internal int balanceRightBranch(ref TtreePage pgRef)
{
if (balance > 0)
{
balance = 0;
return(UNDERFLOW);
}
else if (balance == 0)
{
balance = -1;
return(OK);
}
else
{
TtreePage lp = this.left;
lp.Load();
lp.Modify();
if (lp.balance <= 0)
{ // single LL turn
this.left = lp.right;
lp.right = this;
if (lp.balance == 0)
{
balance = -1;
lp.balance = 1;
pgRef = lp;
return(OK);
}
else
{
balance = 0;
lp.balance = 0;
pgRef = lp;
return(UNDERFLOW);
}
}
else
{ // double LR turn
TtreePage rp = lp.right;
rp.Load();
rp.Modify();
lp.right = rp.left;
rp.left = lp;
this.left = rp.right;
rp.right = this;
balance = rp.balance < 0 ? 1 : 0;
lp.balance = rp.balance > 0 ? -1 : 0;
rp.balance = 0;
pgRef = rp;
return(UNDERFLOW);
}
}
}
internal int remove(PersistentComparator comparator, IPersistent mbr, ref TtreePage pgRef)
{
Load();
TtreePage pg;
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)
{
TtreePage 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)
{
TtreePage 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);
}
internal int insert(PersistentComparator comparator, IPersistent mbr, bool unique, ref TtreePage pgRef)
{
Load();
int n = nItems;
TtreePage pg;
int diff = comparator.CompareMembers(mbr, loadItem(0));
if (diff <= 0)
{
if (unique && diff == 0)
{
return(NOT_UNIQUE);
}
if ((left == null || diff == 0) && n != maxItems)
{
Modify();
//for (int i = n; i > 0; i--) item[i] = item[i-1];
Array.Copy(item, 0, item, 1, n);
item[0] = mbr;
nItems += 1;
return(OK);
}
if (left == null)
{
Modify();
left = new TtreePage(mbr);
}
else
{
pg = pgRef;
pgRef = left;
int result = left.insert(comparator, mbr, unique, ref pgRef);
if (result == NOT_UNIQUE)
{
return(NOT_UNIQUE);
}
Modify();
left = pgRef;
pgRef = pg;
if (result == OK)
{
return(OK);
}
}
if (balance > 0)
{
balance = 0;
return(OK);
}
else if (balance == 0)
{
balance = -1;
return(OVERFLOW);
}
else
{
TtreePage lp = this.left;
lp.Load();
lp.Modify();
if (lp.balance < 0)
{ // single LL turn
this.left = lp.right;
lp.right = this;
balance = 0;
lp.balance = 0;
pgRef = lp;
}
else
{ // double LR turn
TtreePage rp = lp.right;
rp.Load();
rp.Modify();
lp.right = rp.left;
rp.left = lp;
this.left = rp.right;
rp.right = this;
balance = (rp.balance < 0) ? 1 : 0;
lp.balance = (rp.balance > 0) ? -1 : 0;
rp.balance = 0;
pgRef = rp;
}
return(OK);
}
}
diff = comparator.CompareMembers(mbr, loadItem(n - 1));
if (diff >= 0)
{
if (unique && diff == 0)
{
return(NOT_UNIQUE);
}
if ((right == null || diff == 0) && n != maxItems)
{
Modify();
item[n] = mbr;
nItems += 1;
return(OK);
}
if (right == null)
{
Modify();
right = new TtreePage(mbr);
}
else
{
pg = pgRef;
pgRef = right;
int result = right.insert(comparator, mbr, unique, ref pgRef);
if (result == NOT_UNIQUE)
{
return(NOT_UNIQUE);
}
Modify();
right = pgRef;
pgRef = pg;
if (result == OK)
{
return(OK);
}
}
if (balance < 0)
{
balance = 0;
return(OK);
}
else if (balance == 0)
{
balance = 1;
return(OVERFLOW);
}
else
{
TtreePage rp = this.right;
rp.Load();
rp.Modify();
if (rp.balance > 0)
{ // single RR turn
this.right = rp.left;
rp.left = this;
balance = 0;
rp.balance = 0;
pgRef = rp;
}
else
{ // double RL turn
TtreePage lp = rp.left;
lp.Load();
lp.Modify();
rp.left = lp.right;
lp.right = rp;
this.right = lp.left;
lp.left = this;
balance = (lp.balance > 0) ? -1 : 0;
rp.balance = (lp.balance < 0) ? 1 : 0;
lp.balance = 0;
pgRef = lp;
}
return(OK);
}
}
int l = 1, r = n - 1;
while (l < r)
{
int i = (l + r) >> 1;
diff = comparator.CompareMembers(mbr, loadItem(i));
if (diff > 0)
{
l = i + 1;
}
else
{
r = i;
if (diff == 0)
{
if (unique)
{
return(NOT_UNIQUE);
}
break;
}
}
}
// Insert before item[r]
Modify();
if (n != maxItems)
{
Array.Copy(item, r, item, r + 1, n - r);
//for (int i = n; i > r; i--) item[i] = item[i-1];
item[r] = mbr;
nItems += 1;
return(OK);
}
else
{
IPersistent reinsertItem;
if (balance >= 0)
{
reinsertItem = loadItem(0);
Array.Copy(item, 1, item, 0, r - 1);
//for (int i = 1; i < r; i++) item[i-1] = item[i];
item[r - 1] = mbr;
}
else
{
reinsertItem = loadItem(n - 1);
Array.Copy(item, r, item, r + 1, n - r - 1);
//for (int i = n-1; i > r; i--) item[i] = item[i-1];
item[r] = mbr;
}
return(insert(comparator, reinsertItem, unique, ref pgRef));
}
}