sorted_string_map.hpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 
// SPDX-FileCopyrightText: 2022 - 2025 Kohei Yoshida
//
// SPDX-License-Identifier: MIT
 
#pragma once
 
#include "./cref_wrapper.hpp"
 
#include <string_view>
#include <unordered_map>
 
namespace mdds {
 
namespace ssmap {
namespace detail {
 
template<typename ValueT>
struct map_entry
{
    std::string_view key;
    ValueT value;
};
 
} // namespace detail

template<typename ValueT>
class linear_key_finder
{
    using value_type = ValueT;
    using size_type = typename std::string_view::size_type;
    using entry_type = detail::map_entry<ValueT>;
 
    const entry_type* m_entries;
    const entry_type* m_entries_end;
 
public:
    linear_key_finder(const entry_type* entries, const entry_type* entries_end) noexcept;
 
    std::string_view operator()(const value_type& v) const;
};

template<typename ValueT>
class hash_key_finder
{
    using value_type = ValueT;
    using size_type = typename std::string_view::size_type;
    using entry_type = detail::map_entry<ValueT>;
    using keystore_type = std::unordered_map<
        mdds::detail::cref_wrapper<value_type>, size_type, typename mdds::detail::cref_wrapper<value_type>::hash>;
 
    const entry_type* m_entries;
    keystore_type m_keys;
 
public:
    hash_key_finder(const entry_type* entries, const entry_type* entries_end);
 
    std::string_view operator()(const value_type& v) const;
};
 
} // namespace ssmap

template<typename ValueT, template<typename> class KeyFinderT = ssmap::linear_key_finder>
class sorted_string_map
{
    using func_find_key_type = KeyFinderT<ValueT>;
 
public:
    using value_type = ValueT;
    using size_type = typename std::string_view::size_type;

    using entry_type = ssmap::detail::map_entry<ValueT>;

    sorted_string_map(const entry_type* entries, size_type entry_size, value_type null_value);

    const value_type& find(const char* input, size_type len) const;

    const value_type& find(std::string_view input) const;

    std::string_view find_key(const value_type& v) const;

    size_type size() const;
 
private:
    const entry_type* m_entries;
    const value_type m_null_value;
    const size_type m_entry_size;
    const entry_type* m_entries_end;
 
    func_find_key_type m_func_find_key;
};
 
} // namespace mdds
 
#include "sorted_string_map_def.inl"
 
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