X-Git-Url: http://git.tdb.fi/?p=libs%2Fdatafile.git;a=blobdiff_plain;f=source%2Fcollection.h;h=50905ce0d14972d65b24ac37dc74cdd6b5e21be9;hp=ee7eb469cf53d5ee1ab8d9cd06a0b88688511b06;hb=41230218ca007b56932fd34b79b6f3e3e70764f6;hpb=a5d5fa04bcbe360fc55fdb25b45937b29fb5c9cd

diff --git a/source/collection.h b/source/collection.h
index ee7eb46..50905ce 100644
--- a/source/collection.h
+++ b/source/collection.h
@@ -17,17 +17,14 @@ namespace DataFile {
 Helper struct to determine whether a Loader has a Collection typedef.
 */
 template<typename T>
-struct NeedsCollection
+struct NeedsCollection: public Sfinae
 {
-	struct Yes { char c[2]; };
-	struct No { char c; };
-
 	template<typename U>
 	static Yes f(typename U::Collection *);
 	template<typename U>
 	static No f(...);
 
-	enum { value = (sizeof(f<T>(0))==sizeof(Yes)) };
+	enum { value = Evaluate<sizeof(f<T>(0))>::value };
 };
 
 class CollectionItemTypeBase;
@@ -46,8 +43,8 @@ method for details.
 Collections can have sources for loading objects on demand.  Automatic loading
 only works on a non-const Collection.  See class CollectionSource for details.
 
-A fallback collection can be designated as another way of loading items that
-are not present.  Items retrieted from the fallback collection are shared
+As a last resort, a fallback collection can be designated for loading items
+that are not present.  Items retrieted from the fallback collection are shared
 between the collections, and are only deleted when all collections in the chain
 have been destroyed.
 */
@@ -258,12 +255,26 @@ private:
 	template<typename T>
 	CollectionItemTypeBase *get_type() const;
 
+	/// Gets a descriptor with the same type as another descriptor.
+	CollectionItemTypeBase *get_type(const CollectionItemTypeBase &) const;
+
 	/// Returns the descriptor for an item, or null if it's of an unknown type.
 	CollectionItemTypeBase *get_type_for_item(const Variant &) const;
 
 protected:
+	/** Adds a source for automatically loading items.  Sources are consulted
+	in the order they are added. */
 	void add_source(CollectionSource &);
 
+public:
+	/** Opens a raw resource, without interpreting it as object data.  Null is
+	returned if no such file is found.  The caller must dispose of the returned
+	object when done with it. */
+	IO::Seekable *open_raw(const std::string &) const;
+
+protected:
+	IO::Seekable *open_from_sources(const std::string &n) { return open_raw(n); }
+
 private:
 	void gather_names_from_sources(std::list<std::string> &, const CollectionItemTypeBase &) const;
 
@@ -372,7 +383,7 @@ private:
 		Creator(FuncPtr f): func(f) { }
 
 		virtual T *create(Collection &coll, const std::string &name) const
-		{ return (static_cast<C &>(coll).*func)(name); }
+		{ return (dynamic_cast<C &>(coll).*func)(name); }
 	};
 
 	template<typename B>