using System.Collections.Concurrent; using System.Collections.Generic; using System.Linq; namespace System.Reactive.Linq.ObservableImpl { internal sealed class Map<TKey, TValue> { private const int DEFAULT_CONCURRENCY_MULTIPLIER = 4; private readonly ConcurrentDictionary<TKey, TValue> _map; private static int DefaultConcurrencyLevel => 4 * Environment.ProcessorCount; public IEnumerable<TValue> Values => Enumerable.ToArray<TValue>((IEnumerable<TValue>)_map.Values); public Map(int? capacity, IEqualityComparer<TKey> comparer) { if (capacity.HasValue) _map = new ConcurrentDictionary<TKey, TValue>(DefaultConcurrencyLevel, capacity.Value, comparer); else _map = new ConcurrentDictionary<TKey, TValue>(comparer); } public TValue GetOrAdd(TKey key, Func<TValue> valueFactory, out bool added) { added = false; TValue value = default(TValue); TValue val = default(TValue); bool flag = false; while (!_map.TryGetValue(key, out value)) { if (!flag) { val = valueFactory(); flag = true; } if (_map.TryAdd(key, val)) { added = true; value = val; return value; } } return value; } public bool Remove(TKey key) { TValue value; return _map.TryRemove(key, out value); } } }