win32下文件磁盘的操作

刚刚接触win32 编程的时候，就被他的数据类型吓住的，和平时c++常用的变量不一样。

特别是win32 API羞涩难懂，只好硬着头皮去看。由于工作中，主要是处理文件，磁盘，逻辑磁盘

这些设备，主要开发是在windows下 只好用win32 的CreateFile WriteFile ReadFile 等函数去操作。

时间长了发现主要操作就是打开设备，读、写、跳转。好多代码都是重复的，最近把一些常用的操作，

进行了封装。写了几个类。JIO JFile JDisk JLogicalDisk.

JIO是一个借口，定义了几个常用的 功能，包含了基本的设备打开，读写操作。

interface JIO{public:HANDLE  hDevice;public:u64 filesize;virtual u64  GetSize()= 0;virtual void DoSomething(const char* buffer,size_t buffersize){}virtual ~JIO(){CloseHandle(hDevice);}JIO(){filesize = 0;}virtual bool OpenA( const char* filename,bool newfile = false )//处理AsciI{DWORD type = 0;if(newfile){type = CREATE_ALWAYS;}else{type = OPEN_EXISTING;}hDevice=CreateFileA(filename,GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE ,NULL,type,0,NULL);if(hDevice == INVALID_HANDLE_VALUE)return false;GetSize();return true;}bool SeekPos( u64 offset ){LARGE_INTEGER a1,a2;a1.QuadPart = offset;a2.QuadPart = 0;BOOL ret = SetFilePointerEx(hDevice,a1,&a2,SEEK_SET);return ret?true:false;}bool SeekPos(u64 offset,u64& realoffset){LARGE_INTEGER a1,a2;a1.QuadPart = offset;a2.QuadPart = 0;BOOL ret = SetFilePointerEx(hDevice,a1,&a2,SEEK_SET);realoffset = a2.QuadPart;return ret?true:false;}bool WriteData( char* data,size_t size,size_t& realsize ){DWORD rr = 0;BOOL ret = WriteFile(hDevice,data,(DWORD)size,&rr,NULL);realsize = rr;return ret?true:false;}bool ReadData( char* data,size_t size,size_t& realsize ){DWORD rr ;BOOL ret = ReadFile(hDevice,data,(DWORD)size,&rr,NULL);realsize = rr;//DWORD error = GetLastError();return ret?true:false;}bool TellPosition( u64& pos ){LARGE_INTEGER a1,a2;a1.QuadPart = 0;a2.QuadPart = 0;BOOL ret = SetFilePointerEx(hDevice,a1,&a2,SEEK_CUR);pos = a2.QuadPart;return ret?true:false;}virtual bool OpenW(const  wchar_t* filename,bool newfile = false)//处理unicode{DWORD type = 0;if(newfile){type = CREATE_ALWAYS;}else{type = OPEN_EXISTING;}hDevice=CreateFileW(filename,GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE ,NULL,type,0,NULL);if(hDevice == INVALID_HANDLE_VALUE)return false;GetSize();return true;}bool ReadRange(s64 beginset=0,s64 size=-1){size==-1?filesize:size;if(!SeekPos(beginset))return false;u64 loop = size/BUFFERSIZE;char* buffer = new char[BUFFERSIZE];memset(buffer,0,BUFFERSIZE);size_t rr;for(u64 i=0;i<loop;i++){if(!ReadData(buffer,BUFFERSIZE,rr))return false;DoSomething(buffer,BUFFERSIZE);}size_t remain = size% BUFFERSIZE;if(remain){if(!ReadData(buffer,remain,rr))return false;DoSomething(buffer,remain);}return true;}};

Getsize（） 函数是一个虚函数，因为文件，磁盘，硬盘的获取大小的方式不一样，所以写了几个JIO的子类！

JFile类

class JFile:public JIO{public:bool OpenA(const char* name,bool newfile = false){return JIO::OpenA(name,newfile);}bool OpenW(const wchar_t* name,bool newfile = false){return JIO::OpenW(name,newfile);}u64 GetSize(){LARGE_INTEGER rr;rr.QuadPart = 0;GetFileSizeEx(hDevice,&rr);filesize = rr.QuadPart;return filesize;}};

JLogicalDisk类

class JLogicalDisk:public JIO{public:bool OpenA( const char* name){return JIO::OpenA(name,false);}bool OpenW(const wchar_t* name){return JIO::OpenW(name,false);}u64 GetSize(){GET_LENGTH_INFORMATION  lpOutBuffer;DWORD lpBytesReturned=0;if(DeviceIoControl(hDevice,           // handle to deviceIOCTL_DISK_GET_LENGTH_INFO , // dwIoControlCode0,        // lpInBuffer0,      // size of input buffer&lpOutBuffer,       // output buffersizeof(NTFS_VOLUME_DATA_BUFFER),     // size of output buffer&lpBytesReturned,  // number of bytes returnedNULL // OVERLAPPED structure)){filesize =  (u64)lpOutBuffer.Length.QuadPart;}return filesize;}};

JDisk类

class JDisk:public JIO{public:bool OpenA(const char* name){return JIO::OpenA(name,false);}bool OpenW(const wchar_t* name){return JIO::OpenW(name,false);}u64 GetSize(){DISK_GEOMETRY_EX info;DWORD lpBytesReturned=0;if(DeviceIoControl(hDevice,                 // handle to volumeIOCTL_DISK_GET_DRIVE_GEOMETRY_EX, // dwIoControlCodeNULL,                             // lpInBuffer0,                                // nInBufferSize(LPVOID) &info,             // output buffersizeof(DISK_GEOMETRY_EX),           // size of output buffer&lpBytesReturned,        // number of bytes returnedNULL       // OVERLAPPED structure)){filesize =  info.DiskSize.QuadPart;}return filesize;}};

这几个类 主要是自己平时用，封装的也许不是太好，但是使用中没有出现问题，跟着我立下了不少汗马功劳。经过了考验。

使用方法：

              

        char ch[1024];size_t rr;JFile file;file.OpenA("data",flag);//flag 为真表示创建一个新的文件，为false打开一个存在的文件。file.ReadData(ch,1024,rr);//读file.WriteData(ch,1024,rr);//写

JDisk 等的用法和这个一样。

希望自己的代码对小伙伴们有帮助，如果有错误麻烦提醒下 谢谢