...

cxx/mcc_mount_astro_erfa.h

@@ -6,12 +6,14 @@
 /*  ASTROMETRY ENGINE BASED ON ERFA-LIBRARY  */
 
 #include <chrono>
-// #include <cmath>
+#include <mutex>
 
 
 #include "mcc_astrom_iers.h"
 #include "mcc_mount_coord.h"
 
+#include "mcc_mount_astrom.h"
+
 namespace mcc::astrom::erfa
 {
 
@@ -20,8 +22,28 @@ namespace mcc::astrom::erfa
 
 class MccMountAstromEngineERFA
 {
+protected:
+    static constexpr std::array engineErrorString = {"OK",
+                                                     "invalid argument",
+                                                     "invalid year",
+                                                     "invalid month",
+                                                     "time point is out of range",
+                                                     "time point is out of range",
+                                                     "dubious year",
+                                                     "unacceptable year"};
+
 public:
-    typedef int engine_err_t;
+    enum engine_err_t : size_t {
+        ERROR_OK = 0,
+        ERROR_INVALID_INPUT_ARG,
+        ERROR_JULDATE_INVALID_YEAR,
+        ERROR_JULDATE_INVALID_MONTH,
+        ERROR_BULLETINA_OUT_OF_RANGE,
+        ERROR_LEAPSECONDS_OUT_OF_RANGE,
+        ERROR_DUBIOUS_YEAR,
+        ERROR_UNACCEPTABLE_DATE
+    };
+
 
     // meteo parameters (to compute refraction)
     struct meteo_t {
@@ -41,6 +63,7 @@ public:
 
         MccAngleLAT lat = "00:00:00"_dms;  // site latitude
         MccAngleLON lon = "00:00:00"_dms;  // site longitude
+        double elev = 0.0;                 // site elevation (in meters)
 
         mcc::astrom::iers::MccLeapSeconds _leapSeconds{};
         mcc::astrom::iers::MccIersBulletinA _bulletinA{};
@@ -54,6 +77,9 @@ public:
     };
 
     typedef MccAngle coord_t;
+    typedef MccAngle prop_motion_t;
+    typedef double parallax_t;
+
     typedef MccAngle gst_t;
     typedef MccAngle pa_t;
     typedef double eo_t;
@@ -62,8 +88,220 @@ public:
         double refa, refb;
     };
 
+
+    MccMountAstromEngineERFA() = default;
+
+    MccMountAstromEngineERFA(engine_state_t state) : _currentState(std::move(state)) {}
+
+    virtual ~MccMountAstromEngineERFA() = default;
+
+    void updateState(engine_state_t state)
+    {
+        std::lock_guard lock{_stateMutex};
+
+        _currentState = std::move(state);
+    }
+
+    engine_state_t getState() const
+    {
+        std::scoped_lock lock{_stateMutex};
+
+        return _currentState;
+    }
+
+
+    std::string errorString(engine_err_t err) const
+    {
+        return engineErrorString[err];
+    }
+
+    /*   time-related methods    */
+
+    // templated generic version
+    template <mcc::traits::mcc_systime_c TpT>
+    engine_err_t greg2jul(TpT time_point, juldate_t& juldate)
+    {
+        using namespace std::literals::chrono_literals;
+
+        auto dd = std::chrono::floor<std::chrono::days>(time_point);
+        std::chrono::year_month_day ymd{dd};
+
+        static constexpr std::chrono::year MIN_YEAR = -4799y;
+
+        if (ymd.year() < MIN_YEAR) {
+            return ERROR_JULDATE_INVALID_YEAR;
+        }
+        if (!ymd.month().ok()) {
+            return ERROR_JULDATE_INVALID_MONTH;
+        }
+
+        int64_t im = (unsigned)ymd.month();
+        int64_t id = (unsigned)ymd.day();
+        int64_t iy = (int)ymd.year();
+
+        int64_t my = (im - 14LL) / 12LL;
+        int64_t iypmy = iy + my;
+
+        // integer part of result MJD
+        int64_t mjd_int = (1461LL * (iypmy + 4800LL)) / 4LL + (367LL * (im - 2LL - 12LL * my)) / 12LL -
+                          (3LL * ((iypmy + 4900LL) / 100LL)) / 4LL + id - 2432076LL;
+
+        using fd_t = std::chrono::duration<double, std::ratio<86400>>;  // fraction of day
+        juldate.mjd = static_cast<double>(mjd_int) + std::chrono::duration_cast<fd_t>(time_point - dd).count();
+
+        return ERROR_OK;
+    }
+
+    engine_err_t greg2jul(time_point_t time_point, juldate_t& juldate)
+    {
+        return greg2jul<time_point_t>(time_point, juldate);
+    }
+
+
+    engine_err_t apparentSiderTime(juldate_t juldate, gst_t& gst, bool islocal = false)
+    {
+        std::lock_guard lock{_stateMutex};
+
+        using real_days_t = std::chrono::duration<double, std::ratio<86400>>;
+
+        double ut1, tt = juldate.mjd;
+
+        auto dut1 = _currentState._bulletinA.DUT1(juldate.mjd);
+
+        if (dut1.has_value()) {
+            ut1 += std::chrono::duration_cast<real_days_t>(dut1.value()).count();
+        } else {  // out of range
+            return ERROR_BULLETINA_OUT_OF_RANGE;
+        }
+
+        auto tai_utc = _currentState._leapSeconds[juldate.mjd];
+        if (tai_utc.has_value()) {
+            tt += std::chrono::duration_cast<real_days_t>(tai_utc.value()).count();
+        } else {
+            return ERROR_LEAPSECONDS_OUT_OF_RANGE;
+        }
+
+
+        auto tt_tai = _currentState._bulletinA.TT_TAI();
+        tt += std::chrono::duration_cast<real_days_t>(tt_tai).count();
+
+        gst = eraGst06a(juldate.MJD0, ut1, juldate.MJD0, tt);
+        if (islocal) {
+            gst += _currentState.lon;
+        }
+
+        return ERROR_OK;
+    }
+
+
+    /*   atmospheric refraction-related methods   */
+
+    engine_err_t refraction(refract_result_t& refr)
+    {
+        std::lock_guard lock{_stateMutex};
+
+        eraRefco(_currentState.meteo.pressure, _currentState.meteo.temperature, _currentState.meteo.humidity,
+                 _currentState.wavelength, &refr.refa, &refr.refb);
+
+        return ERROR_OK;
+    }
+
+
+    /*    coordinates conversional methods    */
+
+    engine_err_t icrs2obs(coord_t ra,
+                          coord_t dec,
+                          prop_motion_t pm_ra,
+                          prop_motion_t pm_dec,
+                          parallax_t parallax,
+                          juldate_t juldate,
+                          coord_t& ra_app,
+                          coord_t& dec_app,
+                          coord_t& ha,
+                          coord_t& az,
+                          coord_t& alt,
+                          eo_t& eo)
+    {
+        std::lock_guard lock{_stateMutex};
+
+        auto dut1 = _currentState._bulletinA.DUT1(juldate.mjd);
+
+        if (!dut1.has_value()) {
+            return ERROR_BULLETINA_OUT_OF_RANGE;
+        }
+
+        auto pol_pos = _currentState._bulletinA.polarCoords(juldate.mjd);
+        if (!pol_pos.has_value()) {
+            return ERROR_BULLETINA_OUT_OF_RANGE;
+        }
+
+        double oaz, ozd, oha, odec, ora;
+
+        int ret = eraAtco13(ra, dec, pm_ra, pm_dec, parallax, 0.0, juldate.MJD0, juldate.mjd, dut1->count(),
+                            _currentState.lon, _currentState.lat, _currentState.elev, pol_pos->x, pol_pos->y,
+                            _currentState.meteo.pressure, _currentState.meteo.temperature, _currentState.meteo.humidity,
+                            _currentState.wavelength, &oaz, &ozd, &oha, &odec, &ora, &eo);
+
+        if (ret == 1) {
+            return ERROR_DUBIOUS_YEAR;
+        } else if (ret == -1) {
+            return ERROR_UNACCEPTABLE_DATE;
+        }
+
+        ra_app = ora;
+        dec_app = odec;
+        az = oaz;
+        alt = std::numbers::pi / 2.0 - ozd;
+        ha = oha;
+
+        return ERROR_OK;
+    }
+
+
+    engine_err_t hadec2azalt(coord_t ha, coord_t dec, coord_t& az, coord_t& alt)
+    {
+        std::lock_guard lock{_stateMutex};
+
+        double r_az, r_alt;
+        eraHd2ae(ha, dec, _currentState.lat, &r_az, &r_alt);
+
+        az = r_az;
+        alt = r_alt;
+
+        return ERROR_OK;
+    }
+
+    engine_err_t azalt2hadec(coord_t az, coord_t alt, coord_t& ha, coord_t& dec)
+    {
+        std::lock_guard lock{_stateMutex};
+
+        double r_ha, r_dec;
+
+        eraAe2hd(az, alt, _currentState.lat, &r_ha, &r_dec);
+
+        ha = r_ha;
+        dec = r_dec;
+
+        return ERROR_OK;
+    }
+
+
+    engine_err_t hadec2pa(coord_t ha, coord_t dec, pa_t& pa)
+    {
+        std::lock_guard lock{_stateMutex};
+
+        pa = eraHd2pa(ha, dec, _currentState.lat);
+
+        return ERROR_OK;
+    }
+
 protected:
-    engine_state_t _currentState;
+    engine_state_t _currentState{};
+
+    std::mutex _stateMutex;
 };
 
 }  // namespace mcc::astrom::erfa
+
+
+static_assert(mcc::traits::mcc_astrom_engine_c<mcc::astrom::erfa::MccMountAstromEngineERFA>, "");