LongToPrefixCodedBytes() public static method

Returns prefix coded bits after reducing the precision by shift bits. this is method is used by NumericTokenStream. After encoding, {@code bytes.offset} will always be 0.
public static LongToPrefixCodedBytes ( long val, int shift, BytesRef bytes ) : void
val long the numeric value
shift int how many bits to strip from the right
bytes BytesRef will contain the encoded value
return void
Ejemplo n.º 1
0
        public virtual void TestLongSpecialValues()
        {
            long[]     vals       = new long[] { long.MinValue, long.MinValue + 1, long.MinValue + 2, -5003400000000L, -4000L, -3000L, -2000L, -1000L, -1L, 0L, 1L, 10L, 300L, 50006789999999999L, long.MaxValue - 2, long.MaxValue - 1, long.MaxValue };
            BytesRef[] prefixVals = new BytesRef[vals.Length];

            for (int i = 0; i < vals.Length; i++)
            {
                prefixVals[i] = new BytesRef(NumericUtils.BUF_SIZE_LONG);
                NumericUtils.LongToPrefixCodedBytes(vals[i], 0, prefixVals[i]);

                // check forward and back conversion
                Assert.AreEqual(vals[i], NumericUtils.PrefixCodedToLong(prefixVals[i]), "forward and back conversion should generate same long");

                // test if decoding values as int fails correctly
                try
                {
                    NumericUtils.PrefixCodedToInt(prefixVals[i]);
                    Assert.Fail("decoding a prefix coded long value as int should fail");
                }
                catch (FormatException e)
                {
                    // worked
                }
            }

            // check sort order (prefixVals should be ascending)
            for (int i = 1; i < prefixVals.Length; i++)
            {
                Assert.IsTrue(prefixVals[i - 1].CompareTo(prefixVals[i]) < 0, "check sort order");
            }

            // check the prefix encoding, lower precision should have the difference to original value equal to the lower removed bits
            BytesRef @ref = new BytesRef(NumericUtils.BUF_SIZE_LONG);

            for (int i = 0; i < vals.Length; i++)
            {
                for (int j = 0; j < 64; j++)
                {
                    NumericUtils.LongToPrefixCodedBytes(vals[i], j, @ref);
                    long prefixVal = NumericUtils.PrefixCodedToLong(@ref);
                    long mask      = (1L << j) - 1L;
                    Assert.AreEqual(vals[i] & mask, vals[i] - prefixVal, "difference between prefix val and original value for " + vals[i] + " with shift=" + j);
                }
            }
        }
Ejemplo n.º 2
0
        public virtual void TestLongConversionAndOrdering()
        {
            // generate a series of encoded longs, each numerical one bigger than the one before
            BytesRef last = null, act = new BytesRef(NumericUtils.BUF_SIZE_LONG);

            for (long l = -100000L; l < 100000L; l++)
            {
                NumericUtils.LongToPrefixCodedBytes(l, 0, act);
                if (last != null)
                {
                    // test if smaller
                    Assert.IsTrue(last.CompareTo(act) < 0, "actual bigger than last (BytesRef)");
                    //Assert.IsTrue(last.Utf8ToString().CompareTo(act.Utf8ToString()) < 0, "actual bigger than last (as String)");
                }
                // test is back and forward conversion works
                Assert.AreEqual(l, NumericUtils.PrefixCodedToLong(act), "forward and back conversion should generate same long");
                // next step
                last = act;
                act  = new BytesRef(NumericUtils.BUF_SIZE_LONG);
            }
        }