Tests/MathCore.Algorithms/RefList.cs - dev - shmachilin/MathCore

Tests/MathCore.Algorithms/RefList.cs
173 строки4 KB
Infarh
Рефакторинг стиля написания пространств имён во всех файлах
20 окт 2022, 06:08
20 окт 2022, 06:08a94d602
using System.Collections;

namespace MathCore.Algorithms;

public class RefList<T> : IEnumerable<T>
{
    public class Node
    {
        internal RefList<T> _List;

        private readonly T _Value;

        public T Value => _Value;

        public Node Next { get; internal set; }

        public Node Prev { get; internal set; }

        internal Node(RefList<T> List, T Value)
        {
            _List  = List;
            _Value = Value;
        }
    }

    private int _Count;

    public Node First { get; private set; }

    public Node Last { get; private set; }

    public int Count => _Count;

    public RefList() { }

    public RefList(IEnumerable<T> items)
    {
        foreach (var item in items)
            AddLast(item);
    }

    public Node AddFirst(T value)
    {
        var node = new Node(this, value);
        _Count++;

        if (First is null)
        {
            First = node;
            Last  = node;
            return node;
        }

        First.Prev = node;
        node.Next  = First;
        First      = node;

        return node;
    }

    public Node AddLast(T value)
    {
        var node = new Node(this, value);
        _Count++;

        if (Last is null)
        {
            First = node;
            Last  = node;
            return node;
        }

        Last.Next = node;
        node.Prev = First;
        Last      = node;

        return node;
    }

    public Node AddAfter(Node Position, T value)
    {
        if (!ReferenceEquals(Position._List, this))
            throw new InvalidOperationException("Попытка добавления в позицию элемента от другого списка");

        if (ReferenceEquals(Position, Last))
            return AddLast(value);

        var node = new Node(this, value)
        {
            Prev = Position,
            Next = Position.Next
        };
        Position.Next  = node;
        node.Next.Prev = node;
        return node;
    }

    public Node AddBefore(Node Position, T value)
    {
        if (!ReferenceEquals(Position._List, this))
            throw new InvalidOperationException("Попытка добавления в позицию элемента от другого списка");

        if (ReferenceEquals(Position, First))
            return AddFirst(value);

        var node = new Node(this, value)
        {
            Next = Position,
            Prev = Position.Prev
        };
        Position.Prev  = node;
        node.Prev.Next = node;
        return node;
    }

    public T Remove(Node node)
    {
        if (!ReferenceEquals(node._List, this))
            throw new InvalidOperationException("Попытка удаление элемента от другого списка");

        node._List = null;
        _Count--;
        if (_Count == 1)
        {
            First = null;
            Last  = null;
        }
        else if (ReferenceEquals(First, node))
        {
            First      = node.Next;
            First.Prev = null;
        }
        else if (ReferenceEquals(Last, node))
        {
            Last      = node.Prev;
            Last.Next = null;
        }
        else
        {
            node.Prev.Next = node.Next;
            node.Next.Prev = node.Prev;
        }

        return node.Value;
    }

    public void Clear()
    {
        if (_Count == 0) return;
        var node = First;
        while (node != null)
        {
            node._List = null;
            node.Prev  = null;
            var tmp = node;
            node     = node.Next;
            tmp.Next = null;
        }
    }

    public IEnumerator<T> GetEnumerator()
    {
        if (_Count == 0) yield break;
        var node = First;
        while (node != null)
        {
            yield return node.Value;
            node = node.Next;
        }
    }

    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}