public int GetHashCode(Wrapper<T> x)
{
Debug.Assert(_comparer != null);
return _comparer.GetHashCode(x.Value);
}
//---------------------------------------------------------------------------------------
// Walks the two data sources, left and then right, to produce the intersection.
//
internal override bool MoveNext(ref TInputOutput currentElement, ref TLeftKey currentKey)
{
Debug.Assert(_leftSource != null);
Debug.Assert(_rightSource != null);
// Build the set out of the left data source, if we haven't already.
int i = 0;
if (_hashLookup == null)
{
_hashLookup = new Dictionary <Wrapper <TInputOutput>, Pair>(_comparer);
Pair leftElement = new Pair(default(TInputOutput), default(NoKeyMemoizationRequired));
TLeftKey leftKey = default(TLeftKey);
while (_leftSource.MoveNext(ref leftElement, ref leftKey))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// For each element, we track the smallest order key for that element that we saw so far
Pair oldEntry;
Wrapper <TInputOutput> wrappedLeftElem = new Wrapper <TInputOutput>((TInputOutput)leftElement.First);
// If this is the first occurrence of this element, or the order key is lower than all keys we saw previously,
// update the order key for this element.
if (!_hashLookup.TryGetValue(wrappedLeftElem, out oldEntry) || _leftKeyComparer.Compare(leftKey, (TLeftKey)oldEntry.Second) < 0)
{
// For each "elem" value, we store the smallest key, and the element value that had that key.
// Note that even though two element values are "equal" according to the EqualityComparer,
// we still cannot choose arbitrarily which of the two to yield.
_hashLookup[wrappedLeftElem] = new Pair(leftElement.First, leftKey);
}
}
}
// Now iterate over the right data source, looking for matches.
Pair rightElement = new Pair(default(TInputOutput), default(NoKeyMemoizationRequired));
int rightKeyUnused = default(int);
while (_rightSource.MoveNext(ref rightElement, ref rightKeyUnused))
{
if ((i++ & CancellationState.POLL_INTERVAL) == 0)
{
CancellationState.ThrowIfCanceled(_cancellationToken);
}
// If we found the element in our set, and if we haven't returned it yet,
// we can yield it to the caller. We also mark it so we know we've returned
// it once already and never will again.
Pair entry;
Wrapper <TInputOutput> wrappedRightElem = new Wrapper <TInputOutput>((TInputOutput)rightElement.First);
if (_hashLookup.TryGetValue(wrappedRightElem, out entry))
{
currentElement = (TInputOutput)entry.First;
currentKey = (TLeftKey)entry.Second;
_hashLookup.Remove(new Wrapper <TInputOutput>((TInputOutput)entry.First));
return(true);
}
}
return(false);
}
public bool Equals(Wrapper<T> x, Wrapper<T> y)
{
Debug.Assert(_comparer != null);
return _comparer.Equals(x.Value, y.Value);
}
