Outsourced Moon phase calculation to GsweMoonPhaseData

docs/reference/swe-glib/swe-glib-sections.txt

@@ -45,6 +45,8 @@ gswe_moment_get_type
 gswe_moon_phase_data_new
 gswe_moon_phase_data_ref
 gswe_moon_phase_data_unref
+gswe_moon_phase_data_calculate_by_timestamp
+gswe_moon_phase_data_calculate_by_jd
 gswe_moon_phase_data_get_phase
 gswe_moon_phase_data_get_illumination
 GsweMoonPhaseData

src/gswe-moment.c

@@ -32,8 +32,6 @@
  * one given point on Earth at a given time.
  */
 
-#define SYNODIC 29.53058867
-
 #define GSWE_MOMENT_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE((obj), GSWE_TYPE_MOMENT, GsweMomentPrivate))
 
 /**
@@ -972,62 +970,16 @@ gswe_moment_get_quality_points(GsweMoment *moment, GsweQuality quality)
 GsweMoonPhaseData *
 gswe_moment_get_moon_phase(GsweMoment *moment, GError **err)
 {
-    gdouble difference,
-            phase_percent,
-            jd,
-            jdb;
-
     if (moment->priv->moon_phase_revision == moment->priv->revision) {
         return moment->priv->moon_phase;
     }
 
-    jd = gswe_timestamp_get_julian_day(moment->priv->timestamp, err);
+    gswe_moon_phase_data_calculate_by_timestamp(moment->priv->timestamp, err);
 
-    if ((err) && (*err)) {
+    if (!err || !*err) {
-        return NULL;
+        moment->priv->moon_phase_revision = moment->priv->revision;
     }
 
-    jdb = gswe_timestamp_get_julian_day(gswe_full_moon_base_date, err);
-
-    if ((err) && (*err)) {
-        return NULL;
-    }
-
-    difference = (jd - jdb);
-    phase_percent = fmod((difference * 100) / SYNODIC, 100);
-
-    if (phase_percent < 0) {
-        phase_percent += 100.0;
-    }
-
-    if ((phase_percent < 0) || (phase_percent > 100)) {
-        g_error("Error during Moon phase calculation!");
-    }
-
-    moment->priv->moon_phase->illumination = (50.0 - fabs(phase_percent - 50.0)) * 2;
-
-    if (phase_percent == 0) {
-        moment->priv->moon_phase->phase = GSWE_MOON_PHASE_NEW;
-    } else if (phase_percent < 25) {
-        moment->priv->moon_phase->phase = GSWE_MOON_PHASE_WAXING_CRESCENT;
-    } else if (phase_percent == 25) {
-        moment->priv->moon_phase->phase = GSWE_MOON_PHASE_WAXING_HALF;
-    } else if (phase_percent < 50) {
-        moment->priv->moon_phase->phase = GSWE_MOON_PHASE_WAXING_GIBBOUS;
-    } else if (phase_percent == 50) {
-        moment->priv->moon_phase->phase = GSWE_MOON_PHASE_FULL;
-    } else if (phase_percent < 75) {
-        moment->priv->moon_phase->phase = GSWE_MOON_PHASE_WANING_GIBBOUS;
-    } else if (phase_percent == 75) {
-        moment->priv->moon_phase->phase = GSWE_MOON_PHASE_WANING_HALF;
-    } else if (phase_percent < 100) {
-        moment->priv->moon_phase->phase = GSWE_MOON_PHASE_WANING_CRESCENT;
-    } else {
-        moment->priv->moon_phase->phase = GSWE_MOON_PHASE_DARK;
-    }
-
-    moment->priv->moon_phase_revision = moment->priv->revision;
-
     return gswe_moon_phase_data_ref(moment->priv->moon_phase);
 }
 

src/gswe-moon-phase-data.c

@@ -15,10 +15,16 @@
  * You should have received a copy of the GNU General Public License
  * along with this library; if not, see <http://www.gnu.org/licenses/>.
  */
+#include <math.h>
+
 #include "gswe-types.h"
 
+#include "swe-glib-private.h"
 #include "gswe-moon-phase-data.h"
 #include "gswe-moon-phase-data-private.h"
+#include "gswe-timestamp.h"
+
+#define SYNODIC 29.53058867
 
 /**
  * SECTION:gswe-moon-phase-data
@@ -82,6 +88,79 @@ gswe_moon_phase_data_unref(GsweMoonPhaseData *moon_phase_data)
     }
 }
 
+/**
+ * gswe_moon_phase_data_calculate_by_timestamp:
+ * @moon_phase_data: a #GsweMoonPhaseData
+ * @timestamp: a #GsweTimestamp with a valid timestamp set
+ * @err: a #GError
+ *
+ * Calculates the moon at a given time, specified by @jd.
+ */
+void
+gswe_moon_phase_data_calculate_by_jd(GsweMoonPhaseData *moon_phase_data, gdouble jd, GError **err)
+{
+    gdouble jdb,
+            phase_percent;
+
+    jdb = gswe_timestamp_get_julian_day(gswe_full_moon_base_date, err);
+
+    if ((err) && (*err)) {
+        return;
+    }
+
+    if ((phase_percent = fmod(((jd - jdb) * 100) / SYNODIC, 100)) < 0) {
+        phase_percent += 100.0;
+    }
+
+    if ((phase_percent < 0) || (phase_percent > 100)) {
+        g_error("Error during Moon phase calculation!");
+    }
+
+    moon_phase_data->illumination = (50.0 - fabs(phase_percent - 50.0)) * 2;
+
+    if (phase_percent == 0) {
+        moon_phase_data->phase = GSWE_MOON_PHASE_NEW;
+    } else if (phase_percent < 25) {
+        moon_phase_data->phase = GSWE_MOON_PHASE_WAXING_CRESCENT;
+    } else if (phase_percent == 25) {
+        moon_phase_data->phase = GSWE_MOON_PHASE_WAXING_HALF;
+    } else if (phase_percent < 50) {
+        moon_phase_data->phase = GSWE_MOON_PHASE_WAXING_GIBBOUS;
+    } else if (phase_percent == 50) {
+        moon_phase_data->phase = GSWE_MOON_PHASE_FULL;
+    } else if (phase_percent < 75) {
+        moon_phase_data->phase = GSWE_MOON_PHASE_WANING_GIBBOUS;
+    } else if (phase_percent == 75) {
+        moon_phase_data->phase = GSWE_MOON_PHASE_WANING_HALF;
+    } else if (phase_percent < 100) {
+        moon_phase_data->phase = GSWE_MOON_PHASE_WANING_CRESCENT;
+    } else {
+        moon_phase_data->phase = GSWE_MOON_PHASE_DARK;
+    }
+}
+
+/**
+ * gswe_moon_phase_data_calculate_by_timestamp:
+ * @moon_phase_data: a #GsweMoonPhaseData
+ * @timestamp: a #GsweTimestamp with a valid timestamp set
+ * @err: a #GError
+ *
+ * Calculates the moon at a given time, specified by @timestamp.
+ */
+void
+gswe_moon_phase_data_calculate_by_timestamp(GsweMoonPhaseData *moon_phase_data, GsweTimestamp *timestamp, GError **err)
+{
+    gdouble jd;
+
+    jd = gswe_timestamp_get_julian_day(timestamp, err);
+
+    if (*err) {
+        return;
+    }
+
+    gswe_moon_phase_data_calculate_by_jd(moon_phase_data, jd, err);
+}
+
 /**
  * gswe_moon_phase_data_get_phase:
  * @moon_phase_data: (in): a GsweMoonPhaseData

src/gswe-moon-phase-data.h

@@ -39,6 +39,9 @@ GsweMoonPhaseData *gswe_moon_phase_data_new(void);
 GsweMoonPhaseData *gswe_moon_phase_data_ref(GsweMoonPhaseData *moon_phase_data);
 void gswe_moon_phase_data_unref(GsweMoonPhaseData *moon_phase_data);
 
+void gswe_moon_phase_data_calculate_by_jd(GsweMoonPhaseData *moon_phase_data, gdouble jd, GError **err);
+void gswe_moon_phase_data_calculate_by_timestamp(GsweMoonPhaseData *moon_phase_data, GsweTimestamp *timestamp, GError **err);
+
 GsweMoonPhase gswe_moon_phase_data_get_phase(GsweMoonPhaseData *moon_phase_data);
 gdouble gswe_moon_phase_data_get_illumination(GsweMoonPhaseData *moon_phase_data);