Re: [boost] RFC: interest in Unicode codecs?

Subject: Re: [boost] RFC: interest in Unicode codecs?
From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2009-07-21 09:54:44

Sebastian Redl skrev:
> Phil Endecott wrote:
>> Is c_str() allowed to be > O(1) ?
> Yes. In particular, this implementation is valid:
> 
> template <...>
> class basic_string
> {
>  Ch *real_data;
>  mutable Ch *cstr_data;
>  // ...
> 
> public:
>  const Ch *c_str() const {
>    if (!cstr_data) {
>      cstr_data = allocate(size() + 1);
>      copy(cstr_data, size());
>      cstr_data[size()] = 0;
>    }
>    return cstr_data;
>  }
> 
>  void any_modifying_function() {
>    if(cstr_data) {
>      deallocate(cstr_data);
>      cstr_data = 0;
>    }
>  }
> };

But does *any* implementation actually do that? The problem is AFAIK 
that str[size] is valid when str is a const object.

-Thorsten