Extract Gdt reading and writing classes to GdtStream file

src/ObjCommon/Obj/Gdt/GdtStream.h

@@ -0,0 +1,43 @@
+#pragma once
+#include <iostream>
+
+#include "Gdt.h"
+
+class GdtReader
+{
+    std::istream& m_stream;
+    char m_char;
+    bool m_peeked;
+    int m_line;
+
+    static GdtEntry* GetEntryByName(const Gdt& gdt, const std::string& name);
+    void PrintError(const std::string& message) const;
+    int PeekChar();
+    int NextChar();
+    bool ReadStringContent(std::string& str);
+    bool ReadProperties(GdtEntry& entry);
+    bool AddEntry(Gdt& gdt, GdtEntry& entry) const;
+
+public:
+    explicit GdtReader(std::istream& stream);
+    bool Read(Gdt& gdt);
+};
+
+class GdtOutputStream
+{
+    std::ostream& m_stream;
+    bool m_open;
+    unsigned m_intendation_level;
+
+    void DoIntendation() const;
+
+public:
+    explicit GdtOutputStream(std::ostream& stream);
+
+    void BeginStream();
+    void WriteVersion(const GdtVersion& gdtVersion);
+    void WriteEntry(const GdtEntry& entry);
+    void EndStream();
+
+    static void WriteGdt(const Gdt& gdt, std::ostream& stream);
+};