Re: [boost] [Serialization]#3118 basic_binary_oarchive.hpp - save_override possible loss of data warnings

Subject: Re: [boost] [Serialization]#3118 basic_binary_oarchive.hpp - save_override possible loss of data warnings
From: Jeff Flinn (TriumphSprint2000_at_[hidden])
Date: 2009-06-01 16:11:10

Robert Ramey wrote:
>> there is still a possibility of a silent loss of data.
> 
> This would only be an issue in following cases:
> 
> a) A class has more than 255 backward compatible versions.
> b) An archive has more than 64K different classes in it.

That would be 32K different classes, the data type is int_least16_t.

> It is currently inconcievable to me that such a program
> would ever be written.  Setting the sizes of these
> types to larger values would make every single binary
> archive bigger and slower.

I also remember paying $800 for 4MB of ram. ;-)

> The only think I might suggest is that one add an
> assertion so that if either of the above were to occur,
> the program would trap - at least in debug mode. So
> maybe one might use
> 
> assert(t.t < max_value<unsigned char>

I couldn't find a max_value<> template, I assume you mean

   assert(t.t <= boost::integer_traits<unsigned char>::const_max);

>>   const unsigned char x = static_cast<unsigned char>(t.t);
> 
> assert(t.t < max_value<int_least16_t >

and

   assert(t.t <= boost::integer_traits<int_least16_t>::const_max);

Thanks, Jeff