HostTimeUnixImpl.mesa
Copyright Ó 1988, 1991 by Xerox Corporation. All rights reserved.
Carl Hauser, November 14, 1988 11:17:56 am PST
Willie-s, August 13, 1991 12:19 pm PDT
~
BEGIN
Time: TYPE = HostTime.Time;
ExtendedGMT: TYPE = HostTime.ExtendedGMT;
ZoneAndDST: TYPE = HostTime.ZoneAndDST;
gmtBaseYear: CARDINAL = 1968; -- really should come from BasicTime, but it's not exported
unixBaseYear: CARDINAL = 1970; -- Unix times start at 00:00Z Jan 1, 1978.
unixCorrection: CARD = (((unixBaseYear-gmtBaseYear)*365+1) * 24*60*60) -- '68 was a leap year -- ;
HostTimeFromExtendedGMT:
PUBLIC
PROC [egmt: ExtendedGMT]
RETURNS [time: Time ¬ [0, 0, 0, 0]] ~ {
time.a ¬ -unixCorrection + LOOPHOLE[egmt.gmt];
time.b ¬ egmt.usecs;
};
ExtendedGMTFromHostTime:
PUBLIC PROC [time: Time]
RETURNS [egmt: ExtendedGMT] ~ {
egmt.gmt ¬ LOOPHOLE[time.a+unixCorrection];
egmt.usecs ¬ time.b;
};
GetTime:
PUBLIC PROC []
RETURNS [time: Time ¬ [0, 0, 0, 0]] ~
TRUSTED {
timeVal: UnixTypes.TimeVal ¬ [0, 0];
[] ¬ UnixSysCalls.GetTimeOfDay[tp: @timeVal, tzp: NIL];
time.a ¬ timeVal.sec;
time.b ¬ timeVal.usec;
};
TimeToMicroseconds:
PUBLIC PROC [time: Time]
RETURNS [
CARD] ~ {
RETURN [CARD[time.b]+LOOPHOLE[time.a, CARD]*1000000];
};
MicrosecondsToTime:
PUBLIC PROC [usecs:
CARD]
RETURNS [time: Time] ~ {
RETURN [[usecs/1000000, usecs MOD 1000000, 0, 0]];
};
TimeToSeconds:
PUBLIC PROC [time: Time]
RETURNS [
REAL] ~ {
Returns the number of seconds. Beware: reals have only 24 bits of precision, so the fractional part of the result is not as accurate as calling PulsesToMicroseconds. However, the result never overflows.
RETURN [time.a + time.b*1.0e-6];
};
SecondsToTime:
PUBLIC PROC [secs:
REAL]
RETURNS [Time] ~ {
RETURN [[Real.Floor[secs], Real.Round[1000000*(secs-Real.Floor[secs])], 0, 0]];
};
GetZoneAndDST:
PUBLIC
PROC []
RETURNS [tp: ZoneAndDST] ~
TRUSTED {
unixTimeZone: UnixTypes.TimeZone;
TRUSTED {[] ¬ UnixSysCalls.GetTimeOfDay[tp: NIL, tzp: @unixTimeZone]};
tp.zone ¬ unixTimeZone.minutesWest;
This is thoroughly unsatisfactory, but the SunOS doesn't know these things. It's built into their conversion code. These are the right numbers for 1988
IF unixTimeZone.dstTime # 0
THEN {
tp.beginDST ¬ 98;
tp.endDST ¬ 305; }
ELSE {
tp.beginDST ¬ 366; -- never use dst
tp.endDST ¬ 1;
};
};