protected override void ReadImpl(Span <byte> destination, long offset)
{
var iterator = new AllocationTableIterator(Fat, InitialBlock);
long inPos = offset;
int outPos = 0;
int remaining = destination.Length;
while (remaining > 0)
{
int blockNum = (int)(inPos / BlockSize);
iterator.Seek(blockNum);
int segmentPos = (int)(inPos - (long)iterator.VirtualBlock * BlockSize);
long physicalOffset = iterator.PhysicalBlock * BlockSize + segmentPos;
int remainingInSegment = iterator.CurrentSegmentSize * BlockSize - segmentPos;
int bytesToRead = Math.Min(remaining, remainingInSegment);
BaseStorage.Read(destination.Slice(outPos, bytesToRead), physicalOffset);
outPos += bytesToRead;
inPos += bytesToRead;
remaining -= bytesToRead;
}
}
protected override void WriteImpl(ReadOnlySpan <byte> source, long offset)
{
var iterator = new AllocationTableIterator(Fat, InitialBlock);
long inPos = offset;
int outPos = 0;
int remaining = source.Length;
while (remaining > 0)
{
int blockNum = (int)(inPos / BlockSize);
iterator.Seek(blockNum);
int segmentPos = (int)(inPos - (long)iterator.VirtualBlock * BlockSize);
long physicalOffset = iterator.PhysicalBlock * BlockSize + segmentPos;
int remainingInSegment = iterator.CurrentSegmentSize * BlockSize - segmentPos;
int bytesToWrite = Math.Min(remaining, remainingInSegment);
BaseStorage.Write(source.Slice(outPos, bytesToWrite), physicalOffset);
outPos += bytesToWrite;
inPos += bytesToWrite;
remaining -= bytesToWrite;
}
}
public static IEnumerable <(int block, int length)> DumpChain(this AllocationTable table, int startBlock)
{
var iterator = new AllocationTableIterator(table, startBlock);
do
{
yield return(iterator.PhysicalBlock, iterator.CurrentSegmentSize);
} while (iterator.MoveNext());
}