商业编程-源码-其它源代码 clusterdemo.zip

///////////////////////////////////////////////////////////////////////////// // CClusterSize // ------------ // This class can be used to find the cluster size on any Windows95 or 98 // computers. I have not been able to test it under Windows NT, but my guess // is that it wouldn't work, or wouldn't be applicable. // // Author: Daniel Hirsch // danielh@comports.com // // You may use this code freely, but please keep my name and email address // with it. I also request that if you do use it, send me some email and // tell me so. I spent quite a while figuring this out, so I would love // to hear if anybody appreciates my work. ///////////////////////////////////////////////////////////////////////////// // ClusterSize.cpp: implementation of the CClusterSize class. // ////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "ClusterSize.h" #include <ctype.h> // for isalpha() #ifdef _DEBUG #undef THIS_FILE static char THIS_FILE[]=__FILE__; #define new DEBUG_NEW #endif ////////////////////////////////////////////////////////////////////// // Construction/Destruction ////////////////////////////////////////////////////////////////////// CClusterSize::CClusterSize() { m_strDrive = ""; } CClusterSize::CClusterSize(CString strDrive) { m_strDrive = ""; SetDrive(strDrive); } CClusterSize::~CClusterSize() { } ///////////////////////////////////////////////////////////////////////////// // SetDrive // -------- // Sets the current drive to strDrive. strDrive should be in the form of // C:\ for the class to get the cluster size on drive C. In order to get the // cluster size of the drive, you should either pass the drive to the constructor // or call this function before calling GetClusterSize(). // // Returns: true if the string is a valid path format (does not check to see // if the drive is valid), otherwise false. ///////////////////////////////////////////////////////////////////////////// bool CClusterSize::SetDrive(CString strDrive) { TRACE("SetDrive passed the following parameter: %s", strDrive); if(strDrive.GetLength() < 3) { TRACE("Drive length is less than 3, returning false\n"); return false; } if(!isalpha(strDrive[0])) { TRACE("First character of drive string is not alpha\n"); return false; } if(strDrive[1] != ':') { TRACE("Second character of drive string is not :\n"); return false; } if(strDrive[2] != '\\') { TRACE("Third character of drive string is not \\\n"); return false; } m_strDrive = strDrive; return true; } ///////////////////////////////////////////////////////////////////////////// // GetClusterSize // -------------- // Determines the cluster size for the current drive, which is set either using // SetDrive or the second constructor. It uses the DeviceIoControl to set and // poll the registers to execute Int 21h Function 7303h which is only valid // if the system is running OSR2 or greater. ///////////////////////////////////////////////////////////////////////////// DWORD CClusterSize::GetClusterSize() { if(m_strDrive.IsEmpty()) return 0; bool OSR2 = false;; //Running OSR2 or not OSVERSIONINFO os; DWORD SectorsPerCluster; DWORD BytesPerSector; DWORD BytesPerCluster; // determine the OS version os.dwOSVersionInfoSize = sizeof(OSVERSIONINFO); GetVersionEx(&os); if(os.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS) { if(LOWORD(os.dwBuildNumber) > 1000) // is it OSR2 or newer? OSR2 = true; } //If it's not OSR2, this is easy if(!OSR2) { GetDiskFreeSpace((LPCTSTR)m_strDrive,&SectorsPerCluster, &BytesPerSector,NULL,NULL); BytesPerCluster = SectorsPerCluster * BytesPerSector; return BytesPerCluster; } else // otherwise, use the int 21h function { HANDLE hDevice; DIOC_REGISTERS reg; ExtGetDskFreSpcStruc spc; BOOL bResult; DWORD cb; const char *sz[] = { (LPCTSTR) m_strDrive }; spc.ExtFree_Level = 0; //Must initialize before using the structure hDevice = CreateFile("\\\\.\\vwin32",0,0,NULL,0,FILE_FLAG_DELETE_ON_CLOSE,NULL); // initialize the registers to call the correct function reg.reg_EDI = (DWORD)&spc; reg.reg_ECX = sizeof(ExtGetDskFreSpcStruc); reg.reg_EDX = (DWORD)(LPCTSTR)m_strDrive; reg.reg_EAX = 0x7303; reg.reg_Flags = 0x0001; // copies the structure into the registers, performs the function, // and returns the new registers in the structure bResult = DeviceIoControl(hDevice, VWIN32_DIOC_DOS_DRIVEINFO, &reg, sizeof(reg), &reg, sizeof(reg), &cb, 0); CloseHandle(hDevice); // check the error status if(!bResult || (reg.reg_Flags & 0x0001) ) { return 0; } else { BytesPerCluster = spc.ExtFree_SectorsPerCluster * spc.ExtFree_BytesPerSector; return BytesPerCluster; } } }