private void WriteInternal(IEnumerable <BufLen> datablocks, int ix)
{
var thissector = ix;
if (!Bits[ix])
{
throw new Exception("Cannot update an unallocated sector!");
}
TheFile.Position = BitmapToPos(thissector);
if ((Store.SectorTypes)StreamUtils.ReadInt8(TheFile) != Store.SectorTypes.Data)
{
throw new Exception("Trying to write in non data area");
}
var nextsector = StreamUtils.ReadInt32(TheFile);
TheFile.WriteInt64(datablocks.Sum(r => (long)r.Length));
var sectorspaceleft = FirstSectorDataSize;
foreach (var datab in datablocks)
{
var data = (BufRefLen)datab;
while (data.Length > 0)
{
var len = (int)Math.Min(data.Length, sectorspaceleft);
TheFile.Write(data.BaseArray, data.BaseArrayOffset, len);
data.Seek(len);
sectorspaceleft -= len;
if (data.Length == 0)
{
break;
}
if (sectorspaceleft == 0)
{
if (nextsector != LAST_SECTOR_IN_CHAIN)
{
if (!Bits[nextsector])
{
throw new Exception("Cannot update an unallocated sector!");
}
TheFile.Position = BitmapToPos(nextsector);
if ((Store.SectorTypes)StreamUtils.ReadInt8(TheFile) != Store.SectorTypes.Continuation)
{
throw new Exception("Trying to update a sector outside of the allocated sector chain!");
}
thissector = nextsector;
nextsector = StreamUtils.ReadInt32(TheFile);
}
else
{
thissector = ExtendLastSector(thissector);
nextsector = LAST_SECTOR_IN_CHAIN;
}
sectorspaceleft = SectorDataSize;
}
}
}
}