modernuo/Projects/Server/Geometry/Point3DList.cs

using System;

namespace Server;

public class Point3DList
{
    private static readonly Point3D[] m_EmptyList = Array.Empty<Point3D>();
    private Point3D[] m_List;

    public Point3DList()
    {
        m_List = new Point3D[8];
        Count = 0;
    }

    public int Count { get; private set; }

    public Point3D Last => m_List[Count - 1];

    public Point3D this[int index] => m_List[index];

    public void Clear()
    {
        Count = 0;
    }

    public void Add(int x, int y, int z)
    {
        if (Count + 1 > m_List.Length)
        {
            var old = m_List;
            m_List = new Point3D[old.Length * 2];

            for (var i = 0; i < old.Length; ++i)
            {
                m_List[i] = old[i];
            }
        }

        m_List[Count].m_X = x;
        m_List[Count].m_Y = y;
        m_List[Count].m_Z = z;
        ++Count;
    }

    public void Add(Point3D p)
    {
        if (Count + 1 > m_List.Length)
        {
            var old = m_List;
            m_List = new Point3D[old.Length * 2];

            for (var i = 0; i < old.Length; ++i)
            {
                m_List[i] = old[i];
            }
        }

        m_List[Count].m_X = p.m_X;
        m_List[Count].m_Y = p.m_Y;
        m_List[Count].m_Z = p.m_Z;
        ++Count;
    }

    public Point3D[] ToArray()
    {
        if (Count == 0)
        {
            return m_EmptyList;
        }

        var list = new Point3D[Count];

        for (var i = 0; i < Count; ++i)
        {
            list[i] = m_List[i];
        }

        Count = 0;

        return list;
    }
}