using System.Runtime.CompilerServices; namespace System.Security.Cryptography { internal ref struct CryptoPoolLease : IDisposable { private byte[] _rented; private bool _skipClear; internal Span<byte> Span { [System.Runtime.CompilerServices.IsReadOnly] get; private set; } public void Dispose() { Return(); } internal void Return() { Return((!_skipClear) ? Span.Length : 0); } private void Return(int clearSize) { Span<byte> span; if (_rented != null) { System.Security.Cryptography.CryptoPool.Return(_rented, clearSize); _rented = null; } else if (!_skipClear && clearSize > 0) { span = Span; span.Slice(0, clearSize).Clear(); } span = (Span = default(Span<byte>)); } internal static CryptoPoolLease Rent(int length, bool skipClear = false) { byte[] array = System.Security.Cryptography.CryptoPool.Rent(length); CryptoPoolLease result = default(CryptoPoolLease); result._rented = array; result._skipClear = skipClear; result.Span = new Span<byte>(array, 0, length); return result; } internal static CryptoPoolLease RentConditionally(int length, Span<byte> currentBuffer, bool skipClear = false, bool skipClearIfNotRented = false) { bool rented; return RentConditionally(length, currentBuffer, out rented, skipClear, skipClearIfNotRented); } internal static CryptoPoolLease RentConditionally(int length, Span<byte> currentBuffer, out bool rented, bool skipClear = false, bool skipClearIfNotRented = false) { if (currentBuffer.Length >= length) { rented = false; CryptoPoolLease result = default(CryptoPoolLease); result._rented = null; result._skipClear = (skipClearIfNotRented | skipClear); result.Span = currentBuffer.Slice(0, length); return result; } rented = true; return Rent(length, skipClear); } } }