Re: [boost] feed_args.hpp bug (and patch)

From: Peter Dimov (pdimov_at_[hidden])
Date: 2003-08-21 08:32:24

Paul Hamilton wrote:
> Peter Dimov wrote:
> 
>> Paul Hamilton wrote:
>>> [...] I propose that we change the code:
>>> 
>>> static const std::basic_string<Ch, Tr> emptyStr;
>>> 
>>> To:
>>> 
>>> const std::basic_string<Ch, Tr> emptyStr = "";
>>> 
>>> Which basically does exactly the same thing.
>> 
>> = "" is not needed, it just forces a redundant strlen call (at
>> least). 
>> As I
>> already pointed out,
>> 
>> std::basic_string<Ch, Tr> emptyStr;
>> 
>> is enough; or even
>> 
>> os.str(std::basic_string<Ch, Tr>());
>> 
>> (if it doesn't cause parser problems.)
> 
> Like this?
> 
> *** feed_args.hpp.orig Thu Aug 21 22:45:28 2003
> --- feed_args.hpp Thu Aug 21 22:46:40 2003
> ***************
> *** 33,42 ****
>    namespace  {
> 
> -   template<class Tr, class Ch> inline
> -   void empty_buf(BOOST_IO_STD basic_ostringstream<Ch,Tr> & os) {
> - static const std::basic_string<Ch, Tr> emptyStr;
> -     os.str(emptyStr);
> -   }
> -
>      template<class Ch, class Tr>
>      void do_pad( std::basic_string<Ch,Tr> & s,
> --- 33,36 ----
> ***************
> *** 139,143 ****
>      // in order to find width
>      put_head( oss_, x );
> !   empty_buf( oss_);
> 
>      const std::streamsize w=oss_.width();
> --- 133,137 ----
>      // in order to find width
>      put_head( oss_, x );
> !   oss_.str(std::basic_string<Ch, Tr>());
> 
>      const std::streamsize w=oss_.width();
> ***************

This will work, although I had

template<class Tr, class Ch> inline
    void empty_buf(BOOST_IO_STD basic_ostringstream<Ch,Tr> & os) {
        os.str( std::basic_string<Ch, Tr>() );
    }

in mind as it is a smaller change.