FFmpeg/libavformat/cutils.c

189 lines
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/*
* Various simple utilities for ffmpeg system
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "internal.h"
/* add one element to a dynamic array */
void ff_dynarray_add(intptr_t **tab_ptr, int *nb_ptr, intptr_t elem)
{
/* see similar ffmpeg.c:grow_array() */
int nb, nb_alloc;
intptr_t *tab;
nb = *nb_ptr;
tab = *tab_ptr;
if ((nb & (nb - 1)) == 0) {
if (nb == 0)
nb_alloc = 1;
else
nb_alloc = nb * 2;
tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
*tab_ptr = tab;
}
tab[nb++] = elem;
*nb_ptr = nb;
}
time_t mktimegm(struct tm *tm)
{
time_t t;
int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
if (m < 3) {
m += 12;
y--;
}
t = 86400 *
(d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 + y / 400 - 719469);
t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
return t;
}
#define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0))
#define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400)
/* This is our own gmtime_r. It differs from its POSIX counterpart in a
couple of places, though. */
struct tm *brktimegm(time_t secs, struct tm *tm)
{
int days, y, ny, m;
int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
days = secs / 86400;
secs %= 86400;
tm->tm_hour = secs / 3600;
tm->tm_min = (secs % 3600) / 60;
tm->tm_sec = secs % 60;
/* oh well, may be someone some day will invent a formula for this stuff */
y = 1970; /* start "guessing" */
while (days > 365) {
ny = (y + days/366);
days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1);
y = ny;
}
if (days==365 && !ISLEAP(y)) { days=0; y++; }
md[1] = ISLEAP(y)?29:28;
for (m=0; days >= md[m]; m++)
days -= md[m];
tm->tm_year = y; /* unlike gmtime_r we store complete year here */
tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */
tm->tm_mday = days+1;
return tm;
}
/* get a positive number between n_min and n_max, for a maximum length
of len_max. Return -1 if error. */
static int date_get_num(const char **pp,
int n_min, int n_max, int len_max)
{
int i, val, c;
const char *p;
p = *pp;
val = 0;
for(i = 0; i < len_max; i++) {
c = *p;
if (!isdigit(c))
break;
val = (val * 10) + c - '0';
p++;
}
/* no number read ? */
if (p == *pp)
return -1;
if (val < n_min || val > n_max)
return -1;
*pp = p;
return val;
}
/* small strptime for ffmpeg */
const char *small_strptime(const char *p, const char *fmt,
struct tm *dt)
{
int c, val;
for(;;) {
c = *fmt++;
if (c == '\0') {
return p;
} else if (c == '%') {
c = *fmt++;
switch(c) {
case 'H':
val = date_get_num(&p, 0, 23, 2);
if (val == -1)
return NULL;
dt->tm_hour = val;
break;
case 'M':
val = date_get_num(&p, 0, 59, 2);
if (val == -1)
return NULL;
dt->tm_min = val;
break;
case 'S':
val = date_get_num(&p, 0, 59, 2);
if (val == -1)
return NULL;
dt->tm_sec = val;
break;
case 'Y':
val = date_get_num(&p, 0, 9999, 4);
if (val == -1)
return NULL;
dt->tm_year = val - 1900;
break;
case 'm':
val = date_get_num(&p, 1, 12, 2);
if (val == -1)
return NULL;
dt->tm_mon = val - 1;
break;
case 'd':
val = date_get_num(&p, 1, 31, 2);
if (val == -1)
return NULL;
dt->tm_mday = val;
break;
case '%':
goto match;
default:
return NULL;
}
} else {
match:
if (c != *p)
return NULL;
p++;
}
}
return p;
}