private int TranslateClosestForwardWithoutMidpoints(ReaderWorkItem workItem, long pos, long startIndex, long endIndex)
{
PosMap res = ReadPosMap(workItem, endIndex);
// to allow backward reading of the last record, forward read will decline anyway
if (pos > res.LogPos)
{
return(Chunk.PhysicalDataSize);
}
long low = startIndex;
long 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(res.ActualPos);
}
private IEnumerable<PosMap> ReadPosMap(ReaderWorkItem workItem, long index, int count) {
if (Chunk.ChunkFooter.IsMap12Bytes) {
var pos = ChunkHeader.Size + Chunk.ChunkFooter.PhysicalDataSize + index * PosMap.FullSize;
workItem.Stream.Seek(pos, SeekOrigin.Begin);
for (int i = 0; i < count; i++)
yield return PosMap.FromNewFormat(workItem.Reader);
} else {
var pos = ChunkHeader.Size + Chunk.ChunkFooter.PhysicalDataSize + index * PosMap.DeprecatedSize;
workItem.Stream.Seek(pos, SeekOrigin.Begin);
for (int i = 0; i < count; i++)
yield return PosMap.FromOldFormat(workItem.Reader);
}
}
private PosMap ReadPosMap(ReaderWorkItem workItem, long index)
{
if (Chunk.ChunkFooter.IsMap12Bytes)
{
var pos = ChunkHeader.Size + Chunk.ChunkFooter.PhysicalDataSize + index * PosMap.FullSize;
workItem.Stream.Seek(pos, SeekOrigin.Begin);
return(PosMap.FromNewFormat(workItem.Reader));
}
else
{
var pos = ChunkHeader.Size + Chunk.ChunkFooter.PhysicalDataSize + index * PosMap.DeprecatedSize;
workItem.Stream.Seek(pos, SeekOrigin.Begin);
return(PosMap.FromOldFormat(workItem.Reader));
}
}
public Midpoint(int itemIndex, PosMap posmap)
{
ItemIndex = itemIndex;
LogPos = posmap.LogPos;
}
public Midpoint(int itemIndex, PosMap posmap)
{
ItemIndex = itemIndex;
LogPos = posmap.LogPos;
}
