Adding comments and const

3 files changed, 25 insertions, 7 deletions

diff --git a/navit/item.c b/navit/item.c
index 4f64a1edb..c17f31f8b 100644
--- a/navit/item.c
+++ b/navit/item.c
@@ -345,10 +345,10 @@ void item_attr_rewind(struct item *it) {
  * This function is not safe to call after destroying the item's map rect, and doing so may cause errors
  * with some map implementations.
  *
- * @param it The map item whose attribute to retrieve. This must be the active item, i.e. the last one retrieved from the
+ * @param[in] it The map item whose attribute to retrieve. This must be the active item, i.e. the last one retrieved from the
  * {@code map_rect}. There can only be one active item per {@code map_rect}.
- * @param attr_type The attribute type to retrieve, or `attr_any` to retrieve the next attribute
- * @param attr Receives the attribute retrieved
+ * @param[in] attr_type The attribute type to retrieve, or `attr_any` to retrieve the next attribute
+ * @param[out] attr Receives the attribute retrieved
  *
  * @return True on success, false on failure
  */
diff --git a/navit/transform.c b/navit/transform.c
index 4c0cb68b1..771037f8c 100644
--- a/navit/transform.c
+++ b/navit/transform.c
@@ -261,7 +261,16 @@ transform_dup(struct transformation *t) {
 static const navit_float gar2geo_units = 360.0/(1<<24);
 static const navit_float geo2gar_units = 1/(360.0/(1<<24));
 
-void transform_to_geo(enum projection pro, struct coord *c, struct coord_geo *g) {
+/**
+ * @brief Transform the coordinates of a geographical point from a coord representation to a geographical (lat, long) representation
+ *
+ * @note This is the reverse of transform_from_geo()
+ *
+ * @param pro The projection to use during the transformation
+ * @param[in] c The coordinates as a struct coord format
+ * @param[out] g The coordinates converted to coord_geo (latitude, longitude)
+ */
+void transform_to_geo(enum projection pro, const struct coord *c, struct coord_geo *g) {
     int x,y,northern,zone;
     switch (pro) {
     case projection_mg:
@@ -288,7 +297,16 @@ void transform_to_geo(enum projection pro, struct coord *c, struct coord_geo *g)
     }
 }
 
-void transform_from_geo(enum projection pro, struct coord_geo *g, struct coord *c) {
+/**
+ * @brief Transform the coordinates of a geographical point from a geographical (lat, long) representation to a coord representation
+ *
+ * @note This is the reverse of transform_to_geo()
+ *
+ * @param pro The projection to use during the transformation
+ * @param[in] g The coordinates as coord_geo (latitude, longitude)
+ * @param[out] c The coordinates converted to a struct coord format
+ */
+void transform_from_geo(enum projection pro, const struct coord_geo *g, struct coord *c) {
     switch (pro) {
     case projection_mg:
         c->x=g->lng*6371000.0*M_PI/180;
diff --git a/navit/transform.h b/navit/transform.h
index e58e136d5..dab69fd47 100644
--- a/navit/transform.h
+++ b/navit/transform.h
@@ -47,8 +47,8 @@ int transform_set_attr(struct transformation *this_, struct attr *attr);
 int transformation_get_order_base(struct transformation *this_);
 void transform_set_order_base(struct transformation *this_, int order_base);
 struct transformation *transform_dup(struct transformation *t);
-void transform_to_geo(enum projection pro, struct coord *c, struct coord_geo *g);
-void transform_from_geo(enum projection pro, struct coord_geo *g, struct coord *c);
+void transform_to_geo(enum projection pro, const struct coord *c, struct coord_geo *g);
+void transform_from_geo(enum projection pro, const struct coord_geo *g, struct coord *c);
 void transform_from_to_count(struct coord *cfrom, enum projection from, struct coord *cto, enum projection to, int count);
 void transform_from_to(struct coord *cfrom, enum projection from, struct coord *cto, enum projection to);
 void transform_geo_to_cart(struct coord_geo *geo, navit_float a, navit_float b, struct coord_geo_cart *cart);