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1 | /* |
2 | * various simple utilities for libavformat | |
3 | * Copyright (c) 2000, 2001, 2002 Fabrice Bellard | |
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 | #include "avformat.h" | |
22 | #include "internal.h" | |
23 | ||
24 | #define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0)) | |
25 | #define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400) | |
26 | ||
27 | /* This is our own gmtime_r. It differs from its POSIX counterpart in a | |
28 | couple of places, though. */ | |
29 | struct tm *ff_brktimegm(time_t secs, struct tm *tm) | |
30 | { | |
31 | int days, y, ny, m; | |
32 | int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; | |
33 | ||
34 | days = secs / 86400; | |
35 | secs %= 86400; | |
36 | tm->tm_hour = secs / 3600; | |
37 | tm->tm_min = (secs % 3600) / 60; | |
38 | tm->tm_sec = secs % 60; | |
39 | ||
40 | /* oh well, may be someone some day will invent a formula for this stuff */ | |
41 | y = 1970; /* start "guessing" */ | |
42 | while (days > 365) { | |
43 | ny = (y + days/366); | |
44 | days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1); | |
45 | y = ny; | |
46 | } | |
47 | if (days==365 && !ISLEAP(y)) { days=0; y++; } | |
48 | md[1] = ISLEAP(y)?29:28; | |
49 | for (m=0; days >= md[m]; m++) | |
50 | days -= md[m]; | |
51 | ||
52 | tm->tm_year = y; /* unlike gmtime_r we store complete year here */ | |
53 | tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */ | |
54 | tm->tm_mday = days+1; | |
55 | ||
56 | return tm; | |
57 | } |