//***************************************************************
// From the book "Win32 System Services: The Heart of Windows 98
// and Windows 2000"
// by Marshall Brain
// Published by Prentice Hall
//
// Copyright 1995, by Prentice Hall.
//
// This code shows how to handle raw input from a console so that
// you can retrieve input one character at a time.
//***************************************************************

// raw.cpp

#include <windows.h>
#include <iostream.h>

void ErrorHandler(char *s, DWORD err)
{
	cout << s << endl;
	cout << "Error number: " << err << endl;
	ExitProcess(err);
}

void ScrollOneLine(HANDLE stdout)
{
	BOOL success;
	CONSOLE_SCREEN_BUFFER_INFO consoleInfo;
	SMALL_RECT scrollRect;
	CHAR_INFO consoleFill;
	COORD coord;

	// get current console size (may change)
	success = GetConsoleScreenBufferInfo(stdout,
		&consoleInfo);
	if (!success)
    		ErrorHandler(
				"In GetConsoleScreenBufferInfo",
				GetLastError());

	// Define the rectangle to scroll
	scrollRect.Top = 0;
	scrollRect.Left = 0;
	scrollRect.Bottom = consoleInfo.dwSize.Y - 1;
	scrollRect.Right = consoleInfo.dwSize.X - 1;

	// Define destination of scrolled rectangle
	coord.X = 0;
	coord.Y = -1;

	// Define how to fill blank line
	consoleFill.Attributes =
		consoleInfo.wAttributes;
	consoleFill.Char.AsciiChar = ' ';

	// Perform the scroll
	success = ScrollConsoleScreenBuffer(stdout,
    	&scrollRect, 0,
		coord, &consoleFill);
	if (!success)	
		ErrorHandler("In ScrollConsoleScreenBuffer",
			GetLastError());

}

VOID HandleCR(HANDLE stdout)
{
	CONSOLE_SCREEN_BUFFER_INFO consoleInfo;
	BOOL success;

	success = GetConsoleScreenBufferInfo(stdout,
		&consoleInfo);
	if (!success)
		ErrorHandler("In GetConsoleScreenBufferInfo",
			GetLastError());

	// Move cursor to far left
	consoleInfo.dwCursorPosition.X = 0;

	// If the cursor is on the last line of 
	// the console, then scroll the console,
	// else increment position
	if (consoleInfo.dwSize.Y - 1 ==
		consoleInfo.dwCursorPosition.Y)
		ScrollOneLine(stdout);
	else
		consoleInfo.dwCursorPosition.Y += 1;

	// Update the console
	success = SetConsoleCursorPosition(stdout,
		consoleInfo.dwCursorPosition);
	if (!success)
		ErrorHandler("In SetConsoleCursorPosition",
			GetLastError());
}

void ProcessIO(HANDLE stdin, HANDLE stdout)
{
	char buffer;
	DWORD numRead, numWrite;

	do
	{
		ReadFile(stdin, &buffer, 1, &numRead, NULL);
		if (buffer == '\r')
			HandleCR(stdout);
		else
			WriteFile(stdout, &buffer, 1,
                        	&numWrite, NULL);
	} while  (buffer != 'X');
}

VOID main(void)
{
	DWORD oldMode, newMode;
	BOOL success;
	HANDLE stdout, stdin;

	// Get handles for standard in and out
	stdin = GetStdHandle(STD_INPUT_HANDLE);
	stdout = GetStdHandle(STD_OUTPUT_HANDLE);
	if (stdin == stdout) //they must be invalid
		ErrorHandler("In GetStdHandle",
			GetLastError());

	// Get current console mode so can modify it
	success = GetConsoleMode(stdin, &oldMode);
	if (!success)
		ErrorHandler("In GetConsoleMode",
			GetLastError());
	newMode = oldMode & ~ENABLE_LINE_INPUT &
		~ENABLE_ECHO_INPUT;
	success = SetConsoleMode(stdin, newMode);
    	if (!success)
		ErrorHandler("In SetConsoleMode",
			GetLastError());

	// Process user I/O
	ProcessIO(stdin, stdout);

	// put the old mode back
	success = SetConsoleMode(stdin, oldMode);
	if (!success)
		ErrorHandler("In SetConsoleMode",
			GetLastError());
}