1 files changed, 15 insertions, 8 deletions
diff --git a/src/mbgl/map/tile_id.hpp b/src/mbgl/map/tile_id.hpp
index dddbce3bb7..a193b63392 100644
--- a/src/mbgl/map/tile_id.hpp
+++ b/src/mbgl/map/tile_id.hpp
@@ -6,6 +6,7 @@
 #include <string>
 #include <functional>
 #include <forward_list>
+#include <limits>
 
 namespace mbgl {
 
@@ -25,12 +26,6 @@ public:
         return ((std::pow(2, z) * y + x) * 32) + z;
     }
 
-    struct Hash {
-        std::size_t operator()(const TileID& id) const {
-            return std::hash<uint64_t>()(id.to_uint64());
-        }
-    };
-
     inline bool operator==(const TileID& rhs) const {
         return w == rhs.w && z == rhs.z && x == rhs.x && y == rhs.y;
     }
@@ -48,12 +43,24 @@ public:
 
     TileID parent(int8_t z, int8_t sourceMaxZoom) const;
     TileID normalized() const;
-    std::forward_list<TileID> children(int8_t sourceMaxZoom) const;
+    std::forward_list<TileID>
+    children(int8_t sourceMaxZoom = std::numeric_limits<int8_t>::max()) const;
     bool isChildOf(const TileID&) const;
     operator std::string() const;
-
 };
 
 } // namespace mbgl
 
+namespace std {
+template <>
+struct hash<mbgl::TileID> {
+    typedef mbgl::TileID argument_type;
+    typedef std::size_t result_type;
+
+    result_type operator()(const mbgl::TileID& id) const {
+            return std::hash<uint64_t>()(id.to_uint64());
+    }
+};
+} // namespace std
+
 #endif