public static void Sort(Table Element, RecordMatcher Comparer)
{
// Check that this is a heap table //
if (!(Element is HeapTable))
{
throw new Exception("Can only sort heap tables");
}
if (Element.Header.IndexHeaders.Count != 0)
{
throw new Exception("Cannot sort a table with indexes");
}
// Sort each element //
SortEach(Element, Comparer);
// Merge sort //
Table.PageWalker x = new Table.PageWalker(Element);
Table.PageWalker y = new Table.PageWalker(Element);
while (x.CanAdvance)
{
// Get x's page //
Page A = x.SelectNext();
// Break if we on the last page //
if (A.NextPageID == -1)
{
break;
}
// Open a new page walker that starts at the next page //
y.ToPage(A.NextPageID);
// Loop through y //
while (y.CanAdvance)
{
// Get the second page //
Page B = y.SelectNext();
// Merge //
Merge(A, B, Comparer);
// Set B //
Element.SetPage(B);
}
// A is final at this point //
Element.SetPage(A);
}
}
private static void SortEach(Table Element, RecordMatcher Comparer)
{
if (Element.Header.ClusterKey.Count != 0)
{
throw new Exception("Can only sort a heap table");
}
if (Element.RecordCount == 0)
{
return;
}
Table.PageWalker walker = new Table.PageWalker(Element);
while (walker.CanAdvance)
{
Page p = walker.SelectNext();
Sort(p, Comparer);
Element.SetPage(p);
}
}
