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more/gen/outer_product_container.h

Go to the documentation of this file.

//  Copyright (C) 2001  Petter Urkedal (petter.urkedal@matfys.lth.se)
//
//  This file 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 2 of the License, or
//  (at your option) any later version.
//
//  This file 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
//  As a special exception, you may use this file as part of a free
//  software library without restriction.  Specifically, if other files
//  instantiate templates or use macros or inline functions from this
//  file, or you compile this file and link it with other files to
//  produce an executable, this file does not by itself cause the
//  resulting executable to be covered by the GNU General Public
//  License.  This exception does not however invalidate any other
//  reasons why the executable file might be covered by the GNU General
//  Public License.
//
//  $Id: outer_product_container.h,v 1.1 2002/05/30 18:01:37 petter_urkedal Exp $


#ifndef MORE_GEN_OUTER_PRODUCT_CONTAINER_H
#define MORE_GEN_OUTER_PRODUCT_CONTAINER_H


#include <iterator>
#include <assert.h>


namespace more {
namespace gen {

  template< typename Iterator,
            template <typename> class Container,
            typename IteratorCategory
            = typename std::iterator_traits<Iterator>::iterator_category >
    struct outer_product_container {
        struct iterator {
            typedef std::bidirectional_iterator_tag iterator_category;
            typedef Container< typename std::iterator_traits<Iterator>
                               ::value_type > value_type;
            typedef value_type& reference;
            typedef value_type* pointer;

            iterator() : context(0), value(0) {}
            iterator(outer_product_container* context_,
                     Container<Iterator> const& cur_)
                : context(context_), cur(cur_), value(0) {}
            iterator(outer_product_container* context_,
                     Container<Iterator> const& cur_,
                     Container<Iterator> const& last)
                : context(context_), cur(cur_), value(0) {
                *cur.begin() = *last.begin();
                assert(cur.size() == context->first.size());
                assert(cur.size() == context->last.size());
            }
            iterator(iterator const& x)
                : context(x.context), cur(x.cur), value(0) {}
            iterator& operator=(iterator const x) {
                this->~iterator();
                new(this) iterator(x);
            }
            ~iterator() { delete value; }
            iterator& operator++() {
                delete value;
                value = 0;
                typename Container<Iterator>::iterator
                    it_cur = cur.end(),
                    it_first = context->first.end(),
                    it_last = context->last.end();
                assert(it_cur != cur.begin());
                while (--it_cur != cur.begin()) {
                    --it_first, --it_last;
                    if (++*it_cur != *it_last) return *this;
                    *it_cur = *it_first;
                }
                ++*it_cur;
                return *this;
            }
            iterator& operator--() {
                delete value;
                value = 0;
                typename Container<Iterator>::iterator
                    it_cur = cur.end(),
                    it_first = context->first.end(),
                    it_last = context->last.end();
                assert(it_cur != cur.begin());
                while (--it_cur != cur.begin()) {
                    --it_first, --it_last;
                    if (--*it_cur != *it_first) return *this;
                    *it_cur = *it_last;
                }
                --*it_cur;
                return *this;
            }
            iterator operator++(int) {
                iterator tmp = *this;
                ++*this;
                return tmp;
            }
            iterator operator--(int) {
                iterator tmp = *this;
                --*this;
                return tmp;
            }
            bool operator==(iterator const& rhs) const {
                return cur == rhs.cur;
            }
            bool operator!=(iterator const& rhs) const {
                return cur != rhs.cur;
            }

            reference operator*() { update_value(); return *value; }
            pointer operator->() { update_value(); return value; }

          private:
            void update_value() {
                if (value == 0) {
                    value = new value_type;
                    typename Container<Iterator>::iterator
                        it_it = cur.begin();
                    while (it_it != cur.end()) {
                        value->insert(value->end(), **it_it);
                        ++it_it;
                    }
                }
            }
            outer_product_container* context;
            Container<Iterator> cur;
            value_type* value;
        };

        outer_product_container() {}

        void insert_component(Iterator comp_begin, Iterator comp_end) {
            first.insert(first.end(), comp_begin);
            last.insert(last.end(), comp_end);
        }

        iterator begin() { return iterator(this, first); }
        iterator end() { return iterator(this, first, last); }

      private:
        Container<Iterator> first;
        Container<Iterator> last;
    };

}} // more::gen

#endif

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