//Delete a given file in a given directory.
BOOL DeleteFatFile(__FAT32_FS* pFat32Fs,CHAR* pszFileName)
{
__FAT32_SHORTENTRY ShortEntry;
__FAT32_SHORTENTRY* pFileEntry = NULL;
DWORD dwParentClus = 0;
DWORD dwParentOffset = 0;
DWORD dwStartClus = 0;
DWORD dwSector = 0;
BOOL bResult = FALSE;
BYTE* pBuffer = NULL;
if(!GetDirEntry(pFat32Fs,
pszFileName,
&ShortEntry,
&dwParentClus, //Parent directory's cluster where this entry resides.
&dwParentOffset)) //Cluster offset.
{
goto __TERMINAL;
}
//Release the cluster chain this file occupies.
dwStartClus = (DWORD)(ShortEntry.wFirstClusHi) << 16;
dwStartClus += (DWORD)ShortEntry.wFirstClusLow;
ReleaseClusterChain(pFat32Fs,dwStartClus);
//Remove the directory entry in it's parent directory.
pBuffer = (BYTE*)KMemAlloc(pFat32Fs->dwClusterSize,KMEM_SIZE_TYPE_ANY);
if(NULL == pBuffer)
{
goto __TERMINAL;
}
dwSector = GetClusterSector(pFat32Fs,dwParentClus);
if(0 == dwSector)
{
goto __TERMINAL;
}
if(!ReadDeviceSector((__COMMON_OBJECT*)pFat32Fs->pPartition,
dwSector,
pFat32Fs->SectorPerClus,
pBuffer))
{
goto __TERMINAL;
}
pFileEntry = (__FAT32_SHORTENTRY*)(pBuffer + dwParentOffset);
memzero(pFileEntry,sizeof(__FAT32_SHORTENTRY));
pFileEntry->FileName[0] = (CHAR)0xE5; //Empty this short entry.
if(!WriteDeviceSector((__COMMON_OBJECT*)pFat32Fs->pPartition,
dwSector,
pFat32Fs->SectorPerClus,
pBuffer))
{
goto __TERMINAL;
}
bResult = TRUE;
__TERMINAL:
if(pBuffer)
{
KMemFree(pBuffer,KMEM_SIZE_TYPE_ANY,0);
}
return bResult;
}
//Implementation of _SetEndOfFile.
static BOOL _SetEndOfFile( __COMMON_OBJECT* lpDev)
{
__FAT32_FS* pFat32Fs = NULL;
__FAT32_FILE* pFat32File = NULL;
BYTE* pClusBuffer = NULL;
__FAT32_SHORTENTRY* pfse = NULL;
DWORD dwNextCluster = 0;
DWORD dwSector = 0;
BOOL bSetOk = FALSE;
pFat32File = (__FAT32_FILE*)(((__DEVICE_OBJECT*)lpDev)->lpDevExtension);
pFat32Fs = pFat32File->pFileSystem;
pClusBuffer = (BYTE*)FatMem_Alloc(pFat32Fs->dwClusterSize);
if(NULL == pClusBuffer) //Can not allocate buffer.
{
goto __TERMINAL;
}
//Now update the file's directory entry.
dwSector = GetClusterSector(pFat32Fs,pFat32File->dwParentClus);
if(0 == dwSector)
{
goto __TERMINAL;
}
if(!ReadDeviceSector((__COMMON_OBJECT*)pFat32Fs->pPartition,
dwSector,
pFat32Fs->SectorPerClus,
pClusBuffer))
{
goto __TERMINAL;
}
pfse = (__FAT32_SHORTENTRY*)(pClusBuffer + pFat32File->dwParentOffset);
pFat32File->dwFileSize = pFat32File->dwCurrPos;
pfse->dwFileSize = pFat32File->dwFileSize;
WriteDeviceSector((__COMMON_OBJECT*)pFat32Fs->pPartition,
dwSector,
pFat32Fs->SectorPerClus,
pClusBuffer);
if(pFat32File->dwCurrPos < pFat32Fs->dwClusterSize )
{
dwNextCluster = 1;
}
else
{
dwNextCluster = pFat32File->dwCurrPos/pFat32Fs->dwClusterSize;
if((pFat32File->dwCurrPos+1)%pFat32Fs->dwClusterSize)
{
dwNextCluster ++;
}
}
dwNextCluster ++;
ReleaseClusterChain(pFat32Fs,dwNextCluster);
bSetOk = TRUE;
__TERMINAL:
FatMem_Free(pClusBuffer);
return bSetOk;
}
