private int sanityCheckFolder()

in src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java [1763:1850]
78 lines of code
16 McCabe index (conditional complexity)

    private int sanityCheckFolder(final ByteBuffer header, final ArchiveStatistics stats)
        throws IOException {

        final int numCoders = assertFitsIntoNonNegativeInt("numCoders", readUint64(header));
        if (numCoders == 0) {
            throw new IOException("Folder without coders");
        }
        stats.numberOfCoders += numCoders;

        long totalOutStreams = 0;
        long totalInStreams = 0;
        for (int i = 0; i < numCoders; i++) {
            final int bits = getUnsignedByte(header);
            final int idSize = bits & 0xf;
            get(header, new byte[idSize]);

            final boolean isSimple = (bits & 0x10) == 0;
            final boolean hasAttributes = (bits & 0x20) != 0;
            final boolean moreAlternativeMethods = (bits & 0x80) != 0;
            if (moreAlternativeMethods) {
                throw new IOException("Alternative methods are unsupported, please report. " + // NOSONAR
                    "The reference implementation doesn't support them either.");
            }

            if (isSimple) {
                totalInStreams++;
                totalOutStreams++;
            } else {
                totalInStreams +=
                    assertFitsIntoNonNegativeInt("numInStreams", readUint64(header));
                totalOutStreams +=
                    assertFitsIntoNonNegativeInt("numOutStreams", readUint64(header));
            }

            if (hasAttributes) {
                final int propertiesSize =
                    assertFitsIntoNonNegativeInt("propertiesSize", readUint64(header));
                if (skipBytesFully(header, propertiesSize) < propertiesSize) {
                    throw new IOException("invalid propertiesSize in folder");
                }
            }
        }
        assertFitsIntoNonNegativeInt("totalInStreams", totalInStreams);
        assertFitsIntoNonNegativeInt("totalOutStreams", totalOutStreams);
        stats.numberOfOutStreams += totalOutStreams;
        stats.numberOfInStreams += totalInStreams;

        if (totalOutStreams == 0) {
            throw new IOException("Total output streams can't be 0");
        }

        final int numBindPairs =
            assertFitsIntoNonNegativeInt("numBindPairs", totalOutStreams - 1);
        if (totalInStreams < numBindPairs) {
            throw new IOException("Total input streams can't be less than the number of bind pairs");
        }
        final BitSet inStreamsBound = new BitSet((int) totalInStreams);
        for (int i = 0; i < numBindPairs; i++) {
            final int inIndex = assertFitsIntoNonNegativeInt("inIndex", readUint64(header));
            if (totalInStreams <= inIndex) {
                throw new IOException("inIndex is bigger than number of inStreams");
            }
            inStreamsBound.set(inIndex);
            final int outIndex = assertFitsIntoNonNegativeInt("outIndex", readUint64(header));
            if (totalOutStreams <= outIndex) {
                throw new IOException("outIndex is bigger than number of outStreams");
            }
        }

        final int numPackedStreams =
            assertFitsIntoNonNegativeInt("numPackedStreams", totalInStreams - numBindPairs);

        if (numPackedStreams == 1) {
            if (inStreamsBound.nextClearBit(0) == -1) {
                throw new IOException("Couldn't find stream's bind pair index");
            }
        } else {
            for (int i = 0; i < numPackedStreams; i++) {
                final int packedStreamIndex =
                    assertFitsIntoNonNegativeInt("packedStreamIndex", readUint64(header));
                if (packedStreamIndex >= totalInStreams) {
                    throw new IOException("packedStreamIndex is bigger than number of totalInStreams");
                }
            }
        }

        return (int) totalOutStreams;
    }