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#region License
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/* FNA - XNA4 Reimplementation for Desktop Platforms
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* Copyright 2009-2020 Ethan Lee and the MonoGame Team
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*
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* Released under the Microsoft Public License.
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* See LICENSE for details.
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*/
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#endregion
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#region Using Statements
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using System;
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using System.IO;
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using System.Reflection;
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#endregion
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namespace Microsoft.Xna.Framework
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{
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internal static class FNAInternalExtensions
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{
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#region MemoryStream.TryGetBuffer Extension
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private static readonly FieldInfo f_MemoryStream_Public =
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// .NET
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typeof(MemoryStream).GetField("_exposable", BindingFlags.NonPublic | BindingFlags.Instance) ??
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// Old Mono
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typeof(MemoryStream).GetField("allowGetBuffer", BindingFlags.NonPublic | BindingFlags.Instance);
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/// <summary>
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/// Returns the array of unsigned bytes from which this stream was created.
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/// The return value indicates whether the conversion succeeded.
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/// This is similar to .NET 4.6's TryGetBuffer.
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/// </summary>
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/// <param name="stream">The stream to get the buffer from.</param>
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/// <param name="buffer">The byte array from which this stream was created.</param>
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/// <returns><b>true</b> if the conversion was successful; otherwise, <b>false</b>.</returns>
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internal static bool TryGetBuffer(this MemoryStream stream, out byte[] buffer)
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{
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// Check if the buffer is public by reflecting into a known internal field.
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if (f_MemoryStream_Public != null)
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{
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if ((bool) f_MemoryStream_Public.GetValue(stream))
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{
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buffer = stream.GetBuffer();
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return true;
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}
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buffer = null;
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return false;
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}
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// If no known field can be found, use a horribly slow try-catch instead.
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try
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{
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buffer = stream.GetBuffer();
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return true;
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}
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catch (UnauthorizedAccessException)
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{
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buffer = null;
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return false;
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}
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}
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#endregion
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}
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}
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