X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=simgear%2Ftiming%2Fsg_time.cxx;h=a0353d4ec2ca142e36009c4e12a5ae5e1ac1237d;hb=5c3b569e978733fb3d917d0cf3edda82a503d70d;hp=3fca4a8b0ef94ac893b2591e8b0cbd42ef0c3fcf;hpb=a4d60e7bd6e9ab86e6152ed94a1b928e90b508e1;p=simgear.git diff --git a/simgear/timing/sg_time.cxx b/simgear/timing/sg_time.cxx index 3fca4a8b..a0353d4e 100644 --- a/simgear/timing/sg_time.cxx +++ b/simgear/timing/sg_time.cxx @@ -64,16 +64,7 @@ SGTime::SGTime( const string& root ) { - if (cur_time_params) { - FG_LOG( FG_GENERAL, FG_ALERT, - "Error: only one instance of SGTime allowed" ); - exit(-1); - } - - cur_time_params = this; - FGPath zone( root ); - zone.append( "Timezone" ); zone.append( "zone.tab" ); FG_LOG( FG_EVENT, FG_DEBUG, "Reading timezone info from: " << zone.str() ); @@ -92,30 +83,9 @@ SGTime::~SGTime() } } -void SGTime::updateLocal( double lon, double lat, const string& root ) -{ - time_t currGMT; - time_t aircraftLocalTime; - GeoCoord location( RAD_TO_DEG * lat, RAD_TO_DEG * lon ); - GeoCoord* nearestTz = tzContainer->getNearest(location); - FGPath zone( root ); - zone.append ("Timezone" ); - zone.append ( nearestTz->getDescription() ); - if ( zonename ) { - delete zonename; - } - zonename = strdup( zone.c_str() ); - currGMT = get_gmt( gmtime(&cur_time) ); - aircraftLocalTime = get_gmt( (fgLocaltime(&cur_time, zone.c_str())) ); - local_offset = aircraftLocalTime - currGMT; - // cout << "Using " << local_offset << " as local time offset Timezone is " - // << zonename << endl; -} -// Initialize the time dependent variables (maybe I'll put this in the -// constructor later) +// Initialize the time related variables void SGTime::init( double lon, double lat, const string& root ) -// time_t timeOffset, sgTimingOffsetType offsetType ) { FG_LOG( FG_EVENT, FG_INFO, "Initializing Time" ); gst_diff = -9999.0; @@ -137,7 +107,6 @@ void SGTime::init( double lon, double lat, const string& root ) GeoCoord* nearestTz = tzContainer->getNearest(location); FGPath zone( root ); - zone.append( "Timezone" ); zone.append( nearestTz->getDescription() ); // cout << "Using " << zone.str() << " for timezone information" << endl; @@ -158,79 +127,12 @@ void SGTime::init( double lon, double lat, const string& root ) } -// given a date in months, mn, days, dy, years, yr, return the -// modified Julian date (number of days elapsed since 1900 jan 0.5), -// mjd. Adapted from Xephem. - -void SGTime::cal_mjd (int mn, double dy, int yr) -{ - //static double last_mjd, last_dy; - //double mjd; - //static int last_mn, last_yr; - int b, d, m, y; - long c; - - if (mn == last_mn && yr == last_yr && dy == last_dy) { - mjd = last_mjd; - } - - m = mn; - y = (yr < 0) ? yr + 1 : yr; - if (mn < 3) { - m += 12; - y -= 1; - } - - if (yr < 1582 || (yr == 1582 && (mn < 10 || (mn == 10 && dy < 15)))) { - b = 0; - } else { - int a; - a = y/100; - b = 2 - a + a/4; - } - - if (y < 0) { - c = (long)((365.25*y) - 0.75) - 694025L; - } else { - c = (long)(365.25*y) - 694025L; - } - - d = (int)(30.6001*(m+1)); - - mjd = b + c + d + dy - 0.5; - - last_mn = mn; - last_dy = dy; - last_yr = yr; - last_mjd = mjd; -} - - -// given an mjd, calculate greenwich mean sidereal time, gst -void SGTime::utc_gst () -{ - double day = floor(mjd-0.5)+0.5; - double hr = (mjd-day)*24.0; - double T, x; - - T = ((int)(mjd - 0.5) + 0.5 - J2000)/36525.0; - x = 24110.54841 + (8640184.812866 + (0.093104 - 6.2e-6 * T) * T) * T; - x /= 3600.0; - gst = (1.0/SIDRATE)*hr + x; - - FG_LOG( FG_EVENT, FG_DEBUG, " gst => " << gst ); -} - - // given Julian Date and Longitude (decimal degrees West) compute // Local Sidereal Time, in decimal hours. // // Provided courtesy of ecdowney@noao.edu (Elwood Downey) - -double SGTime::sidereal_precise (double lng) +static double sidereal_precise( double mjd, double lng ) { - double lstTmp; - /* printf ("Current Lst on JD %13.5f at %8.4f degrees West: ", mjd + MJD0, lng); */ @@ -238,31 +140,27 @@ double SGTime::sidereal_precise (double lng) lng *= DEG_TO_RAD; // compute LST and print - utc_gst(); - lstTmp = gst - RADHR (lng); - lstTmp -= 24.0*floor(lstTmp/24.0); + double gst = sgTimeCalcGST( mjd ); + double lst = gst - RADHR( lng ); + lst -= 24.0 * floor( lst / 24.0 ); // printf ("%7.4f\n", lstTmp); - // that's all - return (lstTmp); + return lst; } // return a courser but cheaper estimate of sidereal time -double SGTime::sidereal_course(double lng) +static double sidereal_course( time_t cur_time, struct tm *gmt, double lng ) { - //struct tm *gmt; - //double lstTmp; time_t start_gmt, now; double diff, part, days, hours, lstTmp; char tbuf[64]; - //gmt = t->gmt; - //now = t->cur_time; now = cur_time; - start_gmt = get_gmt(gmt->tm_year, 2, 21, 12, 0, 0); + start_gmt = sgTimeGetGMT(gmt->tm_year, 2, 21, 12, 0, 0); - FG_LOG( FG_EVENT, FG_DEBUG, " COURSE: GMT = " << format_time(gmt, tbuf) ); + FG_LOG( FG_EVENT, FG_DEBUG, " COURSE: GMT = " + << sgTimeFormatTime(gmt, tbuf) ); FG_LOG( FG_EVENT, FG_DEBUG, " March 21 noon (GMT) = " << start_gmt ); diff = (now - start_gmt) / (3600.0 * 24.0); @@ -284,12 +182,12 @@ double SGTime::sidereal_course(double lng) " days = " << days << " hours = " << hours << " lon = " << lng << " lst = " << lstTmp ); - return(lstTmp); + return lstTmp; } -// Update time variables such as gmt, julian date, and sidereal time -void SGTime::update( double lon, double lat, double alt_m, long int warp ) { +// Update the time related variables +void SGTime::update( double lon, double lat, long int warp ) { double gst_precise, gst_course; FG_LOG( FG_EVENT, FG_DEBUG, "Updating time" ); @@ -312,8 +210,8 @@ void SGTime::update( double lon, double lat, double alt_m, long int warp ) { // calculate modified Julian date // t->mjd = cal_mjd ((int)(t->gmt->tm_mon+1), (double)t->gmt->tm_mday, // (int)(t->gmt->tm_year + 1900)); - cal_mjd ((int)(gmt->tm_mon+1), (double)gmt->tm_mday, - (int)(gmt->tm_year + 1900)); + mjd = sgTimeCalcMJD( (int)(gmt->tm_mon+1), (double)gmt->tm_mday, + (int)(gmt->tm_year + 1900) ); // add in partial day mjd += (gmt->tm_hour / 24.0) + (gmt->tm_min / (24.0 * 60.0)) + @@ -330,27 +228,138 @@ void SGTime::update( double lon, double lat, double alt_m, long int warp ) { // first time through do the expensive calculation & cheap // calculation to get the difference. FG_LOG( FG_EVENT, FG_INFO, " First time, doing precise gst" ); - gst_precise = gst = sidereal_precise(0.00); - gst_course = sidereal_course(0.00); + gst_precise = gst = sidereal_precise( mjd, 0.00 ); + gst_course = sidereal_course( cur_time, gmt, 0.00 ); gst_diff = gst_precise - gst_course; - lst = sidereal_course(-(lon * RAD_TO_DEG)) + gst_diff; + lst = sidereal_course( cur_time, gmt, -(lon * RAD_TO_DEG) ) + gst_diff; } else { // course + difference should drift off very slowly - gst = sidereal_course( 0.00 ) + gst_diff; - lst = sidereal_course( -(lon * RAD_TO_DEG)) + gst_diff; + gst = sidereal_course( cur_time, gmt, 0.00 ) + gst_diff; + lst = sidereal_course( cur_time, gmt, -(lon * RAD_TO_DEG) ) + gst_diff; } FG_LOG( FG_EVENT, FG_DEBUG, " Current lon=0.00 Sidereal Time = " << gst ); FG_LOG( FG_EVENT, FG_DEBUG, " Current LOCAL Sidereal Time = " << lst << " (" - << sidereal_precise(-(lon * RAD_TO_DEG)) + << sidereal_precise( mjd, -(lon * RAD_TO_DEG) ) << ") (diff = " << gst_diff << ")" ); } +// Given lon/lat, update timezone information and local_offset +void SGTime::updateLocal( double lon, double lat, const string& root ) +{ + time_t currGMT; + time_t aircraftLocalTime; + GeoCoord location( RAD_TO_DEG * lat, RAD_TO_DEG * lon ); + GeoCoord* nearestTz = tzContainer->getNearest(location); + FGPath zone( root ); + zone.append ( nearestTz->getDescription() ); + if ( zonename ) { + delete zonename; + } + zonename = strdup( zone.c_str() ); + currGMT = sgTimeGetGMT( gmtime(&cur_time) ); + aircraftLocalTime = sgTimeGetGMT( (fgLocaltime(&cur_time, zone.c_str())) ); + local_offset = aircraftLocalTime - currGMT; + // cout << "Using " << local_offset << " as local time offset Timezone is " + // << zonename << endl; +} + + +// given a date in months, mn, days, dy, years, yr, return the +// modified Julian date (number of days elapsed since 1900 jan 0.5), +// mjd. Adapted from Xephem. +double sgTimeCalcMJD(int mn, double dy, int yr) { + double mjd; + + // internal book keeping data + static double last_mjd, last_dy; + static int last_mn, last_yr; + + int b, d, m, y; + long c; + + if (mn == last_mn && yr == last_yr && dy == last_dy) { + mjd = last_mjd; + } + + m = mn; + y = (yr < 0) ? yr + 1 : yr; + if (mn < 3) { + m += 12; + y -= 1; + } + + if (yr < 1582 || (yr == 1582 && (mn < 10 || (mn == 10 && dy < 15)))) { + b = 0; + } else { + int a; + a = y/100; + b = 2 - a + a/4; + } + + if (y < 0) { + c = (long)((365.25*y) - 0.75) - 694025L; + } else { + c = (long)(365.25*y) - 694025L; + } + + d = (int)(30.6001*(m+1)); + + mjd = b + c + d + dy - 0.5; + + last_mn = mn; + last_dy = dy; + last_yr = yr; + last_mjd = mjd; + + return mjd; +} + + +// given an mjd, calculate greenwich mean sidereal time, gst +double sgTimeCalcGST( double mjd ) { + double gst; + + double day = floor(mjd-0.5)+0.5; + double hr = (mjd-day)*24.0; + double T, x; + + T = ((int)(mjd - 0.5) + 0.5 - J2000)/36525.0; + x = 24110.54841 + (8640184.812866 + (0.093104 - 6.2e-6 * T) * T) * T; + x /= 3600.0; + gst = (1.0/SIDRATE)*hr + x; + + FG_LOG( FG_EVENT, FG_DEBUG, " gst => " << gst ); + + return gst; +} + + +#if defined( HAVE_TIMEGM ) + // ignore this function +#elif defined( MK_TIME_IS_GMT ) + // ignore this function +#else // ! defined ( MK_TIME_IS_GMT ) + + // Fix up timezone if using ftime() + static long int fix_up_timezone( long int timezone_orig ) { +# if !defined( HAVE_GETTIMEOFDAY ) && defined( HAVE_FTIME ) + // ftime() needs a little extra help finding the current timezone + struct timeb current; + ftime(¤t); + return( current.timezone * 60 ); +# else + return( timezone_orig ); +# endif + } +#endif + + /****************************************************************** * The following are some functions that were included as SGTime * members, although they currently don't make use of any of the @@ -382,7 +391,7 @@ void SGTime::update( double lon, double lat, double alt_m, long int warp ) { // If you are having problems with incorrectly positioned astronomical // bodies, this is a really good place to start looking. -time_t SGTime::get_gmt(int year, int month, int day, int hour, int min, int sec) +time_t sgTimeGetGMT(int year, int month, int day, int hour, int min, int sec) { struct tm mt; @@ -452,27 +461,12 @@ time_t SGTime::get_gmt(int year, int month, int day, int hour, int min, int sec) #endif // ! defined ( MK_TIME_IS_GMT ) } -// Fix up timezone if using ftime() -long int SGTime::fix_up_timezone( long int timezone_orig ) -{ -#if !defined( HAVE_GETTIMEOFDAY ) && defined( HAVE_FTIME ) - // ftime() needs a little extra help finding the current timezone - struct timeb current; - ftime(¤t); - return( current.timezone * 60 ); -#else - return( timezone_orig ); -#endif -} - -char* SGTime::format_time( const struct tm* p, char* buf ) +// format time +char* sgTimeFormatTime( const struct tm* p, char* buf ) { sprintf( buf, "%d/%d/%2d %d:%02d:%02d", p->tm_mon, p->tm_mday, p->tm_year, p->tm_hour, p->tm_min, p->tm_sec); return buf; } - - -SGTime* SGTime::cur_time_params = 0;