settings file and save/restore ui state

src/binary_stream.h

@@ -1,5 +1,6 @@
 #pragma once
 #include <codecvt>
+#include "asset.h"
 
 class BinaryStream
 {
@@ -70,6 +71,7 @@ public:
     BinaryStreamReader() = default;
     ~BinaryStreamReader();
     void init(uint8_t* data_ptr, size_t size, ByteOrder byte_order = ByteOrder::Host);
+    bool load(const std::string& path, ByteOrder byte_order = ByteOrder::Host);
     size_t pos();
     void skip(size_t bytes);
     // snap to the next 4-alignment
@@ -127,6 +129,7 @@ private:
     uint8_t *m_ptr = nullptr;
     uint8_t *m_cur = nullptr;
     size_t m_size = 0;
+    Asset m_asset;
 };
 
 class BinaryStreamWriter : public BinaryStream
@@ -137,6 +140,7 @@ public:
     BinaryStreamWriter() = default;
     ~BinaryStreamWriter() = default;
     void init(ByteOrder byte_order = ByteOrder::Host);
+    bool save(const std::string& path) const;
     void skip(size_t bytes, uint8_t fill = 0);
     // snap to the next 4-alignment
     void snap();