fat.c

MG64+VS1003+SDCARD+nokia5110 之多的MP3

			if(FAT_ReadSector(FirstDirSector+cnt,buffer)){free(buffer);return 1;}
			for(offset=0;offset<512;offset+=32)
			{
				item=(struct direntry *)(&buffer[offset]);
				if((item->deName[0] != 0x00) && (item->deName[0] != 0xe5) && (item->deAttributes != 0x0f))
				{
					for(i=0;i<11;i++)
					{
						if(buffer[offset+i]!=name[i])break;
					}
					if(i==11)
					{
						//return the parameter of the item
						FileInfo->StartCluster = item->deStartCluster + (((unsigned long)item->deHighClust)<<16);//don't care
						FileInfo->Size         = item->deFileSize;
						FileInfo->Attr         = item->deAttributes;
						FileInfo->Sector       = FirstDirSector+cnt;
						FileInfo->Offset       = offset;
						free(buffer);
						return 0;
					}
				}
			}
		}
		free(buffer);//release
	}
	else//other folders
	{
		tempclust=cluster;
		while(1)
		{
			sector=(DWORD)FirstDataSector+(DWORD)(tempclust-2)*(DWORD)SectorsPerClust;//calculate the actual sector number
			buffer=malloc(512);//apply memory
			if(buffer==0)return 1;//if failed
			for(cnt=0;cnt<SectorsPerClust;cnt++)
			{
				if(FAT_ReadSector(sector+cnt,buffer)){free(buffer);return 1;}
				for(offset=0;offset<512;offset+=32)
				{
					item=(struct direntry *)(&buffer[offset]);
					if((item->deName[0] != 0x00) && (item->deName[0] != 0xe5) && (item->deAttributes != 0x0f))
					{
						for(i=0;i<11;i++)
						{
							if(buffer[offset+i]!=name[i])break;
						}
						if(i==11)
						{
							FileInfo->StartCluster = item->deStartCluster + (((unsigned long)item->deHighClust)<<16);//don't care
							FileInfo->Size         = item->deFileSize;
							FileInfo->Attr         = item->deAttributes;
							FileInfo->Sector       = sector+cnt;
							FileInfo->Offset       = offset;
							free(buffer);
							return 0;
						}
					}
				}
			}
			free(buffer);//release
			tempclust=FAT_NextCluster(tempclust);//next cluster
			if((FAT32_Enable == 0 && tempclust == 0xffff) || tempclust == 0x0ffffff8 || tempclust == 0x0fffffff)break;
		}
	}
	return 1;
}


//挑选一个未使用的记录项
//select the first unsed item in the given cluster
//for delete a foler or a file
unsigned char FAT_SelectOneItem(unsigned long cluster,struct FileInfoStruct *FileInfo)
{
	BYTE *buffer;
	DWORD tempclust;
	DWORD sector;
	unsigned int cnt;
	unsigned int offset;
//	unsigned char i;
	struct direntry *item = 0;
	if(cluster==0 && FAT32_Enable==0)// root directory
	{
		buffer=malloc(512);//apply memory
		if(buffer==0)return 1;//if failed
		for(cnt=0;cnt<RootDirSectors;cnt++)
		{
			if(FAT_ReadSector(FirstDirSector+cnt,buffer)){free(buffer);return 1;}
			for(offset=0;offset<512;offset+=32)
			{
				item=(struct direntry *)(&buffer[offset]);
				if((item->deName[0] != 0x00) && (item->deName[0] != 0xe5) && (item->deAttributes != 0x0f))
				{
					//return the parameter of the item
					FileInfo->StartCluster = item->deStartCluster + (((unsigned long)item->deHighClust)<<16);//don't care
					FileInfo->Size         = item->deFileSize;
					FileInfo->Attr         = item->deAttributes;
					FileInfo->Sector       = FirstDirSector+cnt;
					FileInfo->Offset       = offset;
					free(buffer);
					return 0;
				}
			}
		}
		free(buffer);//release
	}
	else//other folders
	{
		tempclust=cluster;
		while(1)
		{
			sector=(DWORD)FirstDataSector+(DWORD)(tempclust-2)*(DWORD)SectorsPerClust;//calculate the actual sector number
			buffer=malloc(512);//apply memory
			if(buffer==0)return 1;//if failed
			for(cnt=0;cnt<SectorsPerClust;cnt++)
			{
				if(FAT_ReadSector(sector+cnt,buffer)){free(buffer);return 1;}
				for(offset=0;offset<512;offset+=32)
				{
					item=(struct direntry *)(&buffer[offset]);
					if((item->deName[0] != 0x2e) && (item->deName[0] != 0x00) && (item->deName[0] != 0xe5) & (item->deAttributes != 0x0f))
					{
						FileInfo->StartCluster = item->deStartCluster + (((unsigned long)item->deHighClust)<<16);//don't care
						FileInfo->Size         = item->deFileSize;
						FileInfo->Attr         = item->deAttributes;
						FileInfo->Sector       = sector+cnt;
						FileInfo->Offset       = offset;
						free(buffer);
						return 0;
					}
				}
			}
			free(buffer);//release
			tempclust=FAT_NextCluster(tempclust);//next cluster
			if((FAT32_Enable == 0 && tempclust == 0xffff) || tempclust == 0x0ffffff8 || tempclust == 0x0fffffff)break;
		}
	}
	return 1;
}

//修改FAT表中响应的项
//modify the fat table item with "val","cluster" specify the location
unsigned char FAT_ModifyFAT(unsigned long cluster,unsigned long val)
{
	BYTE buffer[512];
	DWORD sector;
	DWORD offset;
	if(FAT32_Enable)offset = cluster/128;
	else            offset = cluster/256;

	sector=FirstFATSector+offset;//calculate the actual sector
	if(FAT_ReadSector(sector,buffer))return 1;//read fat table

	if(FAT32_Enable)
	{
		offset=cluster%128;
		offset<<=2;
		buffer[offset+3]=val>>24;
		buffer[offset+2]=val>>16;
		buffer[offset+1]=val>>8;
		buffer[offset]=val;
	}
	else
	{
		offset=cluster%256;//find the position
		offset<<=1;
		buffer[offset+1] = val>>8;
		buffer[offset]   = val;
	}
	//sector=buffer[offset+1];
//	sector<<=8;
	//sector+=buffer[offset];
	if(FAT_WriteSector(sector,buffer))return 1;//write the first fat table
	if(FAT_WriteSector(sector+FATsectors,buffer))return 1;//write the second fat table
	return 0;//return the value
}

// make a dir
unsigned char FAT_MkDir(BYTE * dir)
{
	BYTE name[11];
	BYTE *p=dir;
	BYTE deep=0;
	WORD i,j;
	DWORD cluster=0;
	DWORD lastcluster;//cluster number of last directory
	BYTE *buffer;
	DWORD sector;
	struct direntry *item;
	if(FAT32_Enable)cluster=FirstDirClust;
	if(*p != '\\')return 1;//invalid path
	while(*p)
	{
		if(*p == '\\')
		{
			deep++;//the deepth of the path
		}
		p++;
	}
	p=dir;
	for(i=0;i<deep-1;i++)
	{
		p++;
		for(j=0;j<11;j++)name[j]=0x20;
		j=0;
		while(*p != '\\')
		{
			if((*p) >= 'a' && (*p) <= 'z')name[j] = (*p++)-0x20;
			else name[j] = *p++;
			j++;
		}
		if(FAT_FindItem(cluster,name, &FileInfo))return 1;//find the location of each directory
		cluster = FileInfo.StartCluster;//point to next directory
	}
	p++;
	for(j=0;j<11;j++)name[j]=0x20;
	j=0;
	while(*p)
	{
		if(*p>='a' && *p<='z')name[j]=(*p++)-0x20;
		else name[j]=*p++;
		j++;
	}
	lastcluster=cluster;//save as last directory
	cluster=FAT_FindFreeCluster();//find a unused cluster
	if(cluster==1)return 1;//error
	if(FAT_FindFreeItem(lastcluster,&FileInfo))return 1;//find a unused item
	buffer=malloc(512);
	if(buffer==0)return 1;
	if(FAT_ReadSector(FileInfo.Sector,buffer)){free(buffer);return 1;}//read the sector which the item is in
	item=(struct direntry *)(&buffer[FileInfo.Offset]);//pointer convert

	for(j=0;j<8;j++)item->deName[j] = name[j];
	for(j=0;j<3;j++)item->deExtension[j] = 0x20;
	item->deAttributes = ATTR_DIRECTORY;
	item->deLowerCase = LCASE_BASE | LCASE_EXT;
	item->deCHundredth = 0x00;
	item->deCTime[0] = 0x00;
	item->deCTime[1] = 0x60;
	item->deCDate[0] = 0x5c;
	item->deCDate[1] = 0x09;
	item->deADate[0] = 0x8e;
	item->deADate[1] = 0x35;
	item->deHighClust = cluster>>16;
	item->deMTime[0] = 0x00;
	item->deMTime[1] = 0x60;
	item->deMDate[0] = 0x50;
	item->deMDate[1] = 0x0a;
	item->deStartCluster = cluster;
	item->deFileSize = 0;
	if(FAT_WriteSector(FileInfo.Sector,buffer)){free(buffer);return 1;}//write the item

	for(j=0;j<512;j++)buffer[j]=0x00;
	sector=(DWORD)FirstDataSector+(DWORD)(cluster-2)*(DWORD)SectorsPerClust;
	for(i=0;i<SectorsPerClust;i++)
	{
		if(FAT_WriteSector(sector+i,buffer)){free(buffer);return 1;}//clear the data in the directory
	}

	//create "." directory
	item=(struct direntry *)(&buffer[0]);
	item->deName[0] = '.';
	for(j=1;j<8;j++)item->deName[j] = 0x20;
	for(j=0;j<3;j++)item->deExtension[j] = 0x20;
	item->deAttributes = ATTR_DIRECTORY;
	item->deLowerCase = LCASE_BASE | LCASE_EXT;
	item->deCHundredth = 0x00;
	item->deCTime[0] = 0x00;
	item->deCTime[1] = 0x60;
	item->deCDate[0] = 0x5c;
	item->deCDate[1] = 0x09;
	item->deADate[0] = 0x8e;
	item->deADate[1] = 0x35;
	item->deHighClust = cluster>>16;
	item->deMTime[0] = 0x00;
	item->deMTime[1] = 0x60;
	item->deMDate[0] = 0x50;
	item->deMDate[1] = 0x0a;
	item->deStartCluster = cluster;//the directory itself
	item->deFileSize = 0;

	//creat ".." directory
	item=(struct direntry *)(&buffer[32]);
	item->deName[0] = '.';
	item->deName[1] = '.';
	for(j=2;j<8;j++)item->deName[j] = 0x20;
	for(j=0;j<3;j++)item->deExtension[j] = 0x20;//no extention
	item->deAttributes = ATTR_DIRECTORY;//directory
	item->deLowerCase = LCASE_BASE | LCASE_EXT;
	item->deCHundredth = 0x00;
	item->deCTime[0] = 0x00;
	item->deCTime[1] = 0x60;
	item->deCDate[0] = 0x5c;
	item->deCDate[1] = 0x09;
	item->deADate[0] = 0x8e;
	item->deADate[1] = 0x35;
	item->deHighClust = lastcluster>>16;
	item->deMTime[0] = 0x00;
	item->deMTime[1] = 0x60;
	item->deMDate[0] = 0x50;
	item->deMDate[1] = 0x0a;
	item->deStartCluster = lastcluster;//last directory
	item->deFileSize = 0;

	if(FAT_WriteSector(sector,buffer)){free(buffer);return 1;}//write the data
	free(buffer);
	if(FAT32_Enable)
	{
		if(FAT_ModifyFAT(cluster,0x0fffffff))return 1;//modify the fat table to sign that the cluster was used 
	}
	else
	{
		if(FAT_ModifyFAT(cluster,0xffff))return 1;//modify the fat table to sign that the cluster was used 
	}
	return 0;//done
}

// remove a directory
unsigned char FAT_RmDir(BYTE * dir)
{
	if(FAT_OpenDir(dir)==0)return 1;//find the directory
	if(FAT_DelItem(&FileInfo))return 1;//delete it
	return 0;
}

// creat a file, for convenience we designate the size
// return the start sector of the new file
unsigned long FAT_Create(BYTE * dir,unsigned long size)
{
	BYTE name[11];
	BYTE *p=dir;
	BYTE deep=0;
	BYTE i,j;
	DWORD cluster=0;
	BYTE *buffer;
	//WORD sector;
	struct direntry *item;
	if(FAT32_Enable)cluster=FirstDirClust;
	if(*p != '\\')return 1;//invalid path
	while(*p)
	{
		if(*p == '\\')
		{
			deep++;
		}
		p++;
	}
	p=dir;
	for(i=0;i<deep-1;i++)
	{
		p++;
		for(j=0;j<11;j++)name[j]=0x20;
		j=0;
		while(*p != '\\')
		{
			if((*p) >= 'a' && (*p) <= 'z')name[j] = (*p++)-0x20;
			else name[j] = *p++;
			j++;
		}
		if(FAT_FindItem(cluster,name, &FileInfo))return 1;
		cluster = FileInfo.StartCluster;
	}
	p++;
	for(j=0;j<11;j++)name[j]=0x20;
	j=0;
	while(*p != '.')
	{
		if(*p>='a' && *p<='z')name[j]=(*p++)-0x20;
		else name[j]=*p++;
		j++;
	}
	j=8;
	p++;
	while(*p)
	{
		if(*p>='a' && *p<='z')name[j]=(*p++)-0x20;
		else name[j]=*p++;
		j++;
	}


	if(FAT_FindFreeItem(cluster,&FileInfo))return 1;
	cluster = FAT_FindFreeCluster();
	if(cluster==1)return 1;
	buffer=malloc(512);
	if(buffer==0)return 1;
	if(FAT_ReadSector(FileInfo.Sector,buffer)){free(buffer);return 1;}
	item=(struct direntry *)(&buffer[FileInfo.Offset]);

	for(j=0;j<8;j++)item->deName[j] = name[j];
	for(j=0;j<3;j++)item->deExtension[j] = name[8+j];
	item->deAttributes = ATTR_ARCHIVE;//file
	item->deLowerCase = LCASE_BASE | LCASE_EXT;
	item->deCHundredth = 0x00;
	item->deCTime[0] = 0x00;
	item->deCTime[1] = 0x60;
	item->deCDate[0] = 0x5c;
	item->deCDate[1] = 0x09;
	item->deADate[0] = 0x8e;
	item->deADate[1] = 0x35;
	item->deHighClust = cluster>>16;
	item->deMTime[0] = 0x00;
	item->deMTime[1] = 0x60;
	item->deMDate[0] = 0x50;
	item->deMDate[1] = 0x0a;
	item->deStartCluster = cluster;//the cluster number the file was stored
	item->deFileSize = size;//the file size
	if(FAT_WriteSector(FileInfo.Sector,buffer)){free(buffer);return 1;}//write the item
	free(buffer);
	if(FAT32_Enable)
	{
		if(FAT_ModifyFAT(cluster,0x0fffffff))return 1;//modify the fat table to sign that the cluster was used 
	}
	else
	{
		if(FAT_ModifyFAT(cluster,0xffff))return 1;//modify the fat table
	}
	return cluster;//reutn the first cluster number
}

// find the location with the given path
unsigned long FAT_Open(BYTE * dir)
{
	BYTE name[11];
	BYTE *p=dir;
	BYTE deep=0;
	BYTE i,j;
	DWORD cluster=0;
	if(FAT32_Enable)cluster=FirstDirClust;
	if(*p != '\\')return 1;//invalid path
	while(*p)
	{