www.pudn.com > UDISK.rar > FILE.C

//************************************************************************ 
//author:dragon 
//web:8dragon.com 
//2004.2.5完成于桃龙源 
//************************************************************************* 
#include "AT89X52.h" 
#include "host_811.h" 
#include "file.h" 
#include "math.h" 
#include "string.h" 
#include "ufi.h" 
struct _BPB		SimpleBpb; 
struct _FILE	FileControl; 
FAT_PARAMETER FatParameter; 
WORD FatCache[2][256]; 
BYTE InitFsys() 
{	 
	BYTE buf[512]; 
	UINT m_Offset; 
	DWORD DataSectors,TotalClusters; 
	/////////////////////////////////////////////////////////////////////// 
	DelayMs(100); 
	if(Read(0,1,(BYTE *)buf)==FALSE)	 
		return FALSE; 
	DelayMs(100); 
	if(buf[0x00]==0xEB ||buf[0x02]==0x90)	 
		m_Offset=0; 
	else 
		m_Offset=ConvTwoBytes((buf+0x1c6));	 
	if(Read(0+m_Offset,1,(BYTE *)buf)==FALSE) 
		return FALSE; 
	SimpleBpb.BytsPerSec =ConvTwoBytes((&buf[11])); 
	SimpleBpb.SecPerClus = buf[13]; 
	SimpleBpb.RsvdSecCnt =ConvTwoBytes((&buf[14])); 
	SimpleBpb.NumFATs = buf[16]; 
	SimpleBpb.RootEntCnt = ConvTwoBytes((&buf[17])); 
	if((SimpleBpb.TotSec = ConvTwoBytes((&buf[19])))==0) 
		SimpleBpb.TotSec = ConvFourBytes((&buf[32]));	 
	if((SimpleBpb.FATSz = ConvTwoBytes((&buf[22])))==0) 
		SimpleBpb.FATSz =ConvFourBytes((&buf[36])); 
	//------------------------------------------------------------------------ 
	//Compute the corresponding data for Fat information; 
	//------------------------------------------------------------------------ 
	FatParameter.RootDirSectors= ((SimpleBpb.RootEntCnt * 32) + (SimpleBpb.BytsPerSec - 1)) / SimpleBpb.BytsPerSec; 
	DataSectors = SimpleBpb.TotSec - (SimpleBpb.RsvdSecCnt + (SimpleBpb.NumFATs * SimpleBpb.FATSz) + FatParameter.RootDirSectors); 
	TotalClusters = DataSectors / SimpleBpb.SecPerClus; 
	//判断文件格式是否为fat16; 
	if(TotalClusters < 4085 || TotalClusters >= 65525) 
		return FALSE;	 
	FatParameter.FirstFatSecNum=SimpleBpb.RsvdSecCnt+m_Offset; 
	FatParameter.FirstRootDirSecNum = SimpleBpb.RsvdSecCnt + (SimpleBpb.NumFATs * SimpleBpb.FATSz)+m_Offset; 
	FatParameter.FirstDataSector = SimpleBpb.RsvdSecCnt + (SimpleBpb.NumFATs * SimpleBpb.FATSz) + FatParameter.RootDirSectors+m_Offset;	 
	return TRUE; 
} 
WORD SeekEmptyCluster() 
{	 
//	static WORD  Cluster=2;//加快寻找进度 
	WORD  i,Cache[256],OffSet,j; 
	//	WORD  i,Cache[256],OffSet; 
		for(i=0;iName[0] != '\0') && (j< SimpleBpb.BytsPerSec / sizeof(struct _DIR)); j++) 
		{ 
			if(memcmp((const char*)dir->Name, dirname, 11)== 0)	 
			{ 
				if(file != NULL) 
				{ 
					memset(file, 0, sizeof(struct _FILE)); 
					file->DirSectorNum = Sector; 
					file->DirIndex = j; //j 代表了文件中该扇区中的位置(0-15); 
					memcpy(&file->dir, dir, sizeof(struct _DIR)); 
				} 
				temp=WordSwap(dir->FstClusLO); 
				temp1=ClusterToSec(temp); 
				return temp1; 
			}	 
			dir++; 
		}//end for cycle 
		Sector++; 
	}//end for cycle 
	return  0xffffffff; 
} 
 
DWORD LocateFile(const char *filename, struct _FILE *file) 
{ 
	DWORD Sector = FatParameter.FirstRootDirSecNum; 
	char NewFile[12]; 
	char *p=NewFile; 
	/////////////////////////////////////////////////////////////////////////////// 
	if(!CheckFileName(filename,p)) 
		return FALSE; 
	Sector = SeekSector(Sector, p, file); 
	if(*(p+11)==NULL) 
		return Sector; 
	return 0Xffffffff; 
} 
BYTE LocateDir(struct _DIR* new_dir, struct _FILE * fp) 
{ 
	BYTE Cache[512]; 
	struct _DIR *dir; 
	DWORD i; 
	DWORD DirSectorNum = FatParameter.FirstRootDirSecNum;	 
	//////////////////////////////////////////////////////////////////////////////// 
	for(i=0; iName[0] == '\0'||dir->Name[0] == 0xE5) 
			{ 
				memcpy(dir, new_dir, sizeof(struct _DIR));	 
				if(!Write(DirSectorNum,1,Cache,TRUE)) 
					if(!Write(DirSectorNum,1,Cache,TRUE))	 
						return FALSE;				 
				if(fp) 
				{ 
					fp->DirSectorNum = DirSectorNum; 
					fp->DirIndex = ((BYTE*)dir - Cache)/sizeof(struct _DIR); 
					memcpy(&fp->dir, new_dir, sizeof(struct _DIR)); 
				} 
				return TRUE; 
			} 
		}//--------------------------end for cycle 
		 DirSectorNum++; 
	}//-------------------------------end for cycle 
	return FALSE;  
} 
BYTE CheckFileName(const char * oldfilename,  char newfilename[11]) 
{ 
	char* p=newfilename; 
	char path[12]; 
	char* ppath = path; 
	int dir_len_count; //count dir len. 
	int i; 
	//////////////////////////////////////////////////////////////////////////////////// 
	if(oldfilename==NULL || strlen(oldfilename) >=12) 
		return FALSE; 
	dir_len_count=0; 
	strcpy(path, oldfilename); 
	//变小写字母为大写 
	for(i=0;(*ppath!=NULL&&i<12);i++) 
	{ 
		if(	*ppath > 96 && *ppath < 123) 
			*ppath -= 32;	 
		ppath++; 
	} 
	memset(p, 0, 12); 
	ppath = path; 
	for(;;) 
	{ 
		switch(*ppath) 
		{ 
		case 0: 
			{ 
				if(dir_len_count>=11) 
					return TRUE;		 
				else  
				{ 
				dir_len_count ++; 
				*p = 0x20; 
				p++; 
				} 
				continue; 
			} 
		//////////////////////////////////////////////////////////////////////////////// 
		case '.': 
			{ 
				if(dir_len_count > 8 || dir_len_count ==0) 
				{  
					return FALSE; 
				} 
				if(ppath[1] == '.') 
				{ 
					return FALSE; 
				} 
				for(i=0; i<(8 - dir_len_count); i++) 
				{ 
					*p = 0x20; 
					p++; 
				} 
				dir_len_count =8; 
				ppath++; 
				continue; 
				break; 
			} 
		///////////////////////////////////////////////////////////////////////////////// 
		case 0x22: 
		case 0x2A: 
		case 0x2B: 
		case 0x2C: 
		case 0x2F: 
		case 0x3A: 
		case 0x3B: 
		case 0x3C: 
		case 0x3D: 
		case 0x3E: 
		case 0x3F: 
		case 0x5B: 
		case 0x5D: 
		case 0x7C: 
			return FALSE; 
		///////////////////////////////////////////////////////////////////////////////// 
		default: 
			{ 
				if(*ppath < 0x20) 
					return FALSE;		 
				break;	 
			} 
		//////////////////////////////////////////////////////////////////////////////// 
		} 
		*p = *ppath; 
		dir_len_count ++; 
		if(dir_len_count >= 11) 
			return TRUE; 
		p++; 
		ppath++; 
	}//*end for cycle 
	return FALSE;	 
} 
//************************************************************************ 
//author:dragon 
//web:8dragon.com 
//2004.2.5完成于桃龙源 
//*************************************************************************