ClickHouse/base/poco/Foundation/include/Poco/ListMap.h

//
// ListMap.h
//
// Library: Foundation
// Package: Hashing
// Module:  ListMap
//
// Definition of the ListMap class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_ListMap_INCLUDED
#define Foundation_ListMap_INCLUDED


#include <list>
#include <utility>
#include "Poco/Exception.h"
#include "Poco/Foundation.h"
#include "Poco/String.h"


namespace Poco
{


template <class Key, class Mapped, class Container = std::list<std::pair<Key, Mapped>>, bool CaseSensitive = false>
class ListMap
/// This class implements a multimap in terms of a sequential container.
/// The use for this type of associative container is wherever automatic
/// ordering of elements is not desirable. Naturally, this container will
/// have inferior data retrieval performance and it is not recommended for
/// use with large datasets. The main purpose within POCO is for Internet
/// messages (email message, http headers etc), to prevent automatic
/// header entry reordering.
{
public:
    typedef Key KeyType;
    typedef Mapped MappedType;
    typedef Mapped & Reference;
    typedef const Mapped & ConstReference;
    typedef Mapped * Pointer;
    typedef const Mapped * ConstPointer;

    typedef typename Container::value_type ValueType;
    typedef typename Container::size_type SizeType;
    typedef typename Container::iterator Iterator;
    typedef typename Container::const_iterator ConstIterator;

    ListMap()
    /// Creates an empty ListMap.
    {
    }

    ListMap(std::size_t initialReserve) : _list(initialReserve)
    /// Creates the ListMap with room for initialReserve entries.
    {
    }

    ListMap & operator=(const ListMap & map)
    /// Assigns another ListMap.
    {
        ListMap tmp(map);
        swap(tmp);
        return *this;
    }

    void swap(ListMap & map)
    /// Swaps the ListMap with another one.
    {
        _list.swap(map._list);
    }

    ConstIterator begin() const
    /// Returns the beginning of the map.
    {
        return _list.begin();
    }

    ConstIterator end() const
    /// Returns the end of the map.
    {
        return _list.end();
    }

    Iterator begin()
    /// Returns the beginning of the map.
    {
        return _list.begin();
    }

    Iterator end()
    /// Returns the end of the map.
    {
        return _list.end();
    }

    ConstIterator find(const KeyType & key) const
    /// Finds the first occurrence of the key and
    /// returns iterator pointing to the found entry
    /// or iterator pointing to the end if entry is
    /// not found.
    {
        typename Container::const_iterator it = _list.begin();
        typename Container::const_iterator itEnd = _list.end();
        for (; it != itEnd; ++it)
        {
            if (isEqual(it->first, key))
                return it;
        }
        return itEnd;
    }

    Iterator find(const KeyType & key)
    /// Finds the first occurrence of the key and
    /// returns iterator pointing to the found entry
    /// or iterator pointing to the end if entry is
    /// not found.
    {
        typename Container::iterator it = _list.begin();
        typename Container::iterator itEnd = _list.end();
        for (; it != itEnd; ++it)
        {
            if (isEqual(it->first, key))
                return it;
        }
        return itEnd;
    }

    Iterator insert(const ValueType & val)
    /// Inserts the value into the map. If one or more values
    /// already exist, new value is inserted at the end of the
    /// block. Thus, all the equal value entries are located
    /// sequentially at all times.
    /// Returns iterator pointing to the newly inserted value
    {
        Iterator it = find(val.first);
        while (it != _list.end() && isEqual(it->first, val.first))
            ++it;
        return _list.insert(it, val);
    }

    void erase(Iterator it) { _list.erase(it); }

    SizeType erase(const KeyType & key)
    {
        SizeType count = 0;
        Iterator it = find(key);
        bool removed = false;
        while (it != _list.end())
        {
            if (isEqual(it->first, key))
            {
                ++count;
                it = _list.erase(it);
                removed = true;
            }
            else
            {
                if (removed)
                    return count;
                ++it;
            }
        }
        return count;
    }

    void clear() { _list.clear(); }

    std::size_t size() const { return _list.size(); }

    bool empty() const { return _list.empty(); }

    ConstReference operator[](const KeyType & key) const
    {
        ConstIterator it = find(key);
        if (it != _list.end())
            return it->second;
        else
            throw NotFoundException();
    }

    Reference operator[](const KeyType & key)
    {
        Iterator it = find(key);
        if (it != _list.end())
            return it->second;
        else
        {
            ValueType value(key, Mapped());
            Iterator itInsert = insert(value);
            return itInsert->second;
        }
    }

private:
    template <typename T1, typename T2>
    bool isEqual(T1 val1, T2 val2) const
    {
        return val1 == val2;
    }

    bool isEqual(const std::string & s1, const std::string & s2) const
    {
        if (!CaseSensitive)
            return Poco::icompare(s1, s2) == 0;
        else
            return s1 == s2;
    }

    bool isEqual(const std::string & s1, const char * s2) const { return isEqual(s1, std::string(s2)); }

    bool isEqual(const char * s1, const std::string & s2) const { return isEqual(std::string(s1), s2); }

    bool isEqual(const char * s1, const char * s2) const { return isEqual(std::string(s1), std::string(s2)); }

    Container _list;
};


} // namespace Poco


#endif // Foundation_ListMap_INCLUDED