circular buffer which reconfigure existent objects instead of replacing them?

Question

I was considering to use boost circular_buffer. From here :

In order to achieve maximum efficiency, the circular_buffer stores its elements in a contiguous region of memory, which then enables:

Use of fixed memory and no implicit or unexpected memory allocation.

But I supposed to use circular_buffer calling cb.push_back(myObj) . To make this call I have to instatiate this object. When I call push_back my new object replace the old, outdated object from circular_buffer.

So while using circular_buffer I do intensive allocate memory, because I have to instatiate new object for every push_back .

But I really want to avoid new objects instatiation. Instead I want to "reconfigure" objects from circular_buffer . If it is possible? Can you suggest circular-buffer which allows to reuse objects inside it so avoiding expensive runtime memory allocations?

Answer 1

如果您的对象足够昂贵，无法实例化，则可以预分配它们的池，然后将shared_ptr与池对象放到循环缓冲区中以重用它们。

Answer 2

Perhaps you want a circular iterator rather than a circular buffer . Fill a fixed length buffer with default constructed elements. Then as you fill elements (through the circular iterator) you can just modify the structures instead of copying over.

For an example of a circular iterator, check the accepted answer to this question .