private EliasFanoEncoder TstEFVI(long[] values, long indexInterval, long[] expIndexBits)
{
EliasFanoEncoder efEncVI = MakeEncoder(values, indexInterval);
TstEqual("upperZeroBitPositionIndex", expIndexBits, efEncVI.IndexBits);
return(efEncVI);
}
/// <summary>
/// Construct a decoder for a given <seealso cref="EliasFanoEncoder"/>.
/// The decoding index is set to just before the first encoded value.
/// </summary>
public EliasFanoDecoder(EliasFanoEncoder efEncoder)
{
this.EfEncoder = efEncoder;
this.NumEncoded_Renamed = efEncoder.NumEncoded; // not final in EliasFanoEncoder
this.NumIndexEntries = efEncoder.CurrentEntryIndex; // not final in EliasFanoEncoder
this.IndexMask = (1L << efEncoder.NIndexEntryBits) - 1;
}
/// <summary>
/// Construct a decoder for a given <seealso cref="EliasFanoEncoder"/>.
/// The decoding index is set to just before the first encoded value.
/// </summary>
public EliasFanoDecoder(EliasFanoEncoder efEncoder)
{
this.EfEncoder = efEncoder;
this.NumEncoded_Renamed = efEncoder.NumEncoded; // not final in EliasFanoEncoder
this.NumIndexEntries = efEncoder.CurrentEntryIndex; // not final in EliasFanoEncoder
this.IndexMask = (1L << efEncoder.NIndexEntryBits) - 1;
}
/// <summary>
/// Construct a decoder for a given <seealso cref="EliasFanoEncoder"/>.
/// The decoding index is set to just before the first encoded value.
/// </summary>
public EliasFanoDecoder(EliasFanoEncoder efEncoder)
{
this.efEncoder = efEncoder;
this.numEncoded = efEncoder.numEncoded; // not final in EliasFanoEncoder
this.numIndexEntries = efEncoder.currentEntryIndex; // not final in EliasFanoEncoder
this.indexMask = (1L << efEncoder.nIndexEntryBits) - 1;
}
private static void TstEFS(long[] values, long[] expHighLongs, long[] expLowLongs)
{
EliasFanoEncoder efEncoder = MakeEncoder(values, EliasFanoEncoder.DEFAULT_INDEX_INTERVAL);
TstEqual("upperBits", expHighLongs, efEncoder.UpperBits);
TstEqual("lowerBits", expLowLongs, efEncoder.LowerBits);
TstDecodeAll(efEncoder, values);
}
public virtual void TestIndexAdvanceToFirst()
{
long indexInterval = 2;
long[] twoLongs = new long[] { 0, 2 };
long[] indexLongs = new long[] { 3 }; // high bits 1001
EliasFanoEncoder efEncVI = TstEFVI(twoLongs, indexInterval, indexLongs);
Assert.AreEqual(0, efEncVI.Decoder.AdvanceToValue(0));
}
private static void TstEFSadvanceToAndBackToMultiples(long[] values, long maxValue, long minAdvanceMultiple)
{
EliasFanoEncoder efEncoder = MakeEncoder(values, EliasFanoEncoder.DEFAULT_INDEX_INTERVAL);
for (long m = minAdvanceMultiple; m <= maxValue; m += 1)
{
TstDecodeAdvanceToMultiples(values, efEncoder.Decoder, m);
TstDecodeBackToMultiples(values, efEncoder.Decoder, m);
}
}
public virtual void TestIndexAdvanceToAfterLast()
{
long indexInterval = 2;
long[] twoLongs = new long[] { 0, 2 };
long[] indexLongs = new long[] { 3 }; // high bits 1001
EliasFanoEncoder efEncVI = TstEFVI(twoLongs, indexInterval, indexLongs);
Assert.AreEqual(EliasFanoDecoder.NO_MORE_VALUES, efEncVI.GetDecoder().AdvanceToValue(3));
}
public virtual void TestExample2NoIndex1() // Figure 2 from Vigna 2012 paper, no index, test broadword selection.
{
long indexInterval = 16;
long[] values = new long[] { 5, 8, 8, 15, 32 }; // two low bits, high values 1,2,2,3,8.
long[] indexLongs = new long[0]; // high bits 0b 0001 0000 0101 1010
EliasFanoEncoder efEncVI = TstEFVI(values, indexInterval, indexLongs);
EliasFanoDecoder efDecVI = efEncVI.Decoder;
Assert.AreEqual(32, efDecVI.AdvanceToValue(22), "advance 22");
}
public virtual void TestExample2a() // Figure 2 from Vigna 2012 paper
{
long indexInterval = 4;
long[] values = new long[] { 5, 8, 8, 15, 32 }; // two low bits, high values 1,2,2,3,8.
long[] indexLongs = new long[] { 8 + 12 * 16 }; // high bits 0b 0001 0000 0101 1010
EliasFanoEncoder efEncVI = TstEFVI(values, indexInterval, indexLongs);
EliasFanoDecoder efDecVI = efEncVI.Decoder;
Assert.AreEqual(32, efDecVI.AdvanceToValue(22), "advance 22");
}
public override bool Equals(object other)
{
if (!(other is EliasFanoEncoder))
{
return(false);
}
EliasFanoEncoder oefs = (EliasFanoEncoder)other;
// no equality needed for upperBound
return((this.NumValues == oefs.NumValues) && (this.NumEncoded == oefs.NumEncoded) && (this.NumLowBits == oefs.NumLowBits) && (this.NumIndexEntries == oefs.NumIndexEntries) && (this.IndexInterval == oefs.IndexInterval) && Arrays.Equals(this.UpperLongs, oefs.UpperLongs) && Arrays.Equals(this.LowerLongs, oefs.LowerLongs)); // no need to check index content
}
public virtual void TestTwoIndexEntries()
{
long indexInterval = 2;
long[] twoLongs = new long[] { 0, 1, 2, 3, 4, 5 };
long[] indexLongs = new long[] { 4 + 8 * 16 }; // high bits 0b10101010101
EliasFanoEncoder efEncVI = TstEFVI(twoLongs, indexInterval, indexLongs);
EliasFanoDecoder efDecVI = efEncVI.Decoder;
Assert.AreEqual(0, efDecVI.AdvanceToValue(0), "advance 0");
Assert.AreEqual(5, efDecVI.AdvanceToValue(5), "advance 5");
Assert.AreEqual(EliasFanoDecoder.NO_MORE_VALUES, efDecVI.AdvanceToValue(5), "advance 6");
}
public virtual void TestHashCodeEquals()
{
long[] values = new long[] { 5, 8, 8, 15, 32 };
EliasFanoEncoder efEncoder1 = MakeEncoder(values, EliasFanoEncoder.DEFAULT_INDEX_INTERVAL);
EliasFanoEncoder efEncoder2 = MakeEncoder(values, EliasFanoEncoder.DEFAULT_INDEX_INTERVAL);
Assert.AreEqual(efEncoder1, efEncoder2);
Assert.AreEqual(efEncoder1.GetHashCode(), efEncoder2.GetHashCode());
EliasFanoEncoder efEncoder3 = MakeEncoder(new long[] { 1, 2, 3 }, EliasFanoEncoder.DEFAULT_INDEX_INTERVAL);
Assert.IsFalse(efEncoder1.Equals(efEncoder3));
Assert.IsFalse(efEncoder3.Equals(efEncoder1));
Assert.IsFalse(efEncoder1.GetHashCode() == efEncoder3.GetHashCode()); // implementation ok for these.
}
private static EliasFanoEncoder MakeEncoder(long[] values, long indexInterval)
{
long upperBound = -1L;
foreach (long value in values)
{
Assert.IsTrue(value >= upperBound); // test data ok
upperBound = value;
}
EliasFanoEncoder efEncoder = new EliasFanoEncoder(values.Length, upperBound, indexInterval);
foreach (long value in values)
{
efEncoder.EncodeNext(value);
}
return efEncoder;
}
private static EliasFanoEncoder MakeEncoder(long[] values, long indexInterval)
{
long upperBound = -1L;
foreach (long value in values)
{
Assert.IsTrue(value >= upperBound); // test data ok
upperBound = value;
}
EliasFanoEncoder efEncoder = new EliasFanoEncoder(values.Length, upperBound, indexInterval);
foreach (long value in values)
{
efEncoder.EncodeNext(value);
}
return(efEncoder);
}
/// <summary>
/// Construct an EliasFanoDocIdSet. For efficient encoding, the parameters should be chosen as low as possible. </summary>
/// <param name="numValues"> At least the number of document ids that will be encoded. </param>
/// <param name="upperBound"> At least the highest document id that will be encoded. </param>
public EliasFanoDocIdSet(int numValues, int upperBound)
{
EfEncoder = new EliasFanoEncoder(numValues, upperBound);
}
public static bool SufficientlySmallerThanBitSet(long numValues, long upperBound)
{
return(EliasFanoEncoder.SufficientlySmallerThanBitSet(numValues, upperBound));
}
/// <summary>
/// Construct an EliasFanoDocIdSet. For efficient encoding, the parameters should be chosen as low as possible. </summary>
/// <param name="numValues"> At least the number of document ids that will be encoded. </param>
/// <param name="upperBound"> At least the highest document id that will be encoded. </param>
public EliasFanoDocIdSet(int numValues, int upperBound)
{
efEncoder = new EliasFanoEncoder(numValues, upperBound);
}
private static void TstDecodeAll(EliasFanoEncoder efEncoder, long[] values)
{
TstDecodeAllNext(values, efEncoder.Decoder);
TstDecodeAllPrev(values, efEncoder.Decoder);
TstDecodeAllAdvanceToExpected(values, efEncoder.Decoder);
}
private static void TstDecodeAll(EliasFanoEncoder efEncoder, long[] values)
{
TstDecodeAllNext(values, efEncoder.Decoder);
TstDecodeAllPrev(values, efEncoder.Decoder);
TstDecodeAllAdvanceToExpected(values, efEncoder.Decoder);
}
private static void TstEFS2(long[] values)
{
EliasFanoEncoder efEncoder = MakeEncoder(values, EliasFanoEncoder.DEFAULT_INDEX_INTERVAL);
TstDecodeAll(efEncoder, values);
}
