Re: [boost] Bug in serialization example/boost/libs/serialization/example/portable_binary_oarchive.hpp

From: Robert Ramey (ramey_at_[hidden])
Date: 2006-06-23 12:46:46

Well, its definately a mistake.

But I'm wondering if the real solution is to left fill the value when 
loading with 0xff ?

Think about this.  This would:

a)  leave current archives working.
b) keep portable binary archives as small as possible

Robert Ramey

Stefan van den Oord wrote:
> Hi,
>
> According to the boost web site, this mailing list is the preferred
> way to report bugs, so I subscribed and send you this:
>
> I believe the example
> /boost/libs/serialization/example/portable_binary_oarchive.hpp doesn't
> work correctly. On my platform, Mac OS X, the endian conversion is
> performed. For a small negative number (say -42l), the endian
> conversion results in a big negative number (-687865857). The size,
> however, is computed _before_ the endian conversion, so it is 1 (one)
> in this case, which is not high enough to hold the converted long.
>
> I guess the solution is to do the endian conversion first, then the
> size computation. That seems to work for me. Based on the 1_33_1
> sources, my version of save_impl is now:
>
>    void save_impl(long l){
>        // we choose to use litle endian
>        #ifdef BOOST_BIG_ENDIAN
>            char * first = static_cast<char *>(static_cast<void *>(&
>            l)); char * last = first + sizeof(l) - 1;
>            for(;first < last;++first, --last)
> {
>                char x = *last;
>                *last = *first;
>                *first = x;
>            }
>        #endif
>
> long ll = l;
> char size = 0;
> do{
> ll >>= 8;
> ++size;
> }while(ll != -1 && ll != 0);
> os.put(size);
>
> save_binary(& l, size);
>    }
>
> I hope this helps in improving the example.
>
> Regards,
>
> Stefan van den Oord
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