private bool TryGetPreviousBlockSlower(DataBlock currentBlock, out DataBlock?previousBlock)
{
if (currentBlock == DataBlock.Empty && LastValueOrDefault != null)
{
previousBlock = LastValueOrDefault;
}
else if (!_blockSeries.TryFindBlockAtFromSource(out previousBlock, this,
currentBlock.DangerousRowKey <TKey>(index: 0), Lookup.LT))
{
if (AdditionalCorrectnessChecks.Enabled)
{
ThrowHelper.Assert(previousBlock == null);
}
previousBlock = null;
}
if (previousBlock != null)
{
if (AdditionalCorrectnessChecks.Enabled)
{
ThrowHelper.DebugAssert(previousBlock.RowCount > 0);
}
return(previousBlock.RowCount > 0);
}
return(false);
}
private bool TryGetNextBlockSlower(DataBlock currentBlock, out DataBlock?nextBlock)
{
if (currentBlock == DataBlock.Empty && First.IsPresent)
{
nextBlock = First.Present.Value;
}
else if (!_blockSeries.TryFindBlockAtFromSource(out nextBlock, this,
currentBlock.DangerousRowKey <TKey>(index: 0), Lookup.GT))
{
if (AdditionalCorrectnessChecks.Enabled)
{
ThrowHelper.Assert(nextBlock == null, "nextBlock == null");
}
nextBlock = null;
}
if (nextBlock != null)
{
if (AdditionalCorrectnessChecks.Enabled)
{
ThrowHelper.DebugAssert(nextBlock.RowCount > 0, "nextBlock.RowCount > 0 2");
}
return(nextBlock.RowCount > 0);
}
return(false);
}