SBE Log Decoder Sample

This sample demonstrates how to convert the Base64 encoded \*.summary file into a human-friendly \*.txt file.

Source code

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using OnixS.SimpleBinaryEncoding;
using OnixS.SimpleBinaryEncoding.Templates;
using OnixS.SimpleBinaryEncoding.CodeGenerator;

namespace SbeLogDecoder
{
    internal static class SbeLogDecoder
    {
        private static readonly string version = "1.0.0";

        private static void Main(string[] args)
        {
            if (args.Length < 2)
            {
                Console.WriteLine("SBE Log Decoder, version = " + version + "\n");
                Console.WriteLine("usage: [SbeMessageSchemaFile] [TargetPath|TargetDir]");
                return;
            }

            string tplPath = args[0];
            string targetPath = args[1];

            try
            {
                var decoder = GetDecoder(tplPath);

                foreach (var file in GatherFiles(targetPath))
                {
                    Console.WriteLine(Path.GetFileName(file) + ":\n");
                    Decode(file, decoder);
                    Console.WriteLine("\n***\n");
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }
        }

        private static IDecoder GetDecoder(string tpl)
        {
            TemplateLibrary.LicenseStore = "../../../../../license|../../../../license|.";
            var lib = TemplateLibrary.Parse(File.ReadAllText(tpl));

            var assembly = new Generator().GenerateAssembly<CmeILinkHeader>(lib, "OnixS.SimpleBinaryEncoding.Cme");
            var decoder = (IDecoder)Activator.CreateInstance(assembly.GetType("OnixS.SimpleBinaryEncoding.Cme.Decoder", true));

            return decoder;
        }

        private static List<string> GatherFiles(string path)
        {
            if (File.GetAttributes(path).HasFlag(FileAttributes.Directory))
                return new List<string>(Directory.GetFiles(path, "*.summary"));
            else
                return new List<string>([path]);
        }

        private static void Decode(string filePtah, IDecoder decoder)
        {
            using var fileStream = File.OpenRead(filePtah);
            using var streamReader = new StreamReader(fileStream, Encoding.UTF8, true);
            {
                string line;
                while((line = streamReader.ReadLine()) != null)
                {
                    const int LogLinePrefixSize = 32;
                    string prefix = line[0..LogLinePrefixSize];
                    line = line[LogLinePrefixSize..];

                    byte[] rawData = Convert.FromBase64String(line);

                    // See https://cmegroupclientsite.atlassian.net/wiki/spaces/EPICSANDBOX/pages/46113078/iLink+3+Message+Header.
                    bool sofhDetected = rawData[3] == 0xCA && rawData[2] == 0xFE;

                    byte[] iLinkMessage = null;

                    if (sofhDetected)
                    {
                        iLinkMessage = rawData;
                    }
                    else
                    {
                        // The log record does not contain a Simple Open Framing Header(SOFH), so we need to add it before we can decode the message.
                        const int SofhLength = 4;
                        iLinkMessage = new byte[rawData.Length + SofhLength];
                        Array.Copy(rawData, 0, iLinkMessage, SofhLength, rawData.Length);
                        byte[] messageSizeBytes = BitConverter.GetBytes((ushort)iLinkMessage.Length);
                        // Set the `MessageSize` SOFH field.
                        iLinkMessage[0] = messageSizeBytes[0];
                        iLinkMessage[1] = messageSizeBytes[1];
                    }

                    var memPtr = new MemoryPointer(new Memory<byte>(iLinkMessage));
                    Console.WriteLine(prefix + decoder.Wrap(memPtr).ToString());
                }
            }
        }
    }
}