virtual_container.h

/*
Multiscale Universal Interface Code Coupling Library

Copyright (C) 2017 Y. H. Tang, S. Kudo, X. Bian, Z. Li, G. E. Karniadakis

This software is jointly licensed under the Apache License, Version 2.0
and the GNU General Public License version 3, you may use it according
to either.

** Apache License, version 2.0 **

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

** GNU General Public License, version 3 **

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, either version 3 of the License, or
(at your option) any later version.

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, see <http://www.gnu.org/licenses/>.

** File Details **

Filename: virtual_container.h
Created: Mar 16, 2014
Author: Y. H. Tang
Description:
*/

#ifndef VIRTUAL_CONTAINER_H_
#define VIRTUAL_CONTAINER_H_

#include "util.h"

namespace mui {

template<typename V, typename ARRAY>
struct index_iterator: public std::iterator<std::forward_iterator_tag,V>
{
	typedef std::iterator<std::forward_iterator_tag,V> iterator;

	typedef typename iterator::iterator_category iterator_category;
	typedef typename iterator::value_type value_type;
	typedef typename iterator::difference_type difference_type;
	typedef typename iterator::pointer pointer;
	typedef typename iterator::reference reference;

	index_iterator( ARRAY& array, std::size_t index=0 ): array_(array), index_(index) {}
	index_iterator() = default;
	index_iterator( const index_iterator& ) = default;
	index_iterator& operator=( const index_iterator& ) = default;

	value_type operator*() const { return array_[index_]; }
	reference operator*() { return array_[index_]; }
	const pointer operator->() const { return &(array_[index_]); }
	pointer operator->() { return &(array_[index_]); }


	index_iterator& operator++(){
		++index_;
		return *this;
	}
	index_iterator operator++(int){
		index_iterator prev = *this;
		operator++();
		return prev;
	}
	bool operator==( const index_iterator& rhs ) const { return index_ == rhs.index_; }
	bool operator!=( const index_iterator& rhs ) const { return index_ != rhs.index_; }
private:
	ARRAY& array_;
	std::size_t index_;
};


template < typename TYPE, typename CONFIG>
class virtual_container {
public:
	using elem_type      = std::pair<typename CONFIG::point_type,TYPE>;
	using container_type = std::vector<elem_type>;
	typedef index_iterator<const elem_type,const virtual_container> iterator;

	inline virtual_container( const container_type &container, std::vector<size_t> map ) :
		container_(container), map_(std::move(map)) {
	}
	virtual_container( const container_type &container, const std::vector<bool> &pred ) :
		container_(container) {
		for(size_t i = 0 ; i < pred.size() ; i++) if (pred[i]) map_.push_back(i);
	}

	// opetator [] does no bound check
	inline const elem_type& operator [] ( size_t i ) const {
		return container_[ map_[i] ];
	}

	// at performs bound check
	inline const elem_type& at ( size_t i ) const {
		if ( i >= map_.size() ) typename CONFIG::EXCEPTION(std::out_of_range("virtual container: out of range."));
		return container_[ map_[i] ];
	}

	inline iterator begin() const {
		iterator iter(*this);
		return iter;
	}
	inline iterator cbegin() const { return begin(); }

	inline iterator end()const{
		iterator iter(*this,size());
		return iter;
	}
	inline iterator cend() const { return end(); }

	inline size_t size() const { return map_.size(); }
protected:
	container_type const & container_;
	std::vector<size_t> map_;

};

template < typename TYPE, typename CONFIG>
virtual_container<TYPE,CONFIG> make_vc( const std::vector<typename CONFIG::point_type,TYPE> &container,
                                        const std::vector<size_t> &map )
{
	return virtual_container<TYPE,CONFIG>(container,map);
}

template < typename TYPE, typename CONFIG>
virtual_container<TYPE,CONFIG> make_vc( const std::vector<std::pair<typename CONFIG::point_type,TYPE> > &container,
                                        const std::vector<bool> &pred )
{
	return virtual_container<TYPE,CONFIG>(container,pred);
}

}

#endif /* VIRTUAL_CONTAINER_H_ */