Add gswe_moment_get_aspect_by_planets() function

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

@@ -25,6 +25,7 @@ gswe_moment_get_quality_points
 gswe_moment_get_moon_phase
 gswe_moment_get_all_aspects
 gswe_moment_get_planet_aspects
+gswe_moment_get_aspect_by_planets
 gswe_moment_get_all_antiscia
 gswe_moment_get_all_planet_antiscia
 gswe_moment_get_axis_all_antiscia

src/gswe-moment.c

@@ -1121,6 +1121,43 @@ gswe_moment_get_planet_aspects(GsweMoment *moment, GswePlanet planet, GError **e
     return ret;
 }
 
+/**
+ * gswe_moment_get_aspect_by_planets:
+ * @moment: the GsweMoment to operate on
+ * @planet1: the first planet
+ * @planet2: the second planet
+ * @err: a #GError
+ *
+ * Get the aspect between two given planets. The order of @planet1 and @planet2
+ * doesn’t matter.
+ *
+ * Returns: (transfer none): a #GsweAspectData containing the aspect data of the
+ *          two planets. If an error occurs, like when one of the planets are
+ *          not added to the planet list, returns NULL, and @err is set
+ *          accordingly.
+ */
+GsweAspectData *
+gswe_moment_get_aspect_by_planets(GsweMoment *moment, GswePlanet planet1, GswePlanet planet2, GError **err)
+{
+    struct GsweAspectFinder aspect_finder;
+    GList *aspect_data_element;
+
+    if (!gswe_moment_has_planet(moment, planet1) || !gswe_moment_has_planet(moment, planet2)) {
+        g_set_error(err, GSWE_ERROR, GSWE_ERROR_UNKNOWN_PLANET, "One of the requested planets is not found in the planet list");
+
+        return NULL;
+    }
+
+    aspect_finder.planet1 = planet1;
+    aspect_finder.planet2 = planet2;
+
+    if ((aspect_data_element = g_list_find_custom(moment->priv->aspect_list, &aspect_finder, (GCompareFunc)find_aspect_by_both_planets)) != NULL) {
+        return aspect_data_element->data;
+    }
+
+    return NULL;
+}
+
 static gint
 find_antiscion_by_both_planets(GsweAntiscionData *antiscion, struct GsweAspectFinder *antiscion_finder)
 {

src/gswe-moment.h

@@ -119,6 +119,7 @@ GsweMoonPhaseData *gswe_moment_get_moon_phase(GsweMoment *moment, GError **err);
 
 GList *gswe_moment_get_all_aspects(GsweMoment *moment);
 GList *gswe_moment_get_planet_aspects(GsweMoment *moment, GswePlanet planet, GError **err);
+GsweAspectData *gswe_moment_get_aspect_by_planets(GsweMoment *moment, GswePlanet planet1, GswePlanet planet2, GError **err);
 
 GList *gswe_moment_get_all_antiscia(GsweMoment *moment);
 GList *gswe_moment_get_all_planet_antiscia(GsweMoment *moment, GswePlanet planet, GError **err);