一起学JUCE之HashMap

 class HashEntry
    {
    public:
        HashEntry (KeyTypeParameter k, ValueTypeParameter val, HashEntry* const next)
            : key (k), value (val), nextEntry (next)
        {}

        const KeyType key;
        ValueType value;
        HashEntry* nextEntry;

        JUCE_DECLARE_NON_COPYABLE (HashEntry)
    };

 class Iterator
    {
    public:
        //==============================================================================
        Iterator (const HashMap& hashMapToIterate)
            : hashMap (hashMapToIterate), entry (nullptr), index (0)
        {}

        /** Moves to the next item, if one is available.
            When this returns true, you can get the item‘s key and value using getKey() and
            getValue(). If it returns false, the iteration has finished and you should stop.
        */
        bool next()
        {
            if (entry != nullptr)
                entry = entry->nextEntry;

            while (entry == nullptr)
            {
                if (index >= hashMap.getNumSlots())
                    return false;

                entry = hashMap.hashSlots.getUnchecked (index++);
            }

            return true;
        }

        /** Returns the current item‘s key.
            This should only be called when a call to next() has just returned true.
        */
        KeyType getKey() const
        {
            return entry != nullptr ? entry->key : KeyType();
        }

        /** Returns the current item‘s value.
            This should only be called when a call to next() has just returned true.
        */
        ValueType getValue() const
        {
            return entry != nullptr ? entry->value : ValueType();
        }

    private:
        //==============================================================================
        const HashMap& hashMap;
        HashEntry* entry;
        int index;

        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Iterator)
    };