readfileview.cpp

这是书上的代码

// ReadFileView.cpp : implementation of the CReadFileView class
//

#include "stdafx.h"
#include "ReadFile.h"

#include "ReadFileDoc.h"
#include "ReadFileView.h"


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

//
//#ifndef WM_UPDATE_DXF_DLG_POS
//#define WM_UPDATE_DXF_DLG_POS		WM_USER + 10000
//#endif
//
//#ifndef WM_UPDATE_DXF_DLG_DESTROY
//#define WM_UPDATE_DXF_DLG_DESTROY		WM_USER + 10001
//#endif


/////////////////////////////////////////////////////////////////////////////
// CReadFileView

IMPLEMENT_DYNCREATE(CReadFileView, CView)

BEGIN_MESSAGE_MAP(CReadFileView, CView)
	//{{AFX_MSG_MAP(CReadFileView)
	ON_COMMAND(IDM_READ_DXF_FILE, OnReadDxfFile)
	//}}AFX_MSG_MAP
	// Standard printing commands
	ON_COMMAND(ID_FILE_PRINT, CView::OnFilePrint)
	ON_COMMAND(ID_FILE_PRINT_DIRECT, CView::OnFilePrint)
	ON_COMMAND(ID_FILE_PRINT_PREVIEW, CView::OnFilePrintPreview)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CReadFileView construction/destruction

CReadFileView::CReadFileView()
{
	// TODO: add construction code here

}

CReadFileView::~CReadFileView()
{
}

BOOL CReadFileView::PreCreateWindow(CREATESTRUCT& cs)
{
	// TODO: Modify the Window class or styles here by modifying
	//  the CREATESTRUCT cs

	return CView::PreCreateWindow(cs);
}

/////////////////////////////////////////////////////////////////////////////
// CReadFileView drawing

void CReadFileView::OnDraw(CDC* pDC)
{
	CReadFileDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);
	// TODO: add draw code for native data here
}

/////////////////////////////////////////////////////////////////////////////
// CReadFileView printing

BOOL CReadFileView::OnPreparePrinting(CPrintInfo* pInfo)
{
	// default preparation
	return DoPreparePrinting(pInfo);
}

void CReadFileView::OnBeginPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
	// TODO: add extra initialization before printing
}

void CReadFileView::OnEndPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
	// TODO: add cleanup after printing
}

/////////////////////////////////////////////////////////////////////////////
// CReadFileView diagnostics

#ifdef _DEBUG
void CReadFileView::AssertValid() const
{
	CView::AssertValid();
}

void CReadFileView::Dump(CDumpContext& dc) const
{
	CView::Dump(dc);
}

CReadFileDoc* CReadFileView::GetDocument() // non-debug version is inline
{
	ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CReadFileDoc)));
	return (CReadFileDoc*)m_pDocument;
}
#endif //_DEBUG

/////////////////////////////////////////////////////////////////////////////
// CReadFileView message handlers


CStdioFile * g_pFile = NULL;//全局的文件指针
HANDLE g_hMutex = NULL;//互斥量

//发送进度条位置消息的进程
DWORD WINAPI SetProgressPosThreadProc(LPVOID lParam)
{
	CDialog * pDlg = (CDialog *)lParam;//传入的进度条对话框指针
	if(!pDlg)return 0;		//异常判断
	DWORD dPos=0;			//当前文件指针的位置
	DWORD dLength = 1;		//文件的长度
	DWORD dProssPos = 0;	//计算出来的进度条的位置
	DWORD dPrePos = 0;		//记录前一个进度条的位置

	DWORD dw;
	dw = WaitForSingleObject(g_hMutex,INFINITE);//等待互斥量有信号
	if(dw==WAIT_OBJECT_0)	//判断互斥量是否为有信号
	{
		dLength = g_pFile->GetLength();	//获取文件长度
	}
	else //废弃的信号，说明读取文件的线程有异常
	{
		::SendMessage(pDlg->GetSafeHwnd(),WM_UPDATE_DXF_DLG_POS,100,NULL);	
		//向对话框发送消息, 以销毁对话框
		::SendMessage(pDlg->GetSafeHwnd(),WM_UPDATE_DXF_DLG_DESTROY,NULL,NULL);
		return 0;
	}
	ReleaseMutex(g_hMutex);//释放互斥量
	
	while(dPos < dLength)//当文件未读完时执行循环
	{
		if(!pDlg)return 0;//异常判断
		
		dw = WaitForSingleObject(g_hMutex,INFINITE); //等待互斥量有信号
		if(dw==WAIT_OBJECT_0)	//等待到信号
		{
			dPos = g_pFile->GetPosition(); //获取当前文件指针的位置
			dProssPos = DWORD(double(dPos) / dLength * 100); //计算进度条的位置
		}
		else //废弃的信号
		{
			::SendMessage(pDlg->GetSafeHwnd(),WM_UPDATE_DXF_DLG_POS,100,NULL);	
			//向对话框发送消息, 以销毁对话框
			::SendMessage(pDlg->GetSafeHwnd(),WM_UPDATE_DXF_DLG_DESTROY,NULL,NULL);
			return 0;
		}
		ReleaseMutex(g_hMutex); //释放互斥量
		if(dProssPos!=dPrePos)	//进度条位置相同时不发送更新消息
		{
			::SendMessage(pDlg->GetSafeHwnd(),WM_UPDATE_DXF_DLG_POS,dProssPos,NULL);
		}
		dPrePos = dProssPos;	//当前位置变为前一位置
	}

	//由于计算位置时用的将double 强制转换为 DWORD 型，有可能没有计算到100
	//所以需要发送一个消息将进度条位置刷新到100
	::SendMessage(pDlg->GetSafeHwnd(),WM_UPDATE_DXF_DLG_POS,100,NULL);	
	Sleep(500);	
	//向对话框发送消息, 以销毁对话框
	::SendMessage(pDlg->GetSafeHwnd(),WM_UPDATE_DXF_DLG_DESTROY,NULL,NULL);

	//文件读取完毕以后要对文件指针进行关闭和销毁
	dw = WaitForSingleObject(g_hMutex,INFINITE);
	if(dw==WAIT_OBJECT_0)
	{
		g_pFile->Close();
		delete g_pFile;
		g_pFile = NULL;
	}
	else //废弃的信号
	{
		g_pFile->Close();
		delete g_pFile;
		g_pFile = NULL;
	}
	ReleaseMutex(g_hMutex);
	return 0;
}

//读取文件的线程
DWORD WINAPI ReadDxfThreadProc(LPVOID lParam)
{
	CString strTemp = ""; //存放读取的字符
	BOOL bIsEnd = TRUE;   //指示文件是否读取完毕
	DWORD dw;  //互斥量信号结果
	while(1)
	{
		if(!g_pFile)return 0;//异常判断

		dw = WaitForSingleObject(g_hMutex,INFINITE);
		if(dw==WAIT_OBJECT_0)	//互斥量等待到信号
		{
			bIsEnd = g_pFile->ReadString(strTemp);//读取文件
		}
		else if(dw==WAIT_ABANDONED)
		{
			return 0 ;
		}
		ReleaseMutex(g_hMutex);
		
		if(bIsEnd == FALSE) break;
	}
	return 0 ;
}



void CReadFileView::OnReadDxfFile() 
{
	// TODO: Add your command handler code here
	//如果对话框没有销毁，说明上一个文件读取线程还没有结束，因此要返回
	if(m_ProgressDlg.GetSafeHwnd())
	{
		MessageBox("文件还未读取完毕! 请稍候!",NULL,MB_OK);
		return;
	}
	CString strFileName = "";
	//本实例采用dxf文件为读取的文本文件类型
	CFileDialog  dlg(TRUE,"dxf","*.dxf",OFN_HIDEREADONLY,
		"dxf File (*.dxf)|*.dxf||",NULL);

	if(dlg.DoModal()==IDOK) 
	{
		strFileName=CString(dlg.GetFileName());	
		g_pFile = new CStdioFile(strFileName,CFile::modeRead);//初始化文件指针
		m_ProgressDlg.Create();//开始创建非模态对话框
		g_hMutex = CreateMutex(NULL,FALSE,NULL);//创建互斥量

		//创建读取文件的线程和发送进度条位置消息的进程
		//创建SetProgressPosThreadProc线程时将非模态对话框的指针传入
		HANDLE hThreads[2];
		DWORD dwThreadId; //存放线程ID
		hThreads[0] = CreateThread( NULL,0,SetProgressPosThreadProc, &m_ProgressDlg,0,&dwThreadId); 
		hThreads[1] = CreateThread( NULL,0,ReadDxfThreadProc, NULL,0,&dwThreadId);
		CloseHandle(hThreads[0]);
		CloseHandle(hThreads[1]);
	}
}