Win32 获取磁盘剩余空间+遍历文件目录+wchar_t与char互转

函数GetDiskFreeSpaceEx声明如下：
 
WINBASEAPI
BOOL
WINAPI
GetDiskFreeSpaceExA(
    __in_opt LPCSTR lpDirectoryName,
    __out_opt PULARGE_INTEGER lpFreeBytesAvailableToCaller,
    __out_opt PULARGE_INTEGER lpTotalNumberOfBytes,
    __out_opt PULARGE_INTEGER lpTotalNumberOfFreeBytes
    );
WINBASEAPI
BOOL
WINAPI
GetDiskFreeSpaceExW(
    __in_opt LPCWSTR lpDirectoryName,
    __out_opt PULARGE_INTEGER lpFreeBytesAvailableToCaller,
    __out_opt PULARGE_INTEGER lpTotalNumberOfBytes,
    __out_opt PULARGE_INTEGER lpTotalNumberOfFreeBytes
    );
#ifdef UNICODE
#define GetDiskFreeSpaceEx GetDiskFreeSpaceExW
#else
#define GetDiskFreeSpaceEx GetDiskFreeSpaceExA
#endif // !UNICODE
 
lpDirectoryName是驱动器的名称。
lpFreeBytesAvailableToCaller是用户可用的磁盘空间。
lpTotalNumberOfBytes是磁盘总共的空间。

lpTotalNumberOfFreeBytes是磁盘空闲的空间。以上都是字节为单位。

//跟别的兄台一样，客户说我写的软件会有数据丢失，后来发现是没有做硬盘剩余空间的检测，//不管有N多数据，照单全收，无一漏网。。//以下代码补上之后，再加一个提示对话框就比较保险了。。void DiskFree(void){        //         ULARGE_INTEGER nFreeBytesAvailable;        ULARGE_INTEGER nTotalNumberOfBytes;         ULARGE_INTEGER nTotalNumberOfFreeBytes;        //        if (GetDiskFreeSpaceEx(_T("I:"),               &nFreeBytesAvailable,               &nTotalNumberOfBytes,              &nTotalNumberOfFreeBytes))         {               TCHAR chBuf[256];               wsprintf(chBuf,_T("Av=%I64d,Total=%I64d,Free=%I64d\r\n"),                    nFreeBytesAvailable,                    nTotalNumberOfBytes,                    nTotalNumberOfFreeBytes);               printf("free space == %s \n",chBuf);        }} 

注明: 我用的数据是:nFreeBytesAvailable.QuadPart.

报错:void ATL::CStringT<BaseType,StringTraits>::Format(const wchar_t *,...)

解决方案：

将strInfo.Format("  %d ",mGainParam.nHave);改为==>>

strInfo.Format(_T("  %d "),mGainParam.nHave);即可。

报错:error C2664: 'strlen' : cannot convert parameter 1 from 'LPCTSTR' to 'const char *'
1>        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast

解决方案:

将nLength=strlen((LPCTSTR)strInfo); 改为:

nLength=(UINT)strlen((char *)strInfo.GetBuffer(0)); 即可.

将char转化为wchar_t型：

void c2w(wchar_t *pwstr,size_t len,const char *str){if(str){size_t nu = strlen(str);size_t n =(size_t)MultiByteToWideChar(CP_ACP,0,(const char *)str,(int)nu,0,0);if(n>=len)n=len-1;MultiByteToWideChar(CP_ACP,0,(const char *)str,(int)nu,pwstr,(int)n);pwstr[n]=0;}}

将wchar_t转化为char型：

//将wchar_t* 转成char*的实现函数如下：char *w2c(char *pcstr,const wchar_t *pwstr, size_t len){int nlength=wcslen(pwstr);//获取转换后的长度int nbytes = WideCharToMultiByte( 0, // specify the code page used to perform the conversion0,         // no special flags to handle unmapped characterspwstr,     // wide character string to convertnlength,   // the number of wide characters in that stringNULL,      // no output buffer given, we just want to know how long it needs to be0,NULL,      // no replacement character givenNULL );    // we don't want to know if a character didn't make it through the translation// make sure the buffer is big enough for this, making it larger if necessaryif(nbytes>len)   nbytes=len;// 通过以上得到的结果，转换unicode 字符为ascii 字符WideCharToMultiByte( 0, // specify the code page used to perform the conversion0,         // no special flags to handle unmapped characterspwstr,   // wide character string to convertnlength,   // the number of wide characters in that stringpcstr, // put the output ascii characters at the end of the buffernbytes,                           // there is at least this much space thereNULL,      // no replacement character givenNULL );return pcstr ;}

对于CString类型的字符写入，最好使用WriteString函数，如果像我这块土豆一样，用Write，否则会出现写一个字符，中间空一格。

也就是Unicode字符。

SeekToBegin(); //到达文件开头 

SeekToEnd(); //到达文件尾

下面这个代码是遍历某个目录下所有文件，并对特定格式的文件进行处理的一个实例:

void FindAllFile(CString pSourcePathString){CFileFind finder;CFile tmpFile;ULONGLONG fileLen;CString filepath;CString filename;BYTE *data =NULL;CString tmpDir=pSourcePathString + _T("\\*.ex");BOOL ret=finder.FindFile(tmpDir);while(ret){ret=finder.FindNextFile();if(finder.IsDots())continue;if (finder.IsDirectory()){printf("find a directory ! \n");}else{// 下面就是我们对匹配的文件做处理...filename=finder.GetFileName();filepath=finder.GetFilePath();tmpFile.Open(filepath,CFile::modeRead);fileLen=tmpFile.GetLength();//获取file文件中内容的长度；//CheckDiskFree(pDestPathString,fileLen);// 写入记录信息。//LogFile.SeekToEnd();//LogFile.WriteString(filename);data  =new BYTE[(size_t)fileLen+1];//定义一个存放数据的指针；memset(data  ,0,(size_t)fileLen+1);//将已开辟内存空间 data的,长度为len+1首 个字节的值设为值 0tmpFile.Read(data,(UINT)fileLen);//读取文件内容并赋值给data;tmpFile.Close();delete [] data;}}}

 Ok ,收工。。