/// <summary>
/// Returns a cursor that begins at the start bound.
/// </summary>
/// <param name="start"></param>
/// <returns></returns>
internal static BTree <TK, KeyValuePair <TK, TV> > .Cursor GetStartCursor <TK, TV>(
BTree <TK, KeyValuePair <TK, TV> > underlying,
Bound <TK> start)
{
if (start == null)
{
return(underlying.Begin());
}
return(start.IsInclusive
? underlying.GreaterThanOrEqual(start.Value, underlying.RootCursor)
: underlying.GreaterThan(start.Value, underlying.RootCursor));
}
/// <summary>
/// Returns the last key-value pair in the dictionary. If the dictionary
/// is empty, this method throws an InvalidOperationException.
/// </summary>
internal static KeyValuePair <TK, TV> LastKeyValuePair <TK, TV>(
BTree <TK, KeyValuePair <TK, TV> > underlying,
BoundRange <TK> range)
{
var upper = range.Upper;
var cursor = upper != null
? upper.IsInclusive
? underlying.GreaterThanOrEqual(upper.Value, underlying.RootCursor)
: underlying.GreaterThan(upper.Value, underlying.RootCursor)
: underlying.End().MovePrevious();
if (cursor.IsEnd)
{
throw new InvalidOperationException();
}
return(cursor.Value);
}
public bool TryGreaterThan(
TK value,
out TK result)
{
return(TryWithCursor(_underlying.GreaterThan(value, _underlying.RootCursor), out result));
}