htrie_map.h

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/**
 * MIT License
 * 
 * Copyright (c) 2017 Tessil
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * 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 AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#ifndef TSL_HTRIE_MAP_H
#define TSL_HTRIE_MAP_H

#include <cstddef>
#include <cstring>
#include <initializer_list>
#include <string>
#include <utility>
#include "htrie_hash.h"

namespace tsl {

/**
 * Implementation of a hat-trie map.
 * 
 * The value T must be either nothrow move-constructible/assignable, copy-constuctible or both.
 * 
 * The size of a key string is limited to std::numeric_limits<KeySizeT>::max() - 1. 
 * That is 65 535 characters by default, but can be raised with the KeySizeT template parameter. 
 * See max_key_size() for an easy access to this limit.
 * 
 * Iterators invalidation:
 *  - clear, operator=: always invalidate the iterators.
 *  - insert, emplace, operator[]: always invalidate the iterators.
 *  - erase: always invalidate the iterators.
 */
template<class CharT,
         class T,
         class Hash = tsl::ah::str_hash<CharT>,
         class KeySizeT = std::uint16_t>
class htrie_map {
private:
    template<typename U>
    using is_iterator = tsl::detail_array_hash::is_iterator<U>;

    using ht = tsl::detail_htrie_hash::htrie_hash<CharT, T, Hash, KeySizeT>;

public:
    using char_type = typename ht::char_type;
    using mapped_type = T;
    using key_size_type = typename ht::key_size_type;
    using size_type = typename ht::size_type;
    using hasher = typename ht::hasher;
    using iterator = typename ht::iterator;
    using const_iterator = typename ht::const_iterator;
    using prefix_iterator = typename ht::prefix_iterator;
    using const_prefix_iterator = typename ht::const_prefix_iterator;

public:
    explicit htrie_map(const Hash& hash = Hash()): m_ht(hash, ht::HASH_NODE_DEFAULT_MAX_LOAD_FACTOR,
                                                        ht::DEFAULT_BURST_THRESHOLD)
    {
    }

    explicit htrie_map(size_type burst_threshold,
                       const Hash& hash = Hash()): m_ht(hash, ht::HASH_NODE_DEFAULT_MAX_LOAD_FACTOR,
                                                        burst_threshold)
    {
    }

    template<class InputIt, typename std::enable_if<is_iterator<InputIt>::value>::type* = nullptr>
    htrie_map(InputIt first, InputIt last,
              const Hash& hash = Hash()): htrie_map(hash)
    {
        insert(first, last);
    }



#ifdef TSL_HT_HAS_STRING_VIEW
    htrie_map(std::initializer_list<std::pair<std::basic_string_view<CharT>, T>> init,
              const Hash& hash = Hash()): htrie_map(hash)
    {
        insert(init);
    }
#else
    htrie_map(std::initializer_list<std::pair<const CharT*, T>> init,
              const Hash& hash = Hash()): htrie_map(hash)
    {
        insert(init);
    }
#endif



#ifdef TSL_HT_HAS_STRING_VIEW
    htrie_map& operator=(std::initializer_list<std::pair<std::basic_string_view<CharT>, T>> ilist) {
        clear();
        insert(ilist);

        return *this;
    }
#else
    htrie_map& operator=(std::initializer_list<std::pair<const CharT*, T>> ilist) {
        clear();
        insert(ilist);

        return *this;
    }
#endif



    /*
     * Iterators
     */
    iterator begin() noexcept { return m_ht.begin(); }
    const_iterator begin() const noexcept { return m_ht.begin(); }
    const_iterator cbegin() const noexcept { return m_ht.cbegin(); }

    iterator end() noexcept { return m_ht.end(); }
    const_iterator end() const noexcept { return m_ht.end(); }
    const_iterator cend() const noexcept { return m_ht.cend(); }


    /*
     * Capacity
     */
    bool empty() const noexcept { return m_ht.empty(); }
    size_type size() const noexcept { return m_ht.size(); }
    size_type max_size() const noexcept { return m_ht.max_size(); }
    size_type max_key_size() const noexcept { return m_ht.max_key_size(); }

    /**
     * Call shrink_to_fit() on each hash node of the hat-trie to reduce its size.
     */
    void shrink_to_fit() { m_ht.shrink_to_fit(); }


    /*
     * Modifiers
     */
    void clear() noexcept { m_ht.clear(); }



    std::pair<iterator, bool> insert_ks(const CharT* key, size_type key_size, const T& value) {
        return m_ht.insert(key, key_size, value);
    }
#ifdef TSL_HT_HAS_STRING_VIEW
    std::pair<iterator, bool> insert(const std::basic_string_view<CharT>& key, const T& value) {
        return m_ht.insert(key.data(), key.size(), value);
    }
#else
    std::pair<iterator, bool> insert(const CharT* key, const T& value) {
        return m_ht.insert(key, std::strlen(key), value);
    }

    std::pair<iterator, bool> insert(const std::basic_string<CharT>& key, const T& value) {
        return m_ht.insert(key.data(), key.size(), value);
    }
#endif



    std::pair<iterator, bool> insert_ks(const CharT* key, size_type key_size, T&& value) {
        return m_ht.insert(key, key_size, std::move(value));
    }
#ifdef TSL_HT_HAS_STRING_VIEW
    std::pair<iterator, bool> insert(const std::basic_string_view<CharT>& key, T&& value) {
        return m_ht.insert(key.data(), key.size(), std::move(value));
    }
#else
    std::pair<iterator, bool> insert(const CharT* key, T&& value) {
        return m_ht.insert(key, std::strlen(key), std::move(value));
    }

    std::pair<iterator, bool> insert(const std::basic_string<CharT>& key, T&& value) {
        return m_ht.insert(key.data(), key.size(), std::move(value));
    }
#endif



    template<class InputIt, typename std::enable_if<is_iterator<InputIt>::value>::type* = nullptr>
    void insert(InputIt first, InputIt last) {
        for(auto it = first; it != last; ++it) {
            insert_pair(*it);
        }
    }



#ifdef TSL_HT_HAS_STRING_VIEW
    void insert(std::initializer_list<std::pair<std::basic_string_view<CharT>, T>> ilist) {
        insert(ilist.begin(), ilist.end());
    }
#else
    void insert(std::initializer_list<std::pair<const CharT*, T>> ilist) {
        insert(ilist.begin(), ilist.end());
    }
#endif



    template<class... Args>
    std::pair<iterator, bool> emplace_ks(const CharT* key, size_type key_size, Args&&... args) {
        return m_ht.insert(key, key_size, std::forward<Args>(args)...);
    }
#ifdef TSL_HT_HAS_STRING_VIEW
    template<class... Args>
    std::pair<iterator, bool> emplace(const std::basic_string_view<CharT>& key, Args&&... args) {
        return m_ht.insert(key.data(), key.size(), std::forward<Args>(args)...);
    }
#else
    template<class... Args>
    std::pair<iterator, bool> emplace(const CharT* key, Args&&... args) {
        return m_ht.insert(key, std::strlen(key), std::forward<Args>(args)...);
    }

    template<class... Args>
    std::pair<iterator, bool> emplace(const std::basic_string<CharT>& key, Args&&... args) {
        return m_ht.insert(key.data(), key.size(), std::forward<Args>(args)...);
    }
#endif



    iterator erase(const_iterator pos) { return m_ht.erase(pos); }
    iterator erase(const_iterator first, const_iterator last) { return m_ht.erase(first, last); }



    size_type erase_ks(const CharT* key, size_type key_size) {
        return m_ht.erase(key, key_size);
    }
#ifdef TSL_HT_HAS_STRING_VIEW
    size_type erase(const std::basic_string_view<CharT>& key) {
        return m_ht.erase(key.data(), key.size());
    }
#else
    size_type erase(const CharT* key) {
        return m_ht.erase(key, std::strlen(key));
    }

    size_type erase(const std::basic_string<CharT>& key) {
        return m_ht.erase(key.data(), key.size());
    }
#endif



    /**
     * Erase all the elements which have 'prefix' as prefix. Return the number of erase elements.
     */
    size_type erase_prefix_ks(const CharT* prefix, size_type prefix_size) {
        return m_ht.erase_prefix(prefix, prefix_size);
    }
#ifdef TSL_HT_HAS_STRING_VIEW
    /**
     * @copydoc erase_prefix_ks(const CharT* prefix, size_type prefix_size)
     */
    size_type erase_prefix(const std::basic_string_view<CharT>& prefix) {
        return m_ht.erase_prefix(prefix.data(), prefix.size());
    }
#else
    /**
     * @copydoc erase_prefix_ks(const CharT* prefix, size_type prefix_size)
     */
    size_type erase_prefix(const CharT* prefix) {
        return m_ht.erase_prefix(prefix, std::strlen(prefix));
    }

    /**
     * @copydoc erase_prefix_ks(const CharT* prefix, size_type prefix_size)
     */
    size_type erase_prefix(const std::basic_string<CharT>& prefix) {
        return m_ht.erase_prefix(prefix.data(), prefix.size());
    }
#endif



    void swap(htrie_map& other) { other.m_ht.swap(m_ht); }

    /*
     * Lookup
     */
    T& at_ks(const CharT* key, size_type key_size) { return m_ht.at(key, key_size); }
    const T& at_ks(const CharT* key, size_type key_size) const { return m_ht.at(key, key_size); }

#ifdef TSL_HT_HAS_STRING_VIEW
    T& at(const std::basic_string_view<CharT>& key) { return m_ht.at(key.data(), key.size()); }
    const T& at(const std::basic_string_view<CharT>& key) const { return m_ht.at(key.data(), key.size()); }
#else
    T& at(const CharT* key) { return m_ht.at(key, std::strlen(key)); }
    const T& at(const CharT* key) const { return m_ht.at(key, std::strlen(key)); }

    T& at(const std::basic_string<CharT>& key) { return m_ht.at(key.data(), key.size()); }
    const T& at(const std::basic_string<CharT>& key) const { return m_ht.at(key.data(), key.size()); }
#endif



#ifdef TSL_HT_HAS_STRING_VIEW
    T& operator[](const std::basic_string_view<CharT>& key) { return m_ht.access_operator(key.data(), key.size()); }
#else
    T& operator[](const CharT* key) { return m_ht.access_operator(key, std::strlen(key)); }
    T& operator[](const std::basic_string<CharT>& key) { return m_ht.access_operator(key.data(), key.size()); }
#endif



    size_type count_ks(const CharT* key, size_type key_size) const { return m_ht.count(key, key_size); }
#ifdef TSL_HT_HAS_STRING_VIEW
    size_type count(const std::basic_string_view<CharT>& key) const { return m_ht.count(key.data(), key.size()); }
#else
    size_type count(const CharT* key) const { return m_ht.count(key, std::strlen(key)); }
    size_type count(const std::basic_string<CharT>& key) const { return m_ht.count(key.data(), key.size()); }
#endif



    iterator find_ks(const CharT* key, size_type key_size) {
        return m_ht.find(key, key_size);
    }

    const_iterator find_ks(const CharT* key, size_type key_size) const {
        return m_ht.find(key, key_size);
    }
#ifdef TSL_HT_HAS_STRING_VIEW
    iterator find(const std::basic_string_view<CharT>& key) {
        return m_ht.find(key.data(), key.size());
    }

    const_iterator find(const std::basic_string_view<CharT>& key) const {
        return m_ht.find(key.data(), key.size());
    }
#else
    iterator find(const CharT* key) {
        return m_ht.find(key, std::strlen(key));
    }

    const_iterator find(const CharT* key) const {
        return m_ht.find(key, std::strlen(key));
    }

    iterator find(const std::basic_string<CharT>& key) {
        return m_ht.find(key.data(), key.size());
    }

    const_iterator find(const std::basic_string<CharT>& key) const {
        return m_ht.find(key.data(), key.size());
    }
#endif



    std::pair<iterator, iterator> equal_range_ks(const CharT* key, size_type key_size) {
        return m_ht.equal_range(key, key_size);
    }

    std::pair<const_iterator, const_iterator> equal_range_ks(const CharT* key, size_type key_size) const {
        return m_ht.equal_range(key, key_size);
    }
#ifdef TSL_HT_HAS_STRING_VIEW
    std::pair<iterator, iterator> equal_range(const std::basic_string_view<CharT>& key) {
        return m_ht.equal_range(key.data(), key.size());
    }

    std::pair<const_iterator, const_iterator> equal_range(const std::basic_string_view<CharT>& key) const {
        return m_ht.equal_range(key.data(), key.size());
    }
#else
    std::pair<iterator, iterator> equal_range(const CharT* key) {
        return m_ht.equal_range(key, std::strlen(key));
    }

    std::pair<const_iterator, const_iterator> equal_range(const CharT* key) const {
        return m_ht.equal_range(key, std::strlen(key));
    }

    std::pair<iterator, iterator> equal_range(const std::basic_string<CharT>& key) {
        return m_ht.equal_range(key.data(), key.size());
    }

    std::pair<const_iterator, const_iterator> equal_range(const std::basic_string<CharT>& key) const {
        return m_ht.equal_range(key.data(), key.size());
    }
#endif


    /**
     * Return a range containing all the elements which have 'prefix' as prefix. The range is defined by a pair
     * of iterator, the first being the begin iterator and the second being the end iterator.
     */
    std::pair<prefix_iterator, prefix_iterator> equal_prefix_range_ks(const CharT* prefix, size_type prefix_size) {
        return m_ht.equal_prefix_range(prefix, prefix_size);
    }

    /**
     * @copydoc equal_prefix_range_ks(const CharT* prefix, size_type prefix_size)
     */
    std::pair<const_prefix_iterator, const_prefix_iterator> equal_prefix_range_ks(const CharT* prefix, size_type prefix_size) const {
        return m_ht.equal_prefix_range(prefix, prefix_size);
    }
#ifdef TSL_HT_HAS_STRING_VIEW
    /**
     * @copydoc equal_prefix_range_ks(const CharT* prefix, size_type prefix_size)
     */
    std::pair<prefix_iterator, prefix_iterator> equal_prefix_range(const std::basic_string_view<CharT>& prefix) {
        return m_ht.equal_prefix_range(prefix.data(), prefix.size());
    }

    /**
     * @copydoc equal_prefix_range_ks(const CharT* prefix, size_type prefix_size)
     */
    std::pair<const_prefix_iterator, const_prefix_iterator> equal_prefix_range(const std::basic_string_view<CharT>& prefix) const {
        return m_ht.equal_prefix_range(prefix.data(), prefix.size());
    }
#else
    /**
     * @copydoc equal_prefix_range_ks(const CharT* prefix, size_type prefix_size)
     */
    std::pair<prefix_iterator, prefix_iterator> equal_prefix_range(const CharT* prefix) {
        return m_ht.equal_prefix_range(prefix, std::strlen(prefix));
    }

    /**
     * @copydoc equal_prefix_range_ks(const CharT* prefix, size_type prefix_size)
     */
    std::pair<const_prefix_iterator, const_prefix_iterator> equal_prefix_range(const CharT* prefix) const {
        return m_ht.equal_prefix_range(prefix, std::strlen(prefix));
    }

    /**
     * @copydoc equal_prefix_range_ks(const CharT* prefix, size_type prefix_size)
     */
    std::pair<prefix_iterator, prefix_iterator> equal_prefix_range(const std::basic_string<CharT>& prefix) {
        return m_ht.equal_prefix_range(prefix.data(), prefix.size());
    }

    /**
     * @copydoc equal_prefix_range_ks(const CharT* prefix, size_type prefix_size)
     */
    std::pair<const_prefix_iterator, const_prefix_iterator> equal_prefix_range(const std::basic_string<CharT>& prefix) const {
        return m_ht.equal_prefix_range(prefix.data(), prefix.size());
    }
#endif



    /**
     * Return the element in the trie which is the longest prefix of `key`. If no
     * element in the trie is a prefix of `key`, the end iterator is returned.
     * 
     * Example: 
     * 
     *     tsl::htrie_map<char, int> map = {{"/foo", 1}, {"/foo/bar", 1}};
     *     
     *     map.longest_prefix("/foo"); // returns {"/foo", 1} 
     *     map.longest_prefix("/foo/baz"); // returns {"/foo", 1} 
     *     map.longest_prefix("/foo/bar/baz"); // returns {"/foo/bar", 1} 
     *     map.longest_prefix("/foo/bar/"); // returns {"/foo/bar", 1} 
     *     map.longest_prefix("/bar"); // returns end() 
     *     map.longest_prefix(""); // returns end() 
     */
    iterator longest_prefix_ks(const CharT* key, size_type key_size) {
        return m_ht.longest_prefix(key, key_size);
    }

    /**
     * @copydoc longest_prefix_ks(const CharT* key, size_type key_size)
     */
    const_iterator longest_prefix_ks(const CharT* key, size_type key_size) const {
        return m_ht.longest_prefix(key, key_size);
    }
#ifdef TSL_HT_HAS_STRING_VIEW
    /**
     * @copydoc longest_prefix_ks(const CharT* key, size_type key_size)
     */
    iterator longest_prefix(const std::basic_string_view<CharT>& key) {
        return m_ht.longest_prefix(key.data(), key.size());
    }

    /**
     * @copydoc longest_prefix_ks(const CharT* key, size_type key_size)
     */
    const_iterator longest_prefix(const std::basic_string_view<CharT>& key) const {
        return m_ht.longest_prefix(key.data(), key.size());
    }
#else
    /**
     * @copydoc longest_prefix_ks(const CharT* key, size_type key_size)
     */
    iterator longest_prefix(const CharT* key) {
        return m_ht.longest_prefix(key, std::strlen(key));
    }

    /**
     * @copydoc longest_prefix_ks(const CharT* key, size_type key_size)
     */
    const_iterator longest_prefix(const CharT* key) const {
        return m_ht.longest_prefix(key, std::strlen(key));
    }

    /**
     * @copydoc longest_prefix_ks(const CharT* key, size_type key_size)
     */
    iterator longest_prefix(const std::basic_string<CharT>& key) {
        return m_ht.longest_prefix(key.data(), key.size());
    }

    /**
     * @copydoc longest_prefix_ks(const CharT* key, size_type key_size)
     */
    const_iterator longest_prefix(const std::basic_string<CharT>& key) const {
        return m_ht.longest_prefix(key.data(), key.size());
    }
#endif



    /*
     *  Hash policy 
     */
    float max_load_factor() const { return m_ht.max_load_factor(); }
    void max_load_factor(float ml) { m_ht.max_load_factor(ml); }


    /*
     * Burst policy
     */
    size_type burst_threshold() const { return m_ht.burst_threshold(); }
    void burst_threshold(size_type threshold) { m_ht.burst_threshold(threshold); }


    /*
     * Observers
     */
    hasher hash_function() const { return m_ht.hash_function(); }



    /*
     * Other
     */

    /**
     * Serialize the map through the `serializer` parameter.
     * 
     * The `serializer` parameter must be a function object that supports the following calls:
     *  - `void operator()(const U& value);` where the types `std::uint64_t`, `float` and `T` must be supported for U.
     *  - `void operator()(const CharT* value, std::size_t value_size);`
     * 
     * The implementation leaves binary compatibilty (endianness, IEEE 754 for floats, ...) of the types it serializes
     * in the hands of the `Serializer` function object if compatibilty is required.
     */
    template<class Serializer>
    void serialize(Serializer& serializer) const {
        m_ht.serialize(serializer);
    }


    /**
     * Deserialize a previouly serialized map through the `deserializer` parameter.
     * 
     * The `deserializer` parameter must be a function object that supports the following calls:
     *  - `template<typename U> U operator()();` where the types `std::uint64_t`, `float` and `T` must be supported for U.
     *  - `void operator()(CharT* value_out, std::size_t value_size);`
     * 
     * If the deserialized hash map part of the hat-trie is hash compatible with the serialized map, the deserialization process 
     * can be sped up by setting `hash_compatible` to true. To be hash compatible, the Hash (take care of the 32-bits vs 64 bits), 
     * and KeySizeT must behave the same than the ones used in the serialized map. Otherwise the behaviour is undefined 
     * with `hash_compatible` sets to true.
     * 
     * The behaviour is undefined if the type `CharT` and `T` of the `htrie_map` are not the same as the
     * types used during serialization.
     * 
     * The implementation leaves binary compatibilty (endianness, IEEE 754 for floats, size of int, ...) of the types it 
     * deserializes in the hands of the `Deserializer` function object if compatibilty is required.
     */
    template<class Deserializer>
    static htrie_map deserialize(Deserializer& deserializer, bool hash_compatible = false) {
        htrie_map map;
        map.m_ht.deserialize(deserializer, hash_compatible);

        return map;
    }

    friend bool operator==(const htrie_map& lhs, const htrie_map& rhs) {
        if(lhs.size() != rhs.size()) {
            return false;
        }

        std::string key_buffer;
        for(auto it = lhs.cbegin(); it != lhs.cend(); ++it) {
            it.key(key_buffer);

            const auto it_element_rhs = rhs.find(key_buffer);
            if(it_element_rhs == rhs.cend() || it.value() != it_element_rhs.value()) {
                return false;
            }
        }

        return true;
    }

    friend bool operator!=(const htrie_map& lhs, const htrie_map& rhs) {
        return !operator==(lhs, rhs);
    }

    friend void swap(htrie_map& lhs, htrie_map& rhs) {
        lhs.swap(rhs);
    }

private:
    template<class U, class V>
    void insert_pair(const std::pair<U, V>& value) {
        insert(value.first, value.second);
    }

    template<class U, class V>
    void insert_pair(std::pair<U, V>&& value) {
        insert(value.first, std::move(value.second));
    }

private:
    ht m_ht;
};

} // end namespace tsl

#endif