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/*****************************************************************************
Copyright (c) 2006, 2009, Innobase Oy. All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*****************************************************************************/
/*******************************************************************//**
@file ut/ut0rbt.c
Red-Black tree implementation
Created 2007-03-20 Sunny Bains
***********************************************************************/
#include "ut0rbt.h"
/************************************************************************
Definition of a red-black tree
==============================
A red-black tree is a binary search tree which has the following
red-black properties:
1. Every node is either red or black.
2. Every leaf (NULL - in our case tree->nil) is black.
3. If a node is red, then both its children are black.
4. Every simple path from a node to a descendant leaf contains the
same number of black nodes.
from (3) above, the implication is that on any path from the root
to a leaf, red nodes must not be adjacent.
However, any number of black nodes may appear in a sequence. */
#if defined(IB_RBT_TESTING)
#warning "Testing enabled!"
#endif
#define ROOT(t) (t->root->left)
#define SIZEOF_NODE(t) ((sizeof(ib_rbt_node_t) + t->sizeof_value) - 1)
/****************************************************************//**
Print out the sub-tree recursively. */
static
void
rbt_print_subtree(
/*==============*/
const ib_rbt_t* tree, /*!< in: tree to traverse */
const ib_rbt_node_t* node, /*!< in: node to print */
ib_rbt_print_node print) /*!< in: print key function */
{
/* FIXME: Doesn't do anything yet */
if (node != tree->nil) {
print(node);
rbt_print_subtree(tree, node->left, print);
rbt_print_subtree(tree, node->right, print);
}
}
/****************************************************************//**
Verify that the keys are in order.
@return TRUE of OK. FALSE if not ordered */
static
ibool
rbt_check_ordering(
/*===============*/
const ib_rbt_t* tree) /*!< in: tree to verfify */
{
const ib_rbt_node_t* node;
const ib_rbt_node_t* prev = NULL;
/* Iterate over all the nodes, comparing each node with the prev */
for (node = rbt_first(tree); node; node = rbt_next(tree, prev)) {
if (prev && tree->compare(prev->value, node->value) >= 0) {
return(FALSE);
}
prev = node;
}
return(TRUE);
}
/****************************************************************//**
Check that every path from the root to the leaves has the same count.
Count is expressed in the number of black nodes.
@return 0 on failure else black height of the subtree */
static
ibool
rbt_count_black_nodes(
/*==================*/
const ib_rbt_t* tree, /*!< in: tree to verify */
const ib_rbt_node_t* node) /*!< in: start of sub-tree */
{
ulint result;
if (node != tree->nil) {
ulint left_height = rbt_count_black_nodes(tree, node->left);
ulint right_height = rbt_count_black_nodes(tree, node->right);
if (left_height == 0
|| right_height == 0
|| left_height != right_height) {
result = 0;
} else if (node->color == IB_RBT_RED) {
/* Case 3 */
if (node->left->color != IB_RBT_BLACK
|| node->right->color != IB_RBT_BLACK) {
result = 0;
} else {
result = left_height;
}
/* Check if it's anything other than RED or BLACK. */
} else if (node->color != IB_RBT_BLACK) {
result = 0;
} else {
result = right_height + 1;
}
} else {
result = 1;
}
return(result);
}
/****************************************************************//**
Turn the node's right child's left sub-tree into node's right sub-tree.
This will also make node's right child it's parent. */
static
void
rbt_rotate_left(
/*============*/
const ib_rbt_node_t* nil, /*!< in: nil node of the tree */
ib_rbt_node_t* node) /*!< in: node to rotate */
{
ib_rbt_node_t* right = node->right;
node->right = right->left;
if (right->left != nil) {
right->left->parent = node;
}
/* Right's new parent was node's parent. */
right->parent = node->parent;
/* Since root's parent is tree->nil and root->parent->left points
back to root, we can avoid the check. */
if (node == node->parent->left) {
/* Node was on the left of its parent. */
node->parent->left = right;
} else {
/* Node must have been on the right. */
node->parent->right = right;
}
/* Finally, put node on right's left. */
right->left = node;
node->parent = right;
}
/****************************************************************//**
Turn the node's left child's right sub-tree into node's left sub-tree.
This also make node's left child it's parent. */
static
void
rbt_rotate_right(
/*=============*/
const ib_rbt_node_t* nil, /*!< in: nil node of tree */
ib_rbt_node_t* node) /*!< in: node to rotate */
{
ib_rbt_node_t* left = node->left;
node->left = left->right;
if (left->right != nil) {
left->right->parent = node;
}
/* Left's new parent was node's parent. */
left->parent = node->parent;
/* Since root's parent is tree->nil and root->parent->left points
back to root, we can avoid the check. */
if (node == node->parent->right) {
/* Node was on the left of its parent. */
node->parent->right = left;
} else {
/* Node must have been on the left. */
node->parent->left = left;
}
/* Finally, put node on left's right. */
left->right = node;
node->parent = left;
}
/****************************************************************//**
Append a node to the tree.
@return inserted node */
static
ib_rbt_node_t*
rbt_tree_add_child(
/*===============*/
const ib_rbt_t* tree, /*!< in: rbt tree */
ib_rbt_bound_t* parent, /*!< in: node's parent */
ib_rbt_node_t* node) /*!< in: node to add */
{
/* Cast away the const. */
ib_rbt_node_t* last = (ib_rbt_node_t*) parent->last;
if (last == tree->root || parent->result < 0) {
last->left = node;
} else {
/* FIXME: We don't handle duplicates (yet)! */
ut_a(parent->result != 0);
last->right = node;
}
node->parent = last;
return(node);
}
/****************************************************************//**
Generic binary tree insert
@return inserted node */
static
ib_rbt_node_t*
rbt_tree_insert(
/*============*/
ib_rbt_t* tree, /*!< in: rb tree */
const void* key, /*!< in: key for ordering */
ib_rbt_node_t* node) /*!< in: node hold the insert value */
{
ib_rbt_bound_t parent;
ib_rbt_node_t* current = ROOT(tree);
parent.result = 0;
parent.last = tree->root;
/* Regular binary search. */
while (current != tree->nil) {
parent.last = current;
parent.result = tree->compare(key, current->value);
if (parent.result < 0) {
current = current->left;
} else {
current = current->right;
}
}
ut_a(current == tree->nil);
rbt_tree_add_child(tree, &parent, node);
return(node);
}
/****************************************************************//**
Balance a tree after inserting a node. */
static
void
rbt_balance_tree(
/*=============*/
const ib_rbt_t* tree, /*!< in: tree to balance */
ib_rbt_node_t* node) /*!< in: node that was inserted */
{
const ib_rbt_node_t* nil = tree->nil;
ib_rbt_node_t* parent = node->parent;
/* Restore the red-black property. */
node->color = IB_RBT_RED;
while (node != ROOT(tree) && parent->color == IB_RBT_RED) {
ib_rbt_node_t* grand_parent = parent->parent;
if (parent == grand_parent->left) {
ib_rbt_node_t* uncle = grand_parent->right;
if (uncle->color == IB_RBT_RED) {
/* Case 1 - change the colors. */
uncle->color = IB_RBT_BLACK;
parent->color = IB_RBT_BLACK;
grand_parent->color = IB_RBT_RED;
/* Move node up the tree. */
node = grand_parent;
} else {
if (node == parent->right) {
/* Right is a black node and node is
to the right, case 2 - move node
up and rotate. */
node = parent;
rbt_rotate_left(nil, node);
}
grand_parent = node->parent->parent;
/* Case 3. */
node->parent->color = IB_RBT_BLACK;
grand_parent->color = IB_RBT_RED;
rbt_rotate_right(nil, grand_parent);
}
} else {
ib_rbt_node_t* uncle = grand_parent->left;
if (uncle->color == IB_RBT_RED) {
/* Case 1 - change the colors. */
uncle->color = IB_RBT_BLACK;
parent->color = IB_RBT_BLACK;
grand_parent->color = IB_RBT_RED;
/* Move node up the tree. */
node = grand_parent;
} else {
if (node == parent->left) {
/* Left is a black node and node is to
the right, case 2 - move node up and
rotate. */
node = parent;
rbt_rotate_right(nil, node);
}
grand_parent = node->parent->parent;
/* Case 3. */
node->parent->color = IB_RBT_BLACK;
grand_parent->color = IB_RBT_RED;
rbt_rotate_left(nil, grand_parent);
}
}
parent = node->parent;
}
/* Color the root black. */
ROOT(tree)->color = IB_RBT_BLACK;
}
/****************************************************************//**
Find the given node's successor.
@return successor node or NULL if no successor */
static
ib_rbt_node_t*
rbt_find_successor(
/*===============*/
const ib_rbt_t* tree, /*!< in: rb tree */
const ib_rbt_node_t* current)/*!< in: this is declared const
because it can be called via
rbt_next() */
{
const ib_rbt_node_t* nil = tree->nil;
ib_rbt_node_t* next = current->right;
/* Is there a sub-tree to the right that we can follow. */
if (next != nil) {
/* Follow the left most links of the current right child. */
while (next->left != nil) {
next = next->left;
}
} else { /* We will have to go up the tree to find the successor. */
ib_rbt_node_t* parent = current->parent;
/* Cast away the const. */
next = (ib_rbt_node_t*) current;
while (parent != tree->root && next == parent->right) {
next = parent;
parent = next->parent;
}
next = (parent == tree->root) ? NULL : parent;
}
return(next);
}
/****************************************************************//**
Find the given node's precedecessor.
@return predecessor node or NULL if no predecesor */
static
ib_rbt_node_t*
rbt_find_predecessor(
/*=================*/
const ib_rbt_t* tree, /*!< in: rb tree */
const ib_rbt_node_t* current) /*!< in: this is declared const
because it can be called via
rbt_prev() */
{
const ib_rbt_node_t* nil = tree->nil;
ib_rbt_node_t* prev = current->left;
/* Is there a sub-tree to the left that we can follow. */
if (prev != nil) {
/* Follow the right most links of the current left child. */
while (prev->right != nil) {
prev = prev->right;
}
} else { /* We will have to go up the tree to find the precedecessor. */
ib_rbt_node_t* parent = current->parent;
/* Cast away the const. */
prev = (ib_rbt_node_t*)current;
while (parent != tree->root && prev == parent->left) {
prev = parent;
parent = prev->parent;
}
prev = (parent == tree->root) ? NULL : parent;
}
return(prev);
}
/****************************************************************//**
Replace node with child. After applying transformations eject becomes
an orphan. */
static
void
rbt_eject_node(
/*===========*/
ib_rbt_node_t* eject, /*!< in: node to eject */
ib_rbt_node_t* node) /*!< in: node to replace with */
{
/* Update the to be ejected node's parent's child pointers. */
if (eject->parent->left == eject) {
eject->parent->left = node;
} else if (eject->parent->right == eject) {
eject->parent->right = node;
} else {
ut_a(0);
}
/* eject is now an orphan but otherwise its pointers
and color are left intact. */
node->parent = eject->parent;
}
/****************************************************************//**
Replace a node with another node. */
static
void
rbt_replace_node(
/*=============*/
ib_rbt_node_t* replace, /*!< in: node to replace */
ib_rbt_node_t* node) /*!< in: node to replace with */
{
ib_rbt_color_t color = node->color;
/* Update the node pointers. */
node->left = replace->left;
node->right = replace->right;
/* Update the child node pointers. */
node->left->parent = node;
node->right->parent = node;
/* Make the parent of replace point to node. */
rbt_eject_node(replace, node);
/* Swap the colors. */
node->color = replace->color;
replace->color = color;
}
/****************************************************************//**
Detach node from the tree replacing it with one of it's children.
@return the child node that now occupies the position of the detached node */
static
ib_rbt_node_t*
rbt_detach_node(
/*============*/
const ib_rbt_t* tree, /*!< in: rb tree */
ib_rbt_node_t* node) /*!< in: node to detach */
{
ib_rbt_node_t* child;
const ib_rbt_node_t* nil = tree->nil;
if (node->left != nil && node->right != nil) {
/* Case where the node to be deleted has two children. */
ib_rbt_node_t* successor = rbt_find_successor(tree, node);
ut_a(successor != nil);
ut_a(successor->parent != nil);
ut_a(successor->left == nil);
child = successor->right;
/* Remove the successor node and replace with its child. */
rbt_eject_node(successor, child);
/* Replace the node to delete with its successor node. */
rbt_replace_node(node, successor);
} else {
ut_a(node->left == nil || node->right == nil);
child = (node->left != nil) ? node->left : node->right;
/* Replace the node to delete with one of it's children. */
rbt_eject_node(node, child);
}
/* Reset the node links. */
node->parent = node->right = node->left = tree->nil;
return(child);
}
/****************************************************************//**
Rebalance the right sub-tree after deletion.
@return node to rebalance if more rebalancing required else NULL */
static
ib_rbt_node_t*
rbt_balance_right(
/*==============*/
const ib_rbt_node_t* nil, /*!< in: rb tree nil node */
ib_rbt_node_t* parent, /*!< in: parent node */
ib_rbt_node_t* sibling)/*!< in: sibling node */
{
ib_rbt_node_t* node = NULL;
ut_a(sibling != nil);
/* Case 3. */
if (sibling->color == IB_RBT_RED) {
parent->color = IB_RBT_RED;
sibling->color = IB_RBT_BLACK;
rbt_rotate_left(nil, parent);
sibling = parent->right;
ut_a(sibling != nil);
}
/* Since this will violate case 3 because of the change above. */
if (sibling->left->color == IB_RBT_BLACK
&& sibling->right->color == IB_RBT_BLACK) {
node = parent; /* Parent needs to be rebalanced too. */
sibling->color = IB_RBT_RED;
} else {
if (sibling->right->color == IB_RBT_BLACK) {
ut_a(sibling->left->color == IB_RBT_RED);
sibling->color = IB_RBT_RED;
sibling->left->color = IB_RBT_BLACK;
rbt_rotate_right(nil, sibling);
sibling = parent->right;
ut_a(sibling != nil);
}
sibling->color = parent->color;
sibling->right->color = IB_RBT_BLACK;
parent->color = IB_RBT_BLACK;
rbt_rotate_left(nil, parent);
}
return(node);
}
/****************************************************************//**
Rebalance the left sub-tree after deletion.
@return node to rebalance if more rebalancing required else NULL */
static
ib_rbt_node_t*
rbt_balance_left(
/*=============*/
const ib_rbt_node_t* nil, /*!< in: rb tree nil node */
ib_rbt_node_t* parent, /*!< in: parent node */
ib_rbt_node_t* sibling)/*!< in: sibling node */
{
ib_rbt_node_t* node = NULL;
ut_a(sibling != nil);
/* Case 3. */
if (sibling->color == IB_RBT_RED) {
parent->color = IB_RBT_RED;
sibling->color = IB_RBT_BLACK;
rbt_rotate_right(nil, parent);
sibling = parent->left;
ut_a(sibling != nil);
}
/* Since this will violate case 3 because of the change above. */
if (sibling->right->color == IB_RBT_BLACK
&& sibling->left->color == IB_RBT_BLACK) {
node = parent; /* Parent needs to be rebalanced too. */
sibling->color = IB_RBT_RED;
} else {
if (sibling->left->color == IB_RBT_BLACK) {
ut_a(sibling->right->color == IB_RBT_RED);
sibling->color = IB_RBT_RED;
sibling->right->color = IB_RBT_BLACK;
rbt_rotate_left(nil, sibling);
sibling = parent->left;
ut_a(sibling != nil);
}
sibling->color = parent->color;
sibling->left->color = IB_RBT_BLACK;
parent->color = IB_RBT_BLACK;
rbt_rotate_right(nil, parent);
}
return(node);
}
/****************************************************************//**
Delete the node and rebalance the tree if necessary */
static
void
rbt_remove_node_and_rebalance(
/*==========================*/
ib_rbt_t* tree, /*!< in: rb tree */
ib_rbt_node_t* node) /*!< in: node to remove */
{
/* Detach node and get the node that will be used
as rebalance start. */
ib_rbt_node_t* child = rbt_detach_node(tree, node);
if (node->color == IB_RBT_BLACK) {
ib_rbt_node_t* last = child;
ROOT(tree)->color = IB_RBT_RED;
while (child && child->color == IB_RBT_BLACK) {
ib_rbt_node_t* parent = child->parent;
/* Did the deletion cause an imbalance in the
parents left sub-tree. */
if (parent->left == child) {
child = rbt_balance_right(
tree->nil, parent, parent->right);
} else if (parent->right == child) {
child = rbt_balance_left(
tree->nil, parent, parent->left);
} else {
ut_error;
}
if (child) {
last = child;
}
}
ut_a(last);
last->color = IB_RBT_BLACK;
ROOT(tree)->color = IB_RBT_BLACK;
}
/* Note that we have removed a node from the tree. */
--tree->n_nodes;
}
/****************************************************************//**
Recursively free the nodes. */
static
void
rbt_free_node(
/*==========*/
ib_rbt_node_t* node, /*!< in: node to free */
ib_rbt_node_t* nil) /*!< in: rb tree nil node */
{
if (node != nil) {
rbt_free_node(node->left, nil);
rbt_free_node(node->right, nil);
ut_free(node);
}
}
/****************************************************************//**
Free all the nodes and free the tree. */
UNIV_INTERN
void
rbt_free(
/*=====*/
ib_rbt_t* tree) /*!< in: rb tree to free */
{
rbt_free_node(tree->root, tree->nil);
ut_free(tree->nil);
ut_free(tree);
}
/****************************************************************//**
Create an instance of a red black tree.
@return an empty rb tree */
UNIV_INTERN
ib_rbt_t*
rbt_create(
/*=======*/
size_t sizeof_value, /*!< in: sizeof data item */
ib_rbt_compare compare) /*!< in: fn to compare items */
{
ib_rbt_t* tree;
ib_rbt_node_t* node;
tree = (ib_rbt_t*) ut_malloc(sizeof(*tree));
memset(tree, 0, sizeof(*tree));
tree->sizeof_value = sizeof_value;
/* Create the sentinel (NIL) node. */
node = tree->nil = (ib_rbt_node_t*) ut_malloc(sizeof(*node));
memset(node, 0, sizeof(*node));
node->color = IB_RBT_BLACK;
node->parent = node->left = node->right = node;
/* Create the "fake" root, the real root node will be the
left child of this node. */
node = tree->root = (ib_rbt_node_t*) ut_malloc(sizeof(*node));
memset(node, 0, sizeof(*node));
node->color = IB_RBT_BLACK;
node->parent = node->left = node->right = tree->nil;
tree->compare = compare;
return(tree);
}
/****************************************************************//**
Generic insert of a value in the rb tree.
@return inserted node */
UNIV_INTERN
const ib_rbt_node_t*
rbt_insert(
/*=======*/
ib_rbt_t* tree, /*!< in: rb tree */
const void* key, /*!< in: key for ordering */
const void* value) /*!< in: value of key, this value
is copied to the node */
{
ib_rbt_node_t* node;
/* Create the node that will hold the value data. */
node = (ib_rbt_node_t*) ut_malloc(SIZEOF_NODE(tree));
memcpy(node->value, value, tree->sizeof_value);
node->parent = node->left = node->right = tree->nil;
/* Insert in the tree in the usual way. */
rbt_tree_insert(tree, key, node);
rbt_balance_tree(tree, node);
++tree->n_nodes;
return(node);
}
/****************************************************************//**
Add a new node to the tree, useful for data that is pre-sorted.
@return appended node */
UNIV_INTERN
const ib_rbt_node_t*
rbt_add_node(
/*=========*/
ib_rbt_t* tree, /*!< in: rb tree */
ib_rbt_bound_t* parent, /*!< in: bounds */
const void* value) /*!< in: this value is copied
to the node */
{
ib_rbt_node_t* node;
/* Create the node that will hold the value data */
node = (ib_rbt_node_t*) ut_malloc(SIZEOF_NODE(tree));
memcpy(node->value, value, tree->sizeof_value);
node->parent = node->left = node->right = tree->nil;
/* If tree is empty */
if (parent->last == NULL) {
parent->last = tree->root;
}
/* Append the node, the hope here is that the caller knows
what s/he is doing. */
rbt_tree_add_child(tree, parent, node);
rbt_balance_tree(tree, node);
++tree->n_nodes;
#if defined(IB_RBT_TESTING)
ut_a(rbt_validate(tree));
#endif
return(node);
}
/****************************************************************//**
Find a matching node in the rb tree.
@return NULL if not found else the node where key was found */
UNIV_INTERN
const ib_rbt_node_t*
rbt_lookup(
/*=======*/
const ib_rbt_t* tree, /*!< in: rb tree */
const void* key) /*!< in: key to use for search */
{
const ib_rbt_node_t* current = ROOT(tree);
/* Regular binary search. */
while (current != tree->nil) {
int result = tree->compare(key, current->value);
if (result < 0) {
current = current->left;
} else if (result > 0) {
current = current->right;
} else {
break;
}
}
return(current != tree->nil ? current : NULL);
}
/****************************************************************//**
Delete a node from the red black tree, identified by key.
@return TRUE if success FALSE if not found */
UNIV_INTERN
ibool
rbt_delete(
/*=======*/
ib_rbt_t* tree, /*!< in: rb tree */
const void* key) /*!< in: key to delete */
{
ibool deleted = FALSE;
ib_rbt_node_t* node = (ib_rbt_node_t*) rbt_lookup(tree, key);
if (node) {
rbt_remove_node_and_rebalance(tree, node);
ut_free(node);
deleted = TRUE;
}
return(deleted);
}
/****************************************************************//**
Remove a node from the rb tree, the node is not free'd, that is the
callers responsibility.
@return deleted node but without the const */
UNIV_INTERN
ib_rbt_node_t*
rbt_remove_node(
/*============*/
ib_rbt_t* tree, /*!< in: rb tree */
const ib_rbt_node_t* const_node) /*!< in: node to delete, this
is a fudge and declared const
because the caller can access
only const nodes */
{
/* Cast away the const. */
rbt_remove_node_and_rebalance(tree, (ib_rbt_node_t*) const_node);
/* This is to make it easier to do something like this:
ut_free(rbt_remove_node(node));
*/
return((ib_rbt_node_t*) const_node);
}
/****************************************************************//**
Find the node that has the lowest key that is >= key.
@return node satisfying the lower bound constraint or NULL */
UNIV_INTERN
const ib_rbt_node_t*
rbt_lower_bound(
/*============*/
const ib_rbt_t* tree, /*!< in: rb tree */
const void* key) /*!< in: key to search */
{
ib_rbt_node_t* lb_node = NULL;
ib_rbt_node_t* current = ROOT(tree);
while (current != tree->nil) {
int result = tree->compare(key, current->value);
if (result > 0) {
current = current->right;
} else if (result < 0) {
lb_node = current;
current = current->left;
} else {
lb_node = current;
break;
}
}
return(lb_node);
}
/****************************************************************//**
Find the node that has the greatest key that is <= key.
@return node satisfying the upper bound constraint or NULL */
UNIV_INTERN
const ib_rbt_node_t*
rbt_upper_bound(
/*============*/
const ib_rbt_t* tree, /*!< in: rb tree */
const void* key) /*!< in: key to search */
{
ib_rbt_node_t* ub_node = NULL;
ib_rbt_node_t* current = ROOT(tree);
while (current != tree->nil) {
int result = tree->compare(key, current->value);
if (result > 0) {
ub_node = current;
current = current->right;
} else if (result < 0) {
current = current->left;
} else {
ub_node = current;
break;
}
}
return(ub_node);
}
/****************************************************************//**
Find the node that has the greatest key that is <= key.
@return value of result */
UNIV_INTERN
int
rbt_search(
/*=======*/
const ib_rbt_t* tree, /*!< in: rb tree */
ib_rbt_bound_t* parent, /*!< in: search bounds */
const void* key) /*!< in: key to search */
{
ib_rbt_node_t* current = ROOT(tree);
/* Every thing is greater than the NULL root. */
parent->result = 1;
parent->last = NULL;
while (current != tree->nil) {
parent->last = current;
parent->result = tree->compare(key, current->value);
if (parent->result > 0) {
current = current->right;
} else if (parent->result < 0) {
current = current->left;
} else {
break;
}
}
return(parent->result);
}
/****************************************************************//**
Find the node that has the greatest key that is <= key. But use the
supplied comparison function.
@return value of result */
UNIV_INTERN
int
rbt_search_cmp(
/*===========*/
const ib_rbt_t* tree, /*!< in: rb tree */
ib_rbt_bound_t* parent, /*!< in: search bounds */
const void* key, /*!< in: key to search */
ib_rbt_compare compare) /*!< in: fn to compare items */
{
ib_rbt_node_t* current = ROOT(tree);
/* Every thing is greater than the NULL root. */
parent->result = 1;
parent->last = NULL;
while (current != tree->nil) {
parent->last = current;
parent->result = compare(key, current->value);
if (parent->result > 0) {
current = current->right;
} else if (parent->result < 0) {
current = current->left;
} else {
break;
}
}
return(parent->result);
}
/****************************************************************//**
Get the leftmost node.
Return the left most node in the tree. */
UNIV_INTERN
const ib_rbt_node_t*
rbt_first(
/*======*/
const ib_rbt_t* tree) /* in: rb tree */
{
ib_rbt_node_t* first = NULL;
ib_rbt_node_t* current = ROOT(tree);
while (current != tree->nil) {
first = current;
current = current->left;
}
return(first);
}
/****************************************************************//**
Return the right most node in the tree.
@return the rightmost node or NULL */
UNIV_INTERN
const ib_rbt_node_t*
rbt_last(
/*=====*/
const ib_rbt_t* tree) /*!< in: rb tree */
{
ib_rbt_node_t* last = NULL;
ib_rbt_node_t* current = ROOT(tree);
while (current != tree->nil) {
last = current;
current = current->right;
}
return(last);
}
/****************************************************************//**
Return the next node.
@return node next from current */
UNIV_INTERN
const ib_rbt_node_t*
rbt_next(
/*=====*/
const ib_rbt_t* tree, /*!< in: rb tree */
const ib_rbt_node_t* current)/*!< in: current node */
{
return(current ? rbt_find_successor(tree, current) : NULL);
}
/****************************************************************//**
Return the previous node.
@return node prev from current */
UNIV_INTERN
const ib_rbt_node_t*
rbt_prev(
/*=====*/
const ib_rbt_t* tree, /*!< in: rb tree */
const ib_rbt_node_t* current)/*!< in: current node */
{
return(current ? rbt_find_predecessor(tree, current) : NULL);
}
/****************************************************************//**
Reset the tree. Delete all the nodes. */
UNIV_INTERN
void
rbt_clear(
/*======*/
ib_rbt_t* tree) /*!< in: rb tree */
{
rbt_free_node(ROOT(tree), tree->nil);
tree->n_nodes = 0;
tree->root->left = tree->root->right = tree->nil;
}
/****************************************************************//**
Merge the node from dst into src. Return the number of nodes merged.
@return no. of recs merged */
UNIV_INTERN
ulint
rbt_merge_uniq(
/*===========*/
ib_rbt_t* dst, /*!< in: dst rb tree */
const ib_rbt_t* src) /*!< in: src rb tree */
{
ib_rbt_bound_t parent;
ulint n_merged = 0;
const ib_rbt_node_t* src_node = rbt_first(src);
if (rbt_empty(src) || dst == src) {
return(0);
}
for (/* No op */; src_node; src_node = rbt_next(src, src_node)) {
if (rbt_search(dst, &parent, src_node->value) != 0) {
rbt_add_node(dst, &parent, src_node->value);
++n_merged;
}
}
return(n_merged);
}
/****************************************************************//**
Merge the node from dst into src. Return the number of nodes merged.
Delete the nodes from src after copying node to dst. As a side effect
the duplicates will be left untouched in the src.
@return no. of recs merged */
UNIV_INTERN
ulint
rbt_merge_uniq_destructive(
/*=======================*/
ib_rbt_t* dst, /*!< in: dst rb tree */
ib_rbt_t* src) /*!< in: src rb tree */
{
ib_rbt_bound_t parent;
ib_rbt_node_t* src_node;
ulint old_size = rbt_size(dst);
if (rbt_empty(src) || dst == src) {
return(0);
}
for (src_node = (ib_rbt_node_t*) rbt_first(src); src_node; /* */) {
ib_rbt_node_t* prev = src_node;
src_node = (ib_rbt_node_t*)rbt_next(src, prev);
/* Skip duplicates. */
if (rbt_search(dst, &parent, prev->value) != 0) {
/* Remove and reset the node but preserve
the node (data) value. */
rbt_remove_node_and_rebalance(src, prev);
/* The nil should be taken from the dst tree. */
prev->parent = prev->left = prev->right = dst->nil;
rbt_tree_add_child(dst, &parent, prev);
rbt_balance_tree(dst, prev);
++dst->n_nodes;
}
}
#if defined(IB_RBT_TESTING)
ut_a(rbt_validate(dst));
ut_a(rbt_validate(src));
#endif
return(rbt_size(dst) - old_size);
}
/****************************************************************//**
Check that every path from the root to the leaves has the same count and
the tree nodes are in order.
@return TRUE if OK FALSE otherwise */
UNIV_INTERN
ibool
rbt_validate(
/*=========*/
const ib_rbt_t* tree) /*!< in: RB tree to validate */
{
if (rbt_count_black_nodes(tree, ROOT(tree)) > 0) {
return(rbt_check_ordering(tree));
}
return(FALSE);
}
/****************************************************************//**
Iterate over the tree in depth first order. */
UNIV_INTERN
void
rbt_print(
/*======*/
const ib_rbt_t* tree, /*!< in: tree to traverse */
ib_rbt_print_node print) /*!< in: print function */
{
rbt_print_subtree(tree, ROOT(tree), print);
}
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