/// <summary>
/// The returned 'Sector' is invalidated at the next call.
/// </summary>
public Sector Read(SectorIndex index)
{
_memoryStream.Seek(index.ByteIndex(_sectorSizeInBytes), SeekOrigin.Begin);
_sector.Read(_memoryStream, index.ByteIndex(_sectorSizeInBytes));
return(_sector);
}
/// <remarks>
/// The returned 'Sector' is invalidated at the next call.
/// </remarks>
public Sector Read(SectorIndex index)
{
if (!index.IsWithinRange(_firstNotAllocated))
{
throw new ArgumentOutOfRangeException(
$"Try to read from index {index} out of total {_firstNotAllocated.Value} sectors.");
}
_storeStream.Seek(index.ByteIndex(_sectorSizeInBytes), SeekOrigin.Begin);
_sector.Read(_storeStream, index.ByteIndex(_sectorSizeInBytes));
return(_sector);
}
/// <summary>
/// Write to hot storage first, then regular storage secondly.
/// </summary>
public void Write(SectorIndex index, Sector source)
{
if (!index.IsWithinRange(_firstNotAllocated))
{
throw new ArgumentOutOfRangeException(
$"Try to write to index {index.Value} out of total {_firstNotAllocated.Value} sectors.");
}
_hotStream.Seek(0, SeekOrigin.Begin);
source.Write(_hotStream, index.ByteIndex(_sectorSizeInBytes));
_storeStream.Seek(index.ByteIndex(_sectorSizeInBytes), SeekOrigin.Begin);
source.Write(_storeStream, index.ByteIndex(_sectorSizeInBytes));
}
public SectorIndex AllocateSectors(int count)
{
if (count <= 0)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
var firstNewlyAllocated = _firstNotAllocated;
_firstNotAllocated = _firstNotAllocated.GetNext(count);
_storeStream.SetLength(_storeStream.Length + _sectorSizeInBytes * count);
_sector.Clear();
for (var idx = firstNewlyAllocated;
idx.IsWithinRange(_firstNotAllocated);
idx = idx.GetNext())
{
_sector.Write(_storeStream, idx.ByteIndex(_sectorSizeInBytes));
}
Debug.Assert(_storeStream.Length == _firstNotAllocated.ByteIndex(_sectorSizeInBytes));
return(firstNewlyAllocated);
}
public bool TryRead(SectorIndex index, out Sector sector)
{
sector = null;
// upper layer saved -1 as sectorIndex if child sector doesn't exist.
if (index.IsUnknown())
{
return(false);
}
var position = _storeStream.Seek(index.ByteIndex(_sectorSizeInBytes), SeekOrigin.Begin);
// seek a position beyond file length
if (position == _storeStream.Length)
{
return(false);
}
_sector.Read(_storeStream, index.ByteIndex(_sectorSizeInBytes));
sector = _sector;
return(true);
}
public void Write(SectorIndex index, Sector source)
{
_memoryStream.Seek(index.ByteIndex(_sectorSizeInBytes), SeekOrigin.Begin);
source.Write(_memoryStream, index.ByteIndex(_sectorSizeInBytes));
}