diff --git a/simgear/timing/sg_time.cxx b/simgear/timing/sg_time.cxx index 2e19401e..4c022219 100644 --- a/simgear/timing/sg_time.cxx +++ b/simgear/timing/sg_time.cxx @@ -64,14 +64,6 @@ 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" ); @@ -92,30 +84,9 @@ 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; @@ -158,15 +129,163 @@ void SGTime::init( double lon, double lat, const string& root ) } +// Update the time related variables +void SGTime::update( double lon, double lat, double alt_m, long int warp ) { + double gst_precise, gst_course; + + FG_LOG( FG_EVENT, FG_DEBUG, "Updating time" ); + + // get current Unix calendar time (in seconds) + // warp += warp_delta; + cur_time = time(NULL) + warp; + FG_LOG( FG_EVENT, FG_DEBUG, + " Current Unix calendar time = " << cur_time + << " warp = " << warp ); + + // get GMT break down for current time + gmt = gmtime(&cur_time); + FG_LOG( FG_EVENT, FG_DEBUG, + " Current GMT = " << gmt->tm_mon+1 << "/" + << gmt->tm_mday << "/" << gmt->tm_year << " " + << gmt->tm_hour << ":" << gmt->tm_min << ":" + << gmt->tm_sec ); + + // 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)); + 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)) + + (gmt->tm_sec / (24.0 * 60.0 * 60.0)); + + // convert "back" to Julian date + partial day (as a fraction of one) + jd = mjd + MJD0; + FG_LOG( FG_EVENT, FG_DEBUG, " Current Julian Date = " << jd ); + + // printf(" Current Longitude = %.3f\n", FG_Longitude * RAD_TO_DEG); + + // Calculate local side real time + if ( gst_diff < -100.0 ) { + // 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_diff = gst_precise - gst_course; + + lst = sidereal_course(-(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; + } + + 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)) + << ") (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 ("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; +} + + +// 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 ) +{ + double lstTmp; + + /* printf ("Current Lst on JD %13.5f at %8.4f degrees West: ", + mjd + MJD0, lng); */ + + // convert to required internal units + lng *= DEG_TO_RAD; + + // compute LST and print + gst = sgTimeCalcGST( mjd ); + lstTmp = gst - RADHR (lng); + lstTmp -= 24.0*floor(lstTmp/24.0); + // printf ("%7.4f\n", lstTmp); + + // that's all + return (lstTmp); +} + + +// return a courser but cheaper estimate of sidereal time +double SGTime::sidereal_course( double lng ) +{ + time_t start_gmt, now; + double diff, part, days, hours, lstTmp; + char tbuf[64]; + + now = cur_time; + start_gmt = get_gmt(gmt->tm_year, 2, 21, 12, 0, 0); + + 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); + + FG_LOG( FG_EVENT, FG_DEBUG, + " Time since 3/21/" << gmt->tm_year << " GMT = " << diff ); + + part = fmod(diff, 1.0); + days = diff - part; + hours = gmt->tm_hour + gmt->tm_min/60.0 + gmt->tm_sec/3600.0; + + lstTmp = (days - lng)/15.0 + hours - 12; + + while ( lstTmp < 0.0 ) { + lstTmp += 24.0; + } + + FG_LOG( FG_EVENT, FG_DEBUG, + " days = " << days << " hours = " << hours << " lon = " + << lng << " lst = " << lstTmp ); + + return(lstTmp); +} + + // 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; -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; @@ -203,12 +322,15 @@ void SGTime::cal_mjd (int mn, double dy, int yr) last_dy = dy; last_yr = yr; last_mjd = mjd; + + return mjd; } // given an mjd, calculate greenwich mean sidereal time, gst -void SGTime::utc_gst () -{ +double sgTimeCalcGST( double mjd ) { + double gst; + double day = floor(mjd-0.5)+0.5; double hr = (mjd-day)*24.0; double T, x; @@ -219,136 +341,29 @@ void SGTime::utc_gst () gst = (1.0/SIDRATE)*hr + x; FG_LOG( FG_EVENT, FG_DEBUG, " gst => " << gst ); + + return gst; } -// given Julian Date and Longitude (decimal degrees West) compute -// Local Sidereal Time, in decimal hours. -// -// Provided courtesy of ecdowney@noao.edu (Elwood Downey) +#if defined( HAVE_TIMEGM ) + // ignore this function +#elif defined( MK_TIME_IS_GMT ) + // ignore this function +#else // ! defined ( MK_TIME_IS_GMT ) -double SGTime::sidereal_precise (double lng) -{ - double lstTmp; - - /* printf ("Current Lst on JD %13.5f at %8.4f degrees West: ", - mjd + MJD0, lng); */ - - // convert to required internal units - lng *= DEG_TO_RAD; - - // compute LST and print - utc_gst(); - lstTmp = gst - RADHR (lng); - lstTmp -= 24.0*floor(lstTmp/24.0); - // printf ("%7.4f\n", lstTmp); - - // that's all - return (lstTmp); -} - - -// return a courser but cheaper estimate of sidereal time -double SGTime::sidereal_course(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); - - FG_LOG( FG_EVENT, FG_DEBUG, " COURSE: GMT = " << format_time(gmt, tbuf) ); - FG_LOG( FG_EVENT, FG_DEBUG, " March 21 noon (GMT) = " << start_gmt ); - - diff = (now - start_gmt) / (3600.0 * 24.0); - - FG_LOG( FG_EVENT, FG_DEBUG, - " Time since 3/21/" << gmt->tm_year << " GMT = " << diff ); - - part = fmod(diff, 1.0); - days = diff - part; - hours = gmt->tm_hour + gmt->tm_min/60.0 + gmt->tm_sec/3600.0; - - lstTmp = (days - lng)/15.0 + hours - 12; - - while ( lstTmp < 0.0 ) { - lstTmp += 24.0; + // 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 } - - FG_LOG( FG_EVENT, FG_DEBUG, - " days = " << days << " hours = " << hours << " lon = " - << lng << " lst = " << 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 ) { - double gst_precise, gst_course; - - FG_LOG( FG_EVENT, FG_DEBUG, "Updating time" ); - - // get current Unix calendar time (in seconds) - // warp += warp_delta; - cur_time = time(NULL) + warp; - FG_LOG( FG_EVENT, FG_DEBUG, - " Current Unix calendar time = " << cur_time - << " warp = " << warp ); - - // get GMT break down for current time - gmt = gmtime(&cur_time); - FG_LOG( FG_EVENT, FG_DEBUG, - " Current GMT = " << gmt->tm_mon+1 << "/" - << gmt->tm_mday << "/" << gmt->tm_year << " " - << gmt->tm_hour << ":" << gmt->tm_min << ":" - << gmt->tm_sec ); - - // 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)); - - // add in partial day - mjd += (gmt->tm_hour / 24.0) + (gmt->tm_min / (24.0 * 60.0)) + - (gmt->tm_sec / (24.0 * 60.0 * 60.0)); - - // convert "back" to Julian date + partial day (as a fraction of one) - jd = mjd + MJD0; - FG_LOG( FG_EVENT, FG_DEBUG, " Current Julian Date = " << jd ); - - // printf(" Current Longitude = %.3f\n", FG_Longitude * RAD_TO_DEG); - - // Calculate local side real time - if ( gst_diff < -100.0 ) { - // 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_diff = gst_precise - gst_course; - - lst = sidereal_course(-(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; - } - - 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)) - << ") (diff = " << gst_diff << ")" ); -} +#endif /****************************************************************** @@ -452,27 +467,12 @@ 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; diff --git a/simgear/timing/sg_time.hxx b/simgear/timing/sg_time.hxx index 488937f2..5a6da887 100644 --- a/simgear/timing/sg_time.hxx +++ b/simgear/timing/sg_time.hxx @@ -34,12 +34,6 @@ # include #endif -#ifdef HAVE_WINDOWS_H -# include -#endif - -#include - #include #ifdef FG_HAVE_STD_INCLUDES @@ -48,20 +42,7 @@ # include #endif -// #include - #include "timezone.h" -// #include "lowleveltime.h" - - -enum sgTimingOffsetType { - SG_TIME_SYS_OFFSET = 0, - SG_TIME_GMT_OFFSET = 1, - SG_TIME_LAT_OFFSET = 2, - SG_TIME_SYS_ABSOLUTE = 3, - SG_TIME_GMT_ABSOLUTE = 4, - SG_TIME_LAT_ABSOLUTE = 5 -}; // Define a structure containing time parameters @@ -95,70 +76,71 @@ private: // local sidereal time double lst; - // the difference between the precise sidereal time algorithm - // result and the course result. course_gst + diff has good - // accuracy for the short term + // the difference between the precise / expensive sidereal time + // algorithm result and the quick course result. course_gst + + // gst_diff has pretty good accuracy over the span of a couple hours double gst_diff; - // internal book keeping data - double last_mjd, last_dy; - int last_mn, last_yr; - public: SGTime( const string& root ); ~SGTime(); + // Initialize the time related variables + void init( double lon, double lat, const string& root ); + + // Update the time related variables + void update( double lon, double lat, double alt_m, long int warp ); + + // Given lon/lat, update timezone information and local_offset + void updateLocal( double lon, double lat, const string& root ); + + // given Julian Date and Longitude (decimal degrees West) compute + // Local Sidereal Time, in decimal hours. + // + // Provided courtesy of ecdowney@noao.edu (Elwood Downey) + double sidereal_precise( double lng ); + + // return a courser but cheaper estimate of sidereal time + double sidereal_course( double lng ); + + // Some other stuff which were changed to SGTime members on + // questionable grounds -:) + time_t get_gmt(int year, int month, int day, + int hour, int minute, int second); + time_t get_gmt(struct tm* the_time); + inline double getJD() const { return jd; }; inline double getMjd() const { return mjd; }; inline double getLst() const { return lst; }; inline double getGst() const { return gst; }; inline time_t get_cur_time() const { return cur_time; }; inline struct tm* getGmt()const { return gmt; }; - - // void adjust_warp(int val) { warp += val; }; - // void adjust_warp_delta(int val) { warp_delta += val; }; - - // Initialize the time dependent variables - void init( double lon, double lat, const string& root ); - // time_t timeOffset, sgTimingOffsetType offsetType ); - - // Update the time dependent variables - void update( double lon, double lat, double alt_m, long int warp ); - void updateLocal( double lon, double lat, const string& root ); - - void cal_mjd (int mn, double dy, int yr); - void utc_gst(); - double sidereal_precise (double lng); - double sidereal_course(double lng); - // static SGTime *cur_time_params; - - // Some other stuff which were changed to SGTime members on - // questionable grounds -:) - // time_t get_start_gmt(int year); - time_t get_gmt(int year, int month, int day, - int hour, int minute, int second); - time_t get_gmt(struct tm* the_time); - inline char* get_zonename() const { return zonename; } - - char* format_time( const struct tm* p, char* buf ); - long int fix_up_timezone( long int timezone_orig ); - - // inline int get_warp_delta() const { return warp_delta; } }; -inline time_t SGTime::get_gmt(struct tm* the_time) // this is just a wrapper -{ - //printf("Using: %24s as input\n", asctime(the_time)); - return get_gmt(the_time->tm_year, - the_time->tm_mon, - the_time->tm_mday, - the_time->tm_hour, - the_time->tm_min, - the_time->tm_sec); +// this is just a wrapper +inline time_t SGTime::get_gmt(struct tm* the_time) { + // printf("Using: %24s as input\n", asctime(the_time)); + return get_gmt(the_time->tm_year, + the_time->tm_mon, + the_time->tm_mday, + the_time->tm_hour, + the_time->tm_min, + the_time->tm_sec); } +// 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); + +// given an mjd, calculate greenwich mean sidereal time, gst +double sgTimeCalcGST( double mjd ); + +// format time +char* sgTimeFormatTime( const struct tm* p, char* buf ); + #endif // _SG_TIME_HXX