private unsafe bool TryCreateMemoryMappedFileBlock(long start, int size, out MemoryMappedFileBlock block)
{
if (_lazyMemoryMap == null)
{
// leave the underlying stream open. It will be closed by the Dispose method.
IDisposable newMemoryMap;
// CreateMemoryMap might modify the stream (calls FileStream.Flush)
lock (_streamGuard)
{
newMemoryMap = MemoryMapLightUp.CreateMemoryMap(_stream);
}
if (newMemoryMap == null)
{
block = null;
return(false);
}
if (Interlocked.CompareExchange(ref _lazyMemoryMap, newMemoryMap, null) != null)
{
newMemoryMap.Dispose();
}
}
IDisposable accessor = MemoryMapLightUp.CreateViewAccessor(_lazyMemoryMap, start, size);
if (accessor == null)
{
block = null;
return(false);
}
SafeBuffer safeBuffer;
byte * pointer = MemoryMapLightUp.AcquirePointer(accessor, out safeBuffer);
if (pointer == null)
{
block = null;
return(false);
}
block = new MemoryMappedFileBlock(accessor, safeBuffer, pointer, size);
return(true);
}
internal unsafe MemoryMappedFileBlock(IDisposable accessor, int size)
{
this.accessor = accessor;
this.pointer = MemoryMapLightUp.AcquirePointer(accessor, out safeBuffer);
this.size = size;
}
internal unsafe MemoryMappedFileBlock(IDisposable accessor, int size)
{
_accessor = accessor;
_pointer = MemoryMapLightUp.AcquirePointer(accessor, out _safeBuffer);
_size = size;
}
