private Tuple <int, int> TranslateClosestForwardWithoutMidpoints(ReaderWorkItem workItem, int pos, int startIndex, int endIndex)
{
PosMap res = ReadPosMap(workItem, endIndex);
if (pos > res.LogPos)
{
return(Tuple.Create(_actualDataSize, endIndex + 1)); // to allow backward reading of the last record, forward read will decline anyway
}
int low = startIndex;
int high = endIndex;
while (low < high)
{
var mid = low + (high - low) / 2;
var v = ReadPosMap(workItem, mid);
if (v.LogPos < pos)
{
low = mid + 1;
}
else
{
high = mid;
res = v;
}
}
return(Tuple.Create(res.ActualPos, high));
}
// private int TranslateClosestWithMidpoints(ReaderWorkItem workItem, Midpoint[] midpoints, int prevPos)
// {
// if (prevPos < midpoints[0].LogPos || prevPos >= midpoints[midpoints.Length - 1].LogPos)
// return -1;
//
// var recordRange = LocateClosestPosRange(midpoints, prevPos);
// return TranslateClosestWithoutMidpoints(workItem, prevPos, recordRange.Item1, recordRange.Item2);
// }
private Tuple <PosMap, int> TranslateSameOrClosestWithoutMidpoints(ReaderWorkItem workItem, int pos, int startIndex, int endIndex)
{
PosMap res = ReadPosMap(workItem, endIndex);
if (pos > res.LogPos)
{
return(Tuple.Create(new PosMap(-1, -1), -1));
}
int low = startIndex;
int high = endIndex;
while (low < high)
{
var mid = low + (high - low) / 2;
var v = ReadPosMap(workItem, mid);
if (v.LogPos < pos)
{
low = mid + 1;
}
else
{
high = mid;
res = v;
}
}
return(Tuple.Create(res, high));
}
public Midpoint(int itemIndex, PosMap posmap)
{
ItemIndex = itemIndex;
LogPos = posmap.LogPos;
}
public Midpoint(int itemIndex, PosMap posmap)
{
ItemIndex = itemIndex;
LogPos = posmap.LogPos;
}
