/usr/include/boost/multi_index/detail
Edit: /usr/include/boost/multi_index/detail/index_matcher.hpp (6134B)
/* Copyright 2003-2015 Joaquin M Lopez Munoz.
* 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.
*/
#ifndef BOOST_MULTI_INDEX_DETAIL_INDEX_MATCHER_HPP
#define BOOST_MULTI_INDEX_DETAIL_INDEX_MATCHER_HPP
#if defined(_MSC_VER)
#pragma once
#endif
#include
/* keep it first to prevent nasty warns in MSVC */
#include
#include
#include
#include
#include
#include
namespace boost{
namespace multi_index{
namespace detail{
/* index_matcher compares a sequence of elements against a
* base sequence, identifying those elements that belong to the
* longest subsequence which is ordered with respect to the base.
* For instance, if the base sequence is:
*
* 0 1 2 3 4 5 6 7 8 9
*
* and the compared sequence (not necesarilly the same length):
*
* 1 4 2 3 0 7 8 9
*
* the elements of the longest ordered subsequence are:
*
* 1 2 3 7 8 9
*
* The algorithm for obtaining such a subsequence is called
* Patience Sorting, described in ch. 1 of:
* Aldous, D., Diaconis, P.: "Longest increasing subsequences: from
* patience sorting to the Baik-Deift-Johansson Theorem", Bulletin
* of the American Mathematical Society, vol. 36, no 4, pp. 413-432,
* July 1999.
* http://www.ams.org/bull/1999-36-04/S0273-0979-99-00796-X/
* S0273-0979-99-00796-X.pdf
*
* This implementation is not fully generic since it assumes that
* the sequences given are pointed to by index iterators (having a
* get_node() memfun.)
*/
namespace index_matcher{
/* The algorithm stores the nodes of the base sequence and a number
* of "piles" that are dynamically updated during the calculation
* stage. From a logical point of view, nodes form an independent
* sequence from piles. They are stored together so as to minimize
* allocated memory.
*/
struct entry
{
entry(void* node_,std::size_t pos_=0):node(node_),pos(pos_){}
/* node stuff */
void* node;
std::size_t pos;
entry* previous;
bool ordered;
struct less_by_node
{
bool operator()(
const entry& x,const entry& y)const
{
return std::less()(x.node,y.node);
}
};
/* pile stuff */
std::size_t pile_top;
entry* pile_top_entry;
struct less_by_pile_top
{
bool operator()(
const entry& x,const entry& y)const
{
return x.pile_top
class algorithm_base:private noncopyable
{
protected:
algorithm_base(const Allocator& al,std::size_t size):
spc(al,size),size_(size),n_(0),sorted(false)
{
}
void add(void* node)
{
entries()[n_]=entry(node,n_);
++n_;
}
void begin_algorithm()const
{
if(!sorted){
std::sort(entries(),entries()+size_,entry::less_by_node());
sorted=true;
}
num_piles=0;
}
void add_node_to_algorithm(void* node)const
{
entry* ent=
std::lower_bound(
entries(),entries()+size_,
entry(node),entry::less_by_node()); /* localize entry */
ent->ordered=false;
std::size_t n=ent->pos; /* get its position */
entry dummy(0);
dummy.pile_top=n;
entry* pile_ent= /* find the first available pile */
std::lower_bound( /* to stack the entry */
entries(),entries()+num_piles,
dummy,entry::less_by_pile_top());
pile_ent->pile_top=n; /* stack the entry */
pile_ent->pile_top_entry=ent;
/* if not the first pile, link entry to top of the preceding pile */
if(pile_ent>&entries()[0]){
ent->previous=(pile_ent-1)->pile_top_entry;
}
if(pile_ent==&entries()[num_piles]){ /* new pile? */
++num_piles;
}
}
void finish_algorithm()const
{
if(num_piles>0){
/* Mark those elements which are in their correct position, i.e. those
* belonging to the longest increasing subsequence. These are those
* elements linked from the top of the last pile.
*/
entry* ent=entries()[num_piles-1].pile_top_entry;
for(std::size_t n=num_piles;n--;){
ent->ordered=true;
ent=ent->previous;
}
}
}
bool is_ordered(void * node)const
{
return std::lower_bound(
entries(),entries()+size_,
entry(node),entry::less_by_node())->ordered;
}
private:
entry* entries()const{return raw_ptr(spc.data());}
auto_space spc;
std::size_t size_;
std::size_t n_;
mutable bool sorted;
mutable std::size_t num_piles;
};
/* The algorithm has three phases:
* - Initialization, during which the nodes of the base sequence are added.
* - Execution.
* - Results querying, through the is_ordered memfun.
*/
template
class algorithm:private algorithm_base
{
typedef algorithm_base super;
public:
algorithm(const Allocator& al,std::size_t size):super(al,size){}
void add(Node* node)
{
super::add(node);
}
template
void execute(IndexIterator first,IndexIterator last)const
{
super::begin_algorithm();
for(IndexIterator it=first;it!=last;++it){
add_node_to_algorithm(get_node(it));
}
super::finish_algorithm();
}
bool is_ordered(Node* node)const
{
return super::is_ordered(node);
}
private:
void add_node_to_algorithm(Node* node)const
{
super::add_node_to_algorithm(node);
}
template
static Node* get_node(IndexIterator it)
{
return static_cast(it.get_node());
}
};
} /* namespace multi_index::detail::index_matcher */
} /* namespace multi_index::detail */
} /* namespace multi_index */
} /* namespace boost */
#endif