time.c File Reference

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <time.h>
#include <sys/time.h>
#include <syscall.h>

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Macros
#define	TZ_OFFSET_SECS   0

Functions
time_t	time (time_t *t)
int	gettimeofday (struct timeval *tv, struct timezone *tz)
int	settimeofday (const struct timeval *tv, const struct timezone *tz)
char *	asctime_r (const struct tm *tm, char *buf)
char *	asctime (const struct tm *tm)
char *	ctime_r (const time_t *timep, char *buf)
char *	ctime (const time_t *timep)
static bool	Time_IsLeapYear (uint64_t year)
static int	Time_DaysInMonth (uint64_t year, uint64_t month)
struct tm *	gmtime_r (const time_t *timep, struct tm *tm)
struct tm *	gmtime (const time_t *timep)
struct tm *	localtime_r (const time_t *timep, struct tm *result)
struct tm *	localtime (const time_t *timep)
time_t	mktime (struct tm *tm)

Variables
static const char *	dayOfWeek [7] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }
static const char *	months [12]

Macro Definition Documentation

TZ_OFFSET_SECS

#define TZ_OFFSET_SECS   0

Definition at line 11 of file time.c.

Function Documentation

asctime()

char * asctime

(

const struct tm *

tm

)

Definition at line 64 of file time.c.

{
    static char buf[26];
    return asctime_r(tm, buf);
}

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asctime_r()

char * asctime_r	(	const struct tm *	tm,
		char *	buf
	)

Definition at line 50 of file time.c.

{
    // assert(tm->tm_wday < 7);
    // assert(tm->tm_mon < 12);
 
    snprintf(buf, 26, "%s %s %2d %2d:%02d:%02d %4d\n",
                dayOfWeek[tm->tm_wday], months[tm->tm_mon],
                tm->tm_mday, tm->tm_hour, tm->tm_min,
                tm->tm_sec, tm->tm_year + 1900);
 
    return buf;
}

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ctime()

char * ctime

(

const time_t *

timep

)

Definition at line 78 of file time.c.

{
    return asctime(localtime(timep));
}

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ctime_r()

char * ctime_r	(	const time_t *	timep,
		char *	buf
	)

Definition at line 71 of file time.c.

{
    struct tm tm;
    return asctime_r(localtime_r(timep, &tm), buf);
}

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gettimeofday()

int gettimeofday	(	struct timeval *	tv,
		struct timezone *	tz
	)

Definition at line 32 of file time.c.

{
    uint64_t nsec = OSTime();
 
    tv->tv_sec = nsec / 1000000000;
    tv->tv_usec = (nsec % 1000000000) / 1000;
 
    return 0;
}

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gmtime()

struct tm * gmtime

(

const time_t *

timep

)

Definition at line 164 of file time.c.

{
    static struct tm tm;
    return gmtime_r(timep, &tm);
}

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gmtime_r()

struct tm * gmtime_r	(	const time_t *	timep,
		struct tm *	tm
	)

Definition at line 108 of file time.c.

{
    uint64_t secs, mins, hours;
    uint64_t days;
    uint64_t y, m;
 
    // Compute seconds
    secs = *timep % (60 * 60 * 24);
    days = *timep / (60 * 60 * 24);
    mins = secs / 60;
    secs = secs % 60;
 
    // Compute minutes
    hours = mins / 60;
    mins = mins % 60;
 
    // Compute hours
    hours = hours % 24;
 
    tm->tm_sec = secs;
    tm->tm_min = mins;
    tm->tm_hour = hours;
 
    tm->tm_wday = (days + 3) % 7;
 
    for (y = 1970; ; y++) {
        uint64_t daysOfYear;
        if (Time_IsLeapYear(y)) {
            daysOfYear = 366;
        } else {
            daysOfYear = 365;
        }
 
        if (days < daysOfYear) {
            tm->tm_yday = days;
            tm->tm_year = y - 1900;
            break;
        }
        days -= daysOfYear;
    }
 
    for (m = 0; ; m++) {
        uint64_t daysOfMonth = Time_DaysInMonth(tm->tm_year + 1900, m);
 
        if (days < daysOfMonth) {
            tm->tm_mday = days;
            tm->tm_mon = m;
            break;
        }
        days -= daysOfMonth;
    }
 
    return tm;
}

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localtime()

struct tm * localtime

(

const time_t *

timep

)

Definition at line 178 of file time.c.

{
    static struct tm tm;
    return localtime_r(timep, &tm);
}

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localtime_r()

struct tm * localtime_r	(	const time_t *	timep,
		struct tm *	result
	)

Definition at line 171 of file time.c.

{
    time_t t = *timep - TZ_OFFSET_SECS;
    return gmtime_r(&t, result);
}

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mktime()

time_t mktime

(

struct tm *

tm

)

Definition at line 185 of file time.c.

{
    uint64_t days = 0;
    uint64_t secs = 0;
    uint64_t y, m;
 
    // Convert to UNIX epoch
    for (y = 70; y < tm->tm_year; y++) {
        if (Time_IsLeapYear(y))
            days += 366;
        else
            days += 365;
    }
 
    uint64_t yday = 0;
    for (m = 0; m < tm->tm_mon; m++) {
        yday += Time_DaysInMonth(tm->tm_year + 1900, m);
    }
    yday += tm->tm_mday;
    days += yday;
 
    secs = 24 * days + tm->tm_hour;
    secs = secs * 60 + tm->tm_min;
    secs = secs * 60 + tm->tm_sec;
 
    secs += TZ_OFFSET_SECS;
 
    return secs;
}

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settimeofday()

int settimeofday	(	const struct timeval *	tv,
		const struct timezone *	tz
	)

Definition at line 43 of file time.c.

{
    // set errno
    return -1;
}

time()

time_t time

(

time_t *

t

)

Definition at line 20 of file time.c.

{
    uint64_t nsec = OSTime();
    time_t sec = nsec / 1000000000;
 
    if (t)
        *t = sec;
 
    return sec;
}

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Time_DaysInMonth()

static int Time_DaysInMonth ( uint64_t  year, uint64_t  month  )

static

Definition at line 96 of file time.c.

{
    static const uint64_t days[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
 
    if ((month == 2) && Time_IsLeapYear(year))
        return 29;
    else
        return days[month];
}

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Time_IsLeapYear()

static bool Time_IsLeapYear ( uint64_t  year )

static

Definition at line 84 of file time.c.

{
    if ((year % 4) != 0)
        return false;
    if ((year % 100) != 0)
        return true;
    if ((year % 400) != 0)
        return false;
    return true;
}

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Variable Documentation

dayOfWeek

const char* dayOfWeek[7] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }

static

Definition at line 13 of file time.c.

months

const char* months[12]

static

Initial value:

= {
    "Jan", "Feb", "Mar", "Apr", "May", "Jun",
    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
}

Definition at line 14 of file time.c.