crcfiledlg.cpp

CRC 算法源代码 工程测试确定可用

// CRCfileDlg.cpp : implementation file
//
// Copyright ?2000 Richard A. Ellingson
// http://www.createwindow.com
// mailto:[e-mail]

#include "stdafx.h"
#include "CRCfile.h"
#include "CRCfileDlg.h"
#include ".\crcfiledlg.h"

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

/////////////////////////////////////////////////////////////////////////////
// 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()

/////////////////////////////////////////////////////////////////////////////
// CCRCfileDlg dialog

CCRCfileDlg::CCRCfileDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CCRCfileDlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CCRCfileDlg)
	m_csCRCtext = _T("");
	m_csFileName = _T("");
	m_csURL = _T("");
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CCRCfileDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CCRCfileDlg)
	DDX_Text(pDX, IDC_CRCTEXT, m_csCRCtext);
	DDX_Text(pDX, IDC_FILENAME, m_csFileName);
	DDX_Text(pDX, IDC_URL, m_csURL);
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CCRCfileDlg, CDialog)
	//{{AFX_MSG_MAP(CCRCfileDlg)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_OPEN, OnOpen)
	ON_WM_DROPFILES()
	//}}AFX_MSG_MAP
	ON_BN_CLICKED(IDC_BUTTON1, OnBnClickedButton1)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CCRCfileDlg message handlers

BOOL CCRCfileDlg::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);
			// ******* Begin custom code *******

			// We have a Minimize box on the dialog, but we don't want
			// the Size and Maximize options on the system menu so disable them.
			pSysMenu->EnableMenuItem(SC_SIZE, MF_GRAYED);
			pSysMenu->EnableMenuItem(SC_MAXIMIZE, MF_GRAYED);

			// ******* End custom code *******
		}
	}

	// 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

// ******* Begin custom code *******

	// Don't forget to create the lookup table first
	Init_CRC32_Table();

	// Set the default text for the dialog box
	m_csFileName = "no file selected";
	m_csCRCtext = "0";
	m_csURL = "http://www.createwindow.com";
	UpdateData(FALSE);

	// For convenience, we'll add file Drag and Drop support
	DragAcceptFiles(TRUE);

// ******* End custom code *******
	
	return TRUE;  // return TRUE  unless you set the focus to a control
}

void CCRCfileDlg::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 CCRCfileDlg::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 CCRCfileDlg::OnQueryDragIcon()
{
	return (HCURSOR) m_hIcon;
}
// Everything above this line is AppWizard generated code
// except for a few lines in OnInitDialog()

// ******* Begin custom code *******

// Call this function only once to initialize the CRC table.
void CCRCfileDlg::Init_CRC32_Table()
{// Called by OnInitDialog()

	// This is the official polynomial used by CRC-32 
	// in PKZip, WinZip and Ethernet. 
	ULONG ulPolynomial = 0x04c11db7;

	// 256 values representing ASCII character codes.
	for(int i = 0; i <= 0xFF; i++)
	{
		crc32_table[i]=Reflect(i, 8) << 24;
		for (int j = 0; j < 8; j++)
			crc32_table[i] = (crc32_table[i] << 1) ^ (crc32_table[i] & (1 << 31) ? ulPolynomial : 0);
		crc32_table[i] = Reflect(crc32_table[i], 32);
	}
}

// Reflection is a requirement for the official CRC-32 standard.
// You can create CRCs without it, but they won't conform to the standard.
ULONG CCRCfileDlg::Reflect(ULONG ref, char ch)
{// Used only by Init_CRC32_Table()

	ULONG value(0);

	// Swap bit 0 for bit 7
	// bit 1 for bit 6, etc.
	for(int i = 1; i < (ch + 1); i++)
	{
		if(ref & 1)
			value |= 1 << (ch - i);
		ref >>= 1;
	}
	return value;
}

// Handler for the "Select a file" button.
void CCRCfileDlg::OnOpen() 
{
	CFileDialog dlg(TRUE, NULL, "(all files)", OFN_HIDEREADONLY,
		"All Files (*.*)|*.*||", this);

	if(IDOK != dlg.DoModal())
		return;

	m_csFileName = dlg.GetPathName();
	// Open the file and read it.
	Open_File();
	
}

// This function uses the crc32_table lookup table
// to generate a CRC for csData
int CCRCfileDlg::Get_CRC(CString &csData, DWORD dwSize)
{
	// Be sure to use unsigned variables,
	// because negative values introduce high bits
	// where zero bits are required.
	ULONG  crc(0xffffffff);
	int len;
	unsigned char* buffer;

	len = dwSize;
	// Save the text in the buffer.
	buffer = (unsigned char*)(LPCTSTR)csData;