NHSE/NHSE.Parsing/MSBT/MSBTHeader.cs

using System;

namespace NHSE.Parsing;

public sealed class MSBTHeader
{
    public readonly string Identifier; // MsgStdBn
    public readonly byte[] ByteOrderMark;
    public readonly ushort Unknown1; // Always 0x0000
    public readonly MSBTEncodingByte EncodingByte;
    public readonly byte Unknown2; // Always 0x03
    public readonly ushort NumberOfSections;
    public readonly ushort Unknown3; // Always 0x0000
    public readonly uint FileSize;
    public readonly byte[] Unknown4; // Always 0x0000 0000 0000 0000 0000

    public uint FileSizeOffset;

    internal MSBTHeader(BinaryReaderX br)
    {
        // Header
        Identifier = br.ReadString(8);
        if (Identifier != "MsgStdBn")
            throw new ArgumentException("The file provided is not a valid MSBT file.");

        // Byte Order
        ByteOrderMark = br.ReadBytes(2);
        br.ByteOrder = ByteOrderMark[0] > ByteOrderMark[1] ? ByteOrder.LittleEndian : ByteOrder.BigEndian;

        Unknown1 = br.ReadUInt16();

        // Encoding
        EncodingByte = (MSBTEncodingByte)br.ReadByte();

        Unknown2 = br.ReadByte();
        NumberOfSections = br.ReadUInt16();
        Unknown3 = br.ReadUInt16();
        FileSizeOffset = (uint)br.BaseStream.Position; // Record offset for future use
        FileSize = br.ReadUInt32();
        Unknown4 = br.ReadBytes(10);

        if (FileSize != br.BaseStream.Length)
            throw new ArgumentException("The file provided is not a valid MSBT file.");
    }
}