private byte[] ReadSectorCached(int lba)
{
//read it if we dont have it cached
//we wont be caching very much here, it's no big deal
//identification is not something we want to take a long time
byte[] data;
if (!_sectorCache.TryGetValue(lba, out data))
{
data = new byte[2048];
int read = _dsr.ReadLBA_2048(lba, data, 0);
if (read != 2048)
{
return(null);
}
_sectorCache[lba] = data;
}
return(data);
}
//TODO - I'm not sure everything in here makes sense right now..
public override int Read(byte[] buffer, int offset, int count)
{
long remainInDisc = Length - currPosition;
if (count > remainInDisc)
{
count = (int)Math.Min(remainInDisc, int.MaxValue);
}
int remain = count;
int readed = 0;
while (remain > 0)
{
int lba = (int)(currPosition / SectorSize);
int lba_within = (int)(currPosition % SectorSize);
int todo = remain;
int remains_in_lba = SectorSize - lba_within;
if (remains_in_lba < todo)
{
todo = remains_in_lba;
}
if (cachedSector != lba)
{
dsr.ReadLBA_2048(lba, cachedSectorBuffer, 0);
cachedSector = lba;
}
Array.Copy(cachedSectorBuffer, lba_within, buffer, offset, todo);
offset += todo;
remain -= todo;
currPosition += todo;
readed += todo;
}
return(readed);
}
