juce_LinkedListPointer.h

/*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   The code included in this file is provided 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.
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
//==============================================================================
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;
    }
 
    LinkedListPointer (LinkedListPointer&& other) noexcept
        : item (other.item)
    {
        other.item = nullptr;
    }
 
    LinkedListPointer& operator= (LinkedListPointer&& other) noexcept
    {
        jassert (this != &other); // hopefully the compiler should make this situation impossible!
 
        item = other.item;
        other.item = nullptr;
        return *this;
    }
 
    //==============================================================================
    inline operator ObjectType*() const noexcept
    {
        return item;
    }

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

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

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

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

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

    bool contains (const ObjectType* const itemToLookFor) const noexcept
    {
        for (auto* i = item; i != nullptr; i = i->nextListItem)
            if (itemToLookFor == i)
                return true;
 
        return false;
    }
 
    //==============================================================================
    void insertNext (ObjectType* const newItem)
    {
        JUCE_BEGIN_IGNORE_WARNINGS_MSVC (6011)
        jassert (newItem != nullptr);
        jassert (newItem->nextListItem == nullptr);
        newItem->nextListItem = item;
        item = newItem;
        JUCE_END_IGNORE_WARNINGS_MSVC
    }

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

    ObjectType* replaceNext (ObjectType* const newItem) noexcept
    {
        JUCE_BEGIN_IGNORE_WARNINGS_MSVC (6011 28182)
        jassert (newItem != nullptr);
        jassert (newItem->nextListItem == nullptr);
 
        auto oldItem = item;
        item = newItem;
        item->nextListItem = oldItem->nextListItem.item;
        oldItem->nextListItem.item = nullptr;
        return oldItem;
        JUCE_END_IGNORE_WARNINGS_MSVC
    }

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

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

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

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

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

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

    void copyToArray (ObjectType** destArray) const noexcept
    {
        JUCE_BEGIN_IGNORE_WARNINGS_MSVC (6011)
        jassert (destArray != nullptr);
 
        for (auto* i = item; i != nullptr; i = i->nextListItem)
            *destArray++ = i;
 
        JUCE_END_IGNORE_WARNINGS_MSVC
    }

    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.
            jassert (endOfListPointer.item == nullptr);
        }

        void append (ObjectType* const newItem) noexcept
        {
            *endOfList = newItem;
            endOfList = &(newItem->nextListItem);
        }
 
    private:
        LinkedListPointer* endOfList;
 
        JUCE_DECLARE_NON_COPYABLE (Appender)
    };
 
private:
    //==============================================================================
    ObjectType* item;
 
    JUCE_DECLARE_NON_COPYABLE (LinkedListPointer)
};
 
} // namespace juce