Bend.SegmentBlockBasicDecoder.scanBackward C# (CSharp) Метод

        public IEnumerable<KeyValuePair<RecordKey, RecordUpdate>> scanBackward(IScanner<RecordKey> scanner)
        {
            IComparable<RecordKey> lowkeytest = scanner.genLowestKeyTest();
            IComparable<RecordKey> highkeytest = scanner.genHighestKeyTest();

            RecordLocator rloc = _findRecord(highkeytest, true).before_keytest;

            while (rloc.have_record &&   // while we have a new record to test
                (lowkeytest.CompareTo(rloc.record.Key) < 0))  // and it's above the lowkey
            {
                if (scanner.MatchTo(rloc.record.Key)) {
                    yield return rloc.record;
                }
                _prevRecord(ref rloc);
            }
        }

        public void T02_BasicBlock_Enumerators()
        {
            // exercize the iscannable interface
            string[] testvalues = { "test/1", "test/2", "test/3" };
            byte[] databuffer;

            // encode a buffer
            {
                MemoryStream ms = new MemoryStream();
                // add some values to the block encoder
                SegmentBlockBasicEncoder enc = new SegmentBlockBasicEncoder();
                enc.setStream(ms);
                for (int i = 0; i < testvalues.Length; i++) {
                    RecordKey tkey = new RecordKey().appendParsedKey(testvalues[i]);
                    RecordUpdate tupdate = RecordUpdate.WithPayload("data: " + testvalues[i]);

                    enc.add(tkey, tupdate);
                }
                enc.flush();

                databuffer = ms.ToArray();
            }

            // decode and test the buffer, scan enumerators
            {
                BlockAccessor rs = new BlockAccessor(databuffer);
                SegmentBlockBasicDecoder decoder = new SegmentBlockBasicDecoder(rs);
                int pos = 0;
                IScanner<RecordKey> scanner = ScanRange<RecordKey>.All();
                foreach (KeyValuePair<RecordKey, RecordUpdate> row in decoder.scanForward(scanner)) {
                    RecordKey tkey = new RecordKey().appendParsedKey(testvalues[pos]);
                    RecordUpdate tupdate = RecordUpdate.WithPayload("data: " + testvalues[pos]);

                    Assert.AreEqual(tkey, row.Key, "forward, record keys should match");
                    Assert.AreEqual(tupdate, row.Value, "forward, record values should match:");
                    pos++;
                }
                Assert.AreEqual(testvalues.Length, pos, "forward, should return all values we put in");

                pos = testvalues.Length - 1;
                foreach (KeyValuePair<RecordKey, RecordUpdate> row in decoder.scanBackward(scanner)) {
                    RecordKey tkey = new RecordKey().appendParsedKey(testvalues[pos]);
                    RecordUpdate tupdate = RecordUpdate.WithPayload("data: " + testvalues[pos]);

                    Assert.AreEqual(tkey, row.Key, "backward, record keys should match, pos=" + pos);
                    Assert.AreEqual(tupdate, row.Value, "backward, record values should match:");
                    pos--;
                }
                Assert.AreEqual(-1, pos, "backward, should return all values we put in");

            }
        }