private static StringRebuilder Pivot(StringRebuilder child, StringRebuilder other, bool deepOnRightSide)
{
Debug.Assert(child.Depth > 0); //child's depth is greater than other's depth.
StringRebuilder grandchildOutside = child.Child(deepOnRightSide);
StringRebuilder grandchildInside = child.Child(!deepOnRightSide);
if (grandchildOutside.Depth >= grandchildInside.Depth)
{
//Simple pivot.
//From this (case deepOnRightSide)
// this
// / \
// other child
// ... / \
// gcI gcO
// ... ...
//
//To this:
// child'
// / \
// this' gcO
// / \ ...
// other gcI
StringRebuilder newThis;
StringRebuilder newChild;
if (deepOnRightSide)
{
newThis = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(other, grandchildInside);
newChild = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(newThis, grandchildOutside);
}
else
{
newThis = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(grandchildInside, other);
newChild = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(grandchildOutside, newThis);
}
return(newChild);
}
else
{
//Complex pivot.
//From this (case !deepOnRightSide)
// this
// / \
// other child
// ... / \
// gcI gcO
// / \ ...
// ggcI ggcO
// ... ...
//
//To this:
// gcI'
// / \
// this' child'
// / \ / \
// other ggcI ggcO gcO
// ... ... ... ...
Debug.Assert(grandchildInside.Depth > 0); //The inside's grandchild depth is > the outside grandchild's.
StringRebuilder greatgrandchildOutside = grandchildInside.Child(deepOnRightSide);
StringRebuilder greatgrandchildInside = grandchildInside.Child(!deepOnRightSide);
StringRebuilder newThis;
StringRebuilder newChild;
StringRebuilder newGcI;
if (deepOnRightSide)
{
newThis = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(other, greatgrandchildInside);
newChild = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(greatgrandchildOutside, grandchildOutside);
newGcI = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(newThis, newChild);
}
else
{
newThis = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(greatgrandchildInside, other);
newChild = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(grandchildOutside, greatgrandchildOutside);
newGcI = BinaryStringRebuilder.ConsolidateOrBalanceTreeNode(newChild, newThis);
}
return(newGcI);
}
}