code: private static int[] uncompressTheSurprisingValues(final CompressedState source) {
      final int srcK = 1 << source.lgK;
      final int numPairs = source.numCsv;
      assert numPairs > 0;
      final int[] pairs = new int[numPairs];
      final int numBaseBits = CpcCompression.golombChooseNumberOfBaseBits(srcK + numPairs, numPairs);
      lowLevelUncompressPairs(pairs, numPairs, numBaseBits, source.csvStream, source.csvLengthInts);
      return pairs;
    }
docs: the length of this array is known to the source sketch.