boost/multi_index/detail/ord_index_node.hpp
/* Copyright 2003-2004 Joaqu�n M L�pez Mu�oz.
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* See http://www.boost.org/libs/multi_index for library home page.
*
* The internal implementation of red-black trees is based on that of SGI STL
* stl_tree.h file:
*
* Copyright (c) 1996,1997
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*/
#ifndef BOOST_MULTI_INDEX_DETAIL_ORD_INDEX_NODE_HPP
#define BOOST_MULTI_INDEX_DETAIL_ORD_INDEX_NODE_HPP
#include <algorithm>
#include <cstddef>
namespace boost{
namespace multi_index{
namespace detail{
/* definition of red-black nodes for ordered_index */
enum ordered_index_color{red=false,black=true};
struct ordered_index_node_impl
{
ordered_index_color& color(){return color_;}
const ordered_index_color& color()const{return color_;}
ordered_index_node_impl*& parent(){return parent_;}
ordered_index_node_impl*const & parent()const{return parent_;}
ordered_index_node_impl*& left(){return left_;}
ordered_index_node_impl*const & left()const{return left_;}
ordered_index_node_impl*& right(){return right_;}
ordered_index_node_impl*const & right()const{return right_;}
/* interoperability with index_iterator */
static void increment(ordered_index_node_impl*& x)
{
if(x->right()){
x=x->right();
while(x->left())x=x->left();
}
else{
ordered_index_node_impl* y=x->parent();
while(x==y->right()){
x=y;
y=y->parent();
}
if(x->right()!=y)x=y;
}
}
static void decrement(ordered_index_node_impl*& x)
{
if(x->color()==red&&x->parent()->parent()==x){
x=x->right();
}
else if(x->left()){
ordered_index_node_impl* y=x->left();
while(y->right())y=y->right();
x=y;
}else{
ordered_index_node_impl* y=x->parent();
while(x==y->left()){
x=y;
y=y->parent();
}
x=y;
}
}
/* interoperability with index_proxy */
static ordered_index_node_impl* begin(ordered_index_node_impl* header)
{
return header->left();
}
static ordered_index_node_impl* end(ordered_index_node_impl* header)
{
return header;
}
/* algorithmic stuff */
static void rotate_left(
ordered_index_node_impl* x,ordered_index_node_impl*& root)
{
ordered_index_node_impl* y=x->right();
x->right()=y->left();
if(y->left())y->left()->parent()=x;
y->parent()=x->parent();
if(x==root) root=y;
else if(x==x->parent()->left())x->parent()->left()=y;
else x->parent()->right()=y;
y->left()=x;
x->parent()=y;
}
static ordered_index_node_impl* minimum(ordered_index_node_impl* x)
{
while(x->left())x=x->left();
return x;
}
static ordered_index_node_impl* maximum(ordered_index_node_impl* x)
{
while(x->right())x=x->right();
return x;
}
static void rotate_right(
ordered_index_node_impl* x,ordered_index_node_impl*& root)
{
ordered_index_node_impl* y=x->left();
x->left()=y->right();
if(y->right())y->right()->parent()=x;
y->parent()=x->parent();
if(x==root) root=y;
else if(x==x->parent()->right())x->parent()->right()=y;
else x->parent()->left()=y;
y->right()=x;
x->parent()=y;
}
static void rebalance(
ordered_index_node_impl* x,ordered_index_node_impl*& root)
{
x->color()=red;
while(x!=root&&x->parent()->color()==red){
if(x->parent()==x->parent()->parent()->left()){
ordered_index_node_impl* y=x->parent()->parent()->right();
if(y&&y->color()==red){
x->parent()->color()=black;
y->color()=black;
x->parent()->parent()->color()=red;
x=x->parent()->parent();
}
else{
if(x==x->parent()->right()){
x=x->parent();
rotate_left(x,root);
}
x->parent()->color()=black;
x->parent()->parent()->color()=red;
rotate_right(x->parent()->parent(),root);
}
}
else{
ordered_index_node_impl* y=x->parent()->parent()->left();
if(y&&y->color()==red){
x->parent()->color()=black;
y->color()=black;
x->parent()->parent()->color()=red;
x=x->parent()->parent();
}
else{
if(x==x->parent()->left()){
x=x->parent();
rotate_right(x,root);
}
x->parent()->color()=black;
x->parent()->parent()->color()=red;
rotate_left(x->parent()->parent(),root);
}
}
}
root->color()=black;
}
static ordered_index_node_impl* rebalance_for_erase(
ordered_index_node_impl* z,ordered_index_node_impl*& root,
ordered_index_node_impl*& leftmost,ordered_index_node_impl*& rightmost)
{
ordered_index_node_impl* y=z;
ordered_index_node_impl* x=0;
ordered_index_node_impl* x_parent=0;
if(y->left()==0){ /* z has at most one non-null child. y==z. */
x=y->right(); /* x might be null */
}
else{
if(y->right()==0) { /* z has exactly one non-null child. y==z. */
x=y->left(); /* x is not null */
}
else{ /* z has two non-null children. Set y to */
y=y->right(); /* z's successor. x might be null. */
while(y->left())y=y->left();
x=y->right();
}
}
if(y!=z){
z->left()->parent()=y; /* relink y in place of z. y is z's successor */
y->left()=z->left();
if(y!=z->right()){
x_parent=y->parent();
if(x) x->parent()=y->parent();
y->parent()->left()=x; /* y must be a child of left */
y->right()=z->right();
z->right()->parent()=y;
}
else{
x_parent=y;
}
if(root==z) root=y;
else if(z->parent()->left()==z)z->parent()->left()=y;
else z->parent()->right()=y;
y->parent()=z->parent();
std::swap(y->color(),z->color());
y=z; /* y now points to node to be actually deleted */
}
else{ /* y==z */
x_parent=y->parent();
if(x)x->parent()=y->parent();
if(root==z){
root=x;
}
else{
if(z->parent()->left()==z)z->parent()->left()=x;
else z->parent()->right()=x;
}
if(leftmost==z){
if(z->right()==0){ /* z->left() must be null also */
leftmost=z->parent();
}
else{
leftmost=minimum(x); /* makes leftmost==header if z==root */
}
}
if(rightmost==z){
if(z->left()==0){ /* z->right() must be null also */
rightmost=z->parent();
}
else{ /* x==z->left() */
rightmost=maximum(x); /* makes rightmost==header if z==root */
}
}
}
if(y->color()!=red){
while(x!=root&&(x==0 || x->color()==black)){
if(x==x_parent->left()){
ordered_index_node_impl* w=x_parent->right();
if(w->color()==red){
w->color()=black;
x_parent->color()=red;
rotate_left(x_parent,root);
w=x_parent->right();
}
if((w->left()==0||w->left()->color()==black) &&
(w->right()==0||w->right()->color()==black)){
w->color()=red;
x=x_parent;
x_parent=x_parent->parent();
}
else{
if(w->right()==0
|| w->right()->color()==black){
if(w->left()) w->left()->color()=black;
w->color()=red;
rotate_right(w,root);
w=x_parent->right();
}
w->color()=x_parent->color();
x_parent->color()=black;
if(w->right())w->right()->color()=black;
rotate_left(x_parent,root);
break;
}
}
else{ /* same as above,with right <-> left */
ordered_index_node_impl* w=x_parent->left();
if(w->color()==red){
w->color()=black;
x_parent->color()=red;
rotate_right(x_parent,root);
w=x_parent->left();
}
if((w->right()==0||w->right()->color()==black) &&
(w->left()==0||w->left()->color()==black)){
w->color()=red;
x=x_parent;
x_parent=x_parent->parent();
}
else{
if(w->left()==0||w->left()->color()==black){
if(w->right())w->right()->color()=black;
w->color()=red;
rotate_left(w,root);
w=x_parent->left();
}
w->color()=x_parent->color();
x_parent->color()=black;
if(w->left())w->left()->color()=black;
rotate_right(x_parent,root);
break;
}
}
}
if(x)x->color()=black;
}
return y;
}
static void restore(
ordered_index_node_impl* x,ordered_index_node_impl* prior,
ordered_index_node_impl* next,ordered_index_node_impl* header)
{
if(next->left()==0){
next->left()=x;
x->parent()=next;
if(next==header->left()){
header->left()=x; /* maintain leftmost pointing to min node */
}
}
else if(x!=prior){ /* prior->right() must be null */
prior->right()=x;
x->parent()=prior;
if(prior==header->right()){
header->right()=x; /* maintain rightmost pointing to max node */
}
}
else{
header->parent()=x;
header->left()=x;
header->right()=x;
x->parent()=header;
}
x->left()=0;
x->right()=0;
rebalance(x,header->parent());
}
#if defined(BOOST_MULTI_INDEX_ENABLE_INVARIANT_CHECKING)
/* invariant stuff */
static std::size_t black_count(
ordered_index_node_impl* node,ordered_index_node_impl* root)
{
if(!node)return 0;
std::size_t sum=0;
for(;;){
if(node->color()==black)++sum;
if(node==root)break;
node=node->parent();
}
return sum;
}
#endif
private:
ordered_index_node_impl();
ordered_index_color color_;
ordered_index_node_impl* parent_;
ordered_index_node_impl* left_;
ordered_index_node_impl* right_;
};
template<typename Super>
struct ordered_index_node_trampoline:ordered_index_node_impl{};
template<typename Super>
struct ordered_index_node:Super,ordered_index_node_trampoline<Super>
{
ordered_index_color& color(){return impl_type::color();}
const ordered_index_color& color()const{return impl_type::color();}
ordered_index_node_impl*& parent(){return impl_type::parent();}
ordered_index_node_impl*const & parent()const{return impl_type::parent();}
ordered_index_node_impl*& left(){return impl_type::left();}
ordered_index_node_impl*const & left()const{return impl_type::left();}
ordered_index_node_impl*& right(){return impl_type::right();}
ordered_index_node_impl*const & right()const{return impl_type::right();}
ordered_index_node_impl* impl(){return static_cast<impl_type*>(this);}
const ordered_index_node_impl* impl()const
{return static_cast<const impl_type*>(this);}
static ordered_index_node* from_impl(ordered_index_node_impl *x)
{
return static_cast<ordered_index_node*>(static_cast<impl_type*>(x));
}
static const ordered_index_node* from_impl(const ordered_index_node_impl* x)
{
return static_cast<const ordered_index_node*>(
static_cast<const impl_type*>(x));
}
/* interoperability with index_iterator */
static void increment(ordered_index_node*& x)
{
ordered_index_node_impl* xi=x->impl();
impl_type::increment(xi);
x=from_impl(xi);
}
static void decrement(ordered_index_node*& x)
{
ordered_index_node_impl* xi=x->impl();
impl_type::decrement(xi);
x=from_impl(xi);
}
/* interoperability with index_proxy */
static ordered_index_node* begin(ordered_index_node* header)
{
return from_impl(impl_type::begin(header->impl()));
}
static ordered_index_node* end(ordered_index_node* header)
{
return from_impl(impl_type::end(header->impl()));
}
private:
typedef ordered_index_node_trampoline<Super> impl_type;
};
} /* namespace multi_index::detail */
} /* namespace multi_index */
} /* namespace boost */
#endif