UInt32 GetNumClusters(UInt32 size) const { return (UInt32)(((UInt64)size + ClusterSize() - 1) >> ClusterSizeLog); }
size_t GetClusterSizeByReadName(string read_name) { if(read_index_.find(read_name) == read_index_.end()) return size_t(-1); return ClusterSize(GetCluster(read_name)); }