public override bool Remove(V obj)
{
if (root == null)
{
return(false); // TODO: shouldn't that be an exception too?
}
TtreePage <K, V> newRoot = root;
if (root.remove(comparator, obj, ref newRoot) == TtreePage <K, V> .NOT_FOUND)
{
throw new DatabaseException(DatabaseException.ErrorCode.KEY_NOT_FOUND);
}
Modify();
root = newRoot;
nMembers -= 1;
return(true);
}
internal int remove(PersistentComparator <K, V> comparator, V mbr, ref TtreePage <K, V> pgRef)
{
TtreePage <K, V> pg, next, prev;
Load();
int n = nItems;
int diff = comparator.CompareMembers(mbr, loadItem(0));
if (diff <= 0)
{
if (left != null)
{
Modify();
pg = pgRef;
pgRef = left;
int h = left.remove(comparator, mbr, ref pgRef);
left = pgRef;
pgRef = pg;
if (h == UNDERFLOW)
{
return(balanceLeftBranch(ref pgRef));
}
else if (h == OK)
{
return(OK);
}
}
}
diff = comparator.CompareMembers(mbr, loadItem(n - 1));
if (diff <= 0)
{
for (int i = 0; i < n; i++)
{
if (item[i] == mbr)
{
if (n == 1)
{
if (right == null)
{
Deallocate();
pgRef = left;
return(UNDERFLOW);
}
else if (left == null)
{
Deallocate();
pgRef = right;
return(UNDERFLOW);
}
}
Modify();
if (n <= minItems)
{
if (left != null && balance <= 0)
{
prev = left;
prev.Load();
while (prev.right != null)
{
prev = prev.right;
prev.Load();
}
Array.Copy(item, 0, item, 1, i);
//while (--i >= 0)
//{
// item[i+1] = item[i];
//}
item[0] = prev.item[prev.nItems - 1];
pg = pgRef;
pgRef = left;
int h = left.remove(comparator, loadItem(0), ref pgRef);
left = pgRef;
pgRef = pg;
if (h == UNDERFLOW)
{
h = balanceLeftBranch(ref pgRef);
}
return(h);
}
else if (right != null)
{
next = right;
next.Load();
while (next.left != null)
{
next = next.left;
next.Load();
}
Array.Copy(item, i + 1, item, i, n - i - 1);
//while (++i < n)
//{
// item[i-1] = item[i];
//}
item[n - 1] = next.item[0];
pg = pgRef;
pgRef = right;
int h = right.remove(comparator, loadItem(n - 1), ref pgRef);
right = pgRef;
pgRef = pg;
if (h == UNDERFLOW)
{
h = balanceRightBranch(ref pgRef);
}
return(h);
}
}
Array.Copy(item, i + 1, item, i, n - i - 1);
//while (++i < n)
//{
// item[i-1] = item[i];
//}
item[n - 1] = null;
nItems -= 1;
return(OK);
}
}
}
if (right != null)
{
Modify();
pg = pgRef;
pgRef = right;
int h = right.remove(comparator, mbr, ref pgRef);
right = pgRef;
pgRef = pg;
if (h == UNDERFLOW)
{
return(balanceRightBranch(ref pgRef));
}
else
{
return(h);
}
}
return(NOT_FOUND);
}
