BidirectionalDictionary.cs

Go to the documentation of this file.

using System.Diagnostics.CodeAnalysis;
 
namespace System.Collections.Generic;
 
internal sealed class BidirectionalDictionary<T1, T2> : IEnumerable<KeyValuePair<T1, T2>>, IEnumerable
{
    private readonly Dictionary<T1, T2> _forward;
 
    private readonly Dictionary<T2, T1> _backward;
 
    public BidirectionalDictionary(int capacity)
    {
        _forward = new Dictionary<T1, T2>(capacity);
        _backward = new Dictionary<T2, T1>(capacity);
    }
 
    public void Add(T1 item1, T2 item2)
    {
        _forward.Add(item1, item2);
        _backward.Add(item2, item1);
    }
 
    public bool TryGetForward(T1 item1, [MaybeNullWhen(false)] out T2 item2)
    {
        return _forward.TryGetValue(item1, out item2);
    }
 
    public bool TryGetBackward(T2 item2, [MaybeNullWhen(false)] out T1 item1)
    {
        return _backward.TryGetValue(item2, out item1);
    }
 
    public Dictionary<T1, T2>.Enumerator GetEnumerator()
    {
        return _forward.GetEnumerator();
    }
 
    IEnumerator<KeyValuePair<T1, T2>> IEnumerable<KeyValuePair<T1, T2>>.GetEnumerator()
    {
        return GetEnumerator();
    }
 
    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}