CLUSTER LocatePreviousDir(RDWRHandle handle, CLUSTER firstdircluster)
{
SECTOR* sectbuf;
SECTOR sector;
assert(firstdircluster);
sectbuf = AllocateSector(handle);
if (!sectbuf) RETURN_FTEERR(0xFFFFFFFFL);
sector = ConvertToDataSector(handle, firstdircluster);
if (!sector)
{
FreeSectors(sectbuf);
RETURN_FTEERR(0xFFFFFFFFL);
}
if (!ReadDataSectors(handle, 1, sector, (void*) sectbuf))
{
FreeSectors(sectbuf);
RETURN_FTEERR(0xFFFFFFFFL);
}
if (IsPreviousDir(((struct DirectoryEntry*) sectbuf)[1]))
{
CLUSTER retVal = GetFirstCluster(&(((struct DirectoryEntry*) sectbuf)[1]));
FreeSectors(sectbuf);
return retVal;
}
SetFTEerror(FTE_FILESYSTEM_BAD);
FreeSectors(sectbuf);
RETURN_FTEERR(0xFFFFFFFFL);
}
BOOL GetNthDirectorySector(RDWRHandle handle, CLUSTER cluster,
unsigned long n, char* sector)
{
unsigned long entry;
struct DirectoryPosition temp;
/* Calculate which entry this corresponds to */
entry = n * ENTRIESPERSECTOR;
if (!GetNthDirectoryPosition(handle, cluster, entry, &temp))
{
return FALSE;
}
return ReadDataSectors(handle, 1, temp.sector, sector);
}
/*
Beware of circular references:
fatpos1 = cluster2
cluster1 = clustervalue2
A -> B -> C
D -> A -> B
D -> A -> B -> C => D -> B -> A -> C
A: C
A: A /
B: B A
D: B
cluster1 = fatpos2
clustervalue1 = cluster2
A -> B -> C
B -> C -> D
A -> B -> C -> D => A -> C -> B -> D
C: C B
A: C
B: D
B: B /
*/
BOOL SwapClusters (RDWRHandle handle, CLUSTER clust1, CLUSTER clust2)
{
BOOL found, IsInFAT1 = FALSE, IsInFAT2 = FALSE, error = FALSE;
CLUSTER freeclust, clustervalue1, fatpos1, fatpos2;
CLUSTER clustervalue2, dircluster1, dircluster2;
unsigned char sectorspercluster;
SECTOR startsector;
struct DirectoryPosition dirpos1, dirpos2;
struct DirectoryEntry entry;
unsigned long neededmem;
void *MemCluster;
BOOL DOTSProcessed1, DOTSProcessed2;
SECTOR srcsector, destsector;
/* First check wether we shouldn't be using RelocateCluster instead. */
if (!ReadFatLabel (handle, clust1, &clustervalue1))
return FALSE;
if (!ReadFatLabel (handle, clust2, &clustervalue2))
return FALSE;
if (FAT_FREE (clustervalue1) && (FAT_FREE (clustervalue2)))
{
return TRUE;
}
if (FAT_FREE (clustervalue1))
{
return RelocateCluster (handle, clust2, clust1);
}
if (FAT_FREE (clustervalue2))
{
return RelocateCluster (handle, clust1, clust2);
}
/* See if we have enough memory to load the data for one cluster
into memory. */
sectorspercluster = GetSectorsPerCluster (handle);
if (!sectorspercluster)
return FALSE;
neededmem = sectorspercluster * BYTESPERSECTOR;
MemCluster = malloc (neededmem);
if (MemCluster)
{
/* First prepare the first cluster. */
/* See where the cluster is refered */
/* In FAT? */
if (!FindClusterInFAT (handle, clust1, &fatpos1))
{
free (MemCluster);
return FALSE;
}
/* No, then look if this is the first cluster of a file. */
if (!fatpos1)
{
if (!FindClusterInDirectories (handle, clust1, &dirpos1, &found))
{
free (MemCluster);
return FALSE;
}
if (!found)
{
free (MemCluster);
return FALSE; /* Non valid cluster! */
}
else
{
/*
Special case: if this is the first cluster of a directory
then adjust all the . and .. pointers to
reflect the new position on the volume.
*/
if (!GetDirectory (handle, &dirpos1, &entry))
{
free (MemCluster);
return FALSE;
}
if (entry.attribute & FA_DIREC)
{
dircluster1 = GetFirstCluster (&entry);
if (!AdaptCurrentAndPreviousDirs(handle, dircluster1, clust2))
{
AdaptCurrentAndPreviousDirs (handle, dircluster1,
clust1);
free (MemCluster);
return FALSE;
}
DOTSProcessed1 = TRUE;
}
}
}
else
{
IsInFAT1 = TRUE;
}
/* Then prepare the second cluster. */
/* See where the cluster is refered */
/* In FAT? */
if (!FindClusterInFAT (handle, clust2, &fatpos2))
{
if (DOTSProcessed1)
AdaptCurrentAndPreviousDirs (handle, dircluster1, clust1);
free (MemCluster);
return FALSE;
}
/* No, then look if this is the first cluster of a file. */
if (!fatpos2)
{
if (!FindClusterInDirectories (handle, clust2, &dirpos2, &found))
{
if (DOTSProcessed1)
AdaptCurrentAndPreviousDirs (handle, dircluster1, clust1);
free (MemCluster);
return FALSE;
}
if (!found)
{
if (DOTSProcessed1)
AdaptCurrentAndPreviousDirs (handle, dircluster1, clust1);
free (MemCluster);
return FALSE; /* Non valid cluster! */
}
else
{
/*
Special case: if this is the first cluster of a directory
then adjust all the . and .. pointers to
reflect the new position on the volume.
*/
if (!GetDirectory (handle, &dirpos2, &entry))
{
if (DOTSProcessed1)
AdaptCurrentAndPreviousDirs (handle, dircluster1,
clust1);
free (MemCluster);
return FALSE;
}
if (entry.attribute & FA_DIREC)
{
dircluster2 = GetFirstCluster (&entry);
if (!AdaptCurrentAndPreviousDirs(handle, dircluster2, clust1))
{
AdaptCurrentAndPreviousDirs (handle, dircluster2, clust2);
AdaptCurrentAndPreviousDirs (handle, dircluster1, clust1);
free (MemCluster);
return FALSE;
}
DOTSProcessed2 = TRUE;
}
}
}
else
{
IsInFAT2 = TRUE;
}
startsector = ConvertToDataSector (handle, clust1);
if (!startsector)
{
if (DOTSProcessed1)
AdaptCurrentAndPreviousDirs (handle, dircluster1, clust1);
if (DOTSProcessed2)
AdaptCurrentAndPreviousDirs (handle, dircluster2, clust2);
free (MemCluster);
return FALSE;
}
/* Then copy the data of the second cluster to the new position */
/* Copy all sectors in this cluster to the new position */
srcsector = ConvertToDataSector (handle, clust2);
if (!srcsector)
{
if (DOTSProcessed1)
AdaptCurrentAndPreviousDirs (handle, dircluster1, clust1);
if (DOTSProcessed2)
AdaptCurrentAndPreviousDirs (handle, dircluster2, clust2);
free (MemCluster);
return FALSE;
}
destsector = ConvertToDataSector (handle, clust1);
if (!startsector)
{
if (DOTSProcessed1)
AdaptCurrentAndPreviousDirs (handle, dircluster1, clust1);
if (DOTSProcessed2)
AdaptCurrentAndPreviousDirs (handle, dircluster2, clust2);
free (MemCluster);
return FALSE;
}
/* AS OF THIS POINT WE WILL NOT BE ABLE TO BACKTRACK,
THEREFORE WE KEEP ON GOING EVEN IF THERE WERE ERRORS. */
/* Change the pointers of the first cluster that has to be moved
to the second cluster. */
/* Write the entry in the FAT */
if (clust2 == clustervalue1) /* Beware of circular references */
{
if (!WriteFatLabel (handle, clust2, clust1))
error = TRUE;
}
else
{
if (!WriteFatLabel (handle, clust2, clustervalue1))
error = TRUE;
}
/* Adjust the pointer to the relocated cluster */
if (IsInFAT1) /* the previous one in the file */
{
if (fatpos1 != clust2) /* Beware of circular references */
{
if (!WriteFatLabel (handle, fatpos1, clust2))
error = TRUE;
}
}
else /* or the directory entry to the file */
{
if (!GetDirectory (handle, &dirpos1, &entry))
error = TRUE;
if (GetFirstCluster (&entry) != clust2)
{
SetFirstCluster (clust2, &entry);
if (!WriteDirectory (handle, &dirpos1, &entry))
error = TRUE;
}
}
/* Change the pointers of the second cluster that has to be moved
to the first cluster. */
/* Write the entry in the FAT */
if (clust1 == clustervalue2) /* Beware of circular references */
{
if (!WriteFatLabel (handle, clust1, clustervalue1))
error = TRUE;
}
else
{
if (!WriteFatLabel (handle, clust1, clustervalue2))
error = TRUE;
}
/* Adjust the pointer to the relocated cluster */
if (IsInFAT2) /* the previous one in the file */
{
if (fatpos2 != clust1) /* Beware of circular references */
{
if (!WriteFatLabel (handle, fatpos2, clust1))
error = TRUE;
}
}
else /* or the directory entry to the file */
{
if (!GetDirectory (handle, &dirpos2, &entry))
error = TRUE;
if (GetFirstCluster (&entry) != clust1) /* Beware of circular references */
{
SetFirstCluster (clust1, &entry);
if (!WriteDirectory (handle, &dirpos2, &entry))
error = TRUE;
}
