/// <summary>
/// Creates a FileMappingViewAccessor that maps to a view of the memory-mapped file,
/// and that has the specified offset and size.
/// </summary>
/// <param name="offset">The byte at which to start the view.</param>
/// <param name="size">The size of the view. Specify 0 (zero) to create a view that
/// starts at offset and ends approximately at the end of the memory-mapped file.
/// </param>
/// <returns>A randomly accessible block of memory.</returns>
public FileMappingViewAccessor CreateViewAccessor(long offset, long size)
{
long lengthFromOffsetToTheEnd = (size == 0) ? this.fileSize - offset : size;
SafeFileMappingViewHandle handle = new SafeFileMappingViewHandle(Win32.MapViewOfFile(
this.FileMappingHandle,
Win32.FILE_MAP_WRITE,
unchecked ((UInt32)(offset >> 32)),
unchecked ((UInt32)(offset & 0xFFFFFFFF)),
unchecked ((IntPtr)size)
),
(ulong)lengthFromOffsetToTheEnd);
if (handle.IsInvalid)
{
throw new Exception("Could not create a view of memory-mapped file.");
}
return(new FileMappingViewAccessor(handle, offset, lengthFromOffsetToTheEnd));
// throws
// ArgumentOutOfRangeException
// UnauthorizedAccessException
// IOException
}
internal FileMappingViewAccessor(SafeFileMappingViewHandle handle, long offset, long capacity)
{
Debug.Assert(handle != null);
Debug.Assert(!handle.IsInvalid, "handle is invalid");
FileMappingViewHandle = handle;
PointerOffset = offset;
Capacity = capacity;
}
/// <summary>
/// Creates a stream that maps to a view of the memory-mapped file,
/// and that has the specified offset and size.
/// </summary>
/// <param name="offset">The byte at which to start the view.</param>
/// <param name="size">The size of the view. Specify 0 (zero) to create a view that
/// starts at offset and ends approximately at the end of the memory-mapped file.</param>
/// <returns>A stream of memory that has the specified offset and size.</returns>
public FileMappingViewStream CreateViewStream(long offset, long size)
{
long lengthFromOffsetToTheEnd = (size == 0) ? this.fileSize - offset : size;
// TODO: implement
SafeFileMappingViewHandle handle =
new SafeFileMappingViewHandle(IntPtr.Zero, (ulong)lengthFromOffsetToTheEnd); // =
return(new FileMappingViewStream(handle, offset, lengthFromOffsetToTheEnd));
}
internal FileMappingViewStream(SafeFileMappingViewHandle handle, long offset, long capacity)
{
}
