implement a scrollback buffer

c_os/devices/BufferedCGA.h

@@ -0,0 +1,32 @@
+#ifndef __BUFFEREDCGA_INCLUDE_H_
+#define __BUFFEREDCGA_INCLUDE_H_
+
+#include "devices/CGA.h"
+#include "devices/Keyboard.h"
+#include "lib/ScrollbackBuffer.h"
+
+// NOTE: I added this file
+
+class BufferedCGA : public CGA {
+private:
+    ScrollbackBuffer* scrollback_buffer;
+    bool initialized;  // Don't do ScrollbackBuffer actions if not initialized
+
+    BufferedCGA(const CGA& copy);
+
+    void displaypage();  // Write the current_page to CGA memory
+
+public:
+    BufferedCGA() : CGA(), initialized(false), current_page(0) {};
+
+    void init();                          // Scrollback needs to be initialized after memorymanagement
+    unsigned char current_page;           // The page that is displayed
+    unsigned int scroll_page_backward();  // Scroll up the page history
+    unsigned int scroll_page_forward();   // Scroll down the page history (to the current page)
+
+    void print(char* string, int n, unsigned char attrib = STD_ATTR) override;
+    void scrollup() override;
+    void clear() override;
+};
+
+#endif