trie_map.hpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 * Copyright (c) 2015-2016 Kohei Yoshida
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#ifndef INCLUDED_MDDS_TRIE_MAP_HPP
#define INCLUDED_MDDS_TRIE_MAP_HPP

#include "trie_map_itr.hpp"

#include <vector>
#include <string>
#include <deque>
#include <map>

namespace mdds {

namespace trie {

struct std_string_trait
{
    typedef std::string key_type;

    typedef std::string key_buffer_type;

    typedef char key_unit_type;

    static key_buffer_type to_key_buffer(const key_unit_type* str, size_t length)
    {
        return key_buffer_type(str, length);
    }

    static key_buffer_type to_key_buffer(const key_type& key)
    {
        return key_buffer_type(key);
    }

    static const key_unit_type* buffer_data(const key_buffer_type& buf)
    {
        return buf.data();
    }

    static size_t buffer_size(const key_buffer_type& buf)
    {
        return buf.size();
    }

    static void push_back(key_buffer_type& buffer, key_unit_type c)
    {
        buffer.push_back(c);
    }

    static void pop_back(key_buffer_type& buffer)
    {
        buffer.pop_back();
    }

    static key_type to_key(const key_buffer_type& buf)
    {
        return buf;
    }
};

}

template<typename _KeyTrait, typename _ValueT>
class packed_trie_map;

template<typename _KeyTrait, typename _ValueT>
class trie_map
{
    friend class packed_trie_map<_KeyTrait, _ValueT>;
    friend class trie::detail::iterator_base<trie_map>;
    friend class trie::detail::search_results<trie_map>;

public:
    typedef packed_trie_map<_KeyTrait, _ValueT> packed_type;
    typedef _KeyTrait key_trait_type;
    typedef typename key_trait_type::key_type key_type;
    typedef typename key_trait_type::key_buffer_type key_buffer_type;
    typedef typename key_trait_type::key_unit_type   key_unit_type;
    typedef _ValueT value_type;
    typedef size_t size_type;
    typedef std::pair<key_type, value_type> key_value_type;

    typedef trie::detail::iterator_base<trie_map> const_iterator;
    typedef trie::detail::search_results<trie_map> search_results;

private:

    struct trie_node
    {
        typedef std::map<key_unit_type, trie_node> children_type;

        children_type children;
        value_type value;
        bool has_value;

        trie_node() : value(value_type()), has_value(false) {}
    };

    struct stack_item
    {
        typedef typename trie_node::children_type::const_iterator child_pos_type;
        const trie_node* node;
        child_pos_type child_pos;

        stack_item(const trie_node* _node, const child_pos_type& _child_pos) :
            node(_node), child_pos(_child_pos) {}

        bool operator== (const stack_item& r) const
        {
            return node == r.node && child_pos == r.child_pos;
        }

        bool operator!= (const stack_item& r) const
        {
            return !operator== (r);
        }
    };

    typedef std::vector<stack_item> node_stack_type;

public:

    trie_map();

    const_iterator begin() const;

    const_iterator end() const;

    void insert(const key_type& key, const value_type& value);

    void insert(const key_unit_type* key, size_type len, const value_type& value);

    bool erase(const key_unit_type* key, size_type len);

    const_iterator find(const key_type& key) const;

    const_iterator find(const key_unit_type* input, size_type len) const;

    search_results prefix_search(const key_type& prefix) const;

    search_results prefix_search(const key_unit_type* prefix, size_type len) const;

    size_type size() const;

    void clear();

    packed_type pack() const;

private:
    void insert_into_tree(
        trie_node& node, const key_unit_type* key, const key_unit_type* key_end, const value_type& value);

    const trie_node* find_prefix_node(
        const trie_node& node, const key_unit_type* prefix, const key_unit_type* prefix_end) const;

    void find_prefix_node_with_stack(
        node_stack_type& node_stack,
        const trie_node& node, const key_unit_type* prefix, const key_unit_type* prefix_end) const;

    void count_values(size_type& n, const trie_node& node) const;

private:
    trie_node m_root;
};

template<typename _KeyTrait, typename _ValueT>
class packed_trie_map
{
    friend class trie::detail::packed_iterator_base<packed_trie_map>;
    friend class trie::detail::packed_search_results<packed_trie_map>;

public:
    typedef _KeyTrait key_trait_type;
    typedef typename key_trait_type::key_type key_type;
    typedef typename key_trait_type::key_buffer_type key_buffer_type;
    typedef typename key_trait_type::key_unit_type   key_unit_type;
    typedef _ValueT value_type;
    typedef size_t size_type;
    typedef std::pair<key_type, value_type> key_value_type;
    typedef trie::detail::packed_iterator_base<packed_trie_map> const_iterator;
    typedef trie::detail::packed_search_results<packed_trie_map> search_results;

    struct entry
    {
        const key_unit_type* key;
        size_type keylen;
        value_type value;

        entry(const key_unit_type* _key, size_type _keylen, value_type _value) :
            key(_key), keylen(_keylen), value(_value) {}
    };

private:
    struct trie_node
    {
        key_unit_type key;
        const value_type* value;

        std::deque<trie_node*> children;

        trie_node(key_unit_type _key) : key(_key), value(nullptr) {}
    };

    struct stack_item
    {
        const uintptr_t* node_pos;
        const uintptr_t* child_pos;
        const uintptr_t* child_end;

        stack_item(const uintptr_t* _node_pos, const uintptr_t* _child_pos, const uintptr_t* _child_end) :
            node_pos(_node_pos), child_pos(_child_pos), child_end(_child_end) {}

        bool operator== (const stack_item& other) const
        {
            return node_pos == other.node_pos && child_pos == other.child_pos;
        }

        bool operator!= (const stack_item& other) const
        {
            return !operator==(other);
        }

        bool has_value() const
        {
            const value_type* pv = reinterpret_cast<const value_type*>(*node_pos);
            return pv;
        }

        const value_type* get_value() const
        {
            return reinterpret_cast<const value_type*>(*node_pos);
        }
    };

    typedef std::vector<stack_item> node_stack_type;

    typedef std::deque<trie_node> node_pool_type;
    typedef std::vector<uintptr_t> packed_type;
    typedef std::deque<value_type> value_store_type;
    typedef std::vector<std::tuple<size_t, key_unit_type>> child_offsets_type;

public:

    packed_trie_map() = delete;

    packed_trie_map(const entry* entries, size_type entry_size);

    packed_trie_map(const trie_map<key_trait_type, value_type>& other);

    const_iterator begin() const;

    const_iterator end() const;

    const_iterator find(const key_type& key) const;

    const_iterator find(const key_unit_type* input, size_type len) const;

    search_results prefix_search(const key_type& prefix) const;

    search_results prefix_search(const key_unit_type* prefix, size_type len) const;

    size_type size() const;

private:
    node_stack_type get_root_stack() const;

    void traverse_range(
        trie_node& root, node_pool_type& node_pool, const entry* start, const entry* end,
        size_type pos);

    size_type compact_node(const trie_node& node);
    size_type compact_node(const typename trie_map<_KeyTrait, _ValueT>::trie_node& node);

    void push_child_offsets(size_type offset, const child_offsets_type& child_offsets);

    void compact(const trie_node& root);
    void compact(const typename trie_map<_KeyTrait, _ValueT>::trie_node& root);

    const uintptr_t* find_prefix_node(
        const uintptr_t* p, const key_unit_type* prefix, const key_unit_type* prefix_end) const;

    void find_prefix_node_with_stack(
        node_stack_type& node_stack,
        const uintptr_t* p, const key_unit_type* prefix, const key_unit_type* prefix_end) const;

#ifdef MDDS_TRIE_MAP_DEBUG
    void dump_node(key_buffer_type& buffer, const trie_node& node) const;
    void dump_trie(const trie_node& root) const;
    void dump_packed_trie(const std::vector<uintptr_t>& packed) const;
#endif

private:
    size_type m_entry_size;

    value_store_type m_value_store;
    packed_type m_packed;
};

}

#include "trie_map_def.inl"

#endif

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