public static unsafe bool Is()

in net/JetBrains.FormatRipper/src/MachO/MachOFile.cs [98:156]
50 lines of code
9 McCabe index (conditional complexity)

    public static unsafe bool Is(Stream stream)
    {
      static bool Check(MH magic) => magic is MH.MH_MAGIC or MH.MH_MAGIC_64 or MH.MH_CIGAM or MH.MH_CIGAM_64;

      stream.Position = 0;
      uint rawMagic;
      StreamUtil.ReadBytes(stream, (byte*)&rawMagic, sizeof(uint));
      var magic = (MH)MemoryUtil.GetLeU4(rawMagic);

      if (magic is MH.FAT_MAGIC or MH.FAT_MAGIC_64 or MH.FAT_CIGAM or MH.FAT_CIGAM_64)
      {
        var isFatLittleEndian = magic is MH.FAT_MAGIC or MH.FAT_MAGIC_64;
        var needSwap = BitConverter.IsLittleEndian != isFatLittleEndian;

        uint GetU4(uint v) => needSwap ? MemoryUtil.SwapU4(v) : v;
        ulong GetU8(ulong v) => needSwap ? MemoryUtil.SwapU8(v) : v;

        fat_header fh;
        StreamUtil.ReadBytes(stream, (byte*)&fh, sizeof(fat_header));
        var nFatArch = GetU4(fh.nfat_arch);

        if (magic is MH.FAT_CIGAM_64 or MH.FAT_MAGIC_64)
        {
          var fatNodes = new fat_arch_64[checked((int)nFatArch)];
          fixed (fat_arch_64* ptr = fatNodes)
            StreamUtil.ReadBytes(stream, (byte*)ptr, checked((int)nFatArch * sizeof(fat_arch_64)));
          for (var n = 0; n < nFatArch; n++)
          {
            stream.Position = checked((long)GetU8(fatNodes[n].offset));
            uint rawSubMagic;
            StreamUtil.ReadBytes(stream, (byte*)&rawSubMagic, sizeof(uint));
            var subMagic = (MH)MemoryUtil.GetLeU4(rawSubMagic);

            if (!Check(subMagic))
              return false;
          }
        }
        else
        {
          var fatNodes = new fat_arch[checked((int)nFatArch)];
          fixed (fat_arch* ptr = fatNodes)
            StreamUtil.ReadBytes(stream, (byte*)ptr, checked((int)nFatArch * sizeof(fat_arch)));
          for (var n = 0; n < nFatArch; n++)
          {
            stream.Position = GetU4(fatNodes[n].offset);
            uint rawSubMagic;
            StreamUtil.ReadBytes(stream, (byte*)&rawSubMagic, sizeof(uint));
            var subMagic = (MH)MemoryUtil.GetLeU4(rawSubMagic);

            if (!Check(subMagic))
              return false;
          }
        }

        return true;
      }

      return Check(magic);
    }