文件格式从UTF8转换成ANSII格式

用searech and replace查找UFT8文件格式里的中文字符，始终是找不到，木有办法，只好转了。

（这段代码借签了网上某位兄弟的代码，找不到那网页了）

int ConvStrUtf8ToAnsi(CString& strSource, CString& strChAnsi) 
{   
    if (strSource.GetLength() <= 0) 
        return 0; 

    CString strWChUnicode; 

    strSource.TrimLeft(); 
    strSource.TrimRight();
    strChAnsi.Empty(); 

//返回需要strSource转换成宽字符的缓冲的长度
    int iLenByWChNeed = MultiByteToWideChar(CP_UTF8, 0, 
strSource.GetBuffer(0), 
strSource.GetLength(), //MultiByteToWideChar 
NULL, 0); 
//
    int iLenByWchDone = MultiByteToWideChar(CP_UTF8, 0, 
strSource.GetBuffer(0), 
strSource.GetLength(), 
(LPWSTR)strWChUnicode.GetBuffer(iLenByWChNeed * 2), 
iLenByWChNeed); //MultiByteToWideChar 

    strWChUnicode.ReleaseBuffer(iLenByWchDone * 2); 

    int iLenByChNeed  = WideCharToMultiByte(CP_ACP, 0, 
(LPCWSTR)strWChUnicode.GetBuffer(0), 
iLenByWchDone, 
NULL, 0, 
NULL, NULL);  

    int iLenByChDone  = WideCharToMultiByte(CP_ACP, 0, 
(LPCWSTR)strWChUnicode.GetBuffer(0), 
iLenByWchDone, 
strChAnsi.GetBuffer(iLenByChNeed), 
iLenByChNeed, 
NULL, NULL); 

    strChAnsi.ReleaseBuffer(iLenByChDone); 

    if (iLenByWChNeed != iLenByChNeed || iLenByWchDone != iLenByChDone) 
        return 1; 

    return 0;    
}

思路就是先从utf8转到uncode 再从uncode转到ANSI
读取文件到buffer转换后再写入

BOOL TranslateFileToAnsi(char *sFileName)
{
CFile wFile;

wFile.Open(sFileName,CFile::modeReadWrite,NULL);
int iFileLength = wFile.GetLength();
char *sBuf = new char[iFileLength];

//把文件读入缓冲区
wFile.Read(sBuf,iFileLength);

CString str1,str2;
str1.Format("%s",sBuf);
if(ConvStrUtf8ToAnsi(str1,str2) == 1)
{
//转换成功，写入文件，并删除原有文件
wFile.Close();
DeleteFile(sFileName);
int iRetLen = str2.GetLength();
if(iRetLen < 1) return FALSE;
char *sRetBuf = new char[iRetLen];
memcpy(sRetBuf,str2.GetBuffer(iRetLen),iRetLen);

CFile fNewFile;
fNewFile.Open(sFileName,CFile::modeCreate|CFile::modeReadWrite,NULL);
fNewFile.Write(sRetBuf,iRetLen);
fNewFile.Close();
delete sRetBuf;
delete sBuf;
return TRUE;
}
else
{
//关闭文件
delete sBuf;
wFile.Close();
return FALSE;
}
}

功能实现了，但还是有些问题，在转换之前如保判断文件的编码格式？