qse/lib/cmn/time.c

/*
 * $Id$
 *
    Copyright (c) 2006-2019 Chung, Hyung-Hwan. All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:
    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <qse/cmn/time.h>

#include <qse/cmn/chr.h>
#include "mem-prv.h"

#if defined(_WIN32)
#	include <windows.h>
#	include <time.h>
#elif defined(__OS2__)
#	define INCL_DOSDATETIME
#	define INCL_DOSERRORS
#	include <os2.h>
#	include <time.h>
#elif defined(__DOS__)
#	include <dos.h>
#	include <time.h>
#else
#	include "syscall.h"
#	if defined(HAVE_SYS_TIME_H)
#		include <sys/time.h>
#	endif
#	if defined(HAVE_TIME_H)
#		include <time.h>
#	endif
#endif

#if defined(_WIN32)
	#define EPOCH_DIFF_YEARS (QSE_EPOCH_YEAR-QSE_EPOCH_YEAR_WIN)
	#define EPOCH_DIFF_DAYS  ((qse_long_t)EPOCH_DIFF_YEARS*365+EPOCH_DIFF_YEARS/4-3)
	#define EPOCH_DIFF_SECS  ((qse_long_t)EPOCH_DIFF_DAYS*24*60*60)
#endif

static const int mdays[2][QSE_MONS_PER_YEAR] = 
{
	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
};

/* number of days from the beginning of the year to the end of of
 * a previous month. adjust for leap years in the code. */
static const int mdays_tot[2][QSE_MONS_PER_YEAR] =
{
	{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 },
	{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 }
};

/* number of days from beginning of a previous month to the end of 
 * the year. adjust for leap years in the code. */
static const int mdays_rtot[2][QSE_MONS_PER_YEAR] =
{
	{ 334, 306, 275, 245, 214, 184, 153, 122, 92, 61, 31, 0 },
	{ 335, 306, 275, 245, 214, 184, 153, 122, 92, 61, 31, 0 }
};

/* get number of extra days for leap years between fy and ty inclusive */
static int get_leap_days (int fy, int ty)
{
	fy--; ty--;
	return (ty / 4 - fy / 4) - 
	       (ty / 100 - fy / 100) +
	       (ty / 400 - fy / 400);
}

int qse_gettime (qse_ntime_t* t)
{
#if defined(_WIN32)
	SYSTEMTIME st;
	FILETIME ft;
	ULARGE_INTEGER li;

	/* 
	 * MSDN: The FILETIME structure is a 64-bit value representing the 
	 *       number of 100-nanosecond intervals since January 1, 1601 (UTC).
	 */

	GetSystemTime (&st);
	if (SystemTimeToFileTime (&st, &ft) == FALSE) return -1;

	li.LowPart = ft.dwLowDateTime;
	li.HighPart = ft.dwHighDateTime;

     /* li.QuadPart is in the 100-nanosecond intervals */
	t->sec = (li.QuadPart / (QSE_NSECS_PER_SEC / 100)) - EPOCH_DIFF_SECS;
	t->nsec = (li.QuadPart % (QSE_NSECS_PER_SEC / 100)) * 100;

	return 0;

#elif defined(__OS2__)

	APIRET rc;
	DATETIME dt;
	qse_btime_t bt;

	/* Can I use DosQuerySysInfo(QSV_TIME_LOW) and 
	 * DosQuerySysInfo(QSV_TIME_HIGH) for this instead? 
	 * Maybe, resolution too low as it returns values 
	 * in seconds. */

	rc = DosGetDateTime (&dt);
	if (rc != NO_ERROR) return -1;

	bt.year = dt.year - QSE_BTIME_YEAR_BASE;
	bt.mon = dt.month - 1;
	bt.mday = dt.day;
	bt.hour = dt.hours;
	bt.min = dt.minutes;
	bt.sec = dt.seconds;
	/*bt.msec = dt.hundredths * 10;*/
	bt.isdst = -1; /* determine dst for me */

	if (qse_timelocal (&bt, t) <= -1) return -1;
	t->nsec = QSE_MSEC_TO_NSEC(dt.hundredths * 10);
	return 0;

#elif defined(__DOS__)

	struct dostime_t dt;
	struct dosdate_t dd;
	qse_btime_t bt;

	_dos_gettime (&dt);
	_dos_getdate (&dd);

	bt.year = dd.year - QSE_BTIME_YEAR_BASE;
	bt.mon = dd.month - 1;
	bt.mday = dd.day;
	bt.hour = dt.hour;
	bt.min = dt.minute;
	bt.sec = dt.second;
	/*bt.msec = dt.hsecond * 10; */
	bt.isdst = -1; /* determine dst for me */

	if (qse_timelocal (&bt, t) <= -1) return -1;
	t->nsec = QSE_MSEC_TO_NSEC(dt.hsecond * 10);
	return 0;

#elif defined(macintosh)
	unsigned long tv;
	
	GetDateTime (&tv);
	
	t->sec = tv;
	tv->nsec = 0;
	
	return 0;

#elif defined(HAVE_GETTIMEOFDAY)
	struct timeval tv;
	int n;

	/* TODO: consider using clock_gettime() if it's avaialble.. -lrt may be needed */
	n = QSE_GETTIMEOFDAY (&tv, QSE_NULL);
	if (n == -1) return -1;

	t->sec = tv.tv_sec;
	t->nsec = QSE_USEC_TO_NSEC(tv.tv_usec);
	return 0;

#else
	t->sec = QSE_TIME (QSE_NULL);
	t->nsec = 0;

	return 0;
#endif
}

int qse_getmtime (qse_mtime_t* mt)
{
	qse_ntime_t nt;
	if (qse_gettime(&nt) <= -1) return -1;
	*mt = QSE_SECNSEC_TO_MSEC(nt.sec, nt.nsec);
	return 0;
}

int qse_settime (const qse_ntime_t* t)
{
#if defined(_WIN32)
	FILETIME ft;
	SYSTEMTIME st;

	/**((qse_int64_t*)&ft) = ((t + EPOCH_DIFF_MSECS) * (10 * 1000));*/
	*((qse_int64_t*)&ft) = 
		(QSE_SEC_TO_NSEC(t->sec + EPOCH_DIFF_SECS) / 100)  + (t->nsec / 100);
	if (FileTimeToSystemTime (&ft, &st) == FALSE) return -1;
	if (SetSystemTime(&st) == FALSE) return -1;
	return 0;

#elif defined(__OS2__)

	APIRET rc;
	DATETIME dt;
	qse_btime_t bt;

	if (qse_localtime (t, &bt) <= -1) return -1;

	QSE_MEMSET (&dt, 0, QSE_SIZEOF(dt));
	dt.year = bt.year + QSE_BTIME_YEAR_BASE;
	dt.month = bt.mon + 1;
	dt.day = bt.mday;
	dt.hours = bt.hour;
	dt.minutes = bt.min;
	dt.seconds = bt.sec;
	dt.hundredths = QSE_NSEC_TO_MSEC(t->nsec) / 10;

	rc = DosSetDateTime (&dt);
	return (rc != NO_ERROR)? -1: 0;

#elif defined(__DOS__)

	struct dostime_t dt;
	struct dosdate_t dd;
	qse_btime_t bt;

	if (qse_localtime (t, &bt) <= -1) return -1;

	dd.year = bt.year + QSE_BTIME_YEAR_BASE;
	dd.month = bt.mon + 1;
	dd.day = bt.mday;
	dt.hour = bt.hour;
	dt.minute = bt.min;
	dt.second = bt.sec;
	dt.hsecond = QSE_NSEC_TO_MSEC(t->nsec) / 10;

	if (_dos_settime (&dt) != 0) return -1;
	if (_dos_setdate (&dd) != 0) return -1;

	return 0;

#elif defined(HAVE_SETTIMEOFDAY)
	struct timeval tv;
	int n;

	tv.tv_sec = t->sec;
	tv.tv_usec = QSE_NSEC_TO_USEC(t->nsec);

/*
#if defined(CLOCK_REALTIME) && defined(HAVE_CLOCK_SETTIME)
	{
		int r = clock_settime (CLOCK_REALTIME, ts);
		if (r == 0 || errno == EPERM) return r;
	}
#elif defined(HAVE_STIME)
	return stime (&ts->tv_sec);
#else
*/
	n = QSE_SETTIMEOFDAY (&tv, QSE_NULL);
	if (n == -1) return -1;
	return 0;

#else

	time_t tv;
	tv = t->sec;
	return (QSE_STIME (&tv) == -1)? -1: 0;
#endif
}

static void breakdown_time (const qse_ntime_t* nt, qse_btime_t* bt, qse_long_t gmtoff)
{
	int midx;
	qse_long_t days; /* total days */
	qse_long_t secs; /* the remaining seconds */
	qse_long_t year = QSE_EPOCH_YEAR;
	
	secs = nt->sec + gmtoff; /* offset in seconds */
	days = secs / QSE_SECS_PER_DAY;
	secs %= QSE_SECS_PER_DAY;

	while (secs < 0)
	{
		secs += QSE_SECS_PER_DAY;
		--days;
	}

	while (secs >= QSE_SECS_PER_DAY)
	{
		secs -= QSE_SECS_PER_DAY;
		++days;
	}

	bt->hour = secs / QSE_SECS_PER_HOUR;
	secs %= QSE_SECS_PER_HOUR;
	bt->min = secs / QSE_SECS_PER_MIN;
	bt->sec = secs % QSE_SECS_PER_MIN;

	bt->wday = (days + QSE_EPOCH_WDAY) % QSE_DAYS_PER_WEEK;  
	if (bt->wday < 0) bt->wday += QSE_DAYS_PER_WEEK;

	if (days >= 0)
	{
		while (days >= QSE_DAYS_PER_YEAR(year))
		{
			days -= QSE_DAYS_PER_YEAR(year);
			year++;
	}
	}
	else 
	{
		do 
		{
			year--;
			days += QSE_DAYS_PER_YEAR(year);
		} 
		while (days < 0);
	}

	bt->year = year - QSE_BTIME_YEAR_BASE;
	bt->yday = days;

	midx = QSE_IS_LEAPYEAR(year)? 1: 0;
	for (bt->mon = 0; days >= mdays[midx][bt->mon]; bt->mon++) 
	{
		days -= mdays[midx][bt->mon];
	}

	bt->mday = days + 1;
	bt->isdst = 0; /* TODO: this may vary depeding on offset and time */
	bt->gmtoff = gmtoff;
}

int qse_gmtime (const qse_ntime_t* nt, qse_btime_t* bt)
{
#if 0
	breakdown_time (nt, bt, 0);
	return 0;
#else

	struct tm* tm;
	time_t t = nt->sec;

	/* TODO: remove dependency on gmtime/gmtime_r */
#if defined(_WIN32)
	tm = gmtime(&t);
#elif defined(__OS2__)
#	if defined(__WATCOMC__)
		struct tm btm;
		tm = _gmtime(&t, &btm);
#	else
#		error Please support other compilers 
#	endif
#elif defined(__DOS__)
#	if defined(__WATCOMC__)
		struct tm btm;
		tm = _gmtime(&t, &btm);
#	else
#		error Please support other compilers
#	endif
#elif defined(HAVE_GMTIME_R)
	struct tm btm;
	tm = gmtime_r(&t, &btm);
#else
	/* thread unsafe */
	tm = gmtime_r(&t);
#endif
	if (tm == QSE_NULL) return -1;
	
	QSE_MEMSET (bt, 0, QSE_SIZEOF(*bt));

	bt->sec = tm->tm_sec;
	bt->min = tm->tm_min;
	bt->hour = tm->tm_hour;
	bt->mday = tm->tm_mday;
	bt->mon = tm->tm_mon;
	bt->year = tm->tm_year;
	bt->wday = tm->tm_wday;
	bt->yday = tm->tm_yday;
	bt->isdst = tm->tm_isdst;
#if defined(HAVE_STRUCT_TM_TM_GMTOFF)
	bt->gmtoff = tm->tm_gmtoff;
#elif defined(HAVE_STRUCT_TM___TM_GMTOFF)
	bt->gmtoff = tm->__tm_gmtoff;
#endif

	return 0;

#endif
}

int qse_localtime (const qse_ntime_t* nt, qse_btime_t* bt)
{
	struct tm* tm;
	time_t t = nt->sec;

	/* TODO: remove dependency on localtime/localtime_r */
#if defined(_WIN32)
	tm = localtime(&t);
#elif defined(__OS2__)
#	if defined(__WATCOMC__)
		struct tm btm;
		tm = _localtime(&t, &btm);
#	else
#		error Please support other compilers 
#	endif
#elif defined(__DOS__)
#	if defined(__WATCOMC__)
		struct tm btm;
		tm = _localtime(&t, &btm);
#	else
#		error Please support other compilers
#	endif
#elif defined(HAVE_LOCALTIME_R)
	struct tm btm;
	tm = localtime_r(&t, &btm);
#else
	/* thread unsafe */
	tm = localtime(&t);
#endif
	if (tm == QSE_NULL) return -1;

	QSE_MEMSET (bt, 0, QSE_SIZEOF(*bt));

	bt->sec = tm->tm_sec;
	bt->min = tm->tm_min;
	bt->hour = tm->tm_hour;
	bt->mday = tm->tm_mday;
	bt->mon = tm->tm_mon;
	bt->year = tm->tm_year;
	bt->wday = tm->tm_wday;
	bt->yday = tm->tm_yday;
	bt->isdst = tm->tm_isdst;
#if defined(HAVE_STRUCT_TM_TM_GMTOFF)
	bt->gmtoff = tm->tm_gmtoff;
#elif defined(HAVE_STRUCT_TM___TM_GMTOFF)
	bt->gmtoff = tm->__tm_gmtoff;
#elif defined(_WIN32)
	{
		TIME_ZONE_INFORMATION tzi;
		if (GetTimeZoneInformation(&tzi) != TIME_ZONE_ID_INVALID)
		{
			bt->gmtoff = -((int)tiz.Bias * 60);
		}
		else
		{
			bt->gmtoff = QSE_TYPE_MIN(int); /* unknown */
		}
	}
#else
	bt->gmtoff = QSE_TYPE_MIN(int); /* unknown */
#endif

	return 0;
}

int qse_timegm (const qse_btime_t* bt, qse_ntime_t* nt)
{
#if 0
#if defined(_WIN32)
	/* TODO: verify qse_timegm for WIN32 */
	SYSTEMTIME st;
	FILETIME ft;

	st.wYear = bt->tm_year + QSE_EPOCH_YEAR;
	st.wMonth = bt->tm_mon + WIN_EPOCH_MON;
	st.wDayOfWeek = bt->tm_wday;
	st.wDay = bt->tm_mday;
	st.wHour = bt->tm_hour;
	st.wMinute = bt->tm_min;
	st.mSecond = bt->tm_sec;
	st.mMilliseconds = bt->tm_msec;

	if (SystemTimeToFileTime (&st, &ft) == FALSE) return -1;
	*nt = ((qse_ntime_t)(*((qse_int64_t*)&ft)) / (10 * 1000));
	*nt -= EPOCH_DIFF_MSECS;
	
	return 0;
#elif defined(__OS2__)
#	error NOT IMPLEMENTED YET
#elif defined(__DOS__)
#	error NOT IMPLEMENTED YET
#else

	/* TODO: qse_timegm - remove dependency on timegm */
	struct tm tm;

	tm.tm_sec = bt->sec;
	tm.tm_min = bt->min;
	tm.tm_hour = bt->hour;
	tm.tm_mday = bt->mday;
	tm.tm_mon = bt->mon;
	tm.tm_year = bt->year;
	tm.tm_wday = bt->wday;
	tm.tm_yday = bt->yday;
	tm.tm_isdst = bt->isdst;
#if defined(HAVE_STRUCT_TM_TM_GMTOFF)
	tm->tm_gmtoff = bt->gmtoff; /* i don't think this is needed. but just keep it */
#elif defined(HAVE_STRUCT_TM___TM_GMTOFF)
	tm->__tm_gmtoff = bt->gmtoff;
#endif

#if defined(HAVE_TIMEGM)
	*nt = ((qse_ntime_t)timegm(&tm)*QSE_MSECS_PER_SEC) + bt->msec;
	return 0;
#else
	#warning #### timegm() is not available on this platform ####
	return -1;
#endif

#endif
#endif

	qse_long_t n = 0;
	int y = bt->year + QSE_BTIME_YEAR_BASE;
	int midx = QSE_IS_LEAPYEAR(y)? 1: 0;

	QSE_ASSERT (bt->mon >= 0 && bt->mon < QSE_MONS_PER_YEAR);

	if (y < QSE_EPOCH_YEAR)
	{
		/*int x;

		for (x = y; x < QSE_EPOCH_YEAR - 1; x++)
			n += QSE_DAYS_PER_YEAR(x);*/
		n = QSE_DAYS_PER_NORMYEAR * (QSE_EPOCH_YEAR - 1 - y) + 
		    get_leap_days (y, QSE_EPOCH_YEAR - 1);

		/*for (x = bt->mon + 1; x < QSE_MONS_PER_YEAR; x++)
			n += mdays[midx][x];*/
		n += mdays_rtot[midx][bt->mon];

		n += mdays[midx][bt->mon] - bt->mday;
		if (midx == 1) n -= 1;
		n *= QSE_HOURS_PER_DAY;

		n = (n + QSE_HOURS_PER_DAY - bt->hour - 1) * QSE_MINS_PER_HOUR;
		n = (n + QSE_MINS_PER_HOUR - bt->min - 1) * QSE_SECS_PER_MIN;
		n = (n + QSE_SECS_PER_MIN - bt->sec); /* * QSE_MSECS_PER_SEC;

		if (bt->msec > 0) n += QSE_MSECS_PER_SEC - bt->msec;
		*nt = -n; */

		nt->sec = -n;
		nt->nsec = 0;
	} 
	else
	{
		/*int x;

		for (x = QSE_EPOCH_YEAR; x < y; x++) 
			n += QSE_DAYS_PER_YEAR(x);*/
		n = QSE_DAYS_PER_NORMYEAR * (y - QSE_EPOCH_YEAR) + 
		    get_leap_days (QSE_EPOCH_YEAR, y);

		/*for (x = 0; x < bt->mon; x++) n += mdays[midx][x];*/
		n += mdays_tot[midx][bt->mon];

		n = (n + bt->mday - 1) * QSE_HOURS_PER_DAY;
		n = (n + bt->hour) * QSE_MINS_PER_HOUR;
		n = (n + bt->min) * QSE_SECS_PER_MIN;
		n = (n + bt->sec); /* QSE_MSECS_PER_SEC;

		*nt = n + bt->msec;*/

		nt->sec = n;
		nt->nsec = 0;
	}

	return 0;
}

int qse_timelocal (const qse_btime_t* bt, qse_ntime_t* nt)
{
	/* TODO: qse_timelocal - remove dependency on timelocal */
	struct tm tm;

	QSE_MEMSET (&tm, 0, QSE_SIZEOF(tm));
	tm.tm_sec = bt->sec;
	tm.tm_min = bt->min;
	tm.tm_hour = bt->hour;
	tm.tm_mday = bt->mday;
	tm.tm_mon = bt->mon;
	tm.tm_year = bt->year;
	tm.tm_wday = bt->wday;
	tm.tm_yday = bt->yday;
	tm.tm_isdst = bt->isdst;
#if defined(HAVE_STRUCT_TM_TM_GMTOFF)
	tm.tm_gmtoff = bt->gmtoff; /* i don't think this is needed. but just keep it */
#elif defined(HAVE_STRUCT_TM___TM_GMTOFF)
	tm->__tm_gmtoff = bt->gmtoff;
#endif

#if defined(HAVE_TIMELOCAL)
	nt->sec = timelocal (&tm);
#else
	nt->sec = mktime (&tm);
#endif

	nt->nsec = 0;
	return 0;
}

void qse_add_ntime (qse_ntime_t* z, const qse_ntime_t* x, const qse_ntime_t* y)
{
	QSE_ASSERT (x->nsec >= 0 && x->nsec < QSE_NSECS_PER_SEC);
	QSE_ASSERT (y->nsec >= 0 && y->nsec < QSE_NSECS_PER_SEC);

#if 0
	z->sec = x->sec + y->sec;
	z->nsec = x->nsec + y->nsec;

	while (z->nsec >= QSE_NSECS_PER_SEC)
	{
		z->sec = z->sec + 1;
		z->nsec = z->nsec - QSE_NSECS_PER_SEC;
	}
#else
	qse_ntime_sec_t xs, ys;
	qse_ntime_nsec_t ns;

	ns = x->nsec + y->nsec;
	if (ns >= QSE_NSECS_PER_SEC)
	{
		ns = ns - QSE_NSECS_PER_SEC;
		if (x->sec == QSE_TYPE_MAX(qse_ntime_sec_t))
		{
			if (y->sec >= 0) goto overflow;
			xs = x->sec;
			ys = y->sec + 1; /* this won't overflow */
		}
		else
		{
			xs = x->sec + 1; /* this won't overflow */
			ys = y->sec;
		}
	}
	else
	{
		xs = x->sec;
		ys = y->sec;
	}

	if ((ys >= 1 && xs > QSE_TYPE_MAX(qse_ntime_sec_t) - ys) ||
	    (ys <= -1 && xs < QSE_TYPE_MIN(qse_ntime_sec_t) - ys))
	{
		if (xs >= 0)
		{
		overflow:
			xs = QSE_TYPE_MAX(qse_ntime_sec_t);
			ns = QSE_NSECS_PER_SEC - 1;
		}
		else
		{
			xs = QSE_TYPE_MIN(qse_ntime_sec_t);
			ns = 0;
		}
	}
	else
	{
		xs = xs + ys;
	}

	z->sec = xs;
	z->nsec = ns;
#endif
}

void qse_sub_ntime (qse_ntime_t* z, const qse_ntime_t* x, const qse_ntime_t* y)
{
	QSE_ASSERT (x->nsec >= 0 && x->nsec < QSE_NSECS_PER_SEC);
	QSE_ASSERT (y->nsec >= 0 && y->nsec < QSE_NSECS_PER_SEC);

#if 0
	z->sec = x->sec - y->sec;
	z->nsec = x->nsec - y->nsec;

	while (z->nsec < 0)
	{
		z->sec = z->sec - 1;
		z->nsec = z->nsec + QSE_NSECS_PER_SEC;
	}
#else
	qse_ntime_sec_t xs, ys;
	qse_ntime_nsec_t ns;

	ns = x->nsec - y->nsec;
	if (ns < 0)
	{
		ns = ns + QSE_NSECS_PER_SEC;
		if (x->sec == QSE_TYPE_MIN(qse_ntime_sec_t))
		{
			if (y->sec <= 0) goto underflow;
			xs = x->sec;
			ys = y->sec - 1; /* this won't underflow */
		}
		else
		{
			xs = x->sec - 1; /* this won't underflow */
			ys = y->sec;
		}
	}
	else
	{
		xs = x->sec;
		ys = y->sec;
	}

	if ((ys >= 1 && xs < QSE_TYPE_MIN(qse_ntime_sec_t) + ys) ||
	    (ys <= -1 && xs > QSE_TYPE_MAX(qse_ntime_sec_t) + ys))
	{
		if (xs >= 0)
		{
			xs = QSE_TYPE_MAX(qse_ntime_sec_t);
			ns = QSE_NSECS_PER_SEC - 1;
		}
		else
		{
		underflow:
			xs = QSE_TYPE_MIN(qse_ntime_sec_t);
			ns = 0;
		}
	} 
	else
	{
		xs = xs - ys;
	}

	z->sec = xs;
	z->nsec = ns;
#endif
}

int qse_mbs_to_ntime (const qse_mchar_t* text, qse_ntime_t* ntime)
{
	const qse_mchar_t* p = text, * cp;
	qse_ntime_t tv = { 0, 0 };
	int neg = 0;

	if (*p == QSE_MT('-')) 
	{
		neg = 1;
		p++;
	}
	else if (*p == QSE_MT('+'))
	{
		p++;
	}

	cp = p;
	while (QSE_ISMDIGIT(*p))
	{
		qse_long_t oldsec = tv.sec;
		tv.sec = tv.sec * 10 + (*p - QSE_MT('0'));
		if (tv.sec < oldsec) return -1; /* overflow? */
		p++;
	}
	if (cp == p) return -1;

	if (*p == QSE_MT('.'))
	{
		qse_int32_t base = QSE_SEC_TO_NSEC(1); /* 1000000000 */

		p++;
		base /= 10; /* the max value is 999999999. 9 digits ony */

		while (*p && QSE_ISMDIGIT(*p) && base > 0)
		{
			tv.nsec += (*p - QSE_MT('0')) * base;
			base /= 10;
			p++;
		}
	}

	if (*p != QSE_MT('\0')) return -1;

	if (neg) tv.sec *= -1;
	*ntime = tv;

	return 0;
}

int qse_wcs_to_ntime (const qse_wchar_t* text, qse_ntime_t* ntime)
{
	const qse_wchar_t* p = text, * cp;
	qse_ntime_t tv = { 0, 0 };
	int neg = 0;

	if (*p == QSE_WT('-')) 
	{
		neg = 1;
		p++;
	}
	else if (*p == QSE_WT('+'))
	{
		p++;
	}

	cp = p;
	while (QSE_ISWDIGIT(*p))
	{
		qse_long_t oldsec = tv.sec;
		tv.sec = tv.sec * 10 +  (*p - QSE_WT('0'));
		if (tv.sec < oldsec) return -1; /* overflow? */
		p++;
	}
	if (cp == p) return -1;

	if (*p == QSE_WT('.'))
	{
		qse_int32_t base = QSE_SEC_TO_NSEC(1); /* 1000000000 */

		p++;
		base /= 10; /* the max value is 999999999. 9 digits ony */

		while (*p && QSE_ISWDIGIT(*p) && base > 0)
		{
			tv.nsec += (*p - QSE_WT('0')) * base;
			base /= 10;
			p++;
		}
	}

	if (*p != QSE_WT('\0')) return -1;

	if (neg) tv.sec *= -1;
	*ntime = tv;

	return 0;
}