/// <inheritdoc />
public bool Equals(SortedReadOnlyArray <TValue, TComparer> other)
{
return(m_array == other.m_array);
}
public static SortedReadOnlyArray <TValue, TComparer> Instance(TComparer comparer) =>
SortedReadOnlyArray <TValue, TComparer> .CloneAndSort(
EmptyArray <TValue>().ToReadOnlyArray(),
comparer);
private int ExceptWithVisitor(SortedReadOnlyArray <TValue, TComparer>[] others, Action <int, TValue>?visit = null)
{
// Number of non-excepted items seen so far (returned at the end)
int size = 0;
// Indicates if any of 'others' have valid cursors still (this instance may have items greater than all others).
bool othersRemaining = true;
// Cursor for the current item to compare with in each of the others.
var otherCursors = new int[others.Length];
// We always visit every item in this array since each is potentially (independently) not in the others.
for (int i = 0; i < Length;)
{
bool found = false;
TValue thisCurrent = this[i];
// If there are others to look at, it is possible that we will find this item.
if (othersRemaining)
{
// We now try to find the item in at least one of the others (note we don't need to advance the cursors of the rest).
othersRemaining = false;
for (int otherIdx = 0; !found && otherIdx < others.Length; otherIdx++)
{
SortedReadOnlyArray <TValue, TComparer> other = others[otherIdx];
if (other.Length == otherCursors[otherIdx])
{
continue;
}
othersRemaining = true;
if (Comparer.Compare(other[otherCursors[otherIdx]], thisCurrent) == 0)
{
// Exact match (fast path for heavily overlapping sets).
otherCursors[otherIdx]++;
found = true;
}
else
{
// This cursor may be arbitrarily behind (note that we quit looking at additional others for an item when it is first found).
// Here we catch up efficiently via binary search. We either find an exact match (non-negative index) or an upper-bound
// (encoded negative).
int skipToEncoded = other.BinarySearch(thisCurrent, otherCursors[otherIdx], other.Length - otherCursors[otherIdx]);
if (skipToEncoded >= 0)
{
// Exact match. The binary search may have landed in the middle of a sequence of duplicates,
// but that's fine; the next cursor advance will take care of that (invariant is advancing cursor points
// it at an item at least as high, but not neccesarily higher).
otherCursors[otherIdx] = skipToEncoded + 1;
found = true;
}
else
{
otherCursors[otherIdx] = ~skipToEncoded;
}
}
Contract.Assume(otherCursors[otherIdx] == other.Length || Comparer.Compare(other[otherCursors[otherIdx]], thisCurrent) >= 0);
}
}
if (!found)
{
visit?.Invoke(size, thisCurrent);
size++;
}
i++;
// Skip duplicates in the input sequence (this value was either excepted or not already; cursors have advanced possibly past it).
while (i < Length && Comparer.Compare(thisCurrent, this[i]) == 0)
{
i++;
}
}
return(size);
}