/*
	-----------------------------------
	  FREEMEM.c - Free memory display
	-----------------------------------
			From Programming the OS/2 Presentation Manager
					by Charles Petzold
*/

#define INCL_WIN
#define INCL_GPI
#define INCL_DOS
#include <os2.h>
#include <string.h>

#define ID_TIMER 1

MRESULT EXPENTRY ClientWndProc (HWND, USHORT, MPARAM, MPARAM) ;
VOID	SizeTheWindow (HWND) ;

int main (void)
{
	static CHAR szClientClass[] = "FreeMem" ;
	static ULONG flFrameFlags = FCF_TITLEBAR | FCF_SYSMENU |
								FCF_BORDER	 | FCF_TASKLIST ;
	HAB 	hab;
	HMQ 	hmq;
	HWND	hwndFrame, hwndClient ;
	QMSG	qmsg;

	hab=WinInitialize (0) ;
	hmq = WinCreateMsgQueue (hab, 0) ;

	WinRegisterClass (hab, szClientClass, ClientWndProc, 0L, 0 ) ;
	hwndFrame = WinCreateStdWindow (HWND_DESKTOP, WS_VISIBLE,
									&flFrameFlags, szClientClass, NULL,
									0L, NULL, 0, &hwndClient ) ;
	SizeTheWindow (hwndFrame) ;

	if (WinStartTimer (hab, hwndClient, ID_TIMER, 1000)) {
		while (WinGetMsg (hab, &qmsg, NULL, 0,0))
			WinDispatchMsg (hab, &qmsg) ;
		WinStopTimer (hab, hwndClient, ID_TIMER) ;
	} else
		WinMessageBox (HWND_DESKTOP, hwndClient,
						"Too many clocks or timers",
						szClientClass, 0, MB_OK | MB_ICONEXCLAMATION) ;

	WinDestroyWindow (hwndFrame) ;
	WinDestroyMsgQueue (hmq) ;
	WinTerminate (hab) ;
	return 0;
}
VOID SizeTheWindow (HWND hwndFrame)
{
	static CHAR szText [] = "1,234,567,890 bytes" ;
	HPS 		hps;
	POINTL		aptl[TXTBOX_COUNT];
	RECTL		rcl;

	hps = WinGetPS (hwndFrame) ;
	GpiQueryTextBox (hps, sizeof szText - 1L, szText, TXTBOX_COUNT,aptl) ;
	WinReleasePS (hps) ;

	rcl.yBottom = 0 ;
	rcl.yTop	= 3 * (aptl[TXTBOX_TOPLEFT].y -
					   aptl[TXTBOX_BOTTOMLEFT].y) / 2 ;
	rcl.xLeft	= 0 ;
	rcl.xRight	= (sizeof szText + 1L) * (aptl[TXTBOX_BOTTOMRIGHT].x -
				   aptl[TXTBOX_BOTTOMLEFT].x) / (sizeof szText - 1L) ;

	WinCalcFrameRect (hwndFrame, &rcl, FALSE) ;
	WinSetWindowPos (hwndFrame, NULL, (SHORT) rcl.xLeft, (SHORT) rcl.yBottom,
					 (SHORT) (rcl.xRight - rcl.xLeft),
					 (SHORT) (rcl.yTop - rcl.yBottom), SWP_SIZE | SWP_MOVE) ;
}
VOID FormatNumber (CHAR *pchResult, ULONG ulValue)
{
	BOOL	fDisplay = FALSE;
	SHORT	sDigit;
	ULONG	ulQuotient, ulDivisor = 1000000000L ;

	for (sDigit = 0 ; sDigit < 10 ; sDigit++) {
		ulQuotient = ulValue / ulDivisor;

		if (fDisplay || ulQuotient > 0 || sDigit == 9) {
			fDisplay = TRUE;

			   *pchResult++ = (CHAR) ('0' + ulQuotient) ;

				if ((sDigit % 3 == 0) && sDigit != 9)
					*pchResult++ = ',' ;
		}
		ulValue -= ulQuotient * ulDivisor ;
		ulDivisor /= 10;
	}
	*pchResult = '\0' ;
}

MRESULT EXPENTRY ClientWndProc (HWND hwnd, USHORT msg, MPARAM mp1, MPARAM mp2)
{
	static RECTL rcl;
	static ULONG ulFreeMem, ulPrevMem ;
	CHAR		 szBuffer [24] ;
	HPS 		 hps ;

	switch (msg) {
		case WM_SIZE:
			WinQueryWindowRect (hwnd, &rcl) ;
			return 0;
		case WM_TIMER:
			DosMemAvail (&ulFreeMem) ;
			if (ulFreeMem != ulPrevMem) {
				WinInvalidateRect (hwnd, NULL, FALSE) ;
				ulPrevMem = ulFreeMem;
			}
			return 0;
		case WM_PAINT:
			hps = WinBeginPaint (hwnd, NULL, NULL) ;

			FormatNumber (szBuffer, ulFreeMem) ;
			strcat (szBuffer, " bytes") ;

			WinDrawText (hps, -1, szBuffer, &rcl,
						 CLR_NEUTRAL, CLR_BACKGROUND,
						 DT_CENTER | DT_VCENTER | DT_ERASERECT) ;

			WinEndPaint (hps) ;
			return 0;
	}
	return WinDefWindowProc (hwnd, msg, mp1, mp2) ;
}