ReconcileHelper <T, U, TResult>(EnumerableIterator <T> left,
EnumerableIterator <U> right,
Func <T, U, int> comparison,
Func <T, U, TResult> selector)
{
while (left.IsValid && right.IsValid)
{
// While left < right, the items in left aren't in right
while (left.IsValid && right.IsValid &&
comparison(left.Current, right.Current) < 0)
{
yield return(selector(left.Current, default(U)));
left.MoveNext();
}
// While right < left, the items in right aren't in left
while (left.IsValid && right.IsValid &&
comparison(left.Current, right.Current) > 0)
{
yield return(selector(default(T), right.Current));
right.MoveNext();
}
// While left == right, the items are in both
while (left.IsValid && right.IsValid &&
comparison(left.Current, right.Current) == 0)
{
yield return(selector(left.Current, right.Current));
left.MoveNext();
right.MoveNext();
}
}
// Mop up.
while (left.IsValid)
{
yield return(selector(left.Current, default(U)));
left.MoveNext();
}
while (right.IsValid)
{
yield return(selector(default(T), right.Current));
right.MoveNext();
}
}
public static void CompareSortedCollections <T>(IEnumerable <T> source, IEnumerable <T> destination, IComparer <T> comparer, Action <T> onLeftOnly, Action <T> onRightOnly, Action <T, T> onBoth)
{
EnumerableIterator <T> sourceIterator = new EnumerableIterator <T>(source);
EnumerableIterator <T> destinationIterator = new EnumerableIterator <T>(destination);
while (sourceIterator.HasCurrent && destinationIterator.HasCurrent)
{
// While LHS < RHS, the items in LHS aren't in RHS
while (sourceIterator.HasCurrent && (comparer.Compare(sourceIterator.Current, destinationIterator.Current) < 0))
{
onLeftOnly(sourceIterator.Current);
sourceIterator.MoveNext();
}
// While RHS < LHS, the items in RHS aren't in LHS
while (sourceIterator.HasCurrent && destinationIterator.HasCurrent && (comparer.Compare(sourceIterator.Current, destinationIterator.Current) > 0))
{
onRightOnly(destinationIterator.Current);
destinationIterator.MoveNext();
}
// While LHS==RHS, the items are in both
while (sourceIterator.HasCurrent && destinationIterator.HasCurrent && (comparer.Compare(sourceIterator.Current, destinationIterator.Current) == 0))
{
onBoth(sourceIterator.Current, destinationIterator.Current);
sourceIterator.MoveNext();
destinationIterator.MoveNext();
}
}
// Mop up.
while (sourceIterator.HasCurrent)
{
onLeftOnly(sourceIterator.Current);
sourceIterator.MoveNext();
}
while (destinationIterator.HasCurrent)
{
onRightOnly(destinationIterator.Current);
destinationIterator.MoveNext();
}
}