axmol/cocos/base/CCMap.h

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#ifndef __CCMAP_H__
#define __CCMAP_H__

#include "ccMacros.h"

#include <vector>
#include <unordered_map>
#include <algorithm>    // std::for_each

NS_CC_BEGIN

/**
 * @addtogroup data_structures
 * @{
 */

template <class K, class V>
class CC_DLL Map
{
public:
    // ------------------------------------------
    // Iterators
    // ------------------------------------------
    typedef std::unordered_map<K, V> RefMap;
    
    typedef typename RefMap::iterator iterator;
    typedef typename RefMap::const_iterator const_iterator;
    
    iterator begin() { return _data.begin(); }
    const_iterator begin() const { return _data.begin(); }
    
    iterator end() { return _data.end(); }
    const_iterator end() const { return _data.end(); }
    
    const_iterator cbegin() const { return _data.cbegin(); }
    const_iterator cend() const { return _data.cend(); }
    
    /** Default constructor */
    Map<K, V>()
    : _data()
    {
        CCLOGINFO("In the default constructor of Map!");
    }
    
    /** Contructor with capacity */
    explicit Map<K, V>(int capacity)
    : _data()
    {
        CCLOGINFO("In the constructor with capacity of Map!");
        _data.reserve(capacity);
    }

    /** Copy constructor */
    Map<K, V>(const Map<K, V>& other)
    {
        CCLOGINFO("In the copy constructor of Map!");
        _data = other._data;
        addRefForAllObjects();
    }
    
    /** Move constructor */
    Map<K, V>(Map<K, V>&& other)
    {
        CCLOGINFO("In the move constructor of Map!");
        _data = std::move(other._data);
    }
    
    /** Destructor 
     *  It will release all objects in map.
     */
    ~Map<K, V>()
    {
        CCLOGINFO("In the destructor of Map!");
        clear();
    }

    /** Sets capacity of the map */
    void reserve(int capacity)
    {
        _data.reserve(capacity);
    }
    
    /** Returns capacity of the map */
    size_t capacity() const
    {
        return _data.capacity();
    }
    
    /** The number of elements in the map. */
    size_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())
        {
            for (auto iter = _data.cbegin(); iter != _data.cend(); ++iter)
            {
                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;
        
        for (auto iter = _data.cbegin(); iter != _data.cend(); ++iter)
        {
            if (iter->second == object)
            {
                keys.push_back(iter->first);
            }
        }
        
        return keys;
    }

    /** @brief 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).
     */
    const V at(const K& key) const
    {
        auto iter = _data.find(key);
        if (iter != _data.end())
            return iter->second;
        return nullptr;
    }
    
    V at(const K& key)
    {
        auto iter = _data.find(key);
        if (iter != _data.end())
            return iter->second;
        return nullptr;
    }
    
    /** @brief 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).
     *
     */
    const_iterator find(const K& key) const
    {
        return _data.find(key);
    }
    
    iterator find(const K& key)
    {
        return _data.find(key);
    }
    
    /** @brief 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.
     */
    void insert(const K& key, V object)
    {
        CCASSERT(object != nullptr, "Object is nullptr!");
        erase(key);
        _data.insert(std::make_pair(key, object));
        object->retain();
    }

    /** @brief 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);
    }
    
    /** @brief 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;
    }
    
    /** @brief Removes some elements with a vector which contains keys in the map.
     *  @param keys Keys of elements to be erased.
     */
    void erase(const std::vector<K>& keys)
    {
        std::for_each(keys.cbegin(), keys.cend(), [this](const K& key){
            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 (auto iter = _data.cbegin(); iter != _data.cend(); ++iter)
        {
            iter->second->release();
        }
        
        _data.clear();
    }
    
    /** @brief 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())
        {
            int randIdx = rand() % _data.size();
            return (_data.begin() + randIdx)->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<K, V>& operator= ( const Map<K, V>& other )
    {
        CCLOGINFO("In the copy assignment operator of Map!");
        clear();
        _data = other._data;
        addRefForAllObjects();
        return *this;
    }

    /** Move assignment operator */
    Map<K, V>& operator= ( Map<K, V>&& other )
    {
        CCLOGINFO("In the move assignment operator of Map!");
        _data = std::move(other._data);
        return *this;
    }
    
protected:
    
    /** Retains all the objects in the map */
    void addRefForAllObjects()
    {
        for (auto iter = _data.begin(); iter != _data.end(); ++iter)
        {
            iter->second->retain();
        }
    }
    
    RefMap _data;
};

// end of data_structure group
/// @}

NS_CC_END

#endif /* __CCMAP_H__ */