Initial Commit

Library/PackageCache/com.unity.ide.visualstudio@2.0.7/Editor/Image.cs

@@ -0,0 +1,102 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+using System;
+using System.IO;
+
+namespace Microsoft.Unity.VisualStudio.Editor
+{
+	public sealed class Image : IDisposable
+	{
+
+		long position;
+		Stream stream;
+
+		Image(Stream stream)
+		{
+			this.stream = stream;
+			this.position = stream.Position;
+			this.stream.Position = 0;
+		}
+
+		bool Advance(int length)
+		{
+			if (stream.Position + length >= stream.Length)
+				return false;
+
+			stream.Seek(length, SeekOrigin.Current);
+			return true;
+		}
+
+		bool MoveTo(uint position)
+		{
+			if (position >= stream.Length)
+				return false;
+
+			stream.Position = position;
+			return true;
+		}
+
+		void IDisposable.Dispose()
+		{
+			stream.Position = position;
+		}
+
+		ushort ReadUInt16()
+		{
+			return (ushort)(stream.ReadByte()
+				| (stream.ReadByte() << 8));
+		}
+
+		uint ReadUInt32()
+		{
+			return (uint)(stream.ReadByte()
+				| (stream.ReadByte() << 8)
+				| (stream.ReadByte() << 16)
+				| (stream.ReadByte() << 24));
+		}
+
+		bool IsManagedAssembly()
+		{
+			if (stream.Length < 318)
+				return false;
+			if (ReadUInt16() != 0x5a4d)
+				return false;
+			if (!Advance(58))
+				return false;
+			if (!MoveTo(ReadUInt32()))
+				return false;
+			if (ReadUInt32() != 0x00004550)
+				return false;
+			if (!Advance(20))
+				return false;
+			if (!Advance(ReadUInt16() == 0x20b ? 222 : 206))
+				return false;
+
+			return ReadUInt32() != 0;
+		}
+
+		public static bool IsAssembly(string file)
+		{
+			if (file == null)
+				throw new ArgumentNullException("file");
+
+			using (var stream = new FileStream(file, FileMode.Open, FileAccess.Read, FileShare.Read))
+				return IsAssembly(stream);
+		}
+
+		public static bool IsAssembly(Stream stream)
+		{
+			if (stream == null)
+				throw new ArgumentNullException(nameof(stream));
+			if (!stream.CanRead)
+				throw new ArgumentException(nameof(stream));
+			if (!stream.CanSeek)
+				throw new ArgumentException(nameof(stream));
+
+			using (var image = new Image(stream))
+				return image.IsManagedAssembly();
+		}
+	}
+}