boost_unordered/include/boost/unordered/detail/equivalent.hpp

// Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
// Copyright (C) 2005-2011 Daniel James
// 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)

#ifndef BOOST_UNORDERED_DETAIL_EQUIVALENT_HPP_INCLUDED
#define BOOST_UNORDERED_DETAIL_EQUIVALENT_HPP_INCLUDED

#include <boost/config.hpp>
#if defined(BOOST_HAS_PRAGMA_ONCE)
#pragma once
#endif

#include <boost/unordered/detail/table.hpp>
#include <boost/unordered/detail/extract_key.hpp>

namespace boost { namespace unordered { namespace detail {

    template <typename A, typename T> struct grouped_node;
    template <typename T> struct grouped_ptr_node;
    template <typename Types> struct grouped_table_impl;

    template <typename A, typename T>
    struct grouped_node :
        boost::unordered::detail::value_base<T>
    {
        typedef typename ::boost::unordered::detail::rebind_wrap<
            A, grouped_node<A, T> >::type allocator;
        typedef typename ::boost::unordered::detail::
            allocator_traits<allocator>::pointer node_pointer;
        typedef node_pointer link_pointer;

        link_pointer next_;
        node_pointer group_prev_;
        std::size_t hash_;

        grouped_node() :
            next_(),
            group_prev_(),
            hash_(0)
        {}

        void init(node_pointer self)
        {
            group_prev_ = self;
        }

    private:
        grouped_node& operator=(grouped_node const&);
    };

    template <typename T>
    struct grouped_ptr_node :
        boost::unordered::detail::ptr_bucket
    {
        typedef T value_type;
        typedef boost::unordered::detail::ptr_bucket bucket_base;
        typedef grouped_ptr_node<T>* node_pointer;
        typedef ptr_bucket* link_pointer;

        node_pointer group_prev_;
        std::size_t hash_;
        boost::unordered::detail::value_base<T> value_base_;

        grouped_ptr_node() :
            bucket_base(),
            group_prev_(0),
            hash_(0)
        {}

        void init(node_pointer self)
        {
            group_prev_ = self;
        }

        void* address() { return value_base_.address(); }
        value_type& value() { return value_base_.value(); }
        value_type* value_ptr() { return value_base_.value_ptr(); }

    private:
        grouped_ptr_node& operator=(grouped_ptr_node const&);
    };

    // If the allocator uses raw pointers use grouped_ptr_node
    // Otherwise use grouped_node.

    template <typename A, typename T, typename NodePtr, typename BucketPtr>
    struct pick_grouped_node2
    {
        typedef boost::unordered::detail::grouped_node<A, T> node;

        typedef typename boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A, node>::type
        >::pointer node_pointer;

        typedef boost::unordered::detail::bucket<node_pointer> bucket;
        typedef node_pointer link_pointer;
    };

    template <typename A, typename T>
    struct pick_grouped_node2<A, T,
        boost::unordered::detail::grouped_ptr_node<T>*,
        boost::unordered::detail::ptr_bucket*>
    {
        typedef boost::unordered::detail::grouped_ptr_node<T> node;
        typedef boost::unordered::detail::ptr_bucket bucket;
        typedef bucket* link_pointer;
    };

    template <typename A, typename T>
    struct pick_grouped_node
    {
        typedef boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A,
                boost::unordered::detail::grouped_ptr_node<T> >::type
        > tentative_node_traits;

        typedef boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A,
                boost::unordered::detail::ptr_bucket >::type
        > tentative_bucket_traits;

        typedef pick_grouped_node2<A, T,
            typename tentative_node_traits::pointer,
            typename tentative_bucket_traits::pointer> pick;

        typedef typename pick::node node;
        typedef typename pick::bucket bucket;
        typedef typename pick::link_pointer link_pointer;
    };

    template <typename A, typename T, typename H, typename P>
    struct multiset
    {
        typedef boost::unordered::detail::multiset<A, T, H, P> types;

        typedef A allocator;
        typedef T value_type;
        typedef H hasher;
        typedef P key_equal;
        typedef T key_type;

        typedef boost::unordered::detail::allocator_traits<allocator> traits;
        typedef boost::unordered::detail::pick_grouped_node<allocator,
            value_type> pick;
        typedef typename pick::node node;
        typedef typename pick::bucket bucket;
        typedef typename pick::link_pointer link_pointer;

        typedef boost::unordered::detail::grouped_table_impl<types> table;
        typedef boost::unordered::detail::set_extractor<value_type> extractor;

        typedef typename boost::unordered::detail::pick_policy<T>::type policy;
    };

    template <typename A, typename K, typename M, typename H, typename P>
    struct multimap
    {
        typedef boost::unordered::detail::multimap<A, K, M, H, P> types;

        typedef A allocator;
        typedef std::pair<K const, M> value_type;
        typedef H hasher;
        typedef P key_equal;
        typedef K key_type;

        typedef boost::unordered::detail::allocator_traits<allocator> traits;
        typedef boost::unordered::detail::pick_grouped_node<allocator,
                value_type> pick;
        typedef typename pick::node node;
        typedef typename pick::bucket bucket;
        typedef typename pick::link_pointer link_pointer;

        typedef boost::unordered::detail::grouped_table_impl<types> table;
        typedef boost::unordered::detail::map_extractor<key_type, value_type>
            extractor;

        typedef typename boost::unordered::detail::pick_policy<K>::type policy;
    };

    template <typename Types>
    struct grouped_table_impl : boost::unordered::detail::table<Types>
    {
        typedef boost::unordered::detail::table<Types> table;
        typedef typename table::value_type value_type;
        typedef typename table::bucket bucket;
        typedef typename table::policy policy;
        typedef typename table::node_pointer node_pointer;
        typedef typename table::node_allocator node_allocator;
        typedef typename table::node_allocator_traits node_allocator_traits;
        typedef typename table::bucket_pointer bucket_pointer;
        typedef typename table::link_pointer link_pointer;
        typedef typename table::hasher hasher;
        typedef typename table::key_equal key_equal;
        typedef typename table::key_type key_type;
        typedef typename table::node_constructor node_constructor;
        typedef typename table::extractor extractor;
        typedef typename table::iterator iterator;
        typedef typename table::c_iterator c_iterator;

        // Constructors

        grouped_table_impl(std::size_t n,
                hasher const& hf,
                key_equal const& eq,
                node_allocator const& a)
          : table(n, hf, eq, a)
        {}

        grouped_table_impl(grouped_table_impl const& x)
          : table(x, node_allocator_traits::
                select_on_container_copy_construction(x.node_alloc()))
        {
            this->init(x);
        }

        grouped_table_impl(grouped_table_impl const& x,
                node_allocator const& a)
          : table(x, a)
        {
            this->init(x);
        }

        grouped_table_impl(grouped_table_impl& x,
                boost::unordered::detail::move_tag m)
          : table(x, m)
        {}

        grouped_table_impl(grouped_table_impl& x,
                node_allocator const& a,
                boost::unordered::detail::move_tag m)
          : table(x, a, m)
        {
            this->move_init(x);
        }

        // Accessors

        template <class Key, class Pred>
        iterator find_node_impl(
                std::size_t key_hash,
                Key const& k,
                Pred const& eq) const
        {
            std::size_t bucket_index = this->hash_to_bucket(key_hash);
            iterator n = this->begin(bucket_index);

            for (;;)
            {
                if (!n.node_) return n;

                std::size_t node_hash = n.node_->hash_;
                if (key_hash == node_hash)
                {
                    if (eq(k, this->get_key(*n)))
                        return n;
                }
                else
                {
                    if (this->hash_to_bucket(node_hash) != bucket_index)
                        return iterator();
                }

                n = iterator(n.node_->group_prev_->next_);
            }
        }

        std::size_t count(key_type const& k) const
        {
            iterator n = this->find_node(k);
            if (!n.node_) return 0;

            std::size_t x = 0;
            node_pointer it = n.node_;
            do {
                it = it->group_prev_;
                ++x;
            } while(it != n.node_);

            return x;
        }

        std::pair<iterator, iterator>
            equal_range(key_type const& k) const
        {
            iterator n = this->find_node(k);
            return std::make_pair(
                n, n.node_ ? iterator(n.node_->group_prev_->next_) : n);
        }

        // Equality

        bool equals(grouped_table_impl const& other) const
        {
            if(this->size_ != other.size_) return false;
    
            for(iterator n1 = this->begin(); n1.node_;)
            {
                iterator n2 = other.find_matching_node(n1);
                if (!n2.node_) return false;
                iterator end1(n1.node_->group_prev_->next_);
                iterator end2(n2.node_->group_prev_->next_);
                if (!group_equals(n1, end1, n2, end2)) return false;
                n1 = end1;    
            }
    
            return true;
        }

        static bool group_equals(iterator n1, iterator end1,
                iterator n2, iterator end2)
        {
            for(;;)
            {
                if (*n1 != *n2) break;

                ++n1;
                ++n2;
            
                if (n1 == end1) return n2 == end2;
                if (n2 == end2) return false;
            }
            
            for(iterator n1a = n1, n2a = n2;;)
            {
                ++n1a;
                ++n2a;

                if (n1a == end1)
                {
                    if (n2a == end2) break;
                    else return false;
                }

                if (n2a == end2) return false;
            }

            iterator start = n1;
            for(;n1 != end1; ++n1)
            {
                value_type const& v = *n1;
                if (find(start, n1, v)) continue;
                std::size_t matches = count_equal(n2, end2, v);
                if (!matches) return false;
                iterator next = n1;
                ++next;
                if (matches != 1 + count_equal(next, end1, v)) return false;
            }
            
            return true;
        }

        static bool find(iterator n, iterator end, value_type const& v)
        {
            for(;n != end; ++n)
                if (*n == v)
                    return true;
            return false;
        }

        static std::size_t count_equal(iterator n, iterator end,
            value_type const& v)
        {
            std::size_t count = 0;
            for(;n != end; ++n)
                if (*n == v) ++count;
            return count;
        }

        // Emplace/Insert

        static inline void add_after_node(
                node_pointer n,
                node_pointer pos)
        {
            n->next_ = pos->group_prev_->next_;
            n->group_prev_ = pos->group_prev_;
            pos->group_prev_->next_ = n;
            pos->group_prev_ = n;
        }

        inline iterator add_node(
                node_constructor& a,
                std::size_t key_hash,
                iterator pos)
        {
            node_pointer n = a.release();
            n->hash_ = key_hash;
            if (pos.node_) {
                this->add_after_node(n, pos.node_);
                if (n->next_) {
                    std::size_t next_bucket = this->hash_to_bucket(
                        static_cast<node_pointer>(n->next_)->hash_);
                    if (next_bucket != this->hash_to_bucket(key_hash)) {
                        this->get_bucket(next_bucket)->next_ = n;
                    }
                }
            }
            else {
                bucket_pointer b = this->get_bucket(
                    this->hash_to_bucket(key_hash));

                if (!b->next_)
                {
                    link_pointer start_node = this->get_previous_start();
                    
                    if (start_node->next_) {
                        this->get_bucket(this->hash_to_bucket(
                            static_cast<node_pointer>(start_node->next_)->hash_
                        ))->next_ = n;
                    }
    
                    b->next_ = start_node;
                    n->next_ = start_node->next_;
                    start_node->next_ = n;
                }
                else
                {
                    n->next_ = b->next_->next_;
                    b->next_->next_ = n;
                }
            }
            ++this->size_;
            return iterator(n);
        }

        iterator emplace_impl(node_constructor& a)
        {
            key_type const& k = this->get_key(a.value());
            std::size_t key_hash = this->hash(k);
            iterator position = this->find_node(key_hash, k);

            // reserve has basic exception safety if the hash function
            // throws, strong otherwise.
            this->reserve_for_insert(this->size_ + 1);
            return this->add_node(a, key_hash, position);
        }

        void emplace_impl_no_rehash(node_constructor& a)
        {
            key_type const& k = this->get_key(a.value());
            std::size_t key_hash = this->hash(k);
            this->add_node(a, key_hash, this->find_node(key_hash, k));
        }

#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
#   if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
        iterator emplace(boost::unordered::detail::emplace_args1<
                boost::unordered::detail::please_ignore_this_overload> const&)
        {
            BOOST_ASSERT(false);
            return iterator();
        }
#   else
        iterator emplace(
                boost::unordered::detail::please_ignore_this_overload const&)
        {
            BOOST_ASSERT(false);
            return iterator();
        }
#   endif
#endif

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        iterator emplace(BOOST_UNORDERED_EMPLACE_ARGS)
        {
            node_constructor a(this->node_alloc());
            a.construct_with_value(BOOST_UNORDERED_EMPLACE_FORWARD);

            return iterator(emplace_impl(a));
        }

        ////////////////////////////////////////////////////////////////////////
        // Insert range methods

        // if hash function throws, or inserting > 1 element, basic exception
        // safety. Strong otherwise
        template <class I>
        typename boost::unordered::detail::enable_if_forward<I, void>::type
            insert_range(I i, I j)
        {
            if(i == j) return;

            std::size_t distance = boost::unordered::detail::distance(i, j);
            if(distance == 1) {
                node_constructor a(this->node_alloc());
                a.construct_with_value2(*i);
                emplace_impl(a);
            }
            else {
                // Only require basic exception safety here
                this->reserve_for_insert(this->size_ + distance);

                node_constructor a(this->node_alloc());
                for (; i != j; ++i) {
                    a.construct_with_value2(*i);
                    emplace_impl_no_rehash(a);
                }
            }
        }

        template <class I>
        typename boost::unordered::detail::disable_if_forward<I, void>::type
            insert_range(I i, I j)
        {
            node_constructor a(this->node_alloc());
            for (; i != j; ++i) {
                a.construct_with_value2(*i);
                emplace_impl(a);
            }
        }

        ////////////////////////////////////////////////////////////////////////
        // Erase
        //
        // no throw

        std::size_t erase_key(key_type const& k)
        {
            if(!this->size_) return 0;

            std::size_t key_hash = this->hash(k);
            std::size_t bucket_index = this->hash_to_bucket(key_hash);
            link_pointer prev = this->get_previous_start(bucket_index);
            if (!prev) return 0;

            for (;;)
            {
                if (!prev->next_) return 0;
                std::size_t node_hash =
                    static_cast<node_pointer>(prev->next_)->hash_;
                if (this->hash_to_bucket(node_hash) != bucket_index)
                    return 0;
                if (node_hash == key_hash &&
                    this->key_eq()(k, this->get_key(
                        static_cast<node_pointer>(prev->next_)->value())))
                    break;
                prev = static_cast<node_pointer>(prev->next_)->group_prev_;
            }

            node_pointer first_node = static_cast<node_pointer>(prev->next_);
            link_pointer end = first_node->group_prev_->next_;

            std::size_t deleted_count = this->delete_nodes(prev, end);
            this->fix_bucket(bucket_index, prev);
            return deleted_count;
        }

        iterator erase(c_iterator r)
        {
            BOOST_ASSERT(r.node_);
            iterator next(r.node_);
            ++next;
            erase_nodes(r.node_, next.node_);
            return next;
        }

        iterator erase_range(c_iterator r1, c_iterator r2)
        {
            if (r1 == r2) return iterator(r2.node_);
            erase_nodes(r1.node_, r2.node_);
            return iterator(r2.node_);
        }

        link_pointer erase_nodes(node_pointer i, node_pointer j)
        {
            std::size_t bucket_index = this->hash_to_bucket(i->hash_);

            // Split the groups containing 'i' and 'j'.
            // And get the pointer to the node before i while
            // we're at it.
            link_pointer prev = split_groups(i, j);

            // If we don't have a 'prev' it means that i is at the
            // beginning of a block, so search through the blocks in the
            // same bucket.
            if (!prev) {
                prev = this->get_previous_start(bucket_index);
                while (prev->next_ != i)
                    prev = static_cast<node_pointer>(prev->next_)->group_prev_;
            }

            // Delete the nodes.
            do {
                link_pointer group_end =
                    static_cast<node_pointer>(prev->next_)->group_prev_->next_;
                this->delete_nodes(prev, group_end);
                bucket_index = this->fix_bucket(bucket_index, prev);
            } while(prev->next_ != j);

            return prev;
        }

        static link_pointer split_groups(node_pointer i, node_pointer j)
        {
            node_pointer prev = i->group_prev_;
            if (prev->next_ != i) prev = node_pointer();

            if (j) {
                node_pointer first = j;
                while (first != i && first->group_prev_->next_ == first) {
                    first = first->group_prev_;
                }

                boost::swap(first->group_prev_, j->group_prev_);
                if (first == i) return prev;
            }

            if (prev) {
                node_pointer first = prev;
                while (first->group_prev_->next_ == first) {
                    first = first->group_prev_;
                }
                boost::swap(first->group_prev_, i->group_prev_);
            }

            return prev;
        }

        ////////////////////////////////////////////////////////////////////////
        // fill_buckets

        template <class NodeCreator>
        static void fill_buckets(iterator n, table& dst,
            NodeCreator& creator)
        {
            link_pointer prev = dst.get_previous_start();

            while (n.node_) {
                std::size_t key_hash = n.node_->hash_;
                iterator group_end(n.node_->group_prev_->next_);

                node_pointer first_node = creator.create(*n);
                node_pointer end = first_node;
                first_node->hash_ = key_hash;
                prev->next_ = first_node;
                ++dst.size_;

                for (++n; n != group_end; ++n)
                {
                    end = creator.create(*n);
                    end->hash_ = key_hash;
                    add_after_node(end, first_node);
                    ++dst.size_;
                }

                prev = place_in_bucket(dst, prev, end);
            }
        }

        // strong otherwise exception safety
        void rehash_impl(std::size_t num_buckets)
        {
            BOOST_ASSERT(this->buckets_);

            this->create_buckets(num_buckets);
            link_pointer prev = this->get_previous_start();
            while (prev->next_)
                prev = place_in_bucket(*this, prev,
                    static_cast<node_pointer>(prev->next_)->group_prev_);
        }

        // Iterate through the nodes placing them in the correct buckets.
        // pre: prev->next_ is not null.
        static link_pointer place_in_bucket(table& dst,
                link_pointer prev, node_pointer end)
        {
            bucket_pointer b = dst.get_bucket(dst.hash_to_bucket(end->hash_));

            if (!b->next_) {
                b->next_ = prev;
                return end;
            }
            else {
                link_pointer next = end->next_;
                end->next_ = b->next_->next_;
                b->next_->next_ = prev->next_;
                prev->next_ = next;
                return prev;
            }
        }
    };
}}}

#endif