public ExternalFileListStream(ExternalFileListMessage externalFileList, H5DatasetAccess datasetAccess)
{
var offset = 0L;
_slotStreams = externalFileList
.SlotDefinitions
.Select(slot =>
{
var stream = new SlotStream(externalFileList.Heap, slot, offset, datasetAccess);
offset += stream.Length;
return(stream);
})
.ToArray();
if (_slotStreams.Any())
{
this.Length =
_slotStreams.Last().Offset +
_slotStreams.Last().Length;
}
else
{
throw new Exception("There must at least a single file be defined in the external file list.");
}
}
private void ReadExternalFileList(Span <byte> buffer, ExternalFileListMessage externalFileList, H5DatasetAccess datasetAccess)
{
var bufferOffset = 0;
var remainingSize = buffer.Length;
foreach (var slotDefinition in externalFileList.SlotDefinitions)
{
var length = Math.Min(remainingSize, (int)slotDefinition.Size);
var heap = externalFileList.Heap;
var name = heap.GetObjectName(slotDefinition.NameHeapOffset);
var filePath = H5Utils.ConstructExternalFilePath(name, datasetAccess);
if (!File.Exists(filePath))
{
throw new Exception($"External file '{filePath}' does not exist.");
}
try
{
using var fileStream = File.OpenRead(filePath);
fileStream.Seek((long)slotDefinition.Offset, SeekOrigin.Begin);
var actualLength = Math.Min(length, fileStream.Length);
var currentBuffer = buffer.Slice(bufferOffset, (int)actualLength);
fileStream.Read(currentBuffer);
}
catch
{
throw new Exception($"Unable to open external file '{filePath}'.");
}
bufferOffset += length;
remainingSize -= length;
}
}