public IEnumerable <InternalIByteArrayKeyValuePair> Seek(InternalKey target)
{
var left = 0;
var right = _numRestarts - 1;
var value = default(ArraySegment <byte>); // not used
var keybuf = new AppendableByteArraySegment(DefaultRestartInterval);
while (left < right)
{
var mid = (left + right + 1) / 2;
keybuf.TrimToLength(0);
ParseEntry(GetRestartPointOffset(mid), ref keybuf, ref value);
var midKey = InternalKey.FromUnsafe(keybuf.ToByteArray());
if (_comparer.Compare(midKey, target) < 0)
{
// Key at "mid" is smaller than "target". Therefore all
// blocks before "mid" are uninteresting.
left = mid;
}
else
{
// Key at "mid" is >= "target". Therefore all blocks at or
// after "mid" are uninteresting.
right = mid - 1;
}
}
// Linear search (within restart block) for first key >= target
return(SeekToRestartPoint(left).SkipWhile(kv => _comparer.Compare(kv.InternalKey, target) < 0));
}
// ref key current not use
private void ParseEntry(int offset, ref AppendableByteArraySegment key, ref ArraySegment <byte> value)
{
var pb = new CodedInputStream(_data, offset, _restartOffset - offset);
var shared = pb.ReadInt32();
var nonShared = pb.ReadInt32();
var valueLength = pb.ReadInt32();
if (key.Length < shared)
{
throw new InvalidDataException("bad entry in block - shared > _key.length");
}
var p = (int)pb.Position;
key.TrimToLength(shared);
key.Append(new ArraySegment <byte>(_data, p, nonShared));
value = new ArraySegment <byte>(_data, p + nonShared, valueLength);
}
