minix/lib/libhgfs/time.c
David van Moolenbroek 638ce89250 hgfs: subsecond timestamp precision
Slightly cleaned up version of patch contributed by Antoine Leca.
2012-03-30 01:40:07 +02:00

70 lines
2.1 KiB
C

/* Part of libhgfs - (c) 2009, D.C. van Moolenbroek */
#include "inc.h"
static u64_t time_offset;
/*===========================================================================*
* time_init *
*===========================================================================*/
void time_init(void)
{
/* Initialize the time conversion module.
*/
/* Generate a 64-bit value for the offset to use in time conversion. The
* HGFS time format uses Windows' FILETIME standard, expressing time in
* 100ns-units since Jan 1, 1601 UTC. The value that is generated is
* the difference between that time and the UNIX epoch, in 100ns units.
*/
/* FIXME: we currently do not take into account timezones. */
time_offset = mul64u(116444736, 1000000000);
}
/*===========================================================================*
* time_put *
*===========================================================================*/
void time_put(struct timespec *tsp)
{
/* Store a POSIX timestamp pointed to by the given pointer onto the RPC buffer,
* in HGFS timestamp format. If a NULL pointer is given, store a timestamp of
* zero instead.
*/
u64_t hgfstime;
if (tsp != NULL) {
hgfstime = add64ul(mul64u(tsp->tv_sec, 10000000), tsp->tv_nsec / 100);
hgfstime = add64(hgfstime, time_offset);
RPC_NEXT32 = ex64lo(hgfstime);
RPC_NEXT32 = ex64hi(hgfstime);
} else {
RPC_NEXT32 = 0;
RPC_NEXT32 = 0;
}
}
/*===========================================================================*
* time_get *
*===========================================================================*/
void time_get(struct timespec *tsp)
{
/* Get a HGFS timestamp from the RPC buffer, convert it into a POSIX timestamp,
* and store the result in the given time pointer. If the given pointer is
* NULL, however, simply skip over the timestamp in the RPC buffer.
*/
u64_t hgfstime;
u32_t time_lo, time_hi;
if (tsp != NULL) {
time_lo = RPC_NEXT32;
time_hi = RPC_NEXT32;
hgfstime = sub64(make64(time_lo, time_hi), time_offset);
tsp->tv_sec = div64u(hgfstime, 10000000);
tsp->tv_nsec = rem64u(hgfstime, 10000000) * 100;
}
else RPC_ADVANCE(sizeof(u32_t) * 2);
}