philosdlg.cpp

哲学家编程的算法

// PhilosDlg.cpp : implementation file
//

#include "stdafx.h"
#include "Philos.h"
#include "PhilosDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

//定义state数组记录五个哲学家的活动：
#define NUM 5
struct ThreadParam {
	int i; // the no. of philosopher
	CEdit* pEdit; // the edit box associated with philosopher no.i
};

bool bDone;
//enum {thinking, hungry, eating} state[NUM];
//定义如下线程同步对象
CSemaphore semaphore[NUM]; // for philosopher can turn to eating
CMutex mutex; // for access to state[]

enum {thinking, hungry, eating} state[NUM];

UINT PhilosopherThread(LPVOID pParam);
void Test(int i);

/////////////////////////////////////////////////////////////////////////////
// CAboutDlg dialog used for App About

class CAboutDlg : public CDialog
{
public:
	CAboutDlg();

// Dialog Data
	//{{AFX_DATA(CAboutDlg)
	enum { IDD = IDD_ABOUTBOX };
	//}}AFX_DATA

	// ClassWizard generated virtual function overrides
	//{{AFX_VIRTUAL(CAboutDlg)
	protected:
	virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support
	//}}AFX_VIRTUAL

// Implementation
protected:
	//{{AFX_MSG(CAboutDlg)
	//}}AFX_MSG
	DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
	//{{AFX_DATA_INIT(CAboutDlg)
	//}}AFX_DATA_INIT
}

void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CAboutDlg)
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
	//{{AFX_MSG_MAP(CAboutDlg)
		// No message handlers
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CPhilosDlg dialog

CPhilosDlg::CPhilosDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CPhilosDlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CPhilosDlg)
		// NOTE: the ClassWizard will add member initialization here
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CPhilosDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CPhilosDlg)
	DDX_Control(pDX, IDC_EDIT5, m_Edit5);
	DDX_Control(pDX, IDC_EDIT4, m_Edit4);
	DDX_Control(pDX, IDC_EDIT3, m_Edit3);
	DDX_Control(pDX, IDC_EDIT2, m_Edit2);
	DDX_Control(pDX, IDC_EDIT1, m_Edit1);
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CPhilosDlg, CDialog)
	//{{AFX_MSG_MAP(CPhilosDlg)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_Start, OnStart)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CPhilosDlg message handlers

BOOL CPhilosDlg::OnInitDialog()
{
	CDialog::OnInitDialog();

	// Add "About..." menu item to system menu.

	// IDM_ABOUTBOX must be in the system command range.
	ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
	ASSERT(IDM_ABOUTBOX < 0xF000);

	CMenu* pSysMenu = GetSystemMenu(FALSE);
	if (pSysMenu != NULL)
	{
		CString strAboutMenu;
		strAboutMenu.LoadString(IDS_ABOUTBOX);
		if (!strAboutMenu.IsEmpty())
		{
			pSysMenu->AppendMenu(MF_SEPARATOR);
			pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
		}
	}

	// Set the icon for this dialog.  The framework does this automatically
	//  when the application's main window is not a dialog
	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon
	
	// TODO: Add extra initialization here
	
	return TRUE;  // return TRUE  unless you set the focus to a control
}

void CPhilosDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
	if ((nID & 0xFFF0) == IDM_ABOUTBOX)
	{
		CAboutDlg dlgAbout;
		dlgAbout.DoModal();
	}
	else
	{
		CDialog::OnSysCommand(nID, lParam);
	}
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CPhilosDlg::OnPaint() 
{
	if (IsIconic())
	{
		CPaintDC dc(this); // device context for painting

		SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

		// Center icon in client rectangle
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;

		// Draw the icon
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CDialog::OnPaint();
	}
}

// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CPhilosDlg::OnQueryDragIcon()
{
	return (HCURSOR) m_hIcon;
}

void CPhilosDlg::OnStart() 
{
	int k;
	CEdit *pEditArray[NUM] = {&m_Edit1, &m_Edit2, &m_Edit3,
		&m_Edit4, &m_Edit5
	};

	// frobid second click on Start
	GetDlgItem(IDC_Start)->EnableWindow(FALSE);

	// initialize
	bDone = false;

	// create 5 thread for every philopher
	for (k = 0; k < NUM; k++) {
		ThreadParam* param = new ThreadParam; 
		param->i = k;
		param->pEdit = pEditArray[k];
		AfxBeginThread(PhilosopherThread, (LPVOID)param);
		// Note: here needn’t delete param
		// for PhilosopherThread() will access them
	}
}

//实现线程函数PhilosopherThread()：
UINT PhilosopherThread(LPVOID pParam)
{
	int i = ((ThreadParam *)pParam)->i;
	int Left=i;
	int Right=(i+1)%NUM;

	CEdit* pEdit = ((ThreadParam *)pParam)->pEdit;

	while (! bDone) {
		// thinking for a random time
		state[i] = thinking;
		pEdit->SetWindowText(CString("thinking"));
		Sleep(2000);
		// hungry and wait for fork
		state[i] = hungry;
		pEdit->SetWindowText(CString("hungry"));
		do
		{
			// test itself, if passed,
			// turn to eating and release its semaphore
			mutex.Lock();
			if(semaphore[Left].Lock(0)!=0)
			{
				if(semaphore[Right].Lock(0)!=0)
				{
					state[i] = eating;
				}
				else
					semaphore[Right].Unlock();
			}
			mutex.Unlock();
		}while(state[i]!=eating);

		// eating for a random time
		pEdit->SetWindowText(CString("eating"));
		Sleep(2000);
		
		//mutex.Lock();
		semaphore[Left].Unlock();
		semaphore[Right].Unlock();
		//mutex.Unlock();
	}
	return 0;
}