libdivecomputer/src/datetime.c
Jef Driesen 9b65159a57 Mark the dc_datetime_mktime parameter as const.
Unlike the corresponding mktime C library function, the libdivecomputer
function will never modify its argument. By marking the parameter as
const this is made more explicit.
2013-05-23 14:17:41 +02:00

131 lines
2.5 KiB
C

/*
* libdivecomputer
*
* Copyright (C) 2010 Jef Driesen
*
* This library 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.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <time.h>
#include <libdivecomputer/datetime.h>
static struct tm *
dc_localtime_r (const time_t *t, struct tm *tm)
{
#ifdef HAVE_LOCALTIME_R
return localtime_r (t, tm);
#else
struct tm *p = localtime (t);
if (p == NULL)
return NULL;
if (tm)
*tm = *p;
return tm;
#endif
}
static struct tm *
dc_gmtime_r (const time_t *t, struct tm *tm)
{
#ifdef HAVE_GMTIME_R
return gmtime_r (t, tm);
#else
struct tm *p = gmtime (t);
if (p == NULL)
return NULL;
if (tm)
*tm = *p;
return tm;
#endif
}
dc_ticks_t
dc_datetime_now (void)
{
return time (NULL);
}
dc_datetime_t *
dc_datetime_localtime (dc_datetime_t *result,
dc_ticks_t ticks)
{
time_t t = ticks;
struct tm tm;
if (dc_localtime_r (&t, &tm) == NULL)
return NULL;
if (result) {
result->year = tm.tm_year + 1900;
result->month = tm.tm_mon + 1;
result->day = tm.tm_mday;
result->hour = tm.tm_hour;
result->minute = tm.tm_min;
result->second = tm.tm_sec;
}
return result;
}
dc_datetime_t *
dc_datetime_gmtime (dc_datetime_t *result,
dc_ticks_t ticks)
{
time_t t = ticks;
struct tm tm;
if (dc_gmtime_r (&t, &tm) == NULL)
return NULL;
if (result) {
result->year = tm.tm_year + 1900;
result->month = tm.tm_mon + 1;
result->day = tm.tm_mday;
result->hour = tm.tm_hour;
result->minute = tm.tm_min;
result->second = tm.tm_sec;
}
return result;
}
dc_ticks_t
dc_datetime_mktime (const dc_datetime_t *dt)
{
if (dt == NULL)
return -1;
struct tm tm;
tm.tm_year = dt->year - 1900;
tm.tm_mon = dt->month - 1;
tm.tm_mday = dt->day;
tm.tm_hour = dt->hour;
tm.tm_min = dt->minute;
tm.tm_sec = dt->second;
tm.tm_isdst = -1;
return mktime (&tm);
}