00001 /* 00002 * various simple utilities for libavformat 00003 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 #include "avformat.h" 00022 #include "internal.h" 00023 00024 #define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0)) 00025 #define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400) 00026 00027 /* This is our own gmtime_r. It differs from its POSIX counterpart in a 00028 couple of places, though. */ 00029 struct tm *ff_brktimegm(time_t secs, struct tm *tm) 00030 { 00031 int days, y, ny, m; 00032 int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; 00033 00034 days = secs / 86400; 00035 secs %= 86400; 00036 tm->tm_hour = secs / 3600; 00037 tm->tm_min = (secs % 3600) / 60; 00038 tm->tm_sec = secs % 60; 00039 00040 /* oh well, may be someone some day will invent a formula for this stuff */ 00041 y = 1970; /* start "guessing" */ 00042 while (days > 365) { 00043 ny = (y + days/366); 00044 days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1); 00045 y = ny; 00046 } 00047 if (days==365 && !ISLEAP(y)) { days=0; y++; } 00048 md[1] = ISLEAP(y)?29:28; 00049 for (m=0; days >= md[m]; m++) 00050 days -= md[m]; 00051 00052 tm->tm_year = y; /* unlike gmtime_r we store complete year here */ 00053 tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */ 00054 tm->tm_mday = days+1; 00055 00056 return tm; 00057 }