yading@11: /*
yading@11:  * various simple utilities for libavformat
yading@11:  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: #include "avformat.h"
yading@11: #include "internal.h"
yading@11: 
yading@11: #define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0))
yading@11: #define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400)
yading@11: 
yading@11: /* This is our own gmtime_r. It differs from its POSIX counterpart in a
yading@11:    couple of places, though. */
yading@11: struct tm *ff_brktimegm(time_t secs, struct tm *tm)
yading@11: {
yading@11:     int days, y, ny, m;
yading@11:     int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
yading@11: 
yading@11:     days = secs / 86400;
yading@11:     secs %= 86400;
yading@11:     tm->tm_hour = secs / 3600;
yading@11:     tm->tm_min = (secs % 3600) / 60;
yading@11:     tm->tm_sec =  secs % 60;
yading@11: 
yading@11:     /* oh well, may be someone some day will invent a formula for this stuff */
yading@11:     y = 1970; /* start "guessing" */
yading@11:     while (days > 365) {
yading@11:         ny = (y + days/366);
yading@11:         days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1);
yading@11:         y = ny;
yading@11:     }
yading@11:     if (days==365 && !ISLEAP(y)) { days=0; y++; }
yading@11:     md[1] = ISLEAP(y)?29:28;
yading@11:     for (m=0; days >= md[m]; m++)
yading@11:          days -= md[m];
yading@11: 
yading@11:     tm->tm_year = y;  /* unlike gmtime_r we store complete year here */
yading@11:     tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */
yading@11:     tm->tm_mday = days+1;
yading@11: 
yading@11:     return tm;
yading@11: }