void ngx_rbtree_delete(ngx_rbtree_t **root, ngx_rbtree_t *sentinel,
ngx_rbtree_t *node)
{
ngx_int_t is_red;
ngx_rbtree_t *subst, *temp, *w;
/* a binary tree delete */
if (node->left == sentinel) {
temp = node->right;
subst = node;
} else if (node->right == sentinel) {
temp = node->left;
subst = node;
} else {
subst = ngx_rbtree_min(node->right, sentinel);
if (subst->left != sentinel) {
temp = subst->left;
} else {
temp = subst->right;
}
}
if (subst == *root) {
*root = temp;
ngx_rbt_black(temp);
/* DEBUG stuff */
node->left = NULL;
node->right = NULL;
node->parent = NULL;
node->key = 0;
return;
}
is_red = ngx_rbt_is_red(subst);
if (subst == subst->parent->left) {
subst->parent->left = temp;
} else {
subst->parent->right = temp;
}
if (subst == node) {
temp->parent = subst->parent;
} else {
if (subst->parent == node) {
temp->parent = subst;
} else {
temp->parent = subst->parent;
}
subst->left = node->left;
subst->right = node->right;
subst->parent = node->parent;
ngx_rbt_copy_color(subst, node);
if (node == *root) {
*root = subst;
} else {
if (node == node->parent->left) {
node->parent->left = subst;
} else {
node->parent->right = subst;
}
}
if (subst->left != sentinel) {
subst->left->parent = subst;
}
if (subst->right != sentinel) {
subst->right->parent = subst;
}
/* DEBUG stuff */
node->left = NULL;
node->right = NULL;
node->parent = NULL;
node->key = 0;
}
if (is_red) {
return;
}
/* a delete fixup */
while (temp != *root && ngx_rbt_is_black(temp)) {
if (temp == temp->parent->left) {
w = temp->parent->right;
if (ngx_rbt_is_red(w)) {
ngx_rbt_black(w);
ngx_rbt_red(temp->parent);
ngx_rbtree_left_rotate(root, sentinel, temp->parent);
w = temp->parent->right;
}
if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {
ngx_rbt_red(w);
temp = temp->parent;
} else {
if (ngx_rbt_is_black(w->right)) {
ngx_rbt_black(w->left);
ngx_rbt_red(w);
ngx_rbtree_right_rotate(root, sentinel, w);
w = temp->parent->right;
}
ngx_rbt_copy_color(w, temp->parent);
ngx_rbt_black(temp->parent);
ngx_rbt_black(w->right);
ngx_rbtree_left_rotate(root, sentinel, temp->parent);
temp = *root;
}
} else {
w = temp->parent->left;
if (ngx_rbt_is_red(w)) {
ngx_rbt_black(w);
ngx_rbt_red(temp->parent);
ngx_rbtree_right_rotate(root, sentinel, temp->parent);
w = temp->parent->left;
}
if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {
ngx_rbt_red(w);
temp = temp->parent;
} else {
if (ngx_rbt_is_black(w->left)) {
ngx_rbt_black(w->right);
ngx_rbt_red(w);
ngx_rbtree_left_rotate(root, sentinel, w);
w = temp->parent->left;
}
ngx_rbt_copy_color(w, temp->parent);
ngx_rbt_black(temp->parent);
ngx_rbt_black(w->left);
ngx_rbtree_right_rotate(root, sentinel, temp->parent);
temp = *root;
}
}
}
ngx_rbt_black(temp);
}
void ngx_rbtree_insert(ngx_rbtree_t **root, ngx_rbtree_t *sentinel,
ngx_rbtree_t *node)
{
ngx_rbtree_t *temp;
/* a binary tree insert */
if (*root == sentinel) {
node->parent = NULL;
node->left = sentinel;
node->right = sentinel;
ngx_rbt_black(node);
*root = node;
return;
}
temp = *root;
for ( ;; ) {
if (node->key < temp->key) {
if (temp->left == sentinel) {
temp->left = node;
break;
}
temp = temp->left;
continue;
}
if (temp->right == sentinel) {
temp->right = node;
break;
}
temp = temp->right;
continue;
}
node->parent = temp;
node->left = sentinel;
node->right = sentinel;
/* re-balance tree */
ngx_rbt_red(node);
while (node != *root && ngx_rbt_is_red(node->parent)) {
if (node->parent == node->parent->parent->left) {
temp = node->parent->parent->right;
if (ngx_rbt_is_red(temp)) {
ngx_rbt_black(node->parent);
ngx_rbt_black(temp);
ngx_rbt_red(node->parent->parent);
node = node->parent->parent;
} else {
if (node == node->parent->right) {
node = node->parent;
ngx_rbtree_left_rotate(root, sentinel, node);
}
ngx_rbt_black(node->parent);
ngx_rbt_red(node->parent->parent);
ngx_rbtree_right_rotate(root, sentinel, node->parent->parent);
}
} else {
temp = node->parent->parent->left;
if (ngx_rbt_is_red(temp)) {
ngx_rbt_black(node->parent);
ngx_rbt_black(temp);
ngx_rbt_red(node->parent->parent);
node = node->parent->parent;
} else {
if (node == node->parent->left) {
node = node->parent;
ngx_rbtree_right_rotate(root, sentinel, node);
}
ngx_rbt_black(node->parent);
ngx_rbt_red(node->parent->parent);
ngx_rbtree_left_rotate(root, sentinel, node->parent->parent);
}
}
}
ngx_rbt_black(*root);
}
void
ngx_rbtree_insert(ngx_thread_volatile ngx_rbtree_t *tree,
ngx_rbtree_node_t *node)
{
ngx_rbtree_node_t **root, *temp, *sentinel;
/* a binary tree insert */
root = (ngx_rbtree_node_t **) &tree->root;
sentinel = tree->sentinel;
if (*root == sentinel) {
node->parent = NULL;
node->left = sentinel;
node->right = sentinel;
ngx_rbt_black(node);
*root = node;
return;
}
tree->insert(*root, node, sentinel);
/* re-balance tree */
while (node != *root && ngx_rbt_is_red(node->parent)) {
if (node->parent == node->parent->parent->left) {
temp = node->parent->parent->right;
if (ngx_rbt_is_red(temp)) {
ngx_rbt_black(node->parent);
ngx_rbt_black(temp);
ngx_rbt_red(node->parent->parent);
node = node->parent->parent;
} else {
if (node == node->parent->right) {
node = node->parent;
ngx_rbtree_left_rotate(root, sentinel, node);
}
ngx_rbt_black(node->parent);
ngx_rbt_red(node->parent->parent);
ngx_rbtree_right_rotate(root, sentinel, node->parent->parent);
}
} else {
temp = node->parent->parent->left;
if (ngx_rbt_is_red(temp)) {
ngx_rbt_black(node->parent);
ngx_rbt_black(temp);
ngx_rbt_red(node->parent->parent);
node = node->parent->parent;
} else {
if (node == node->parent->left) {
node = node->parent;
ngx_rbtree_right_rotate(root, sentinel, node);
}
ngx_rbt_black(node->parent);
ngx_rbt_red(node->parent->parent);
ngx_rbtree_left_rotate(root, sentinel, node->parent->parent);
}
}
}
ngx_rbt_black(*root);
}
void
ngx_rbtree_insert(ngx_thread_volatile ngx_rbtree_t *tree,//插入节点
ngx_rbtree_node_t *node)//插入的节点
{
ngx_rbtree_node_t **root, *temp, *sentinel;//树节点 root temp 哨兵
/* a binary tree insert */
root = (ngx_rbtree_node_t **) &tree->root;//定位root
sentinel = tree->sentinel;//定位哨兵
if (*root == sentinel) {//如果树为空
node->parent = NULL;//节点的父亲节点是空
node->left = sentinel;//左
node->right = sentinel;
ngx_rbt_black(node);//父节点一定得是黑色的
*root = node;
return;
}
tree->insert(*root, node, sentinel);//如果不是空的树进行插入 按照二叉搜索树插入节点
/* re-balance tree */
while (node != *root && ngx_rbt_is_red(node->parent)) {//重新平衡树 当父节点是红色的 并且不是根节点
if (node->parent == node->parent->parent->left) {//如果是正向的
temp = node->parent->parent->right;//父节点的兄弟节点
if (ngx_rbt_is_red(temp)) {//I3 x为red p为red s为red 导出pp为black
ngx_rbt_black(node->parent);//p设为黑
ngx_rbt_black(temp);//s 设为黑
ngx_rbt_red(node->parent->parent);//pp设置为红
node = node->parent->parent;//当前节点指向pp 不需要旋转
} else {
if (node == node->parent->right) {//I2 x为red p为red s为black 右节点
node = node->parent;//当前节点指向p
ngx_rbtree_left_rotate(root, sentinel, node);//进行左旋 即插入的节点替代p p转成插入节点的左节点
}
ngx_rbt_black(node->parent);//I1 x为red p为red s为black pp为black 设置p为黑
ngx_rbt_red(node->parent->parent);//设置pp为红
ngx_rbtree_right_rotate(root, sentinel, node->parent->parent);//右旋
}
} else {//反向同理 方向相反
temp = node->parent->parent->left;
if (ngx_rbt_is_red(temp)) {
ngx_rbt_black(node->parent);
ngx_rbt_black(temp);
ngx_rbt_red(node->parent->parent);
node = node->parent->parent;
} else {
if (node == node->parent->left) {
node = node->parent;
ngx_rbtree_right_rotate(root, sentinel, node);
}
ngx_rbt_black(node->parent);
ngx_rbt_red(node->parent->parent);
ngx_rbtree_left_rotate(root, sentinel, node->parent->parent);
}
}
}
ngx_rbt_black(*root);//无脑设置根节点为黑
}
//http://www.360doc.com/content/15/082609/10504424_494791577.shtml
void
ngx_rbtree_delete(ngx_thread_volatile ngx_rbtree_t *tree,
ngx_rbtree_node_t *node)
{
ngx_uint_t red;
ngx_rbtree_node_t **root, *sentinel, *subst, *temp, *w;
/* a binary tree delete */
root = (ngx_rbtree_node_t **) &tree->root;
sentinel = tree->sentinel;
if (node->left == sentinel) {//zuo情况1 2 删除节点y为单支节点或者叶子节点
temp = node->right;
subst = node;
} else if (node->right == sentinel) {//情况1 2 删除节点y为单支节点或者叶子节点
temp = node->left;
subst = node;
} else {//情况1 3 删除节点y为双支节点
subst = ngx_rbtree_min(node->right, sentinel);
if (subst->left != sentinel) {
temp = subst->left;
} else {
temp = subst->right;
}
}
if (subst == *root) {
*root = temp;
ngx_rbt_black(temp);
/* DEBUG stuff */
node->left = NULL;
node->right = NULL;
node->parent = NULL;
node->key = 0;
return;
}
red = ngx_rbt_is_red(subst);//记录y的颜色
if (subst == subst->parent->left) {//这里按照二叉树的性质，删除节点后重新生成二叉搜索树
subst->parent->left = temp;
} else {
subst->parent->right = temp;
}
if (subst == node) {
temp->parent = subst->parent;
} else {
if (subst->parent == node) {
temp->parent = subst;
} else {
temp->parent = subst->parent;
}
subst->left = node->left;
subst->right = node->right;
subst->parent = node->parent;
ngx_rbt_copy_color(subst, node);
if (node == *root) {
*root = subst;
} else {
if (node == node->parent->left) {
node->parent->left = subst;
} else {
node->parent->right = subst;
}
}
if (subst->left != sentinel) {
subst->left->parent = subst;
}
if (subst->right != sentinel) {
subst->right->parent = subst;
}
}
/* DEBUG stuff */
node->left = NULL;
node->right = NULL;
node->parent = NULL;
node->key = 0;
if (red) {//如果删除的节点y为red 直接退出
return;
}
/* a delete fixup */
while (temp != *root && ngx_rbt_is_black(temp)) {//temp就是上文中的x，开始平衡红黑节点，知道x为红色，或者到达root
if (temp == temp->parent->left) {
w = temp->parent->right;
if (ngx_rbt_is_red(w)) {//D1
ngx_rbt_black(w);
ngx_rbt_red(temp->parent);
ngx_rbtree_left_rotate(root, sentinel, temp->parent);
w = temp->parent->right;
}
if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {//d2
ngx_rbt_red(w);
temp = temp->parent;
} else {//d3
if (ngx_rbt_is_black(w->right)) {
ngx_rbt_black(w->left);
ngx_rbt_red(w);
ngx_rbtree_right_rotate(root, sentinel, w);
w = temp->parent->right;
}
ngx_rbt_copy_color(w, temp->parent);//d4
ngx_rbt_black(temp->parent);
ngx_rbt_black(w->right);
ngx_rbtree_left_rotate(root, sentinel, temp->parent);
temp = *root;
}
} else {
w = temp->parent->left;
if (ngx_rbt_is_red(w)) {
ngx_rbt_black(w);
ngx_rbt_red(temp->parent);
ngx_rbtree_right_rotate(root, sentinel, temp->parent);
w = temp->parent->left;
}
if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {
ngx_rbt_red(w);
temp = temp->parent;
} else {
if (ngx_rbt_is_black(w->left)) {
ngx_rbt_black(w->right);
ngx_rbt_red(w);
ngx_rbtree_left_rotate(root, sentinel, w);
w = temp->parent->left;
}
ngx_rbt_copy_color(w, temp->parent);
ngx_rbt_black(temp->parent);
ngx_rbt_black(w->left);
ngx_rbtree_right_rotate(root, sentinel, temp->parent);
temp = *root;
}
}
}
ngx_rbt_black(temp);
}
void
ngx_rbtree_insert(ngx_thread_volatile ngx_rbtree_t *tree,
ngx_rbtree_node_t *node) /*插入一个节点*/
{
ngx_rbtree_node_t **root, *temp, *sentinel;
/* a binary tree insert */
root = (ngx_rbtree_node_t **) &tree->root; /*为什么要转换成 ngx_rbtree_node_t **类型,??todo*/
sentinel = tree->sentinel;
if (*root == sentinel) { /**/
node->parent = NULL;
node->left = sentinel;
node->right = sentinel;
ngx_rbt_black(node);
*root = node;
return;
}
tree->insert(*root, node, sentinel); /*??todo*/
/* re-balance tree */
while (node != *root && ngx_rbt_is_red(node->parent)) {
if (node->parent == node->parent->parent->left) { /*node的父亲节点为左节点*/
temp = node->parent->parent->right; /*叔节点*/
if (ngx_rbt_is_red(temp)) {/*叔节点为红色*/
ngx_rbt_black(node->parent);
ngx_rbt_black(temp);
ngx_rbt_red(node->parent->parent);
node = node->parent->parent;
} else { /*叔节点为黑色*/
if (node == node->parent->right) { /*node为右孩子*/
node = node->parent;
ngx_rbtree_left_rotate(root, sentinel, node);
}
/*node为左孩子*/
ngx_rbt_black(node->parent);
ngx_rbt_red(node->parent->parent);
ngx_rbtree_right_rotate(root, sentinel, node->parent->parent);
}
} else { /*node的父亲节点为右节点*/
temp = node->parent->parent->left;
if (ngx_rbt_is_red(temp)) {
ngx_rbt_black(node->parent);
ngx_rbt_black(temp);
ngx_rbt_red(node->parent->parent);
node = node->parent->parent;
} else {
if (node == node->parent->left) {
node = node->parent;
ngx_rbtree_right_rotate(root, sentinel, node);
}
ngx_rbt_black(node->parent);
ngx_rbt_red(node->parent->parent);
ngx_rbtree_left_rotate(root, sentinel, node->parent->parent);
}
}
}
ngx_rbt_black(*root);
}
void
ngx_rbtree_delete(ngx_thread_volatile ngx_rbtree_t *tree,
ngx_rbtree_node_t *node)
{
ngx_uint_t red;
ngx_rbtree_node_t **root, *sentinel, *subst, *temp, *w;
/* a binary tree delete */
root = (ngx_rbtree_node_t **) &tree->root; /*why ??todo*/
sentinel = tree->sentinel;
if (node->left == sentinel) { /* 左节点为nil */
temp = node->right;
subst = node;
} else if (node->right == sentinel) { /* 右节点为nil */
temp = node->left;
subst = node;
} else { /*左/右节点都有孩子*/
subst = ngx_rbtree_min(node->right, sentinel);
if (subst->left != sentinel) {
temp = subst->left;
} else {
temp = subst->right;
}
}
if (subst == *root) {
*root = temp;
ngx_rbt_black(temp);
/* DEBUG stuff */
node->left = NULL;
node->right = NULL;
node->parent = NULL;
node->key = 0;
return;
}
red = ngx_rbt_is_red(subst);
if (subst == subst->parent->left) { /**/
subst->parent->left = temp;
} else {
subst->parent->right = temp;
}
if (subst == node) {
temp->parent = subst->parent;
} else { /*subst为node后继*/
if (subst->parent == node) {
temp->parent = subst; /**/
} else {
temp->parent = subst->parent;
}
subst->left = node->left;
subst->right = node->right;
subst->parent = node->parent;
ngx_rbt_copy_color(subst, node);
if (node == *root) {
*root = subst;
} else {
if (node == node->parent->left) {
node->parent->left = subst;
} else {
node->parent->right = subst;
}
}
if (subst->left != sentinel) {
subst->left->parent = subst;
}
if (subst->right != sentinel) {
subst->right->parent = subst;
}
}
/* DEBUG stuff */
node->left = NULL;
node->right = NULL;
node->parent = NULL;
node->key = 0;
if (red) {
return;
}
/* a delete fixup */
while (temp != *root && ngx_rbt_is_black(temp)) {
if (temp == temp->parent->left) {
w = temp->parent->right;
if (ngx_rbt_is_red(w)) {
ngx_rbt_black(w);
ngx_rbt_red(temp->parent);
ngx_rbtree_left_rotate(root, sentinel, temp->parent);
w = temp->parent->right;
}
if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {
ngx_rbt_red(w);
temp = temp->parent;
} else {
if (ngx_rbt_is_black(w->right)) {
ngx_rbt_black(w->left);
ngx_rbt_red(w);
ngx_rbtree_right_rotate(root, sentinel, w);
w = temp->parent->right;
}
ngx_rbt_copy_color(w, temp->parent);
ngx_rbt_black(temp->parent);
ngx_rbt_black(w->right);
ngx_rbtree_left_rotate(root, sentinel, temp->parent);
temp = *root;
}
} else {
w = temp->parent->left;
if (ngx_rbt_is_red(w)) {
ngx_rbt_black(w);
ngx_rbt_red(temp->parent);
ngx_rbtree_right_rotate(root, sentinel, temp->parent);
w = temp->parent->left;
}
if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {
ngx_rbt_red(w);
temp = temp->parent;
} else {
if (ngx_rbt_is_black(w->left)) {
ngx_rbt_black(w->right);
ngx_rbt_red(w);
ngx_rbtree_left_rotate(root, sentinel, w);
w = temp->parent->left;
}
ngx_rbt_copy_color(w, temp->parent);
ngx_rbt_black(temp->parent);
ngx_rbt_black(w->left);
ngx_rbtree_right_rotate(root, sentinel, temp->parent);
temp = *root;
}
}
}
ngx_rbt_black(temp);
}