Fix for AMI NVAR parser based on kaitai struct

[chunqing286]

modify 1 line in ami_nvar.ksy (line 128).

Bug scenario:
nvar_entry.attributes.valid = 0
nvar_entry.attributes.extended_header = 1

Now, extended_header_size_field 's value is undefined, as defined in ami_nvar.ksy

extended_header_size_field:
     pos: _io.pos - sizeof<u2>
     type: u2
     if: _parent.attributes.valid
      and _parent.attributes.extended_header
      and _parent.size > sizeof<u4> + sizeof<u2> + sizeof<u4> + sizeof<u2>

but this value would be used by other instances, e.g. extended_header_size, as defined in ami_nvar.ksy

extended_header_size:
     value: '_parent.attributes.extended_header ? (extended_header_size_field >= sizeof<nvar_extended_attributes> + sizeof<u2> ? extended_header_size_field : 0) : 0'

finally leads to parse error/exception or program crash.

[NikolajSchlej]

Thanks for the fix, makes sense. Need to regenerate the files by calling the most recent kaitai_regenerate.sh, because the current ones seem to be generated without C++11 additions (kaitai-struct-compiler --target cpp_stl --cpp-standard 11).

[chunqing286]

Hi, thanks for your instructions about C++ 11 standard.

I have regenerate the C++ header and source file by kaitai-struct-compiler --target cpp_stl --cpp-standard 11.

By the way , I use the lastest Kaitai Struct release version 0.10.