Cleaned up and optimized Message2.cpp. It avoids as many unnecessary copies as it can now.

The unflatten time is now reduced to about a third of the current BMessage implementation but it's still
about half as quick as R5 (we're talking about microseconds here).
A third version of BMessage that operates purely on a flat buffer is in the works. We'll see which one
will be faster for normal uses.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@13821 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/app/MessageBody2.h

@@ -41,6 +41,7 @@ public:
 
 		ssize_t				FlattenedSize() const;
 		status_t			Flatten(BDataIO *stream) const;
+		status_t			Unflatten(BDataIO *stream);
 
 		status_t			AddData(const char *name, BMallocIO *buffer,
 								type_code type);
@@ -68,8 +69,10 @@ public:
 
 private:
 		status_t			InitCommon();
+		BMessageField		*AddField(const char *name, type_code type,
+								status_t &error);
 		BMessageField		*FindData(const char *name, type_code type,
-								 status_t &error) const;
+								status_t &error) const;
 
 		BList				fFieldList;
 		BMessageField		**fFieldTable;