/// <summary>
/// Asks the <see cref="SelectableScheme">scheme</see> for a
/// <see cref="SelectableScheme"/> object that describes a
/// sub-set of the set handled by this scheme.
/// </summary>
/// <param name="subsetTable"></param>
/// <param name="subsetColumn"></param>
/// <remarks>
/// Since a <see cref="Table">table</see> stores a subset of a given
/// <see cref="DataTable"/>, we pass this as the argument. It returns
/// a new <see cref="SelectableScheme"/> that orders the rows in the
/// given columns order.
/// The <see cref="Column"/> variable specifies the column index of
/// this column in the given table.
/// </remarks>
/// <returns></returns>
public SelectableScheme GetSubsetScheme(Table subsetTable, int subsetColumn)
{
// Resolve table rows in this table scheme domain.
List <long> rowSet = new List <long>((int)subsetTable.RowCount);
IEnumerator <long> e = subsetTable.GetRowEnumerator();
while (e.MoveNext())
{
rowSet.Add(e.Current);
}
subsetTable.SetToRowTableDomain(subsetColumn, rowSet, Table);
// Generates an IIndex which contains indices into 'rowSet' in
// sorted order.
IIndex <long> newSet = GetOrderedIndex(rowSet);
// Our 'new_set' should be the same size as 'rowSet'
if (newSet.Count != rowSet.Count)
{
throw new Exception("Internal sort error in finding sub-set.");
}
// Set up a new SelectableScheme with the sorted index set.
// Move the sorted index set into the new scheme.
InsertSearch scheme = new InsertSearch(subsetTable, subsetColumn, newSet);
// Don't let subset schemes create uid caches.
scheme.RecordUid = false;
return(scheme);
}
/// <summary>
/// Constructs this as a copy of the given, either mutable or readOnly copy.
/// </summary>
/// <param name="table"></param>
/// <param name="from"></param>
/// <param name="readOnly"></param>
private InsertSearch(ITable table, InsertSearch from, bool readOnly)
: base(table, from.Column)
{
IsReadOnly = readOnly;
if (readOnly)
{
// Immutable is a shallow copy
list = from.list;
debugReadOnlySetSize = list.Count;
}
else
{
list = new BlockIndex <long>(from.list);
}
// Do we generate lookup caches?
recordUid = from.recordUid;
// The internal comparator that enables us to sort and lookup on the data
// in this column.
SetupComparer();
}
public IndexComparerImpl(InsertSearch scheme)
{
this.scheme = scheme;
}
