Update about Manager.

PriFormat/StreamHelper.cs

@@ -0,0 +1,171 @@
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Runtime.InteropServices.ComTypes;
+
+namespace PriFormat
+{
+	public static class StreamHelper
+	{
+		public static Stream FromIStream (IStream comStream)
+		{
+			if (comStream == null) return null;
+			return new ComIStreamBufferedReader (comStream);
+		}
+
+		public static Stream FromIStream (IntPtr comStreamPtr)
+		{
+			if (comStreamPtr == IntPtr.Zero) return null;
+
+			IStream comStream =
+				(IStream)Marshal.GetObjectForIUnknown (comStreamPtr);
+
+			return new ComIStreamBufferedReader (comStream);
+		}
+	}
+
+	internal sealed class ComIStreamBufferedReader: Stream
+	{
+		private readonly MemoryStream _memory;
+		private bool _disposed;
+
+		public ComIStreamBufferedReader (IStream comStream)
+		{
+			if (comStream == null)
+				throw new ArgumentNullException ("comStream");
+
+			_memory = LoadAll (comStream);
+		}
+
+		/// <summary>
+		/// 一次性把 IStream 全部复制到托管内存
+		/// </summary>
+		private static MemoryStream LoadAll (IStream stream)
+		{
+			// 保存原始位置
+			long originalPos = GetPosition (stream);
+
+			try
+			{
+				// Seek 到头
+				stream.Seek (0, 0 /* STREAM_SEEK_SET */, IntPtr.Zero);
+
+				// 获取长度
+				System.Runtime.InteropServices.ComTypes.STATSTG stat;
+				stream.Stat (out stat, 1); // STATFLAG_NONAME
+				long length = stat.cbSize;
+
+				if (length < 0 || length > int.MaxValue)
+					throw new NotSupportedException ("Stream too large to buffer.");
+
+				MemoryStream ms = new MemoryStream ((int)length);
+
+				byte [] buffer = new byte [64 * 1024]; // 64KB
+				IntPtr pcbRead = Marshal.AllocHGlobal (sizeof (int));
+
+				try
+				{
+					while (true)
+					{
+						stream.Read (buffer, buffer.Length, pcbRead);
+						int read = Marshal.ReadInt32 (pcbRead);
+						if (read <= 0)
+							break;
+
+						ms.Write (buffer, 0, read);
+					}
+				}
+				finally
+				{
+					Marshal.FreeHGlobal (pcbRead);
+				}
+
+				ms.Position = 0;
+				return ms;
+			}
+			finally
+			{
+				// 恢复 COM IStream 的原始位置
+				stream.Seek (originalPos, 0 /* STREAM_SEEK_SET */, IntPtr.Zero);
+			}
+		}
+
+		private static long GetPosition (IStream stream)
+		{
+			IntPtr posPtr = Marshal.AllocHGlobal (sizeof (long));
+			try
+			{
+				stream.Seek (0, 1 /* STREAM_SEEK_CUR */, posPtr);
+				return Marshal.ReadInt64 (posPtr);
+			}
+			finally
+			{
+				Marshal.FreeHGlobal (posPtr);
+			}
+		}
+
+		// ===== Stream 重写，全部委托给 MemoryStream =====
+
+		public override bool CanRead { get { return !_disposed; } }
+		public override bool CanSeek { get { return !_disposed; } }
+		public override bool CanWrite { get { return false; } }
+
+		public override long Length
+		{
+			get { EnsureNotDisposed (); return _memory.Length; }
+		}
+
+		public override long Position
+		{
+			get { EnsureNotDisposed (); return _memory.Position; }
+			set { EnsureNotDisposed (); _memory.Position = value; }
+		}
+
+		public override int Read (byte [] buffer, int offset, int count)
+		{
+			EnsureNotDisposed ();
+			return _memory.Read (buffer, offset, count);
+		}
+
+		public override long Seek (long offset, SeekOrigin origin)
+		{
+			EnsureNotDisposed ();
+			return _memory.Seek (offset, origin);
+		}
+
+		public override void Flush ()
+		{
+			// no-op
+		}
+
+		public override void SetLength (long value)
+		{
+			throw new NotSupportedException ();
+		}
+
+		public override void Write (byte [] buffer, int offset, int count)
+		{
+			throw new NotSupportedException ();
+		}
+
+		protected override void Dispose (bool disposing)
+		{
+			if (_disposed)
+				return;
+
+			if (disposing)
+			{
+				_memory.Dispose ();
+			}
+
+			_disposed = true;
+			base.Dispose (disposing);
+		}
+
+		private void EnsureNotDisposed ()
+		{
+			if (_disposed)
+				throw new ObjectDisposedException ("ComIStreamBufferedReader");
+		}
+	}
+}