// synchconsole.h 
//	Data structures for synchronized access to the keyboard
//	and console display devices.
//
//	NOTE: this abstraction is not completely implemented.
//
// Copyright (c) 1992-1996 The Regents of the University of California.
// All rights reserved.  See copyright.h for copyright notice and limitation 
// of liability and disclaimer of warranty provisions.

#ifndef SYNCHCONSOLE_H
#define SYNCHCONSOLE_H

#include "copyright.h"
#include "utility.h"
#include "callback.h"
#include "console.h"
#include "synch.h"

// The following two classes define synchronized input and output to
// a console device

class SynchConsoleInput : public CallBackObj {
public:
  SynchConsoleInput(char* inputFile); // Initialize the console device
  ~SynchConsoleInput();		// Deallocate console device

  char GetChar();		// Read a character, waiting if necessary

private:
  ConsoleInput* consoleInput;	// the hardware keyboard
  Lock* lock;			// only one reader at a time
  Semaphore* waitFor;		// wait for callBack

  void CallBack();		// called when a keystroke is available
};

class SynchConsoleOutput : public CallBackObj {
public:
  SynchConsoleOutput(char* outputFile); // Initialize the console device
  ~SynchConsoleOutput();

  void PutChar(char ch);	// Write a character, waiting if necessary
  void PutInt(int value);

private:
  ConsoleOutput* consoleOutput;// the hardware display
  Lock* lock;			// only one writer at a time
  Semaphore* waitFor;		// wait for callBack

  void CallBack();		// called when more data can be written
};

#endif // SYNCHCONSOLE_H