boost_unordered/include/boost/unordered/detail/unique.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_UNIQUE_HPP_INCLUDED
#define BOOST_UNORDERED_DETAIL_UNIQUE_HPP_INCLUDED

#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif

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

namespace boost { namespace unordered { namespace detail {

    template <typename A, typename T> struct node;
    template <typename T> struct ptr_node;
    template <typename Types> struct table_impl;

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

        link_pointer next_;
        std::size_t hash_;

        node() :
            next_(),
            hash_(0)
        {}

        void init(link_pointer)
        {
        }
    };

    template <typename T>
    struct ptr_node :
        boost::unordered::detail::value_base<T>,
        boost::unordered::detail::ptr_bucket
    {
        typedef boost::unordered::detail::ptr_bucket bucket_base;
        typedef ptr_bucket* link_pointer;

        std::size_t hash_;

        ptr_node() :
            bucket_base(),
            hash_(0)
        {}

        void init(link_pointer)
        {
        }
    };

    // If the allocator uses raw pointers use ptr_node
    // Otherwise use node.

    template <typename A, typename T, typename NodePtr, typename BucketPtr>
    struct pick_node2
    {
        typedef boost::unordered::detail::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_node2<A, T,
        boost::unordered::detail::ptr_node<T>*,
        boost::unordered::detail::ptr_bucket*>
    {
        typedef boost::unordered::detail::ptr_node<T> node;
        typedef boost::unordered::detail::ptr_bucket bucket;
        typedef bucket* link_pointer;
    };

    template <typename A, typename T>
    struct pick_node
    {
        typedef boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A,
                boost::unordered::detail::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_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 H, typename P>
    struct set
    {
        typedef boost::unordered::detail::set<A, H, P> types;

        typedef A allocator;
        typedef H hasher;
        typedef P key_equal;

        typedef boost::unordered::detail::allocator_traits<A> traits;
        typedef typename traits::value_type value_type;
        typedef value_type key_type;

        typedef boost::unordered::detail::pick_node<A, value_type> pick;
        typedef typename pick::node node;
        typedef typename pick::bucket bucket;
        typedef typename pick::link_pointer link_pointer;

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

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

        typedef A allocator;
        typedef H hasher;
        typedef P key_equal;
        typedef K key_type;

        typedef boost::unordered::detail::allocator_traits<A> traits;
        typedef typename traits::value_type value_type;

        typedef boost::unordered::detail::pick_node<A, value_type> pick;
        typedef typename pick::node node;
        typedef typename pick::bucket bucket;
        typedef typename pick::link_pointer link_pointer;

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

    template <typename Types>
    struct 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::buckets buckets;
        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::previous_pointer previous_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 std::pair<node_pointer, bool> emplace_return;

        // Constructors

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

        table_impl(table_impl const& x)
          : table(x, node_allocator_traits::
                select_on_container_copy_construction(x.node_alloc())) {}

        table_impl(table_impl const& x,
                node_allocator const& a)
          : table(x, a)
        {}

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

        table_impl(table_impl& x,
                node_allocator const& a,
                boost::unordered::detail::move_tag m)
          : table(x, a, m)
        {}

        // Accessors

        template <class Key, class Pred>
        node_pointer find_node_impl(
                std::size_t hash,
                Key const& k,
                Pred const& eq) const
        {
            std::size_t bucket_index = hash % this->bucket_count_;
            node_pointer n = this->get_start(bucket_index);

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

                std::size_t node_hash = n->hash_;
                if (hash == node_hash)
                {
                    if (eq(k, this->get_key(n->value())))
                        return n;
                }
                else
                {
                    if (node_hash % this->bucket_count_ != bucket_index)
                        return node_pointer();
                }

                n = static_cast<node_pointer>(n->next_);
            }
        }

        std::size_t count(key_type const& k) const
        {
            return this->find_node(k) ? 1 : 0;
        }

        value_type& at(key_type const& k) const
        {
            if (this->size_) {
                node_pointer it = this->find_node(k);
                if (it) return it->value();
            }

            boost::throw_exception(
                std::out_of_range("Unable to find key in unordered_map."));
        }

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

        // equals

        bool equals(table_impl const& other) const
        {
            if(this->size_ != other.size_) return false;
            if(!this->size_) return true;
    
            for(node_pointer n1 = this->get_start(); n1;
                n1 = static_cast<node_pointer>(n1->next_))
            {
                node_pointer n2 = other.find_matching_node(n1);

#if !defined(BOOST_UNORDERED_DEPRECATED_EQUALITY)
                if(!n2 || n1->value() != n2->value())
                    return false;
#else
                if(!n2 || !extractor::compare_mapped(
                        n1->value(), n2->value()))
                    return false;
#endif
            }
    
            return true;
        }

        // Emplace/Insert

        inline node_pointer add_node(
                node_constructor& a,
                std::size_t hash)
        {
            node_pointer n = a.release();
            n->hash_ = hash;
    
            bucket_pointer b = this->get_bucket(hash % this->bucket_count_);

            if (!b->next_)
            {
                previous_pointer start_node = this->get_previous_start();
                
                if (start_node->next_) {
                    this->get_bucket(
                        static_cast<node_pointer>(start_node->next_)->hash_ %
                            this->bucket_count_)->next_ = n;
                }

                b->next_ = start_node;
                n->next_ = start_node->next_;
                start_node->next_ = static_cast<link_pointer>(n);
            }
            else
            {
                n->next_ = b->next_->next_;
                b->next_->next_ = static_cast<link_pointer>(n);
            }

            ++this->size_;
            return n;
        }

        value_type& operator[](key_type const& k)
        {
            typedef typename value_type::second_type mapped_type;
    
            std::size_t hash = this->hash_function()(k);
            node_pointer pos = this->find_node(hash, k);
    
            if (pos) return pos->value();
    
            // Create the node before rehashing in case it throws an
            // exception (need strong safety in such a case).
            node_constructor a(this->node_alloc());
            a.construct_node();
#if defined(BOOST_UNORDERED_STD_FORWARD_MOVE)
            a.construct_value(boost::unordered::piecewise_construct,
                boost::make_tuple(k), boost::make_tuple());
#else
            a.construct_value(
                boost::unordered::detail::create_emplace_args(
                    boost::unordered::piecewise_construct,
                    boost::make_tuple(k),
                    boost::make_tuple()));
#endif
    
            this->reserve_for_insert(this->size_ + 1);
            return add_node(a, hash)->value();
        }

#if defined(BOOST_NO_RVALUE_REFERENCES)
        emplace_return emplace(boost::unordered::detail::emplace_args1<
                boost::unordered::detail::please_ignore_this_overload> const&)
        {
            BOOST_ASSERT(false);
            return emplace_return(this->begin(), false);
        }
#endif

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        emplace_return emplace(BOOST_UNORDERED_EMPLACE_ARGS)
        {
#if defined(BOOST_UNORDERED_STD_FORWARD_MOVE)
            return emplace_impl(
                extractor::extract(BOOST_UNORDERED_EMPLACE_FORWARD),
                BOOST_UNORDERED_EMPLACE_FORWARD);

#else
            return emplace_impl(
                extractor::extract(args.a0, args.a1),
                BOOST_UNORDERED_EMPLACE_FORWARD);
#endif
        }

#if !defined(BOOST_UNORDERED_STD_FORWARD_MOVE)
        template <typename A0>
        emplace_return emplace(
                boost::unordered::detail::emplace_args1<A0> const& args)
        {
            return emplace_impl(extractor::extract(args.a0), args);
        }
#endif

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        emplace_return emplace_impl(key_type const& k,
            BOOST_UNORDERED_EMPLACE_ARGS)
        {
            std::size_t hash = this->hash_function()(k);
            node_pointer pos = this->find_node(hash, k);
    
            if (pos) return emplace_return(pos, false);
    
            // Create the node before rehashing in case it throws an
            // exception (need strong safety in such a case).
            node_constructor a(this->node_alloc());
            a.construct_node();
            a.construct_value(BOOST_UNORDERED_EMPLACE_FORWARD);
    
            // reserve has basic exception safety if the hash function
            // throws, strong otherwise.
            this->reserve_for_insert(this->size_ + 1);
            return emplace_return(this->add_node(a, hash), true);
        }

        emplace_return emplace_impl_with_node(node_constructor& a)
        {
            key_type const& k = this->get_key(a.value());
            std::size_t hash = this->hash_function()(k);
            node_pointer pos = this->find_node(hash, k);

            if (pos) return emplace_return(pos, false);

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

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        emplace_return emplace_impl(no_key, BOOST_UNORDERED_EMPLACE_ARGS)
        {
            // Don't have a key, so construct the node first in order
            // to be able to lookup the position.
            node_constructor a(this->node_alloc());
            a.construct_node();
            a.construct_value(BOOST_UNORDERED_EMPLACE_FORWARD);
            return emplace_impl_with_node(a);
        }

        ////////////////////////////////////////////////////////////////////////
        // Insert range methods
        //
        // if hash function throws, or inserting > 1 element, basic exception
        // safety strong otherwise

        template <class InputIt>
        void insert_range(InputIt i, InputIt j)
        {
            if(i != j)
                return insert_range_impl(extractor::extract(*i), i, j);
        }

        template <class InputIt>
        void insert_range_impl(key_type const& k, InputIt i, InputIt j)
        {
            node_constructor a(this->node_alloc());

            // Special case for empty buckets so that we can use
            // max_load_ (which isn't valid when buckets_ is null).
            if (!this->buckets_) {
                insert_range_empty(a, k, i, j);
                if (++i == j) return;
            }

            do {
                // Note: can't use get_key as '*i' might not be value_type - it
                // could be a pair with first_types as key_type without const or
                // a different second_type.
                //
                // TODO: Might be worth storing the value_type instead of the
                // key here. Could be more efficient if '*i' is expensive. Could
                // be less efficient if copying the full value_type is
                // expensive.
                insert_range_impl2(a, extractor::extract(*i), i, j);
            } while(++i != j);
        }

        template <class InputIt>
        void insert_range_empty(node_constructor& a, key_type const& k,
            InputIt i, InputIt j)
        {
            std::size_t hash = this->hash_function()(k);
            a.construct_node();
            a.construct_value2(*i);
            this->reserve_for_insert(this->size_ +
                boost::unordered::detail::insert_size(i, j));
            this->add_node(a, hash);
        }

        template <class InputIt>
        void insert_range_impl2(node_constructor& a, key_type const& k,
            InputIt i, InputIt j)
        {
            // No side effects in this initial code
            std::size_t hash = this->hash_function()(k);
            node_pointer pos = this->find_node(hash, k);
    
            if (!pos) {
                a.construct_node();
                a.construct_value2(*i);
    
                if(this->size_ + 1 >= this->max_load_)
                    this->reserve_for_insert(this->size_ +
                        boost::unordered::detail::insert_size(i, j));
    
                // Nothing after this point can throw.
                this->add_node(a, hash);
            }
        }

        template <class InputIt>
        void insert_range_impl(no_key, InputIt i, InputIt j)
        {
            node_constructor a(this->node_alloc());

            do {
                a.construct_node();
                a.construct_value2(*i);
                emplace_impl_with_node(a);
            } while(++i != j);
        }

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

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

            std::size_t hash = this->hash_function()(k);
            std::size_t bucket_index = hash % this->bucket_count_;
            bucket_pointer bucket = this->get_bucket(bucket_index);

            previous_pointer prev = bucket->next_;
            if (!prev) return 0;

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

            node_pointer pos = static_cast<node_pointer>(prev->next_);
            node_pointer end = static_cast<node_pointer>(pos->next_);
            prev->next_ = pos->next_;
            this->fix_buckets(bucket, prev, end);
            return this->delete_nodes(pos, end);
        }

        node_pointer erase(node_pointer r)
        {
            BOOST_ASSERT(r);
            node_pointer next = static_cast<node_pointer>(r->next_);

            bucket_pointer bucket = this->get_bucket(
                r->hash_ % this->bucket_count_);
            previous_pointer prev = unlink_node(*bucket, r);

            this->fix_buckets(bucket, prev, next);

            this->delete_node(r);

            return next;
        }

        node_pointer erase_range(node_pointer r1, node_pointer r2)
        {
            if (r1 == r2) return r2;

            std::size_t bucket_index = r1->hash_ % this->bucket_count_;
            previous_pointer prev = unlink_nodes(
                *this->get_bucket(bucket_index), r1, r2);
            this->fix_buckets_range(bucket_index, prev, r1, r2);
            this->delete_nodes(r1, r2);

            return r2;
        }

        static previous_pointer unlink_node(bucket& b, node_pointer n)
        {
            return unlink_nodes(b, n, static_cast<node_pointer>(n->next_));
        }

        static previous_pointer unlink_nodes(bucket& b,
                node_pointer begin, node_pointer end)
        {
            previous_pointer prev = b.next_;
            link_pointer begin_void = static_cast<link_pointer>(begin);
            while(prev->next_ != begin_void)
                prev = static_cast<previous_pointer>(prev->next_);
            prev->next_ = static_cast<link_pointer>(end);
            return prev;
        }

        ////////////////////////////////////////////////////////////////////////
        // copy_buckets_to
        //
        // Basic exception safety. If an exception is thrown this will
        // leave dst partially filled and the buckets unset.

        static void copy_buckets_to(buckets const& src, buckets& dst)
        {
            BOOST_ASSERT(!dst.buckets_);

            dst.create_buckets();

            node_constructor a(dst.node_alloc());

            node_pointer n = src.get_start();
            previous_pointer prev = dst.get_previous_start();

            while(n) {
                a.construct_node();
                a.construct_value2(n->value());

                node_pointer node = a.release();
                node->hash_ = n->hash_;
                prev->next_ = static_cast<link_pointer>(node);
                ++dst.size_;
                n = static_cast<node_pointer>(n->next_);

                prev = place_in_bucket(dst, prev);
            }
        }

        ////////////////////////////////////////////////////////////////////////
        // move_buckets_to
        //
        // Basic exception safety. The source nodes are left in an unusable
        // state if an exception throws.

        static void move_buckets_to(buckets& src, buckets& dst)
        {
            BOOST_ASSERT(!dst.buckets_);

            dst.create_buckets();

            node_constructor a(dst.node_alloc());

            node_pointer n = src.get_start();
            previous_pointer prev = dst.get_previous_start();

            while(n) {
                a.construct_node();
                a.construct_value2(boost::move(n->value()));

                node_pointer node = a.release();
                node->hash_ = n->hash_;
                prev->next_ = static_cast<link_pointer>(node);
                ++dst.size_;
                n = static_cast<node_pointer>(n->next_);

                prev = place_in_bucket(dst, prev);
            }
        }

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

            buckets dst(this->node_alloc(), num_buckets);
            dst.create_buckets();

            previous_pointer src_start = this->get_previous_start();
            previous_pointer dst_start = dst.get_previous_start();

            dst_start->next_ = src_start->next_;
            src_start->next_ = link_pointer();
            dst.size_ = this->size_;
            this->size_ = 0;

            previous_pointer prev = dst.get_previous_start();
            while (prev->next_)
                prev = place_in_bucket(dst, prev);

            // Swap the new nodes back into the container and setup the
            // variables.
            dst.swap(*this); // no throw
        }

        // Iterate through the nodes placing them in the correct buckets.
        // pre: prev->next_ is not null.
        static previous_pointer place_in_bucket(buckets& dst,
                previous_pointer prev)
        {
            node_pointer n = static_cast<node_pointer>(prev->next_);
            bucket_pointer b = dst.get_bucket(n->hash_ % dst.bucket_count_);

            if (!b->next_) {
                b->next_ = prev;
                return static_cast<previous_pointer>(n);
            }
            else {
                prev->next_ = n->next_;
                n->next_ = b->next_->next_;
                b->next_->next_ = static_cast<link_pointer>(n);
                return prev;
            }
        }
    };
}}}

#endif