/// <summary>
/// Updates values of all keys. For each key in the dictionary, the
/// value is replaced with <code>func(key, this[key])</code>.
/// </summary>
/// <typeparam name="TValue1">The type of the values in the returned dictionary.</typeparam>
/// <param name="func">The updating function.</param>
/// <returns>The resulting dictionary.</returns>
public TreeDictionary <TKey, TValue1, TComparer> MapPartial <TValue1>(Func <TKey, TValue, Optional <TValue1> > func)
{
if (Count == 0)
{
return(TreeDictionary <TKey, TValue1, TComparer> .Empty);
}
var newValue = func(_key, _value);
return(newValue.HasValue
? TreeDictionary <TKey, TValue1, TComparer> .Unbalanced(_key, newValue.Value, _left.MapPartial(func), _right.MapPartial(func))
: TreeDictionary <TKey, TValue1, TComparer> .GlueUnbalanced(_left.MapPartial(func), _right.MapPartial(func)));
}
private TreeDictionary <TKey, TValue, TComparer> UnionTrim(
TreeDictionary <TKey, TValue, TComparer> otherDict,
TKey low, TKey high,
Func <TKey, TValue, TValue, TValue> combiner)
{
if (otherDict.Count == 0)
{
return(this);
}
if (Count == 0)
{
var otherLeft = otherDict._left.FilterLess(high);
var otherRight = otherDict._right.FilterGreater(low);
return(ReferenceEquals(otherDict._left, otherLeft) && ReferenceEquals(otherDict._right, otherRight)
? otherDict
: otherDict.Unbalanced(otherDict._value, otherLeft, otherRight));
}
Debug.Assert(_Comparer.Compare(low, _key) < 0 && _Comparer.Compare(high, _key) > 0);
return(Unbalanced(
_value,
_left.UnionTrim(otherDict.Trim(low, _key), low, _key, combiner),
_right.UnionTrim(otherDict.Trim(_key, high), _key, high, combiner)));
}