timexsup.c revision 358659 
1/*
2 * timexsup.c - 'struct timex' support functions
3 *
4 * Written by Juergen Perlinger (perlinger@ntp.org) for the NTP project.
5 * The contents of 'html/copyright.html' apply.
6 */
7
8#include "config.h"
9#include "timexsup.h"
10#include <limits.h>
11#include <math.h>
12
13#ifdef HAVE_SYS_TIMEX_H
14# include <sys/timex.h>
15#endif
16
17#if defined(MOD_NANO) != defined(STA_NANO)
18# warning inconsistent definitions of MOD_NANO vs STA_NANO
19#endif
20
21static long
22clamp_rounded(
23	double dval
24	)
25{
26	/* round */
27	dval = floor(dval + 0.5);
28
29	/* clamp / saturate */
30	if (dval >= LONG_MAX)
31		return LONG_MAX;
32	if (dval <= LONG_MIN)
33		return LONG_MIN;
34	return (long)dval;
35
36}
37double
38dbl_from_var_long(
39	long	lval,
40	int	status
41	)
42{
43#ifdef STA_NANO
44	if (status & STA_NANO)
45		return (double)lval * 1e-9;
46#else
47	(void)status;
48#endif
49	return (double)lval * 1e-6;
50}
51
52double
53dbl_from_usec_long(
54	long	lval
55	)
56{
57	return (double)lval * 1e-6;
58}
59
60long
61var_long_from_dbl(
62	double		dval,
63	unsigned int *	modes
64	)
65{
66#ifdef MOD_NANO
67	*modes |= MOD_NANO;
68	dval *= 1e+9;
69#else
70	(void)modes;
71	dval *= 1e+6;
72#endif
73	return clamp_rounded(dval);
74}
75
76long
77usec_long_from_dbl(
78	double	dval
79	)
80{
81	return clamp_rounded(dval * 1e+6);
82}
83
84