-
- private static boolean REDbool = false;
- private static boolean BLACKbool = true;
-
- public final Box peerTree_leftmost() { for (Box p = this; ; p = p.left) if (p.left == null) return p; }
- public final Box peerTree_rightmost() { for (Box p = this; ; p = p.right) if (p.right == null) return p; }
- static Box peerTree_parent(Box p) { return (p == null)? null: p.peerTree_parent; }
-
- public Box insertBeforeMe(Box cell) { left = cell; cell.peerTree_parent = this; return cell.fixAfterInsertion(); }
- public Box insertAfterMe(Box cell) { right = cell; cell.peerTree_parent = this; return cell.fixAfterInsertion(); }
-
- static boolean colorOf(Box p) { return (p == null) ? BLACKbool : p.test(BLACK); }
- static void setColor(Box p, boolean c) { if (p != null) { if (c) p.set(BLACK); else p.clear(BLACK); } }
- static Box leftOf(Box p) { return (p == null)? null: p.left; }
- static Box rightOf(Box p) { return (p == null)? null: p.right; }
-
- public final Box nextSibling() {
- if (right != null)
- return right.peerTree_leftmost();
- else {
- Box p = peerTree_parent;
- Box ch = this;
- while (p != null && ch == p.right) { ch = p; p = p.peerTree_parent; }
- return p;
- }
- }
-
- public final Box prevSibling() {
- if (left != null)
- return left.peerTree_rightmost();
- else {
- Box p = peerTree_parent;
- Box ch = this;
- while (p != null && ch == p.left) { ch = p; p = p.peerTree_parent; }
- return p;
- }
- }
-
- public Box removeNode() {
- Box root = peerTree_parent.rootChild;
-
- // handle case where we are only node
- if (left == null && right == null && peerTree_parent == null) return null;
-
- // if strictly internal, swap places with a successor
- if (left != null && right != null) {
- Box s = nextSibling();
- // To work nicely with arbitrary subclasses of Box, we don't want to
- // just copy successor's fields. since we don't know what
- // they are. Instead we swap positions in the tree.
- root = swapPosition(this, s);
- }
-
- // Start fixup at replacement node (normally a child).
- // But if no children, fake it by using self
-
- if (left == null && right == null) {
-
- if (test(BLACK)) root = this.fixAfterDeletion();
-
- // Unlink (Couldn't before since fixAfterDeletion needs peerTree_parent ptr)
-
- if (peerTree_parent != null) {
- if (this == peerTree_parent.left)
- peerTree_parent.left = null;
- else if (this == peerTree_parent.right)
- peerTree_parent.right = null;
- peerTree_parent = null;
- }
-
- }
- else {
- Box replacement = left;
- if (replacement == null) replacement = right;
-
- // link replacement to peerTree_parent
- replacement.peerTree_parent = peerTree_parent;
-
- if (peerTree_parent == null) root = replacement;
- else if (this == peerTree_parent.left) peerTree_parent.left = replacement;
- else peerTree_parent.right = replacement;
-
- left = null;
- right = null;
- peerTree_parent = null;
-
- // fix replacement
- if (test(BLACK)) root = replacement.fixAfterDeletion();
-
- }
-
- return root;
- }
-
- /**
- * Swap the linkages of two nodes in a tree.
- * Return new root, in case it changed.
- **/
- Box swapPosition(Box x, Box y) {
- Box root = peerTree_parent.rootChild;
-
- /* Too messy. TODO: find sequence of assigments that are always OK */
-
- Box px = x.peerTree_parent;
- boolean xpl = px != null && x == px.left;
- Box lx = x.left;
- Box rx = x.right;
-
- Box py = y.peerTree_parent;
- boolean ypl = py != null && y == py.left;
- Box ly = y.left;
- Box ry = y.right;
-
- if (x == py) {
- y.peerTree_parent = px;
- if (px != null) if (xpl) px.left = y; else px.right = y;
- x.peerTree_parent = y;
- if (ypl) {
- y.left = x;
- y.right = rx; if (rx != null) rx.peerTree_parent = y;
- }
- else {
- y.right = x;
- y.left = lx; if (lx != null) lx.peerTree_parent = y;
- }
- x.left = ly; if (ly != null) ly.peerTree_parent = x;
- x.right = ry; if (ry != null) ry.peerTree_parent = x;
- }
- else if (y == px) {
- x.peerTree_parent = py;
- if (py != null) if (ypl) py.left = x; else py.right = x;
- y.peerTree_parent = x;
- if (xpl) {
- x.left = y;
- x.right = ry; if (ry != null) ry.peerTree_parent = x;
- }
- else {
- x.right = y;
- x.left = ly; if (ly != null) ly.peerTree_parent = x;
- }
- y.left = lx; if (lx != null) lx.peerTree_parent = y;
- y.right = rx; if (rx != null) rx.peerTree_parent = y;
- }
- else {
- x.peerTree_parent = py; if (py != null) if (ypl) py.left = x; else py.right = x;
- x.left = ly; if (ly != null) ly.peerTree_parent = x;
- x.right = ry; if (ry != null) ry.peerTree_parent = x;
-
- y.peerTree_parent = px; if (px != null) if (xpl) px.left = y; else px.right = y;
- y.left = lx; if (lx != null) lx.peerTree_parent = y;
- y.right = rx; if (rx != null) rx.peerTree_parent = y;
- }
-
- boolean c = x.test(BLACK);
- if (y.test(BLACK)) x.set(BLACK); else x.clear(BLACK);
- if (c) y.set(BLACK); else y.clear(BLACK);
-
- if (root == x) root = y;
- else if (root == y) root = x;
- return parent.rootChild = root;
- }
-
- Box rotateLeft() {
- Box root = parent.rootChild;
- Box r = right;
- right = r.left;
- if (r.left != null) r.left.peerTree_parent = this;
- r.peerTree_parent = peerTree_parent;
- if (peerTree_parent == null) root = r;
- else if (peerTree_parent.left == this) peerTree_parent.left = r;
- else peerTree_parent.right = r;
- r.left = this;
- peerTree_parent = r;
- return parent.rootChild = root;
- }
-
- Box rotateRight() {
- Box root = parent.rootChild;
- Box l = left;
- left = l.right;
- if (l.right != null) l.right.peerTree_parent = this;
- l.peerTree_parent = peerTree_parent;
- if (peerTree_parent == null) root = l;
- else if (peerTree_parent.right == this) peerTree_parent.right = l;
- else peerTree_parent.left = l;
- l.right = this;
- peerTree_parent = l;
- return parent.rootChild;
- }
-
- Box fixAfterInsertion() {
- Box root = parent.rootChild;
- clear(BLACK);
- Box x = this;
-
- while (x != null && x != root && !x.peerTree_parent.test(BLACK)) {
- if (peerTree_parent(x) == leftOf(peerTree_parent(peerTree_parent(x)))) {
- Box y = rightOf(peerTree_parent(peerTree_parent(x)));
- if (colorOf(y) == REDbool) {
- setColor(peerTree_parent(x), BLACKbool);
- setColor(y, BLACKbool);
- setColor(peerTree_parent(peerTree_parent(x)), REDbool);
- x = peerTree_parent(peerTree_parent(x));
- }
- else {
- if (x == rightOf(peerTree_parent(x))) {
- x = peerTree_parent(x);
- root = x.rotateLeft();
- }
- setColor(peerTree_parent(x), BLACKbool);
- setColor(peerTree_parent(peerTree_parent(x)), REDbool);
- if (peerTree_parent(peerTree_parent(x)) != null)
- root = peerTree_parent(peerTree_parent(x)).rotateRight();
- }
- }
- else {
- Box y = leftOf(peerTree_parent(peerTree_parent(x)));
- if (colorOf(y) == REDbool) {
- setColor(peerTree_parent(x), BLACKbool);
- setColor(y, BLACKbool);
- setColor(peerTree_parent(peerTree_parent(x)), REDbool);
- x = peerTree_parent(peerTree_parent(x));
- }
- else {
- if (x == leftOf(peerTree_parent(x))) {
- x = peerTree_parent(x);
- root = x.rotateRight();
- }
- setColor(peerTree_parent(x), BLACKbool);
- setColor(peerTree_parent(peerTree_parent(x)), REDbool);
- if (peerTree_parent(peerTree_parent(x)) != null)
- root = peerTree_parent(peerTree_parent(x)).rotateLeft();
- }
- }
- }
- root.set(BLACK);
- return parent.rootChild = root;
- }
-
- /** From CLR **/
- Box fixAfterDeletion() {
- Box root = peerTree_parent.rootChild;
- Box x = this;
- while (x != root && colorOf(x) == BLACKbool) {
- if (x == leftOf(peerTree_parent(x))) {
- Box sib = rightOf(peerTree_parent(x));
- if (colorOf(sib) == REDbool) {
- setColor(sib, BLACKbool);
- setColor(peerTree_parent(x), REDbool);
- root = peerTree_parent(x).rotateLeft();
- sib = rightOf(peerTree_parent(x));
- }
- if (colorOf(leftOf(sib)) == BLACKbool && colorOf(rightOf(sib)) == BLACKbool) {
- setColor(sib, REDbool);
- x = peerTree_parent(x);
- }
- else {
- if (colorOf(rightOf(sib)) == BLACKbool) {
- setColor(leftOf(sib), BLACKbool);
- setColor(sib, REDbool);
- root = sib.rotateRight();
- sib = rightOf(peerTree_parent(x));
- }
- setColor(sib, colorOf(peerTree_parent(x)));
- setColor(peerTree_parent(x), BLACKbool);
- setColor(rightOf(sib), BLACKbool);
- root = peerTree_parent(x).rotateLeft();
- x = root;
- }
- }
- else {
- Box sib = leftOf(peerTree_parent(x));
- if (colorOf(sib) == REDbool) {
- setColor(sib, BLACKbool);
- setColor(peerTree_parent(x), REDbool);
- root = peerTree_parent(x).rotateRight();
- sib = leftOf(peerTree_parent(x));
- }
- if (colorOf(rightOf(sib)) == BLACKbool && colorOf(leftOf(sib)) == BLACKbool) {
- setColor(sib, REDbool);
- x = peerTree_parent(x);
- }
- else {
- if (colorOf(leftOf(sib)) == BLACKbool) {
- setColor(rightOf(sib), BLACKbool);
- setColor(sib, REDbool);
- root = sib.rotateLeft();
- sib = leftOf(peerTree_parent(x));
- }
- setColor(sib, colorOf(peerTree_parent(x)));
- setColor(peerTree_parent(x), BLACKbool);
- setColor(leftOf(sib), BLACKbool);
- root = peerTree_parent(x).rotateRight();
- x = root;
- }
- }
- }
- setColor(x, BLACKbool);
- return parent.rootChild = root;