Files
Syntriax.Engine/Engine.Core/Helpers/FastList.cs

79 lines
2.0 KiB
C#

using System.Collections;
using System.Collections.Generic;
namespace Engine.Core;
public class FastList<T> : IList<T>, IReadOnlyList<T>, IEnumerable<T> where T : notnull
{
private readonly List<T> items = [];
private readonly Dictionary<T, int> indexMap = [];
public int Count => items.Count;
public bool IsReadOnly { get; set; } = false;
public T this[int index] { get => items[index]; set => items[index] = value; }
public void Add(T item)
{
indexMap[item] = items.Count;
items.Add(item);
}
public void RemoveAt(int i) => Remove(items[i], i);
public bool Remove(T item)
{
if (!indexMap.TryGetValue(item, out int index))
return false;
Remove(item, index);
return true;
}
private void Remove(T item, int index)
{
int lastIndex = items.Count - 1;
T lastItem = items[lastIndex];
items[index] = lastItem;
indexMap[lastItem] = index;
items.RemoveAt(lastIndex);
indexMap.Remove(item);
}
public void Insert(int index, T item)
{
items.Insert(index, item);
for (int i = index; i < items.Count; i++)
indexMap[items[i]] = i;
}
public void Clear()
{
items.Clear();
indexMap.Clear();
}
public bool Contains(T item) => indexMap.ContainsKey(item);
public int BinarySearch(T item, IComparer<T>? comparer = null) => items.BinarySearch(item, comparer);
public void Sort(IComparer<T> comparer)
{
items.Sort(comparer);
for (int i = 0; i < items.Count; i++)
indexMap[items[i]] = i;
}
public int IndexOf(T item) => items.IndexOf(item);
public void CopyTo(T[] array, int arrayIndex) => items.CopyTo(array, arrayIndex);
public IEnumerator<T> GetEnumerator() => items.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
public FastList() { }
public FastList(int count) { items.Capacity = count; }
}