Libav 0.7.1
libavformat/cutils.c
Go to the documentation of this file.
00001 /*
00002  * Various simple utilities for ffmpeg system
00003  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav 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  * Libav 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 Libav; 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 /* add one element to a dynamic array */
00025 void ff_dynarray_add(intptr_t **tab_ptr, int *nb_ptr, intptr_t elem)
00026 {
00027     /* see similar ffmpeg.c:grow_array() */
00028     int nb, nb_alloc;
00029     intptr_t *tab;
00030 
00031     nb = *nb_ptr;
00032     tab = *tab_ptr;
00033     if ((nb & (nb - 1)) == 0) {
00034         if (nb == 0)
00035             nb_alloc = 1;
00036         else
00037             nb_alloc = nb * 2;
00038         tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
00039         *tab_ptr = tab;
00040     }
00041     tab[nb++] = elem;
00042     *nb_ptr = nb;
00043 }
00044 
00045 #define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0))
00046 #define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400)
00047 
00048 /* This is our own gmtime_r. It differs from its POSIX counterpart in a
00049    couple of places, though. */
00050 struct tm *brktimegm(time_t secs, struct tm *tm)
00051 {
00052     int days, y, ny, m;
00053     int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
00054 
00055     days = secs / 86400;
00056     secs %= 86400;
00057     tm->tm_hour = secs / 3600;
00058     tm->tm_min = (secs % 3600) / 60;
00059     tm->tm_sec =  secs % 60;
00060 
00061     /* oh well, may be someone some day will invent a formula for this stuff */
00062     y = 1970; /* start "guessing" */
00063     while (days > 365) {
00064         ny = (y + days/366);
00065         days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1);
00066         y = ny;
00067     }
00068     if (days==365 && !ISLEAP(y)) { days=0; y++; }
00069     md[1] = ISLEAP(y)?29:28;
00070     for (m=0; days >= md[m]; m++)
00071          days -= md[m];
00072 
00073     tm->tm_year = y;  /* unlike gmtime_r we store complete year here */
00074     tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */
00075     tm->tm_mday = days+1;
00076 
00077     return tm;
00078 }