private static Permissions MapPermissions()

in foreign/csharp/Iggy_SDK/Mappers/BinaryMapper.cs [97:176]
71 lines of code
9 McCabe index (conditional complexity)

    private static Permissions MapPermissions(ReadOnlySpan<byte> bytes)
    {
        var streamMap = new Dictionary<int, StreamPermissions>();
        int index = 0;

        var globalPermissions = new GlobalPermissions
        {
            ManageServers = bytes[index++] == 1,
            ReadServers = bytes[index++] == 1,
            ManageUsers = bytes[index++] == 1,
            ReadUsers = bytes[index++] == 1,
            ManageStreams = bytes[index++] == 1,
            ReadStreams = bytes[index++] == 1,
            ManageTopics = bytes[index++] == 1,
            ReadTopics = bytes[index++] == 1,
            PollMessages = bytes[index++] == 1,
            SendMessages = bytes[index++] == 1,
        };

        if (bytes[index++] == 1)
        {
            while (true)
            {
                var streamId = BinaryPrimitives.ReadInt32LittleEndian(bytes[index..(index + 4)]);
                index += sizeof(int);

                var manageStream = bytes[index++] == 1;
                var readStream = bytes[index++] == 1;
                var manageTopics = bytes[index++] == 1;
                var readTopics = bytes[index++] == 1;
                var pollMessagesStream = bytes[index++] == 1;
                var sendMessagesStream = bytes[index++] == 1;
                var topicsMap = new Dictionary<int, TopicPermissions>();

                if (bytes[index++] == 1)
                {
                    while (true)
                    {
                        var topicId = BinaryPrimitives.ReadInt32LittleEndian(bytes[index..(index + 4)]);
                        index += sizeof(int);

                        var manageTopic = bytes[index++] == 1;
                        var readTopic = bytes[index++] == 1;
                        var pollMessagesTopic = bytes[index++] == 1;
                        var sendMessagesTopic = bytes[index++] == 1;

                        topicsMap.Add(topicId, new TopicPermissions
                        {
                            ManageTopic = manageTopic,
                            ReadTopic = readTopic,
                            PollMessages = pollMessagesTopic,
                            SendMessages = sendMessagesTopic,
                        });

                        if (bytes[index++] == 0)
                            break;
                    }
                }
                streamMap.Add(streamId, new StreamPermissions
                {
                    ManageStream = manageStream,
                    ReadStream = readStream,
                    ManageTopics = manageTopics,
                    ReadTopics = readTopics,
                    PollMessages = pollMessagesStream,
                    SendMessages = sendMessagesStream,
                    Topics = topicsMap.Count > 0 ? topicsMap : null,
                });

                if (bytes[index++] == 0)
                    break;
            }
        }

        return new Permissions
        {
            Global = globalPermissions,
            Streams = streamMap.Count > 0 ? streamMap : null
        };
    }