small garages revision + small template stuff

src/core/templates.h

@@ -124,12 +124,18 @@ public:
 		       (T*)&m_entries[handle >> 8] : nil;
 	}
 	int GetIndex(T *entry){
-		int i = GetJustIndex(entry);
+		int i = GetJustIndex_NoFreeAssert(entry);
 		return m_flags[i].u + (i<<8);
 	}
 	int GetJustIndex(T *entry){
-		// TODO: the cast is unsafe
-		return (int)((U*)entry - m_entries);
+		int index = GetJustIndex_NoFreeAssert(entry);
+		assert(!IsFreeSlot(index));
+		return index;
+	}
+	int GetJustIndex_NoFreeAssert(T* entry){
+		int index = ((U*)entry - m_entries);
+		assert((U*)entry == (U*)&m_entries[index]); // cast is unsafe - check required
+		return index;
 	}
 	int GetNoOfUsedSpaces(void) const{
 		int i;