Revert "Address the poor performance of the existing unique-name generation (#17944)"

This reverts commit 83202d8ad6.

# Conflicts:
#	src/Base/Tools.cpp
#	src/Base/Tools.h

src/Base/Reader.h

@@ -251,8 +251,8 @@ public:
     const char* addFile(const char* Name, Base::Persistence* Object);
     /// process the requested file writes
     void readFiles(zipios::ZipInputStream& zipstream) const;
-    /// Returns whether reader has any registered filenames
-    bool hasFilenames() const;
+    /// get all registered file names
+    const std::vector<std::string>& getFilenames() const;
     /// returns true if reading the file \a filename has failed
     bool hasReadFailed(const std::string& filename) const;
     bool isRegistered(Base::Persistence* Object) const;
@@ -364,6 +364,7 @@ public:
     std::vector<FileEntry> FileList;
 
 private:
+    std::vector<std::string> FileNames;
     mutable std::vector<std::string> FailedFiles;
 
     std::bitset<32> StatusBits;