static Map deserializeStatsMetadata()

in cassandra-four-zero/src/main/java/org/apache/cassandra/spark/reader/ReaderUtils.java [256:337]
66 lines of code
8 McCabe index (conditional complexity)

    static Map<MetadataType, MetadataComponent> deserializeStatsMetadata(InputStream is,
                                                                         EnumSet<MetadataType> selectedTypes,
                                                                         Descriptor descriptor) throws IOException
    {
        DataInputStream in = new DataInputPlus.DataInputStreamPlus(is);
        boolean isChecksummed = descriptor.version.hasMetadataChecksum();
        CRC32 crc = new CRC32();

        int count = in.readInt();
        updateChecksumInt(crc, count);
        maybeValidateChecksum(crc, in, descriptor);

        int[] ordinals = new int[count];
        int[] offsets = new int[count];
        int[] lengths = new int[count];

        for (int index = 0; index < count; index++)
        {
            ordinals[index] = in.readInt();
            updateChecksumInt(crc, ordinals[index]);

            offsets[index] = in.readInt();
            updateChecksumInt(crc, offsets[index]);
        }
        maybeValidateChecksum(crc, in, descriptor);

        for (int index = 0; index < count - 1; index++)
        {
            lengths[index] = offsets[index + 1] - offsets[index];
        }

        MetadataType[] allMetadataTypes = MetadataType.values();
        Map<MetadataType, MetadataComponent> components = new EnumMap<>(MetadataType.class);
        for (int index = 0; index < count - 1; index++)
        {
            MetadataType type = allMetadataTypes[ordinals[index]];

            if (!selectedTypes.contains(type))
            {
                in.skipBytes(lengths[index]);
                continue;
            }

            byte[] bytes = new byte[isChecksummed ? lengths[index] - CHECKSUM_LENGTH : lengths[index]];
            in.readFully(bytes);

            crc.reset();
            crc.update(bytes);
            maybeValidateChecksum(crc, in, descriptor);

            components.put(type, deserializeMetadataComponent(descriptor.version, bytes, type));
        }

        MetadataType type = allMetadataTypes[ordinals[count - 1]];
        if (!selectedTypes.contains(type))
        {
            return components;
        }

        // We do not have in.bytesRemaining() (as in FileDataInput),
        // so need to read remaining bytes to get final component
        byte[] remainingBytes = ByteBufferUtils.readRemainingBytes(in, 256);
        byte[] bytes;
        if (descriptor.version.hasMetadataChecksum())
        {
            ByteBuffer buffer = ByteBuffer.wrap(remainingBytes);
            int length = buffer.remaining() - 4;
            bytes = new byte[length];
            buffer.get(bytes, 0, length);
            crc.reset();
            crc.update(bytes);
            validateChecksum(crc, buffer.getInt(), descriptor);
        }
        else
        {
            bytes = remainingBytes;
        }

        components.put(type, deserializeMetadataComponent(descriptor.version, bytes, type));

        return components;
    }