/// <summary>
/// Adds a new cluster to the end of the existing chain, by allocating a free cluster.
/// </summary>
/// <returns>The cluster allocated</returns>
/// <remarks>This method does not initialize the data in the cluster, the caller should
/// perform a write to ensure the cluster data is in known state.</remarks>
private uint ExtendChain()
{
// Sanity check - make sure the final known cluster is the EOC marker
if (!_fat.IsEndOfChain(_knownClusters[_knownClusters.Count - 1]))
{
throw new IOException("Corrupt file system: final cluster isn't End-of-Chain");
}
uint cluster;
if (!_fat.TryGetFreeCluster(out cluster))
{
throw new IOException("Out of disk space");
}
_fat.SetEndOfChain(cluster);
if (_knownClusters.Count == 1)
{
FireFirstClusterAllocated(cluster);
}
else
{
_fat.SetNext(_knownClusters[_knownClusters.Count - 2], cluster);
}
_knownClusters[_knownClusters.Count - 1] = cluster;
_knownClusters.Add(_fat.GetNext(cluster));
return(cluster);
}
