using System; namespace MemoryPools.Collections.Linq { internal class WhereExprEnumerable<T> : IPoolingEnumerable<T> { private int _count; private IPoolingEnumerable<T> _src; private Func<T, bool> _condition; public WhereExprEnumerable<T> Init(IPoolingEnumerable<T> src, Func<T, bool> condition) { _count = 0; _src = src; _condition = condition; return this; } public IPoolingEnumerator<T> GetEnumerator() { _count++; return Pool<WhereExprEnumerator>.Get().Init(_src.GetEnumerator(), this, _condition); } private void Dispose() { if (_count == 0) return; _count--; if (_count == 0) { _src = default; _condition = default; Pool<WhereExprEnumerable<T>>.Return(this); } } internal class WhereExprEnumerator : IPoolingEnumerator<T> { private Func<T, bool> _mutator; private IPoolingEnumerator<T> _src; private WhereExprEnumerable<T> _parent; public WhereExprEnumerator Init(IPoolingEnumerator<T> src, WhereExprEnumerable<T> parent, Func<T, bool> mutator) { _src = src; _mutator = mutator; _parent = parent; return this; } public bool MoveNext() { do { var next = _src.MoveNext(); if (!next) return false; } while (!_mutator(_src.Current)); return true; } public void Reset() { _src.Reset(); } object IPoolingEnumerator.Current => Current; public T Current => _src.Current; public void Dispose() { _parent?.Dispose(); _parent = default; _src?.Dispose(); _src = default; Pool<WhereExprEnumerator>.Return(this); } } IPoolingEnumerator IPoolingEnumerable.GetEnumerator() { return GetEnumerator(); } } }