relations_map.hpp

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#ifndef OSMIUM_INDEX_RELATIONS_MAP_HPP
#define OSMIUM_INDEX_RELATIONS_MAP_HPP
 
/*
 
This file is part of Osmium (https://osmcode.org/libosmium).
 
Copyright 2013-2025 Jochen Topf <jochen@topf.org> and others (see README).
 
Boost Software License - Version 1.0 - August 17th, 2003
 
Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
this license (the "Software") to use, reproduce, display, distribute,
execute, and transmit the Software, and to prepare derivative works of the
Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:
 
The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
a source language processor.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
 
*/
 
#include <osmium/osm/item_type.hpp>
#include <osmium/osm/relation.hpp>
#include <osmium/osm/types.hpp>
 
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <limits>
#include <tuple>
#include <type_traits>
#include <utility>
#include <vector>
 
namespace osmium {
 
    namespace index {
 
        namespace detail {
 
            template <typename TKey, typename TKeyInternal, typename TValue, typename TValueInternal>
            class flat_map {
 
            public:
 
                using key_type   = TKey;
                using value_type = TValue;
 
            private:
 
                struct kv_pair {
                    TKeyInternal key;
                    TValueInternal value;
 
                    explicit kv_pair(const key_type key_id) :
                        key(static_cast<TKeyInternal>(key_id)),
                        value() {
                    }
 
                    kv_pair(const key_type key_id, const value_type value_id) :
                        key(static_cast<TKeyInternal>(key_id)),
                        value(static_cast<TValueInternal>(value_id)) {
                    }
 
                    bool operator<(const kv_pair& other) const noexcept {
                        return std::tie(key, value) < std::tie(other.key, other.value);
                    }
 
                    bool operator==(const kv_pair& other) const noexcept {
                        return std::tie(key, value) == std::tie(other.key, other.value);
                    }
                }; // struct kv_pair
 
                std::vector<kv_pair> m_map;
 
            public:
 
                using const_iterator = typename std::vector<kv_pair>::const_iterator;
 
                void set(const key_type key, const value_type value) {
                    m_map.emplace_back(key, value);
                }
 
                std::enable_if_t<std::is_same<TKey, TValue>::value> flip_in_place() {
                    for (auto& p : m_map) {
                        using std::swap;
                        swap(p.key, p.value);
                    }
                }
 
                flat_map<TValue, TValueInternal, TKey, TKeyInternal> flip_copy() {
                    flat_map<TValue, TValueInternal, TKey, TKeyInternal> map;
                    map.reserve(m_map.size());
 
                    for (const auto& p : m_map) {
                        map.set(p.value, p.key);
                    }
 
                    return map;
                }
 
                void sort_unique() {
                    std::sort(m_map.begin(), m_map.end());
                    const auto last = std::unique(m_map.begin(), m_map.end());
                    m_map.erase(last, m_map.end());
                }
 
                std::pair<const_iterator, const_iterator> get(const key_type key) const noexcept {
                    return std::equal_range(m_map.begin(), m_map.end(), kv_pair{key}, [](const kv_pair& lhs, const kv_pair& rhs) {
                        return lhs.key < rhs.key;
                    });
                }
 
                bool empty() const noexcept {
                    return m_map.empty();
                }
 
                std::size_t size() const noexcept {
                    return m_map.size();
                }
 
                void reserve(const std::size_t size) {
                    m_map.reserve(size);
                }
 
                void clear() {
                    m_map.clear();
                    m_map.shrink_to_fit();
                }
 
                typename std::vector<kv_pair>::const_iterator begin() const noexcept {
                    return m_map.cbegin();
                }
 
                typename std::vector<kv_pair>::const_iterator end() const noexcept {
                    return m_map.cend();
                }
 
            }; // class flat_map
 
            template <typename VType>
            using rel_index_map_type = detail::flat_map<osmium::unsigned_object_id_type, VType,
                                                        osmium::unsigned_object_id_type, VType>;
 
        } // namespace detail
 
        class RelationsMapIndex {
 
            friend class RelationsMapStash;
            friend class RelationsMapIndexes;
 
            detail::rel_index_map_type<uint32_t> m_map32;
            detail::rel_index_map_type<uint64_t> m_map64;
 
            bool m_small;
 
            explicit RelationsMapIndex(detail::rel_index_map_type<uint32_t>&& map) :
                m_map32(std::move(map)), m_small(true) {
            }
 
            explicit RelationsMapIndex(detail::rel_index_map_type<uint64_t>&& map) :
                m_map64(std::move(map)), m_small(false) {
            }
 
        public:
 
            RelationsMapIndex() = delete;
 
            RelationsMapIndex(const RelationsMapIndex&) = delete;
            RelationsMapIndex& operator=(const RelationsMapIndex&) = delete;
 
            RelationsMapIndex(RelationsMapIndex&& /*other*/) noexcept;
            RelationsMapIndex& operator=(RelationsMapIndex&& /*other*/) noexcept;
 
            ~RelationsMapIndex() noexcept = default;
 
            template <typename TFunc>
            void for_each(const osmium::unsigned_object_id_type id, TFunc&& func) const {
                if (m_small) {
                    const auto parents = m_map32.get(id);
                    for (auto it = parents.first; it != parents.second; ++it) {
                        std::forward<TFunc>(func)(it->value);
                    }
                } else {
                    const auto parents = m_map64.get(id);
                    for (auto it = parents.first; it != parents.second; ++it) {
                        std::forward<TFunc>(func)(it->value);
                    }
                }
            }
 
            bool empty() const noexcept {
                return m_small ? m_map32.empty() : m_map64.empty();
            }
 
            std::size_t size() const noexcept {
                return m_small ? m_map32.size() : m_map64.size();
            }
 
        }; // class RelationsMapIndex
 
        // defined outside the class on purpose
        // see https://akrzemi1.wordpress.com/2015/09/11/declaring-the-move-constructor/
        inline RelationsMapIndex::RelationsMapIndex(RelationsMapIndex&&) noexcept = default; // NOLINT(readability-redundant-inline-specifier)
        inline RelationsMapIndex& RelationsMapIndex::operator=(RelationsMapIndex&&) noexcept = default; // NOLINT(readability-redundant-inline-specifier)
 
        class RelationsMapIndexes {
 
            friend class RelationsMapStash;
 
            RelationsMapIndex m_member_to_parent;
            RelationsMapIndex m_parent_to_member;
 
            RelationsMapIndexes(detail::rel_index_map_type<uint32_t>&& map1, detail::rel_index_map_type<uint32_t>&& map2) :
                m_member_to_parent(std::move(map1)),
                m_parent_to_member(std::move(map2)) {
            }
 
            RelationsMapIndexes(detail::rel_index_map_type<uint64_t>&& map1, detail::rel_index_map_type<uint64_t>&& map2) :
                m_member_to_parent(std::move(map1)),
                m_parent_to_member(std::move(map2)) {
            }
 
        public:
 
            const RelationsMapIndex& member_to_parent() const noexcept {
                return m_member_to_parent;
            }
 
            const RelationsMapIndex& parent_to_member() const noexcept {
                return m_parent_to_member;
            }
 
            bool empty() const noexcept {
                return m_member_to_parent.empty();
            }
 
            std::size_t size() const noexcept {
                return m_member_to_parent.size();
            }
 
        }; // class RelationsMapIndexes
 
        class RelationsMapStash {
 
            detail::rel_index_map_type<uint32_t> m_map32;
            detail::rel_index_map_type<uint64_t> m_map64;
 
#ifndef NDEBUG
            bool m_valid = true;
#endif
 
            static void append32to64(detail::rel_index_map_type<uint32_t>& map32, detail::rel_index_map_type<uint64_t>& map64) {
                map64.sort_unique();
                map64.reserve(map64.size() + map32.size());
                for (const auto& item : map32) {
                    map64.set(item.key, item.value);
                }
                map64.sort_unique();
                map32.clear();
            }
 
        public:
 
            RelationsMapStash() = default;
 
            RelationsMapStash(const RelationsMapStash&) = delete;
            RelationsMapStash& operator=(const RelationsMapStash&) = delete;
 
            RelationsMapStash(RelationsMapStash&& /*other*/) noexcept;
            RelationsMapStash& operator=(RelationsMapStash&& /*other*/) noexcept;
 
            ~RelationsMapStash() noexcept = default;
 
            void add(const osmium::unsigned_object_id_type member_id, const osmium::unsigned_object_id_type relation_id) {
                assert(m_valid && "You can't use the RelationsMap any more after calling build_index()");
                constexpr const osmium::unsigned_object_id_type max32 = std::numeric_limits<uint32_t>::max();
                if (member_id <= max32 && relation_id <= max32) {
                    m_map32.set(member_id, relation_id);
                } else {
                    m_map64.set(member_id, relation_id);
                }
            }
 
            void add_members(const osmium::Relation& relation) {
                assert(m_valid && "You can't use the RelationsMap any more after calling build_index()");
                for (const auto& member : relation.members()) {
                    if (member.type() == osmium::item_type::relation) {
                        add(member.positive_ref(), relation.positive_id());
                    }
                }
            }
 
            bool empty() const noexcept {
                assert(m_valid && "You can't use the RelationsMap any more after calling build_index()");
                return m_map32.empty() && m_map64.empty();
            }
 
            std::size_t size() const noexcept {
                assert(m_valid && "You can't use the RelationsMap any more after calling build_index()");
                return m_map32.size() + m_map64.size();
            }
 
            std::pair<std::size_t, std::size_t> sizes() const noexcept {
                return std::make_pair(m_map32.size(), m_map64.size());
            }
 
            RelationsMapIndex build_member_to_parent_index() {
                assert(m_valid && "You can't use the RelationsMap any more after calling build_member_to_parent_index()");
#ifndef NDEBUG
                m_valid = false;
#endif
                m_map32.sort_unique();
                if (m_map64.empty()) {
                    return RelationsMapIndex{std::move(m_map32)};
                }
 
                append32to64(m_map32, m_map64);
 
                return RelationsMapIndex{std::move(m_map64)};
            }
 
            RelationsMapIndex build_parent_to_member_index() {
                assert(m_valid && "You can't use the RelationsMap any more after calling build_parent_to_member_index()");
#ifndef NDEBUG
                m_valid = false;
#endif
                m_map32.flip_in_place();
                m_map32.sort_unique();
                if (m_map64.empty()) {
                    return RelationsMapIndex{std::move(m_map32)};
                }
 
                m_map64.flip_in_place();
                append32to64(m_map32, m_map64);
 
                return RelationsMapIndex{std::move(m_map64)};
            }
 
            RelationsMapIndexes build_indexes() {
                assert(m_valid && "You can't use the RelationsMap any more after calling build_indexes()");
#ifndef NDEBUG
                m_valid = false;
#endif
                auto reverse_map32 = m_map32.flip_copy();
                reverse_map32.sort_unique();
                m_map32.sort_unique();
                if (m_map64.empty()) {
                    return RelationsMapIndexes{std::move(m_map32), std::move(reverse_map32)};
                }
 
                auto reverse_map64 = m_map64.flip_copy();
                append32to64(reverse_map32, reverse_map64);
                append32to64(m_map32, m_map64);
 
                return RelationsMapIndexes{std::move(m_map64), std::move(reverse_map64)};
            }
 
        }; // class RelationsMapStash
 
        // defined outside the class on purpose
        // see https://akrzemi1.wordpress.com/2015/09/11/declaring-the-move-constructor/
        inline RelationsMapStash::RelationsMapStash(RelationsMapStash&&) noexcept = default; // NOLINT(readability-redundant-inline-specifier)
        inline RelationsMapStash& RelationsMapStash::operator=(RelationsMapStash&&) noexcept = default; // NOLINT(readability-redundant-inline-specifier)
 
    } // namespace index
 
} // namespace osmium
 
#endif // OSMIUM_INDEX_RELATIONS_MAP_HPP