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Replaced epoch offset calculation, fixes problem on vxWorks.

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This commit is contained in:
Andrew Johnson
2007-11-13 22:54:20 +00:00
parent 08804b05d5
commit 4b7d838b20
1 changed files with 51 additions and 54 deletions
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src/libCom/osi/epicsTime.cpp
+51 -54
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@@ -43,17 +43,19 @@ static const char pEpicsTimeVersion[] =
// useful public constants
//
static const unsigned mSecPerSec = 1000u;
static const unsigned uSecPerSec = 1000u * mSecPerSec;
static const unsigned nSecPerSec = 1000u * uSecPerSec;
static const unsigned uSecPerMSec = 1000u;
static const unsigned uSecPerSec = uSecPerMSec * mSecPerSec;
static const unsigned nSecPerUSec = 1000u;
static const unsigned secPerMin = 60u;
static const unsigned nSecPerSec = nSecPerUSec * uSecPerSec;
static const unsigned nSecFracDigits = 9u;
static const unsigned tmStructEpochYear = 1900;
static const unsigned tmEpochYear = 1900;
static const unsigned ansiEpochYear = 1970;
static const unsigned epicsEpochYear = 1990;
static const unsigned epicsEpocMonth = 0; // January
static const unsigned epicsEpocDayOfTheMonth = 1; // the 1st day of the month
static const unsigned epochMonth = 0; // January
static const unsigned epochDayOfTheMonth = 1; // the 1st
//
// epicsTime (const unsigned long secIn, const unsigned long nSecIn)
@@ -80,53 +82,47 @@ static const epicsTimeLoadTimeInit lti;
//
epicsTimeLoadTimeInit::epicsTimeLoadTimeInit ()
{
static const time_t ansiEpoch = 0;
double secWest;
// All we know about time_t is that it is an arithmetic type.
time_t t_zero = static_cast<time_t> (0);
time_t t_one = static_cast<time_t> (1);
this->time_tSecPerTick = difftime (t_one, t_zero);
{
time_t current = time ( NULL );
time_t error;
struct tm date; // vxWorks 6.0 requires "struct" here
/* We calculate the difference in seconds between the ANSI and EPICS
* epochs (1970-1-1, 1990-1-1). However mktime() takes a local time
* and adds a timezone-specified Daylight Savings Time offset to the
* result it returns. Luckily we only need the time difference in
* seconds between the two epochs, so the two DST corrections cancel
* each other out. We offset the local time used by 12 hours so the
* ANSI result can never go negative whatever timezone we're in.
*/
int status = epicsTime_gmtime ( &current, &date );
assert ( status == epicsTimeOK );
error = mktime ( &date );
assert ( error != (time_t) - 1 );
secWest = difftime ( error, current );
}
{
time_t first = static_cast<time_t> (0);
time_t last = static_cast<time_t> (1);
this->time_tSecPerTick = difftime (last, first);
}
struct tm tmEpoch;
tmEpoch.tm_sec = 0;
tmEpoch.tm_min = 0;
tmEpoch.tm_hour = 12;
tmEpoch.tm_mday = epochDayOfTheMonth;
tmEpoch.tm_mon = epochMonth;
tmEpoch.tm_isdst = 0;
{
struct tm tmEpicsEpoch;
time_t epicsEpoch;
tmEpoch.tm_year = ansiEpochYear - tmEpochYear;
time_t ansiEpoch = mktime(&tmEpoch);
assert(ansiEpoch != (time_t) -1);
tmEpicsEpoch.tm_sec = 0;
tmEpicsEpoch.tm_min = 0;
tmEpicsEpoch.tm_hour = 0;
tmEpicsEpoch.tm_mday = epicsEpocDayOfTheMonth;
tmEpicsEpoch.tm_mon = epicsEpocMonth;
tmEpicsEpoch.tm_year = epicsEpochYear - tmStructEpochYear;
// must not correct for DST because secWest does
// not include a DST offset
tmEpicsEpoch.tm_isdst = 0;
tmEpoch.tm_year = epicsEpochYear - tmEpochYear;
time_t epicsEpoch = mktime(&tmEpoch);
assert(epicsEpoch != (time_t) -1);
epicsEpoch = mktime (&tmEpicsEpoch);
assert (epicsEpoch!=(time_t)-1);
this->epicsEpochOffset = difftime ( epicsEpoch, ansiEpoch ) - secWest;
}
this->epicsEpochOffset = difftime (epicsEpoch, ansiEpoch);
if ( this->time_tSecPerTick == 1.0 && this->epicsEpochOffset <= ULONG_MAX &&
this->epicsEpochOffset >= 0 ) {
if (this->time_tSecPerTick == 1.0 &&
this->epicsEpochOffset <= ULONG_MAX &&
this->epicsEpochOffset >= 0) {
// We can use simpler code on Posix-compliant systems
this->useDiffTimeOptimization = true;
this->epicsEpochOffsetAsAnUnsignedLong =
static_cast < unsigned long > ( this->epicsEpochOffset );
}
else {
static_cast<unsigned long>(this->epicsEpochOffset);
} else {
// Forced to use the slower but correct code
this->useDiffTimeOptimization = false;
this->epicsEpochOffsetAsAnUnsignedLong = 0;
}
@@ -204,9 +200,10 @@ epicsTime::epicsTime (const epicsTimeStamp &ts)
}
}
epicsTime::epicsTime () : secPastEpoch(0u), nSec(0u) {}
epicsTime::epicsTime () :
secPastEpoch(0u), nSec(0u) {}
epicsTime::epicsTime (const epicsTime &t) :
epicsTime::epicsTime (const epicsTime &t) :
secPastEpoch (t.secPastEpoch), nSec (t.nSec) {}
epicsTime epicsTime::getCurrent ()
@@ -229,7 +226,7 @@ epicsTime epicsTime::getEvent (const epicsTimeEvent &event)
return epicsTime ( current );
}
void epicsTime::synchronize () {} // depricated
void epicsTime::synchronize () {} // deprecated
//
// operator time_t_wrapper ()
@@ -451,12 +448,12 @@ epicsTime::operator epicsTimeStamp () const
// specifying its nnnn
// C) returning a pointer to the postfix (which might be passed again
// to fracFormatFind.
static const char * fracFormatFind (
const char * const pFormat,
static const char * fracFormatFind (
const char * const pFormat,
char * const pPrefixBuf,
const size_t prefixBufLen,
bool & fracFmtFound,
unsigned long & fracFmtWidth )
unsigned long & fracFmtWidth )
{
assert ( prefixBufLen > 1 );
unsigned long width = ULONG_MAX;
@@ -535,7 +532,7 @@ size_t epicsTime::strftime (
char strftimePrefixBuf [256];
bool fracFmtFound;
unsigned long fracWid;
pFmt = fracFormatFind (
pFmt = fracFormatFind (
pFmt,
strftimePrefixBuf, sizeof ( strftimePrefixBuf ),
fracFmtFound, fracWid );
@@ -547,7 +544,7 @@ size_t epicsTime::strftime (
// all but fractional seconds use strftime formatting
if ( strftimePrefixBuf[0] != '\0' ) {
local_tm_nano_sec tmns = *this;
size_t strftimeNumChar = :: strftime (
size_t strftimeNumChar = :: strftime (
pBufCur, bufLenLeft, strftimePrefixBuf, & tmns.ansi_tm );
pBufCur [ strftimeNumChar ] = '\0';
pBufCur += strftimeNumChar;