Re: [boost] [circular_buffer] some comments and suggestions

From: Jan Gaspar (jano_gaspar_at_[hidden])
Date: 2008-01-21 17:37:10

#1
yes, I agree the default capacity will be zero then. And I like the idea of assertion in push_back, insert...

I can change it in the trunk but I'm not sure I should chage it in the 1.35 release branch at this stage.

#2
Coud you show the example how do you want to get the special iterator?

#3
yes, it makes sense

Jan

----- Original Message ----
From: Thorsten Ottosen <thorsten.ottosen_at_[hidden]>
To: boost_at_[hidden]
Sent: Monday, 21 January, 2008 9:54:46 PM
Subject: Re: [boost] [circular_buffer] some comments and suggestions

Jan Gaspar skrev:
> #1
> I don't agree. I tried to design the circular_buffer as close as possible to the other std containers. 
> Suppose the cirular_buffer does not allocate anything on construction 
- this means when you insert an element to the buffer, it will not be 
inserted because the capacity is 0.
> I think this is unnatural for std containers. On the other hand there 
is a note in the documentation that you should
>avoid using this constructor: "This constructor has been defined only 
due to compatibility with the STL container definition. Avoid using it 
because it may allocate very large amount of memory."

My point is that you cannot always control the use of the default 
constructor ... libraries call it now and then, and it pretty much 
renders circular_buffer unusable with those libraries.

Insertion is already different for circular_buffer, so I don't think it 
is that important that push_back() does not insert anything. Instead, 
add an assertion check to all insertion function that the capacity is > 
0, and specify this as a precondition to all those functions.

> #2
> Agree with is_linearized(), I don't agree with special iterator - I cannot see the point - just use pointers as you mentioned.

Right, but I would prefer an easy, idiomatic way to get those pointers.

> #3
> Yes, maybe in the next version. What would be the method signature?

I guess this would be handy:

void rotate( const_iterator newBegin );
    precondition: newBegin in [begin(),end()).

if we added a new overload taking three iterator arguments like, 
std::rotate(), I think it might not yield any performance improvement 
over the std::version.

-Thorsten
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