axmol/cocos/base/CCMap.h

/****************************************************************************
 Copyright (c) 2013-2017 Chukong Technologies
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

 http://www.cocos2d-x.org

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 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

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#ifndef __CCMAP_H__
#define __CCMAP_H__

#define USE_STD_UNORDERED_MAP 1

#include "base/ccMacros.h"
#include "base/CCRef.h"
#include <vector>

#if USE_STD_UNORDERED_MAP
#    include <unordered_map>
#else
#    include <map>
#endif

/**
 * @addtogroup base
 * @{
 */
NS_CC_BEGIN

/**
 * Similar to std::unordered_map, but it will manage reference count automatically internally.
 * Which means it will invoke Ref::retain() when adding an element, and invoke Ref::release() when removing an element.
 * @warning The element should be `Ref` or its sub-class.
 * @js NA
 * @lua NA
 */
template <class K, class V, typename H = std::hash<K>, typename E = std::equal_to<K>>
class Map
{
public:
#if USE_STD_UNORDERED_MAP
    typedef tsl::robin_map<K, V, H, E> RefMap;
#else
    typedef std::map<K, V> RefMap;
#endif

    // ------------------------------------------
    // Iterators
    // ------------------------------------------

    /** Iterator, can be used to loop the Map. */
    typedef typename RefMap::iterator iterator;
    /** Const iterator, can be used to loop the Map. */
    typedef typename RefMap::const_iterator const_iterator;

    /** Return iterator to beginning. */
    iterator begin() { return _data.begin(); }
    /** Return const_iterator to beginning. */
    const_iterator begin() const { return _data.begin(); }

    /** Return iterator to end.*/
    iterator end() { return _data.end(); }
    /** Return const_iterator to end.*/
    const_iterator end() const { return _data.end(); }

    /** Return const_iterator to beginning.*/
    const_iterator cbegin() const { return _data.cbegin(); }
    /** Return const_iterator to end.*/
    const_iterator cend() const { return _data.cend(); }

    /** Default constructor */
    Map() : _data()
    {
        static_assert(std::is_convertible<V, Ref*>::value, "Invalid Type for cocos2d::Map<K, V>!");
        CCLOGINFO("In the default constructor of Map!");
    }

    /** Constructor with capacity. */
    explicit Map(ssize_t capacity) : _data()
    {
        static_assert(std::is_convertible<V, Ref*>::value, "Invalid Type for cocos2d::Map<K, V>!");
        CCLOGINFO("In the constructor with capacity of Map!");
        _data.reserve(capacity);
    }

    /** Copy constructor. */
    Map(const Map& other)
    {
        static_assert(std::is_convertible<V, Ref*>::value, "Invalid Type for cocos2d::Map<K, V>!");
        CCLOGINFO("In the copy constructor of Map!");
        _data = other._data;
        addRefForAllObjects();
    }

    /** Move constructor. */
    Map(Map&& other)
    {
        static_assert(std::is_convertible<V, Ref*>::value, "Invalid Type for cocos2d::Map<K, V>!");
        CCLOGINFO("In the move constructor of Map!");
        _data = std::move(other._data);
    }

    /**
     * Destructor.
     * It will release all objects in map.
     */
    ~Map()
    {
        CCLOGINFO("In the destructor of Map!");
        clear();
    }

    /** Sets capacity of the map. */
    void reserve(ssize_t capacity)
    {
#if USE_STD_UNORDERED_MAP
        _data.reserve(capacity);
#endif
    }

    /** Returns the number of buckets in the Map container. */
    ssize_t bucketCount() const
    {
#if USE_STD_UNORDERED_MAP
        return _data.bucket_count();
#else
        return 0;
#endif
    }

    /** Returns the number of elements in bucket n. */
    ssize_t bucketSize(ssize_t n) const
    {
#if USE_STD_UNORDERED_MAP
        return _data.bucket_size(n);
#else
        return 0;
#endif
    }

    /** Returns the bucket number where the element with key k is located. */
    ssize_t bucket(const K& k) const
    {
#if USE_STD_UNORDERED_MAP
        return _data.bucket(k);
#else
        return 0;
#endif
    }

    /** The number of elements in the map. */
    ssize_t size() const { return _data.size(); }

    /**
     * Returns a bool value indicating whether the map container is empty, i.e. whether its size is 0.
     *  @note This function does not modify the content of the container in any way.
     *        To clear the content of an array object, member function unordered_map::clear exists.
     */
    bool empty() const { return _data.empty(); }

    /** Returns all keys in the map. */
    std::vector<K> keys() const
    {
        std::vector<K> keys;

        if (!_data.empty())
        {
            keys.reserve(_data.size());

            for (const auto& iter : _data)
            {
                keys.push_back(iter.first);
            }
        }
        return keys;
    }

    /** Returns all keys that matches the object. */
    std::vector<K> keys(V object) const
    {
        std::vector<K> keys;

        if (!_data.empty())
        {
            keys.reserve(_data.size() / 10);

            for (const auto& iter : _data)
            {
                if (iter.second == object)
                {
                    keys.push_back(iter.first);
                }
            }
        }

        keys.shrink_to_fit();

        return keys;
    }

    /**
     * Returns a reference to the mapped value of the element with key k in the map.
     *
     *  @note If key does not match the key of any element in the container, the function return nullptr.
     *  @param key Key value of the element whose mapped value is accessed.
     *       Member type K is the keys for the elements in the container. defined in Map<K, V> as an alias of its first
     * template parameter (Key).
     */
    template<typename K2>
    const V at(const K2& key) const
    {
        auto iter = _data.find(key);
        if (iter != _data.end())
            return iter->second;
        return nullptr;
    }

    template <typename K2>
    V at(const K2& key)
    {
        auto iter = _data.find(key);
        if (iter != _data.end())
            return iter->second;
        return nullptr;
    }

    /**
     * Searches the container for an element with 'key' as key and returns an iterator to it if found,
     *         otherwise it returns an iterator to Map<K, V>::end (the element past the end of the container).
     *
     * @param key Key to be searched for.
     *        Member type 'K' is the type of the keys for the elements in the container,
     *        defined in Map<K, V> as an alias of its first template parameter (Key).
     */
    template <typename K2>
    const_iterator find(const K2& key) const
    {
        return _data.find(key);
    }

    template <typename K2>
    iterator find(const K2& key)
    {
        return _data.find(key);
    }

    /**
     * Inserts new elements in the map.
     *
     * @note If the container has already contained the key, this function will erase the old pair(key, object)  and
     * insert the new pair.
     * @param key The key to be inserted.
     * @param object The object to be inserted.
     */
    template <typename K2>
    void insert(const K2& key, V object)
    {
        CCASSERT(object != nullptr, "Object is nullptr!");
        object->retain();
        erase(key);
        _data.emplace(key, object);
    }

    /**
     * Removes an element with an iterator from the Map<K, V> container.
     *
     * @param position Iterator pointing to a single element to be removed from the Map<K, V>.
     *        Member type const_iterator is a forward iterator type.
     */
    iterator erase(const_iterator position)
    {
        CCASSERT(position != _data.cend(), "Invalid iterator!");
        position->second->release();
        return _data.erase(position);
    }

    iterator erase(iterator position)
    {
        CCASSERT(position != _data.cend(), "Invalid iterator!");
        position->second->release();
        return _data.erase(position);
    }

    /**
     * Removes an element with an iterator from the Map<K, V> container.
     *
     * @param k Key of the element to be erased.
     *        Member type 'K' is the type of the keys for the elements in the container,
     *        defined in Map<K, V> as an alias of its first template parameter (Key).
     */
    //size_t erase(const K& k)
    //{
    //    auto iter = _data.find(k);
    //    if (iter != _data.end())
    //    {
    //        iter->second->release();
    //        _data.erase(iter);
    //        return 1;
    //    }
    //    return 0;
    //}

    template<typename _K2>
    size_t erase(const _K2& k)
    {
        auto iter = _data.find(k);
        if (iter != _data.end())
        {
            iter->second->release();
            _data.erase(iter);
            return 1;
        }
        return 0;
    }

    /**
     * Removes some elements with a vector which contains keys in the map.
     *
     * @param keys Keys of elements to be erased.
     */
    template<typename _K2>
    void erase(const std::vector<_K2>& keys)
    {
        for (const auto& key : keys)
        {
            this->erase(key);
        }
    }

    /**
     * All the elements in the Map<K,V> container are dropped:
     *  their reference count will be decreased, and they are removed from the container,
     *  leaving it with a size of 0.
     */
    void clear()
    {
        for (const auto& iter : _data)
        {
            iter.second->release();
        }

        _data.clear();
    }

    /**
     * Gets a random object in the map.
     * @return Returns the random object if the map isn't empty, otherwise it returns nullptr.
     */
    V getRandomObject() const
    {
        if (!_data.empty())
        {
            ssize_t randIdx         = RandomHelper::random_int<int>(0, static_cast<int>(_data.size()) - 1);
            const_iterator randIter = _data.begin();
            std::advance(randIter, randIdx);
            return randIter->second;
        }
        return nullptr;
    }

    // Don't uses operator since we could not decide whether it needs 'retain'/'release'.
    //    V& operator[] ( const K& key )
    //    {
    //        CCLOG("copy: [] ref");
    //        return _data[key];
    //    }
    //
    //    V& operator[] ( K&& key )
    //    {
    //        CCLOG("move [] ref");
    //        return _data[key];
    //    }

    //    const V& operator[] ( const K& key ) const
    //    {
    //        CCLOG("const copy []");
    //        return _data.at(key);
    //    }
    //
    //    const V& operator[] ( K&& key ) const
    //    {
    //        CCLOG("const move []");
    //        return _data.at(key);
    //    }

    /** Copy assignment operator. */
    Map& operator=(const Map& other)
    {
        if (this != &other)
        {
            CCLOGINFO("In the copy assignment operator of Map!");
            clear();
            _data = other._data;
            addRefForAllObjects();
        }
        return *this;
    }

    /** Move assignment operator. */
    Map& operator=(Map&& other)
    {
        if (this != &other)
        {
            CCLOGINFO("In the move assignment operator of Map!");
            clear();
            _data = std::move(other._data);
        }
        return *this;
    }

protected:
    /** Retains all the objects in the map */
    void addRefForAllObjects()
    {
        for (auto& iter : _data)
        {
            iter.second->retain();
        }
    }

    RefMap _data;
};

template<typename _Valty>
using StringMap = Map<std::string, _Valty, hlookup::string_hash, hlookup::equal_to>;

NS_CC_END
// end group
/// @}

#endif /* __CCMAP_H__ */