Re: [boost] [Root Pointer] Benchmark

Subject: Re: [boost] [Root Pointer] Benchmark
From: Phil Bouchard (philippeb8_at_[hidden])
Date: 2016-03-15 21:57:22

On 03/15/2016 09:07 PM, Glen Fernandes wrote:
> On Tue, Mar 15, 2016 at 8:58 PM, Phil Bouchard <philippeb8_at_[hidden]> wrote:
>>
>> Yes you're right.  I need to make my references const.
>>
> [snip]
>>
>> Thanks for the clarifications.
>
> No problem. Remember the goal isn't to provide convoluted interfaces
> that are strange to people who are used to a simpler convention
> established in the C++ standard library (or Boost, or any other
> library that supports C++ allocator concepts).
>
> The Allocator class template in the example you have is a valid C++
> stateful allocator. Observe how it is used with existing C++ standard
> library facilities that are allocator aware:
>
>      int c1 = 0, c2 = 0;
>
>      vector<char, Allocator<char> > v(Allocator<char>(c1, c2));
>
>      list<int, Allocator<int> > l(Allocator<int>(c1, c2));
>
>      function<void(int)> f(allocator_arg, Allocator<void>(c1, c2), [](int){ });
>
>      auto p = allocate_shared<double>(Allocator<double>(c1, c2), 1.5);
>
> With your root_ptr, the interface for creation should be equally
> simple. No temporaries required. No extremely long type definitions
> required. And certainly no expressions that look like:  new
> (temporary) Type(temporary, ...)  (i.e. an expression that looks like
> 'temporary' is both the subject of the placement-new and an argument
> to the constructor of Type).

I'm still working on it but right now I have already simplified the 
syntax, by adding a wrapper function, to:

int main()
{
     int n1 = 0, m1 = 0;
     int n2 = 0, m2 = 0;
     {
         typedef boost::node<U, Allocator<U> > node;

         boost::root_ptr<U> p1, p2, p3;

         node::allocator_type a1(n1, m1);
         node::allocator_type a2(n2, m2);
         node::allocator_type a3(n2, m2);

         p1 = node::allocate(a1, 1, 'a');
         p2 = node::allocate(a2, 2, 'b');
         p3 = node::allocate(a3, 3, 'c');

         if (n1 != 1 || m1 != 1 || n2 != 2 || m2 != 2) {
             throw 3;
         }
     }
     if (n1 != 0 || m1 != 0 || n2 != 0 || m2 != 0) {
         throw 4;
     }
}

-Phil