private void sanityCheckSubStreamsInfo()

in src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java [2076:2131]
50 lines of code
17 McCabe index (conditional complexity)

    private void sanityCheckSubStreamsInfo(final ByteBuffer header, final ArchiveStatistics stats) throws IOException {

        int nid = getUnsignedByte(header);
        final List<Integer> numUnpackSubStreamsPerFolder = new LinkedList<>();
        if (nid == NID.kNumUnpackStream) {
            for (int i = 0; i < stats.numberOfFolders; i++) {
                numUnpackSubStreamsPerFolder.add(assertFitsIntoNonNegativeInt("numStreams", readUint64(header)));
            }
            stats.numberOfUnpackSubStreams = numUnpackSubStreamsPerFolder.stream().mapToLong(Integer::longValue).sum();
            nid = getUnsignedByte(header);
        } else {
            stats.numberOfUnpackSubStreams = stats.numberOfFolders;
        }

        assertFitsIntoNonNegativeInt("totalUnpackStreams", stats.numberOfUnpackSubStreams);

        if (nid == NID.kSize) {
            for (final int numUnpackSubStreams : numUnpackSubStreamsPerFolder) {
                if (numUnpackSubStreams == 0) {
                    continue;
                }
                for (int i = 0; i < numUnpackSubStreams - 1; i++) {
                    final long size = readUint64(header);
                    if (size < 0) {
                        throw new IOException("negative unpackSize");
                    }
                }
            }
            nid = getUnsignedByte(header);
        }

        int numDigests = 0;
        if (numUnpackSubStreamsPerFolder.isEmpty()) {
            numDigests = stats.folderHasCrc == null ? stats.numberOfFolders : stats.numberOfFolders - stats.folderHasCrc.cardinality();
        } else {
            int folderIdx = 0;
            for (final int numUnpackSubStreams : numUnpackSubStreamsPerFolder) {
                if (numUnpackSubStreams != 1 || stats.folderHasCrc == null || !stats.folderHasCrc.get(folderIdx++)) {
                    numDigests += numUnpackSubStreams;
                }
            }
        }

        if (nid == NID.kCRC) {
            assertFitsIntoNonNegativeInt("numDigests", numDigests);
            final int missingCrcs = readAllOrBits(header, numDigests).cardinality();
            if (skipBytesFully(header, 4 * missingCrcs) < 4 * missingCrcs) {
                throw new IOException("invalid number of missing CRCs in SubStreamInfo");
            }
            nid = getUnsignedByte(header);
        }

        if (nid != NID.kEnd) {
            throw new IOException("Badly terminated SubStreamsInfo");
        }
    }