📄 fat.cpp

📁 fat file system api in VC
💻 CPP
📖 第 1 页 / 共 2 页
字号:
12 下一页
// FAT.cpp: implementation of the FAT class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include <afxtempl.h>
#include "FS.h"
#include "FAT.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif


//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

FAT::FAT(LPCTSTR pVolumeLab)
{
	BPB.BytesPerSector=512;
	char pVolTemp[3];
    pVolTemp[0]=pVolumeLab[0];
    pVolTemp[1]=pVolumeLab[1];
	pVolTemp[2]=0;
	pVolume=pVolTemp;
	
	if(!GetDevice(pVolume))
	{
		return;
	}
	if(!GetSpecificBPB(BPB))
	{
		return;
	}
}

FAT::~FAT()
{
	if(m_hDevice!=INVALID_HANDLE_VALUE)//关闭设备句柄
	{
		CloseHandle(m_hDevice);
	}
}

BOOL FAT::GetDevice(LPCTSTR lpRoot)
{
    CHAR FileSysType[10];//存储文件系统类型
	ASSERT(GetVolumeInformation(lpRoot,NULL,0,NULL,0,NULL,FileSysType,sizeof(FileSysType)));
	if(!strcmp(FileSysType,"FAT32"))//检测文件系统是否是 FAT32
	{
		m_hDevice=CreateFile(CString("\\\\.\\") + lpRoot,//获得设备句柄
			GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,
			NULL,OPEN_EXISTING,0,NULL);
		if(m_hDevice==INVALID_HANDLE_VALUE)
		{
			MessageBox(NULL,"获得设备句柄失败！","错误",MB_ICONSTOP);
			CloseHandle(m_hDevice);
            return FALSE;
		}
	}
	else
	{//当文件系统不是FAT32时
		CString sMessage;
		sMessage.Format("你当前所选择的不是FAT32文件系统的磁盘，操作中止！ ");
		MessageBox(NULL,sMessage,"错误",MB_OK);
	}
	
	return TRUE;
}

BOOL FAT::GetSpecificBPB(BPB_FAT &bpb)
{
	ABS_SEC_BUF	buffer;
	buffer.IsValid=0;
	if(!ReadSector(0,buffer))
	{
		return FALSE;
	}
    if(buffer.IsValid){
		bpb.BigTotalSectors=buffer.Data[0x20+3]*0x100*0x100*0x100
			+buffer.Data[0x20+2]*0x100*0x100+buffer.Data[0x20+1]*0x100+buffer.Data[0x20];
		
		bpb.boot_rec_sig=-1; /*含义未知*/
	
		CopyElements(bpb.BootCode,&buffer.Data[0x3E],sizeof(bpb.BootCode));
		
		bpb.BytesPerSector=buffer.Data[0x0B+1]*0x100+buffer.Data[0x0B];
		
		bpb.Drive=buffer.Data[0x24];
		
		CopyElements(bpb.FileSys_ID,(char*)&buffer.Data[0x36],sizeof(bpb.FileSys_ID));
		
		bpb.Head=-1;
		
		bpb.Heads=buffer.Data[0x1A+1]*0x100+buffer.Data[0x1A];
		
		bpb.HiddenSectorNum=buffer.Data[0x0E+1]*0x100+buffer.Data[0x0E];
		
		CopyElements((char*)bpb.JMPCode,(char*)&buffer.Data[0x00],sizeof(bpb.JMPCode));
		
		CopyElements((char*)bpb.Label,(char*)&buffer.Data[0x2B],sizeof(bpb.Label));
		
		bpb.Media=(MediaType)(buffer.Data[0x15]);
		
		bpb.FatNum=buffer.Data[0x10];
		
		bpb.ReservedSectors=buffer.Data[0x0E+1]*0x100+buffer.Data[0x0E];
		
		bpb.RootEntry=buffer.Data[0x2F]*0x100*0x100*0x100+buffer.Data[0x2E]*0x100*0x100
			+buffer.Data[0x2D]*0x100+buffer.Data[0x2C];
		
		bpb.SectorsPerCluster=buffer.Data[0x0D];
		
		bpb.SectorsPerFAT=buffer.Data[0x24+3]*0x100*0x100*0x100
			+buffer.Data[0x24+2]*0x100*0x100+buffer.Data[0x24+1]*0x100+buffer.Data[0x24];
		
		bpb.SectorsPerTrack=buffer.Data[0x18+1]*0x100+buffer.Data[0x18];
		
		CopyElements((char*)bpb.FileSys_ID,(char*)&buffer.Data[0x03],sizeof(bpb.System_ID));
		
		bpb.TotalSectors=buffer.Data[0x13+1]*0x100+buffer.Data[0x13];
		
		bpb.Vol_Serial_NoL=buffer.Data[0x27+1]*0x100+buffer.Data[0x27];
		bpb.Vol_Serial_NoH=0;       /*待定*/
	}//if
	
	return TRUE;
}

BOOL FAT::GetDPB(DPB &dpb)
{
	dpb.BytePerSec=BPB.BytesPerSector;
	dpb.DriveNo=pVolume[0];
	dpb.FirstDataSec=0;            /*待定*/
	dpb.FirstFATSec=BPB.ReservedSectors;
	dpb.FirstFreeClu=0;            /*待定*/
	dpb.FreeClu=0;                 /*待定*/
	dpb.LastClu=0;                 /*待定*/
	dpb.MediaID=BPB.Media;
	dpb.FATNum=BPB.FatNum;
	dpb.PhyDrive=BPB.Drive;
	dpb.RelativeSectors=0;          /*待定*/
	dpb.RootEntryNum=0;             /*待定*/     
	dpb.RootStartSec=BPB.RootEntry;
	dpb.SecPerClu=BPB.SectorsPerCluster;
	dpb.SecPreFAT=BPB.SectorsPerFAT;
	dpb.SectorsPerTrack=BPB.SectorsPerTrack;
	dpb.TotalSectors=BPB.BigTotalSectors+BPB.TotalSectors;//one of them is 0
	
	return TRUE;
}

BOOL FAT::ReadSector(INT SectorNum,ABS_SEC_BUF &buffer)
{
	if(SectorNum<0)
	{
		AfxMessageBox("扇区号必须大于0");
		return FALSE;
	}
	INT StartAddress=SectorNum*BPB.BytesPerSector;
    DWORD BytesRead;
	
	if(SetFilePointer(m_hDevice,StartAddress,0,FILE_BEGIN)== 0xFFFFFFFF)
	{//将指针移到指定位置处
		return FALSE;
	}
	CHAR Buffer[512];
	if(!ReadFile(m_hDevice,Buffer,BPB.BytesPerSector,&BytesRead,NULL))
	{
		TRACE("ReadFile Error: %d\n",GetLastError());
		return FALSE;
	}
	else
	{
		CopyElements((char*)buffer.Data,Buffer,512);
		buffer.SectorNum=SectorNum;
		buffer.IsValid=1;
	}
	
	return TRUE;
}

BOOL FAT::ReadFAT(INT SectorNum,	FAT_BUF	&buffer)
{
	ABS_SEC_BUF Buffer;
    Buffer.IsValid=0;
	
	if(!ReadSector(SectorNum,Buffer))
	{
		return FALSE;
	}
	if(Buffer.IsValid)
	{
        for(int i=0;	i<sizeof(buffer.Data)/4;	i++)
		{
			buffer.Data[i]=Buffer.Data[4*i+3]*0x100*0x100*0x100
				+Buffer.Data[4*i+2]*0x100*0x100+Buffer.Data[4*i+1]*0x100+Buffer.Data[4*i];
		}
		buffer.IsValid=Buffer.IsValid;
		buffer.SectorNum=Buffer.SectorNum;
	}
	
	return TRUE;
}

BOOL FAT::ReadSector(INT SectorNum, WORD_SEC_BUF &buffer)
{
    ABS_SEC_BUF Buffer;
    Buffer.IsValid=0;
	
	if(!ReadSector(SectorNum,Buffer))
	{
		return FALSE;
	}
	if(Buffer.IsValid)
	{
        for(int i=0;	i<sizeof(buffer.Data)/2;	i++)
		{
			buffer.Data[i]=Buffer.Data[2*i+1]*0x100+Buffer.Data[2*i];
		}
		buffer.IsValid=Buffer.IsValid;
		buffer.SectorNum=Buffer.SectorNum;
	}
	
	return TRUE;
}

BOOL FAT::WriteSector(INT SectorNum,	ABS_SEC_BUF &buffer)
{
	if(SectorNum<0)
	{
		AfxMessageBox("扇区号必须大于0");
		return FALSE;
	}
	INT StartAddress=SectorNum*BPB.BytesPerSector;
    DWORD BytesRead;
	
	if(SetFilePointer(m_hDevice,StartAddress,0,FILE_BEGIN)== 0xFFFFFFFF)
	{//将指针移到指定位置处
		return FALSE;
	}
	
	if(!buffer.IsValid)
	{
		AfxMessageBox("数据无效！");
		return FALSE;
	}
	
	CHAR Buffer[512];
	CopyElements((char*)Buffer,(char*)buffer.Data,512);

	if(!WriteFile(m_hDevice,Buffer,BPB.BytesPerSector,&BytesRead,NULL))
	{
		return FALSE;
	}
	
	return TRUE;
}

BOOL FAT::WriteFAT(INT SectorNum,	FAT_BUF &buffer)
{
	if(SectorNum<0)
	{
		AfxMessageBox("扇区号必须大于0");
		return FALSE;
	}
	INT StartAddress=SectorNum*BPB.BytesPerSector;
    DWORD BytesRead;
	
	if(SetFilePointer(m_hDevice,StartAddress,0,FILE_BEGIN)== 0xFFFFFFFF)
	{//将指针移到指定位置处
		return FALSE;
	}
	
	if(!buffer.IsValid)
	{
		AfxMessageBox("数据无效！");
		return FALSE;
	}
	
	CHAR Buffer[512];
	CopyElements((char*)buffer.Data,Buffer,512);

	if(!WriteFile(m_hDevice,Buffer,BPB.BytesPerSector,&BytesRead,NULL))
	{
		return FALSE;
	}
	
	return TRUE;
}

BOOL FAT::WriteSector(INT SectorNum, WORD_SEC_BUF &buffer)
{
	if(SectorNum<0)
	{
		AfxMessageBox("扇区号必须大于0");
		return FALSE;
	}
	INT StartAddress=SectorNum*BPB.BytesPerSector;
    DWORD BytesRead;
	
	if(SetFilePointer(m_hDevice,StartAddress,0,FILE_BEGIN)== 0xFFFFFFFF)
	{//将指针移到指定位置处
		return FALSE;
	}
	
	if(!buffer.IsValid)
	{
		AfxMessageBox("数据无效！");
		return FALSE;
	}
	
	CHAR Buffer[512];
	CopyElements((char*)buffer.Data,Buffer,512);

	if(!WriteFile(m_hDevice,Buffer,BPB.BytesPerSector,&BytesRead,NULL))
	{
		return FALSE;
	}
	
	return TRUE;
}

BOOL FAT::ReadCluster(INT ClusterNum, CHAR *buffer)
{
	if(ClusterNum<0)
	{
		AfxMessageBox("簇号必须大于0");
		return FALSE;
	}
	
	INT SectorNum=GetFirstSecOfClu(ClusterNum);
	int i=0;
	ABS_SEC_BUF Buffer;
	Buffer.IsValid=0;
	
	while(i<BPB.SectorsPerCluster)
	{
		ReadSector(SectorNum,Buffer);
		if(Buffer.IsValid)
		{
			CopyElements(&buffer[BPB.BytesPerSector*i],(char*)(Buffer.Data),512);
			i++;
			SectorNum++;
			Buffer.IsValid=0;
		}
		else
		{
			return FALSE;
		}
	}
	return TRUE;
}

BOOL FAT::ReadCluster(INT ClusterNum, WORD *buffer)
{
    if(ClusterNum<0)
	{
		AfxMessageBox("簇号必须大于0");
		return FALSE;
	}
	
	INT SectorNum=GetFirstSecOfClu(ClusterNum);
	int i=0;
	WORD_SEC_BUF Buffer;
	Buffer.IsValid=0;
	
	while(i<BPB.SectorsPerCluster)
	{
		ReadSector(SectorNum,Buffer);
		if(Buffer.IsValid)
		{
			CopyElements((WORD*)buffer[BPB.BytesPerSector+i],(WORD*)Buffer.Data,(BPB.BytesPerSector)/2);
			i++;
			SectorNum++;
			Buffer.IsValid=0;
		}
		else
		{
			return FALSE;
		}
	}
	return TRUE;
}

BOOL FAT::WriteCluster(INT ClusterNum,CHAR *buffer)
{
	if(ClusterNum<0)
	{
		AfxMessageBox("簇号必须大于0");
		return FALSE;
	}
	INT SectorNum=GetFirstSecOfClu(ClusterNum);
	
	ABS_SEC_BUF Buffer;
	Buffer.IsValid=0;
	
	int i=0;
	while(i<BPB.SectorsPerCluster)
	{
		CopyElements((CHAR*)Buffer.Data,(CHAR*)&buffer[BPB.BytesPerSector*i],BPB.BytesPerSector);
		Buffer.IsValid=1;
		Buffer.SectorNum=SectorNum;
		
		if(!WriteSector(SectorNum,Buffer))
		{
			return FALSE;
		}
		
		i++;
		SectorNum++;
	}
	
	return TRUE;
}

BOOL FAT::WriteCluster(INT ClusterNum,WORD *buffer)
{
	if(ClusterNum<0)
	{
		AfxMessageBox("簇号必须大于0");
		return FALSE;
	}
	INT SectorNum=GetFirstSecOfClu(ClusterNum);
	
	WORD_SEC_BUF Buffer;
	Buffer.IsValid=0;
	
	int i=0;
	while(i<BPB.SectorsPerCluster)
	{
		for(int j=0;j<(BPB.BytesPerSector)/2;j++)
		{
			Buffer.Data[j]=buffer[BPB.BytesPerSector*i+2*j+1]*0x100
				+buffer[BPB.BytesPerSector*i+2*j];
		}
		Buffer.IsValid=1;
		Buffer.SectorNum=SectorNum;
		
		if(!WriteSector(SectorNum,Buffer))
		{
			return FALSE;
		}
		
		i++;
		SectorNum++;
	}
12 下一页
💿 文件大小 78 K
👤 上传用户 Fiona1207
📂 所属分类驱动编程
🏷️ 相关标签

#system #file #fat #api
⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -