Question

I have this hexadecimal data:

byte[] data = new Byte[] {
    0xC1, 0x3A, 0x00, 0x01, 0x5D, 0xDA, 0x47, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0xF0, 0xFC, 0x12, 0x00, 0x00, 0x00
};

I have C++ struct:

struct SERVICE
{
    unsigned char c;
    unsigned char size;
    unsigned char headcode;
    unsigned char Type;
    unsigned short Port;
    char ServiceName[50];
    unsigned short ServiceCode;
};

My question is: How to get from data ServiceName, Port and etc…?

Sorry for my bad english

Answer 1

Here is one way to do it:

struct SERVICE
{
    public byte c;
    public byte size;
    public byte headcode;
    public byte Type;
    public ushort Port;
    public string ServiceName;
    public ushort ServiceCode;
};

string GetNullTerminatedString(byte[] data, Encoding encoding)
{
    int index = Array.IndexOf(data, (byte)0);
    if (index < 0)
    {
        Debug.WriteLine("No string terminator found.");
        index = data.Length;
    }

    return encoding.GetString(data, 0, index);
}

SERVICE ByteArrayToService(byte[] array, Encoding encoding)
{
    using (MemoryStream stream = new MemoryStream(array))
    {
        using (BinaryReader reader = new BinaryReader(stream))
        {
            SERVICE service = new SERVICE();
            service.c = reader.ReadByte();
            service.size = reader.ReadByte();
            service.headcode = reader.ReadByte();
            service.Type = reader.ReadByte();
            service.Port = reader.ReadUInt16();
            service.ServiceName = GetNullTerminatedString(reader.ReadBytes(50), encoding);
            service.ServiceCode = reader.ReadUInt16();
            return service;
        }
    }
}

void Main(string[] args)
{
    byte[] data = new Byte[]
    {
        0xC1, 0x3A, 0x00, 0x01, 0x5D, 0xDA, 0x47, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0xF0, 0xFC, 0x12, 0x00, 0x00, 0x00
    };

    SERVICE s = ByteArrayToService(data, Encoding.Default);
}

This assumes, that the binary array uses the same Endianess as your architecture. If that is not the case you can use the EndianBinaryReader from the MiscUtil library.

Edit: this is also a nice solution, that avoids the reader altogether. You can’t directly specify the encoding to use for the string however and the memory layout of the structure has to match the layout used in the byte array.

[StructLayout(LayoutKind.Sequential)]
struct SERVICE
{
    public byte c;
    public byte size;
    public byte headcode;
    public byte Type;
    public ushort Port;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 50)]
    public string ServiceName;
    public ushort ServiceCode;
};

SERVICE ByteArrayToService(byte[] array)
{
    GCHandle handle = GCHandle.Alloc(array, GCHandleType.Pinned);
    SERVICE service = (SERVICE)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(SERVICE));
    handle.Free();
    return service;
}