linux_time.h

Newlib 嵌入式 C库 标准实现代码

#ifndef _LINUX_TIME_H
#define _LINUX_TIME_H

#include <asm/param.h>
#include <sys/types.h>

#ifndef _STRUCT_TIMESPEC
#define _STRUCT_TIMESPEC
struct timespec {
	time_t	tv_sec;		/* seconds */
	long	tv_nsec;	/* nanoseconds */
};
#endif /* _STRUCT_TIMESPEC */

/*
 * Change timeval to jiffies, trying to avoid the
 * most obvious overflows..
 *
 * And some not so obvious.
 *
 * Note that we don't want to return MAX_LONG, because
 * for various timeout reasons we often end up having
 * to wait "jiffies+1" in order to guarantee that we wait
 * at _least_ "jiffies" - so "jiffies+1" had better still
 * be positive.
 */
#define MAX_JIFFY_OFFSET ((~0UL >> 1)-1)

static __inline__ unsigned long
timespec_to_jiffies(struct timespec *value)
{
	unsigned long sec = value->tv_sec;
	long nsec = value->tv_nsec;

	if (sec >= (MAX_JIFFY_OFFSET / HZ))
		return MAX_JIFFY_OFFSET;
	nsec += 1000000000L / HZ - 1;
	nsec /= 1000000000L / HZ;
	return HZ * sec + nsec;
}

static __inline__ void
jiffies_to_timespec(unsigned long jiffies, struct timespec *value)
{
	value->tv_nsec = (jiffies % HZ) * (1000000000L / HZ);
	value->tv_sec = jiffies / HZ;
}
 
#ifndef _STRUCT_TIMEVAL
#define _STRUCT_TIMEVAL
struct timeval {
	time_t		tv_sec;		/* seconds */
	suseconds_t	tv_usec;	/* microseconds */
};
#endif

struct timezone {
	int	tz_minuteswest;	/* minutes west of Greenwich */
	int	tz_dsttime;	/* type of dst correction */
};

#define	ITIMER_REAL	0
#define	ITIMER_VIRTUAL	1
#define	ITIMER_PROF	2

struct  itimerspec {
        struct  timespec it_interval;    /* timer period */
        struct  timespec it_value;       /* timer expiration */
};

struct	itimerval {
	struct	timeval it_interval;	/* timer interval */
	struct	timeval it_value;	/* current value */
};

#endif