f94442f1bdef2d305c5083a6568f8746684f6a87
[libav.git] / libavformat / cutils.c
1 /*
2 * Various simple utilities for ffmpeg system
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
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 #include "avformat.h"
22 #include "internal.h"
23
24 /* add one element to a dynamic array */
25 void ff_dynarray_add(intptr_t **tab_ptr, int *nb_ptr, intptr_t elem)
26 {
27 /* see similar avconv.c:grow_array() */
28 int nb, nb_alloc;
29 intptr_t *tab;
30
31 nb = *nb_ptr;
32 tab = *tab_ptr;
33 if ((nb & (nb - 1)) == 0) {
34 if (nb == 0)
35 nb_alloc = 1;
36 else
37 nb_alloc = nb * 2;
38 tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
39 *tab_ptr = tab;
40 }
41 tab[nb++] = elem;
42 *nb_ptr = nb;
43 }
44
45 #define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0))
46 #define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400)
47
48 /* This is our own gmtime_r. It differs from its POSIX counterpart in a
49 couple of places, though. */
50 struct tm *brktimegm(time_t secs, struct tm *tm)
51 {
52 int days, y, ny, m;
53 int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
54
55 days = secs / 86400;
56 secs %= 86400;
57 tm->tm_hour = secs / 3600;
58 tm->tm_min = (secs % 3600) / 60;
59 tm->tm_sec = secs % 60;
60
61 /* oh well, may be someone some day will invent a formula for this stuff */
62 y = 1970; /* start "guessing" */
63 while (days > 365) {
64 ny = (y + days/366);
65 days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1);
66 y = ny;
67 }
68 if (days==365 && !ISLEAP(y)) { days=0; y++; }
69 md[1] = ISLEAP(y)?29:28;
70 for (m=0; days >= md[m]; m++)
71 days -= md[m];
72
73 tm->tm_year = y; /* unlike gmtime_r we store complete year here */
74 tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */
75 tm->tm_mday = days+1;
76
77 return tm;
78 }