MFC File crc 计算

创建单文档对话框之后，编辑OnOpen函数，并加入crc算法函数，代码如下：

/******************************************************************************
Public external variables declaration
******************************************************************************/
const unsigned short crc_table[256]={ 
        0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, 
        0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 
        0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, 
        0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, 
        0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, 
        0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, 
        0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, 
        0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 
        0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, 
        0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, 
        0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, 
        0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, 
        0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, 
        0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, 
        0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, 
        0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, 
        0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, 
        0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, 
        0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, 
        0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, 
        0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, 
        0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 
        0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, 
        0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, 
        0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, 
        0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, 
        0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, 
        0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, 
        0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 
        0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, 
        0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, 
        0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0 
}; 


/************************************************
function name: crc 16
using e.g.
  crc = 0xffff;
  for(i=0;i<bytes_length;i++)
  {
    crc = crc_16(crc,data_bytes_buf[i]);
  }
  return crc;
***
parameter: crc, data
return: crc-16
************************************************/
unsigned short crc_16(unsigned short crc,  BYTE data)
{ 
  BYTE da;
  
  da=(BYTE)(crc/256);
  crc<<=8;              //crc=crc*256
  crc ^= crc_table[da^data];
  return(crc);
}
//0x12a5 --> "12a5"
void swap_word_byte(WORD wd,BYTE *by)
{
	unsigned char i,k;
	for(i=0;i<4;i++)
	{
		k = (wd & 0xF000)>>12;
		if(9>=k)
		{
			*by++=k+'0';
		}
		else if((k>=0x0a)&&(0x0f>=k))
		{
			*by++=k+0x37;
		}
		wd<<=4;
	}
}
void CFileCrcDlg::OnOpen() 
{
	// TODO: Add your control notification handler code here
	WORD n;
	WORD i;
	BYTE szchar[21];
	BYTE crc_hex[4],bt;
	CString strtemp="";
	CFileDialog fileDlg(TRUE);
	fileDlg.m_ofn.lpstrFilter="All files (*.*)";
	if(fileDlg.DoModal()==IDOK)
	{
		CFile file(fileDlg.m_ofn.lpstrFile,CFile::modeRead);
		UpdateData(TRUE);
		m_path = file.GetFilePath();
		//clear the Edit Dlg
		i=0xffff;
		memset(szchar,0,21);
		while(file.Read(szchar,20))
		{
			n=0;
			while(szchar[n])
			{
				i=crc_16(i,szchar[n]);
				n++;
			}
			memset(szchar,0,21);
		}
		m_crc_dec = i;
		m_crc_hex="";
		swap_word_byte(i,crc_hex);
		for(i=0;i<4;i++)
		{
			bt =*(char*)(crc_hex+i);
			strtemp.Format("%c",bt);
			m_crc_hex+=strtemp;
		}
		file.Close();
		UpdateData(FALSE);
	}
}

 对应的变量声明如图：

Running:

OK， this is my first home work! Enjoy. thank you !