MemoryMappedViewStream.cs

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using Microsoft.Win32.SafeHandles;
 
namespace System.IO.MemoryMappedFiles;
 
public sealed class MemoryMappedViewStream : UnmanagedMemoryStream
{
    private readonly MemoryMappedView _view;
 
    public SafeMemoryMappedViewHandle SafeMemoryMappedViewHandle => _view.ViewHandle;
 
    public long PointerOffset => _view.PointerOffset;
 
    internal MemoryMappedViewStream(MemoryMappedView view)
    {
        _view = view;
        Initialize(_view.ViewHandle, _view.PointerOffset, _view.Size, MemoryMappedFile.GetFileAccess(_view.Access));
    }
 
    public override void SetLength(long value)
    {
        if (value < 0)
        {
            throw new ArgumentOutOfRangeException("value", System.SR.ArgumentOutOfRange_NeedNonNegNum);
        }
        throw new NotSupportedException(System.SR.NotSupported_MMViewStreamsFixedLength);
    }
 
    protected override void Dispose(bool disposing)
    {
        try
        {
            if (disposing && !_view.IsClosed)
            {
                Flush();
            }
        }
        finally
        {
            try
            {
                _view.Dispose();
            }
            finally
            {
                base.Dispose(disposing);
            }
        }
    }
 
    public override void Flush()
    {
        if (!CanSeek)
        {
            throw new ObjectDisposedException(null, System.SR.ObjectDisposed_StreamIsClosed);
        }
        _view.Flush((UIntPtr)(ulong)base.Capacity);
    }
}