Re: smart ptr changes

From: Greg Colvin (gcolvin_at_[hidden])
Date: 2001-08-17 13:20:04

I like it fine, but I'd like more review of this and other changes.

----- Original Message ----- 
From: "Darin Adler" <darin_at_[hidden]>
To: "Greg Colvin" <gcolvin_at_[hidden]>; "Beman Dawes" <bdawes_at_[hidden]>
Cc: <boost_at_[hidden]>
Sent: Friday, August 17, 2001 8:33 AM
Subject: smart ptr changes

> Greg, Beman, maybe one or both of you can OK this change to smart_ptr.hpp.
>   If you do, I'll be happy to check it in.
> 
> Index: boost/smart_ptr.hpp
> ===================================================================
> RCS file: /cvsroot/boost/boost/boost/smart_ptr.hpp,v
> retrieving revision 1.12
> diff -p -u -r1.12 smart_ptr.hpp
> --- boost/smart_ptr.hpp 2001/07/06 13:23:07 1.12
> +++ boost/smart_ptr.hpp 2001/08/17 15:30:54
> @@ -9,6 +9,9 @@
>   //  See http://www.boost.org for most recent version including 
> documentation.
> 
>   //  Revision History
> +//  17 Aug 01  added operator <, and got rid of std::swap and std::less 
> since
> +//             std::swap is already non-throwing for shared_ptr and 
> operator <
> +//             is better than specializing std::less (Darin Adler)
>   //   6 Jul 01  Reorder shared_ptr code so VC++ 6 member templates work, 
> allowing
>   //             polymorphic pointers to now work with that compiler (Gary 
> Powell)
>   //  21 May 01  Require complete type where incomplete type is unsafe.
> @@ -268,6 +271,12 @@ template<typename T, typename U>
>     inline bool operator!=(const shared_ptr<T>& a, const shared_ptr<U>& b)
>       { return a.get() != b.get(); }
> 
> +template<typename T>
> +  inline bool operator<(const shared_ptr<T>& a, const shared_ptr<T>& b)
> +    { return std::less(a.get(), b.get()); }
> +
> +// Should we also supply <=, >, and >=?
> +
>   //  
> shared_array  ------------------------------------------------------------/
> /
> 
>   //  shared_array extends shared_ptr to arrays.
> @@ -345,53 +354,13 @@ template<typename T>
>     inline bool operator!=(const shared_array<T>& a, const shared_array<T>& 
> b)
>       { return a.get() != b.get(); }
> 
> -} // namespace boost
> -
> -//  specializations for things in namespace 
> std  -----------------------------//
> -
> -#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
> -
> -namespace std {
> -
> -// Specialize std::swap to use the fast, non-throwing swap that's provided
> -// as a member function instead of using the default algorithm which 
> creates
> -// a temporary and uses assignment.
> -
>   template<typename T>
> -  inline void swap(boost::shared_ptr<T>& a, boost::shared_ptr<T>& b)
> -    { a.swap(b); }
> +  inline bool operator<(const shared_array<T>& a, const shared_array<T>& 
> b)
> +    { return std::less(a.get(), b.get()); }
> 
> -template<typename T>
> -  inline void swap(boost::shared_array<T>& a, boost::shared_array<T>& b)
> -    { a.swap(b); }
> -
> -// Specialize std::less so we can use shared pointers and arrays as keys 
> in
> -// associative collections.
> -
> -// It's still a controversial question whether this is better than 
> supplying
> -// a full range of comparison operators (<, >, <=, >=).
> -
> -template<typename T>
> -  struct less< boost::shared_ptr<T> >
> -    : binary_function<boost::shared_ptr<T>, boost::shared_ptr<T>, bool>
> -  {
> -    bool operator()(const boost::shared_ptr<T>& a,
> -        const boost::shared_ptr<T>& b) const
> -      { return less<T*>()(a.get(),b.get()); }
> -  };
> +// Should we also supply <=, >, and >=?
> 
> -template<typename T>
> -  struct less< boost::shared_array<T> >
> -    : binary_function<boost::shared_array<T>, boost::shared_array<T>, 
> bool>
> -  {
> -    bool operator()(const boost::shared_array<T>& a,
> -        const boost::shared_array<T>& b) const
> -      { return less<T*>()(a.get(),b.get()); }
> -  };
> -
> -} // namespace std
> -
> -#endif  // ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
> +} // namespace boost
> 
>   #ifdef BOOST_MSVC
>   # pragma warning(pop)
> ===================================================================
> 
>      -- Darin
>