AVBPrint *avbuf, uint64_t *data_size)
81 {
82 int i, ret, image = 0;
83 char buf[FITS_BLOCK_SIZE] = { 0 };
84 int64_t buf_size = 0, size = 0, t;
85
86 do {
87 ret = avio_read(s->pb, buf, FITS_BLOCK_SIZE);
88 if (ret < 0) {
89 return ret;
90 } else if (ret < FITS_BLOCK_SIZE) {
91 return AVERROR_INVALIDDATA;
92 }
93
94 av_bprint_append_data(avbuf, buf, FITS_BLOCK_SIZE);
95 ret = 0;
96 buf_size = 0;
97 while(!ret && buf_size < FITS_BLOCK_SIZE) {
98 ret = avpriv_fits_header_parse_line(s, header, buf + buf_size, NULL);
99 buf_size += 80;
100 }
101 } while (!ret);
102 if (ret < 0)
103 return ret;
104
105 image = fits->first_image || header->image_extension;
106 fits->first_image = 0;
107
108 if (header->groups) {
109 image = 0;
110 if (header->naxis > 1)
111 size = 1;
112 } else if (header->naxis) {
113 size = header->naxisn[0];
114 } else {
115 image = 0;
116 }
117
118 for (i = 1; i < header->naxis; i++) {
119 if(size && header->naxisn[i] > UINT64_MAX / size)
120 return AVERROR_INVALIDDATA;
121 size *= header->naxisn[i];
122 }
123
124 if(header->pcount > UINT64_MAX - size)
125 return AVERROR_INVALIDDATA;
126 size += header->pcount;
127
128 t = (abs(header->bitpix) >> 3) * ((int64_t) header->gcount);
129 if(size && t > INT64_MAX / size)
130 return AVERROR_INVALIDDATA;
131 size *= t;
132
133 if (!size) {
134 image = 0;
135 } else {
136 if(FITS_BLOCK_SIZE - 1 > INT64_MAX - size)
137 return AVERROR_INVALIDDATA;
138 size = ((size + FITS_BLOCK_SIZE - 1) / FITS_BLOCK_SIZE) * FITS_BLOCK_SIZE;
139 }
140 *data_size = size;
141 return image;
142 }
143
fits_read_packet(AVFormatContext * s,AVPacket * pkt)144 static int fits_read_packet(AVFormatContext *s, AVPacket *pkt)
145 {
146 int64_t pos, ret;
147 uint64_t size;
148 FITSContext *fits = s->priv_data;
149 FITSHeader header;
150 AVBPrint avbuf;
151 char *buf;
152
153 if (fits->first_image) {
154 avpriv_fits_header_init(&header, STATE_SIMPLE);
155 } else {
156 avpriv_fits_header_init(&header, STATE_XTENSION);
157 }
158
159 av_bprint_init(&avbuf, FITS_BLOCK_SIZE, AV_BPRINT_SIZE_UNLIMITED);
160 while ((ret = is_image(s, fits, &header, &avbuf, &size)) == 0) {
161 av_bprint_finalize(&avbuf, NULL);
162 pos = avio_skip(s->pb, size);
163 if (pos < 0)
164 return pos;
165
166 av_bprint_init(&avbuf, FITS_BLOCK_SIZE, AV_BPRINT_SIZE_UNLIMITED);
167 avpriv_fits_header_init(&header, STATE_XTENSION);
168 }
169 if (ret < 0)
170 goto fail;
171
172 if (!av_bprint_is_complete(&avbuf)) {
173 ret = AVERROR(ENOMEM);
174 goto fail;
175 }
176
177 av_assert0(avbuf.len <= INT64_MAX && size <= INT64_MAX);
178 if (avbuf.len + size > INT_MAX - 80) {
179 ret = AVERROR_INVALIDDATA;
180 goto fail;
181 }
182 // Header is sent with the first line removed...
183 ret = av_new_packet(pkt, avbuf.len - 80 + size);
184 if (ret < 0)
185 goto fail;
186
187 pkt->stream_index = 0;
188 pkt->flags |= AV_PKT_FLAG_KEY;
189
190 ret = av_bprint_finalize(&avbuf, &buf);
191 if (ret < 0) {
192 return ret;
193 }
194
195 memcpy(pkt->data, buf + 80, avbuf.len - 80);
196 pkt->size = avbuf.len - 80;
197 av_freep(&buf);
198 ret = avio_read(s->pb, pkt->data + pkt->size, size);
199 if (ret < 0) {
200 return ret;
201 }
202
203 pkt->size += ret;
204 pkt->pts = fits->pts;
205 fits->pts++;
206
207 return 0;
208
209 fail:
210 av_bprint_finalize(&avbuf, NULL);
211 return ret;
212 }
213
214 static const AVOption fits_options[] = {
215 { "framerate", "set the framerate", offsetof(FITSContext, framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "1"}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
216 { NULL },
217 };
218
219 static const AVClass fits_demuxer_class = {
220 .class_name = "FITS demuxer",
221 .item_name = av_default_item_name,
222 .option = fits_options,
223 .version = LIBAVUTIL_VERSION_INT,
224 };
225
226 AVInputFormat ff_fits_demuxer = {
227 .name = "fits",
228 .long_name = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"),
229 .priv_data_size = sizeof(FITSContext),
230 .read_probe = fits_probe,
231 .read_header = fits_read_header,
232 .read_packet = fits_read_packet,
233 .priv_class = &fits_demuxer_class,
234 .raw_codec_id = AV_CODEC_ID_FITS,
235 };
236