LinkedListPointer.h

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/*
  ==============================================================================
 
   This file is part of the Water library.
   Copyright (c) 2016 ROLI Ltd.
   Copyright (C) 2017-2022 Filipe Coelho <falktx@falktx.com>
 
   Permission is granted to use this software under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license/
 
   Permission to use, copy, modify, and/or distribute this software for any
   purpose with or without fee is hereby granted, provided that the above
   copyright notice and this permission notice appear in all copies.
 
   THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
   FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
   OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
   USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
   TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
   OF THIS SOFTWARE.
 
  ==============================================================================
*/
 
#ifndef WATER_LINKEDLISTPOINTER_H_INCLUDED
#define WATER_LINKEDLISTPOINTER_H_INCLUDED
 
#include "../water.h"
 
namespace water {
 
//==============================================================================
template <class ObjectType>
class LinkedListPointer
{
public:
    //==============================================================================
    LinkedListPointer() noexcept
        : item (nullptr)
    {
    }

    explicit LinkedListPointer (ObjectType* const headItem) noexcept
        : item (headItem)
    {
    }

    LinkedListPointer& operator= (ObjectType* const newItem) noexcept
    {
        item = newItem;
        return *this;
    }
 
    //==============================================================================
    inline operator ObjectType*() const noexcept
    {
        return item;
    }

    inline ObjectType* get() const noexcept
    {
        return item;
    }

    LinkedListPointer& getLast() noexcept
    {
        LinkedListPointer* l = this;
 
        while (l->item != nullptr)
            l = &(l->item->nextListItem);
 
        return *l;
    }

    int size() const noexcept
    {
        int total = 0;
 
        for (ObjectType* i = item; i != nullptr; i = i->nextListItem)
            ++total;
 
        return total;
    }

    LinkedListPointer& operator[] (int index) noexcept
    {
        LinkedListPointer* l = this;
 
        while (--index >= 0 && l->item != nullptr)
            l = &(l->item->nextListItem);
 
        return *l;
    }

    const LinkedListPointer& operator[] (int index) const noexcept
    {
        const LinkedListPointer* l = this;
 
        while (--index >= 0 && l->item != nullptr)
            l = &(l->item->nextListItem);
 
        return *l;
    }

    bool contains (const ObjectType* const itemToLookFor) const noexcept
    {
        for (ObjectType* i = item; i != nullptr; i = i->nextListItem)
            if (itemToLookFor == i)
                return true;
 
        return false;
    }
 
    //==============================================================================
    void insertNext (ObjectType* const newItem)
    {
        wassert (newItem != nullptr);
        wassert (newItem->nextListItem == nullptr);
        newItem->nextListItem = item;
        item = newItem;
    }

    void insertAtIndex (int index, ObjectType* newItem)
    {
        wassert (newItem != nullptr);
        LinkedListPointer* l = this;
 
        while (index != 0 && l->item != nullptr)
        {
            l = &(l->item->nextListItem);
            --index;
        }
 
        l->insertNext (newItem);
    }

    ObjectType* replaceNext (ObjectType* const newItem) noexcept
    {
        wassert (newItem != nullptr);
        wassert (newItem->nextListItem == nullptr);
 
        ObjectType* const oldItem = item;
        item = newItem;
        item->nextListItem = oldItem->nextListItem.item;
        oldItem->nextListItem.item = nullptr;
        return oldItem;
    }

    void append (ObjectType* const newItem)
    {
        getLast().item = newItem;
    }

    void addCopyOfList (const LinkedListPointer& other)
    {
        LinkedListPointer* insertPoint = this;
 
        for (ObjectType* i = other.item; i != nullptr; i = i->nextListItem)
        {
            insertPoint->insertNext (new ObjectType (*i));
            insertPoint = &(insertPoint->item->nextListItem);
        }
    }

    ObjectType* removeNext() noexcept
    {
        ObjectType* const oldItem = item;
 
        if (oldItem != nullptr)
        {
            item = oldItem->nextListItem;
            oldItem->nextListItem.item = nullptr;
        }
 
        return oldItem;
    }

    void remove (ObjectType* const itemToRemove)
    {
        if (LinkedListPointer* const l = findPointerTo (itemToRemove))
            l->removeNext();
    }

    void deleteAll()
    {
        while (item != nullptr)
        {
            ObjectType* const oldItem = item;
            item = oldItem->nextListItem;
            delete oldItem;
        }
    }

    LinkedListPointer* findPointerTo (ObjectType* const itemToLookFor) noexcept
    {
        LinkedListPointer* l = this;
 
        while (l->item != nullptr)
        {
            if (l->item == itemToLookFor)
                return l;
 
            l = &(l->item->nextListItem);
        }
 
        return nullptr;
    }

    void copyToArray (ObjectType** destArray) const noexcept
    {
        wassert (destArray != nullptr);
 
        for (ObjectType* i = item; i != nullptr; i = i->nextListItem)
            *destArray++ = i;
    }

    void swapWith (LinkedListPointer& other) noexcept
    {
        std::swap (item, other.item);
    }
 
    //==============================================================================
    class Appender
    {
    public:
        Appender (LinkedListPointer& endOfListPointer) noexcept
            : endOfList (&endOfListPointer)
        {
            // This can only be used to add to the end of a list.
            wassert (endOfListPointer.item == nullptr);
        }

        void append (ObjectType* const newItem) noexcept
        {
            *endOfList = newItem;
            endOfList = &(newItem->nextListItem);
        }
 
    private:
        LinkedListPointer* endOfList;
 
        CARLA_DECLARE_NON_COPYABLE (Appender)
    };
 
private:
    //==============================================================================
    ObjectType* item;
 
    CARLA_DECLARE_NON_COPYABLE (LinkedListPointer)
};
 
}
 
#endif // WATER_LINKEDLISTPOINTER_H_INCLUDED