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refclock: improve TAI-UTC conversion

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Instead of using the TAI-UTC offset which corresponds to the current
system time, get the offset for the reference time. This allows the
clock to be accurately stepped from a time with different TAI-UTC
offset.
This commit is contained in:
Miroslav Lichvar 2017-10-11 16:57:10 +02:00
parent a349b2803c
commit f35c81c871
1 changed files with 25 additions and 9 deletions
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34
refclock.c
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@ -357,6 +357,28 @@ RCL_GetDriverOption(RCL_Instance instance, char *name)
return NULL;
}
static int
convert_tai_offset(struct timespec *sample_time, double *offset)
{
struct timespec tai_ts, utc_ts;
int tai_offset;
/* Get approximate TAI-UTC offset for the reference time in TAI */
UTI_AddDoubleToTimespec(sample_time, *offset, &tai_ts);
tai_offset = REF_GetTaiOffset(&tai_ts);
/* Get TAI-UTC offset for the reference time in UTC +/- 1 second */
UTI_AddDoubleToTimespec(&tai_ts, -tai_offset, &utc_ts);
tai_offset = REF_GetTaiOffset(&utc_ts);
if (!tai_offset)
return 0;
*offset -= tai_offset;
return 1;
}
int
RCL_AddSample(RCL_Instance instance, struct timespec *sample_time, double offset, int leap)
{
@ -386,15 +408,9 @@ RCL_AddSample(RCL_Instance instance, struct timespec *sample_time, double offset
return 0;
}
if (instance->tai) {
int tai_offset = REF_GetTaiOffset(sample_time);
if (!tai_offset) {
DEBUG_LOG("refclock sample ignored unknown TAI offset");
return 0;
}
offset -= tai_offset;
if (instance->tai && !convert_tai_offset(sample_time, &offset)) {
DEBUG_LOG("refclock sample ignored unknown TAI offset");
return 0;
}
filter_add_sample(&instance->filter, &cooked_time, offset - correction + instance->offset, dispersion);