private static CompactSketch wrap()

in src/main/java/org/apache/datasketches/theta/CompactSketch.java [185:229]
43 lines of code
14 McCabe index (conditional complexity)

  private static CompactSketch wrap(final Memory srcMem, final long seed, final boolean enforceSeed) {
    final int serVer = extractSerVer(srcMem);
    final int familyID = extractFamilyID(srcMem);
    final Family family = Family.idToFamily(familyID);
    if (family != Family.COMPACT) {
      throw new IllegalArgumentException("Corrupted: " + family + " is not Compact!");
    }
    final short seedHash = ThetaUtil.computeSeedHash(seed);

    if (serVer == 4) {
      return DirectCompactCompressedSketch.wrapInstance(srcMem,
          enforceSeed ? seedHash : (short) extractSeedHash(srcMem));
    }
    else if (serVer == 3) {
      if (PreambleUtil.isEmptyFlag(srcMem)) {
        return EmptyCompactSketch.getHeapInstance(srcMem);
      }
      if (otherCheckForSingleItem(srcMem)) {
        return SingleItemSketch.heapify(srcMem, enforceSeed ? seedHash : (short) extractSeedHash(srcMem));
      }
      //not empty & not singleItem
      final int flags = extractFlags(srcMem);
      final boolean compactFlag = (flags & COMPACT_FLAG_MASK) > 0;
      if (!compactFlag) {
        throw new SketchesArgumentException(
            "Corrupted: COMPACT family sketch image must have compact flag set");
      }
      final boolean readOnly = (flags & READ_ONLY_FLAG_MASK) > 0;
      if (!readOnly) {
        throw new SketchesArgumentException(
            "Corrupted: COMPACT family sketch image must have Read-Only flag set");
      }
      return DirectCompactSketch.wrapInstance(srcMem,
          enforceSeed ? seedHash : (short) extractSeedHash(srcMem));
    } //end of serVer 3
    else if (serVer == 1) {
      return ForwardCompatibility.heapify1to3(srcMem, seedHash);
    }
    else if (serVer == 2) {
      return ForwardCompatibility.heapify2to3(srcMem,
          enforceSeed ? seedHash : (short) extractSeedHash(srcMem));
    }
    throw new SketchesArgumentException(
        "Corrupted: Serialization Version " + serVer + " not recognized.");
  }