[set/map] Expose hash API publicly

New API:
+ hb_set_hash()
+ hb_map_hash()

docs/harfbuzz-sections.txt

@@ -462,6 +462,7 @@ hb_map_get_population
 hb_map_is_equal
 hb_map_get_user_data
 hb_map_has
+hb_map_hash
 hb_map_is_empty
 hb_map_reference
 hb_map_set
@@ -652,6 +653,7 @@ hb_set_get_min
 hb_set_get_population
 hb_set_get_user_data
 hb_set_has
+hb_set_hash
 hb_set_intersect
 hb_set_invert
 hb_set_is_empty

src/hb-map.cc

@@ -309,3 +309,20 @@ hb_map_is_equal (const hb_map_t *map,
   return map->is_equal (*other);
 }
 
+/**
+ * hb_map_hash:
+ * @map: A map
+ *
+ * Creates a hash representing @map.
+ *
+ * Return value:
+ * A hash of @map.
+ *
+ * Since: REPLACEME
+ **/
+HB_EXTERN unsigned int
+hb_map_hash (const hb_map_t *map)
+{
+  return map->hash ();
+}
+

src/hb-map.h

@@ -95,6 +95,9 @@ HB_EXTERN hb_bool_t
 hb_map_is_equal (const hb_map_t *map,
 		 const hb_map_t *other);
 
+HB_EXTERN unsigned int
+hb_map_hash (const hb_map_t *map);
+
 HB_EXTERN void
 hb_map_set (hb_map_t       *map,
 	    hb_codepoint_t  key,

src/hb-set.cc

@@ -358,6 +358,23 @@ hb_set_is_equal (const hb_set_t *set,
   return set->is_equal (*other);
 }
 
+/**
+ * hb_set_hash:
+ * @set: A set
+ *
+ * Creates a hash representing @set.
+ *
+ * Return value:
+ * A hash of @set.
+ *
+ * Since: REPLACEME
+ **/
+HB_EXTERN unsigned int
+hb_set_hash (const hb_set_t *set)
+{
+  return set->hash ();
+}
+
 /**
  * hb_set_is_subset:
  * @set: A set

src/hb-set.h

@@ -128,6 +128,9 @@ HB_EXTERN hb_bool_t
 hb_set_is_equal (const hb_set_t *set,
 		 const hb_set_t *other);
 
+HB_EXTERN unsigned int
+hb_set_hash (const hb_set_t *set);
+
 HB_EXTERN hb_bool_t
 hb_set_is_subset (const hb_set_t *set,
 		  const hb_set_t *larger_set);