public bool VerifyFsChecksum(iQueFsHeader fatHeader, int fatBlockIdx)
{
io.Stream.Position = (fatBlockIdx * BLOCK_SZ);
ushort sum = 0;
for (int i = 0; i < 0x1FFF; i++)
{
sum += io.Reader.ReadUInt16().EndianSwap();
}
sum += fatHeader.CheckSum; // should be EndianSwap'd already by ReadFilesystem
return(sum == 0xCAD7);
}
private bool ReadFilesystem()
{
FsHeaders = new List <iQueFsHeader>();
FsBlocks = new List <int>();
FsBadBlocks = new List <int>();
FsInodes = new List <List <iQueFsInode> >();
FsAllocationTables = new List <List <short> >();
int latestSeqNo = -1;
for (int i = 0; i < NUM_FAT_BLOCKS; i++)
{
var blockNum = (NUM_BLOCKS_IN_FAT - 1) - i; // read FAT area from end to beginning
SeekToBlock(blockNum);
io.Stream.Position += FS_HEADER_ADDR;
var header = io.Reader.ReadStruct <iQueFsHeader>();
header.EndianSwap();
if (header.Magic != MAGIC_BBFS) // todo: && header.Magic != MAGIC_BBFL, once we know what BBFL/"linked fats" actually are
{
continue;
}
if (!SkipVerifyFsChecksums && InodesOffset == 0) // only care about fs checksum if this is a proper dump and we aren't using hacky InodesOffset hack
{
if (!VerifyFsChecksum(header, blockNum))
{
FsBadBlocks.Add(blockNum);
continue; // bad FS checksum :(
}
}
FsHeaders.Add(header);
FsBlocks.Add(blockNum);
if (header.SeqNo > latestSeqNo)
{
MainFs = header;
MainFsBlock = blockNum;
MainFsIndex = FsHeaders.Count - 1;
latestSeqNo = header.SeqNo;
}
io.Stream.Position = blockNum * BLOCK_SZ;
var allocTable = new List <short>();
for (int y = 0; y < NUM_BLOCKS_IN_FAT; y++)
{
allocTable.Add((short)(io.Reader.ReadUInt16().EndianSwap()));
}
int numEntries = NUM_FS_ENTRIES;
if (InodesOffset > 0)
{
io.Stream.Position += InodesOffset; // skip weird truncated inode if needed
numEntries--; // and now we'll have to read one less entry
}
// now begin reading inodes
var inodes = new List <iQueFsInode>();
for (int y = 0; y < numEntries; y++)
{
var inode = io.Reader.ReadStruct <iQueFsInode>();
inode.EndianSwap();
inodes.Add(inode);
}
FsAllocationTables.Add(allocTable);
FsInodes.Add(inodes);
}
return(latestSeqNo >= 0);
}
