📄 fat32.c
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#include "main.h"
SYS_INFO_BLOCK DeviceInfo;
FILE_INFO ThisFile;
unsigned char FATBUF[512];//far表的扇区缓冲
unsigned long DirStartCluster32=0,NowCluster32=0;
unsigned long NowSector=0;
unsigned long FirstSectorofCluster32(unsigned long clusterNum)
{
unsigned long temp;
temp=clusterNum-2;
temp=temp*DeviceInfo.BPB_SecPerClus;
temp=temp+DeviceInfo.FirstDataSector;
return temp;
}
unsigned long ThisFatSecNum32(unsigned long clusterNum)
{
unsigned long temp;
temp=clusterNum*4;
temp=temp/DeviceInfo.BPB_BytesPerSec;
temp=temp+DeviceInfo.FatStartSector;
return temp;
}
unsigned long ThisFatEntOffset32(unsigned long clusterNum)
{
unsigned long temp1,temp2;
temp1=4*clusterNum;
temp2=temp1/DeviceInfo.BPB_BytesPerSec;
temp1=temp1-temp2*DeviceInfo.BPB_BytesPerSec;
return temp1;
}
unsigned long GetNextClusterNum32(unsigned long clusterNum)
{
unsigned long FatSecNum,FatEntOffset;
FatSecNum=ThisFatSecNum32(clusterNum);
FatEntOffset=ThisFatEntOffset32(clusterNum);
if(ThisFile.FatSectorPointer!=FatSecNum)
{
if(ReadSector(FatSecNum,1,FATBUF)!=TRUE)
return 0xFFFFFFFF;
ThisFile.FatSectorPointer=FatSecNum;
}
///////////////////////////////////////////////////
clusterNum=LSwapINT32(FATBUF[FatEntOffset],FATBUF[FatEntOffset+1],FATBUF[FatEntOffset+2],FATBUF[FatEntOffset+3]);
return clusterNum;
}
unsigned char GoToPointer32(unsigned long pointer)
{
unsigned int clusterSize;
clusterSize=DeviceInfo.BPB_SecPerClus*DeviceInfo.BPB_BytesPerSec;
ThisFile.ClusterPointer=ThisFile.StartCluster;
while(pointer>clusterSize)
{
pointer-=clusterSize;
ThisFile.ClusterPointer=GetNextClusterNum32(ThisFile.ClusterPointer);
if(ThisFile.ClusterPointer==0xffffffff)
{
return 0;
}
}
ThisFile.SectorofCluster=pointer/DeviceInfo.BPB_BytesPerSec;
ThisFile.SectorPointer=FirstSectorofCluster32(ThisFile.ClusterPointer)+ThisFile.SectorofCluster;
ThisFile.OffsetofSector=pointer-ThisFile.SectorofCluster*DeviceInfo.BPB_BytesPerSec;
ThisFile.FatSectorPointer=0;
return 1;
}
unsigned char DeleteClusterLink32(unsigned long clusterNum)
{
unsigned long FatSecNum,FatEntOffset;
unsigned char i;
while((clusterNum>1)&&(clusterNum<DeviceInfo.TotCluster))
{
FatSecNum=ThisFatSecNum32(clusterNum);
FatEntOffset=ThisFatEntOffset32(clusterNum);
if(ReadSector(FatSecNum,1,diskbuff)==TRUE)
clusterNum=LSwapINT32(diskbuff[FatEntOffset],diskbuff[FatEntOffset+1],diskbuff[FatEntOffset+2],diskbuff[FatEntOffset+3]);
else
return 0;
diskbuff[FatEntOffset]=0x00;diskbuff[FatEntOffset+1]=0x00;diskbuff[FatEntOffset+2]=0x00;diskbuff[FatEntOffset+3]=0x00;
for(i=0;i<DeviceInfo.BPB_NumFATs;i++)
{
delay_ms(5);
if(WriteSector(FatSecNum+i*DeviceInfo.BPB_FATSz32,1,diskbuff)!=TRUE)
return 0;
}
}
return 1;
}
unsigned long GetFreeCusterNum32(void)
{
unsigned long clusterNum,i;
unsigned long sectorNum;
unsigned char j;
clusterNum=0;
sectorNum=DeviceInfo.FatStartSector;
while(sectorNum<DeviceInfo.BPB_FATSz32+DeviceInfo.FatStartSector)
{
if(ReadSector(sectorNum,1,diskbuff)!=TRUE)
return 0x0;
for(i=0;i<DeviceInfo.BPB_BytesPerSec;i=i+4)
{
if((diskbuff[i]==0)&&(diskbuff[i+1]==0)&&(diskbuff[i+2]==0)&&(diskbuff[i+3]==0))
{
diskbuff[i]=0xff;diskbuff[i+1]=0xff;diskbuff[i+2]=0xff;diskbuff[i+3]=0xff;
for(j=0;j<DeviceInfo.BPB_NumFATs;j++)
{
delay_ms(5);
if(WriteSector(sectorNum+j*DeviceInfo.BPB_FATSz32,1,diskbuff)!=TRUE)
return 0;
}
return clusterNum;
}
clusterNum++;
}
sectorNum=4*clusterNum/DeviceInfo.BPB_BytesPerSec+DeviceInfo.FatStartSector;
delay_ms(10);
}
return 0x0;
}
unsigned long CreateClusterLink32(unsigned long currentCluster)
{
unsigned long newCluster;
unsigned long FatSecNum,FatEntOffset;
unsigned char i;
newCluster=GetFreeCusterNum32();
FatSecNum=ThisFatSecNum32(currentCluster);
FatEntOffset=ThisFatEntOffset32(currentCluster);
if(ReadSector(FatSecNum,1,diskbuff)==TRUE)
{
diskbuff[FatEntOffset]=newCluster;
diskbuff[FatEntOffset+1]=newCluster>>8;
diskbuff[FatEntOffset+2]=newCluster>>16;
diskbuff[FatEntOffset+3]=newCluster>>24;
for(i=0;i<DeviceInfo.BPB_NumFATs;i++)
{
delay_ms(5);
if(WriteSector(FatSecNum+i*DeviceInfo.BPB_FATSz32,1,diskbuff)!=TRUE)
return 0;
}
}
else
return 0x00;
return newCluster;
}
//////////////////////////////////////////////////////////////////////////////////////////////
//文件操作
////////////////////////////////////////////////////////////////////////////////////////////////
unsigned char OpenFile32(unsigned char *pBuffer)
{
unsigned int i;
unsigned char j,bstop,sector;
unsigned char UARTBUF[32];
ThisFile.bFileOpen=0;
NowCluster32=DirStartCluster32;
do
{
NowSector=FirstSectorofCluster32(NowCluster32);
for(sector=0;sector<DeviceInfo.BPB_SecPerClus;sector++)
{
if(ReadSector(NowSector+sector,1,diskbuff)!=TRUE)
return FALSE;
for(i=0;i<DeviceInfo.BPB_BytesPerSec;i=i+32)
{
if(diskbuff[i]==0x00)
return FALSE;
j=0;
while(diskbuff[i+j]==*(pBuffer+j))
{
j=j+1;
if(j>10)
break;
}
if(j>10&&(diskbuff[i+11]&0x10)!=0x10)
{
for(j=0;j<32;j++)
UARTBUF[j]=diskbuff[i+j];
bstop=1;
break;
}
}
if(bstop==1)break;
}
if(bstop==1)break;
NowCluster32=GetNextClusterNum32(NowCluster32);
}while(NowCluster32<=DeviceInfo.TotCluster);
if(NowCluster32>DeviceInfo.TotCluster)
return FALSE;
ThisFile.bFileOpen=1;
ThisFile.StartCluster=LSwapINT32(UARTBUF[26],UARTBUF[27],UARTBUF[20],UARTBUF[21]);
ThisFile.LengthInByte=LSwapINT32(UARTBUF[28],UARTBUF[29],UARTBUF[30],UARTBUF[31]);
ThisFile.ClusterPointer=ThisFile.StartCluster;
ThisFile.SectorPointer=FirstSectorofCluster32(ThisFile.StartCluster);
ThisFile.OffsetofSector=0;
ThisFile.SectorofCluster=0;
ThisFile.FatSectorPointer=0;
ThisFile.pointer=0;
//Response.len=32;
return TRUE;
}
unsigned char ReadFile32(unsigned long readLength,unsigned char *pBuffer)
{
unsigned int len,i;
unsigned int tlen;
unsigned long blen;
if(!ThisFile.bFileOpen)
return FALSE;
blen=readLength;
tlen=0;
if(readLength>MAX_READ_LENGTH)
return FALSE;
if(readLength+ThisFile.pointer>ThisFile.LengthInByte)
return FALSE;
////////////////////////////////////////////
while(readLength>0)
{
if(readLength+ThisFile.OffsetofSector>DeviceInfo.BPB_BytesPerSec)
len=DeviceInfo.BPB_BytesPerSec;
else
len=readLength+ThisFile.OffsetofSector;
//////////////////////////////////////////////////////
if(ThisFile.OffsetofSector>0)
{
if(ReadSector(ThisFile.SectorPointer,1,diskbuff)==TRUE)
{
len=len-ThisFile.OffsetofSector;
for(i=0;i<len;i++)
*(pBuffer+i)=diskbuff[ThisFile.OffsetofSector+i];
ThisFile.OffsetofSector=ThisFile.OffsetofSector+len;
}
else
return FALSE;
}
else
{
if(ReadSector(ThisFile.SectorPointer,1,pBuffer+tlen)!=TRUE)
return FALSE;
ThisFile.OffsetofSector=len;
}
////////////////////////////////////////////////////////////
readLength-=len;
tlen+=len;
/////////////////////////////////////////////////////////
if((ThisFile.OffsetofSector>DeviceInfo.BPB_BytesPerSec-1)&&(tlen+ThisFile.pointer<ThisFile.LengthInByte))
{
ThisFile.OffsetofSector-=DeviceInfo.BPB_BytesPerSec;
ThisFile.SectorofCluster+=1;
if(ThisFile.SectorofCluster>DeviceInfo.BPB_SecPerClus-1)
{
ThisFile.SectorofCluster=0;
ThisFile.ClusterPointer=GetNextClusterNum32(ThisFile.ClusterPointer);
if(ThisFile.ClusterPointer>DeviceInfo.TotCluster)
return FALSE;
ThisFile.SectorPointer=FirstSectorofCluster32(ThisFile.ClusterPointer);
}
else
ThisFile.SectorPointer=ThisFile.SectorPointer+1;
}
//////////////////////////////////////////////////////////////////
}//end while
ThisFile.bFileOpen=1;
ThisFile.pointer+=tlen;
//////////////////////////////////////////////
//Response.len=blen;
return TRUE;
}
unsigned char SetFilePointer32(unsigned long pointer)
{
//if(!bFlags.bits.SLAVE_IS_ATTACHED)
//return FALSE;
if(!ThisFile.bFileOpen)
return FALSE;
///////////////////////////////////////////////////////////
ThisFile.pointer=pointer;
if(ThisFile.pointer>ThisFile.LengthInByte)
return FALSE;
if(!GoToPointer32(ThisFile.pointer))
{
ThisFile.bFileOpen=0;
return FALSE;
}
//////////////////////////////////////////////
return TRUE;
}
//输入量：len－长文件名所占的字节数，必须为32 的整数倍。当
//为0 时表示该文件为短文件名；
//*pBuffer－32 字节的短文件名目录项；
//*pName－长文件名的目录项。
unsigned char CreateFile32(unsigned long len,unsigned char *pBuffer,unsigned char *pName)
{
unsigned int sector,i,j,DirCount;
unsigned long cnum;
unsigned char bstop,InByte,bwrite;
unsigned long ClusterPointer;
//if(!bFlags.bits.SLAVE_IS_ATTACHED)
// return FALSE;
if((len%32)!=0)
return FALSE;
if((len+32)>DeviceInfo.BPB_BytesPerSec)
return FALSE;
ThisFile.bFileOpen=0;
cnum=GetFreeCusterNum32();
if(cnum<0x02)
return FALSE;
pBuffer[21]=(unsigned char)(cnum>>24);
pBuffer[20]=(unsigned char)(cnum>>16);
pBuffer[27]=(unsigned char)(cnum>>8);
pBuffer[26]=(unsigned char)(cnum);
pBuffer[28]=0;pBuffer[29]=0;pBuffer[30]=0;pBuffer[31]=0;
bstop=0;
NowCluster32=DirStartCluster32;
do
{
NowSector=FirstSectorofCluster32(NowCluster32);
ClusterPointer=NowCluster32;
for(sector=0;sector<DeviceInfo.BPB_SecPerClus;sector++)
{
if(ReadSector(NowSector+sector,1,diskbuff)!=TRUE)
return FALSE;
DirCount=0;bwrite=0;
for(i=0;i<DeviceInfo.BPB_BytesPerSec;i=i+32)
{
if(len==0)
{
if((diskbuff[i]==0x00)||(diskbuff[i]==0xE5))
{
for(j=0;j<32;j++)
diskbuff[i+j]=*(pBuffer+j);
if(WriteSector(NowSector+sector,1,diskbuff)!=TRUE)
return FALSE;
bstop=1;
break;
}
}
else
{
if(DirCount==0)
InByte=i;
if(diskbuff[i]==0xE5)
DirCount++;
else if(diskbuff[i]==0x00)
{
DirCount++;
diskbuff[i]=0xE5;
bwrite=1;
}
else
DirCount=0;
if((DirCount*32)>=(len+32))
{
for(j=0;j<len;j++)
diskbuff[InByte+j]=*(pName+j);
for(j=0;j<32;j++)
diskbuff[InByte+len+j]=*(pBuffer+j);
if(WriteSector(NowSector+sector,1,diskbuff)!=TRUE)
return FALSE;
bstop=1;
break;
}
}
}
if(bstop==1)break;
if((len!=0)&&(bwrite==1))
{
if(WriteSector(NowSector+sector,1,diskbuff)!=TRUE)
return FALSE;
}
}
if(bstop==1)break;
NowCluster32=GetNextClusterNum32(NowCluster32);
if(NowCluster32>DeviceInfo.TotCluster)
{
NowCluster32=CreateClusterLink32(ClusterPointer);
if(NowCluster32==0x00)
return FALSE;
NowSector=FirstSectorofCluster32(NowCluster32);
for(i=0;i<DeviceInfo.BPB_BytesPerSec;i++) diskbuff[i]=0x00;
for(sector=0;sector<DeviceInfo.BPB_SecPerClus;sector++)
{
if(WriteSector(NowSector+sector,1,diskbuff)!=TRUE)
return FALSE;
}
}
}while(NowCluster32<=DeviceInfo.TotCluster);
////////////////////////////////////////////////////////////////
ThisFile.StartCluster=cnum;
ThisFile.LengthInByte=0;
ThisFile.ClusterPointer=ThisFile.StartCluster;
ThisFile.SectorPointer=FirstSectorofCluster32(ThisFile.StartCluster);
ThisFile.OffsetofSector=0;
ThisFile.SectorofCluster=0;
ThisFile.bFileOpen=1;
ThisFile.pointer=0;
ThisFile.FatSectorPointer=0;
return TRUE;
}
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