Oops, I stand corrected. I had not understood the convention properly!
In a nutshell:
1. The capacity is preserved unless explicity adjusted via set_capacity, or implicitly changed by resize.
2. insert may cause front elements to be overwritten
3. rinsert may cause back elements to be overwritten
In this way, insert is related to push_back in terms of semantics, and rinsert is related to push_front.
Given that this could conceivably be swapped around, do we have a rationale that we could state in the documentation?
As the caveats:
Inserting to the front of a full buffer would result in those front-most elements being overwritten by the back-most. (No effect, overall)
Reverse inserting to the back of a full buffer would result in those back-most elements being overwritten by the front-most. (No effect, overall)
Nigel
Jan Gaspar wrote:
Hi Nigel,
It cannot be done as you propose. Please check the archive. It can be done like this: cb.rinsert(cb.begin(), 2); // rinsert cb.push_front(2); // this is equivalent
It will be documented and I think not everything can be driven by "the principle of least surprise".
Jan
> Inserting at the beginning or "close to the beginning" > of the circular_buffer is another trap. > > boost::circular_buffer<int> cb(5, 1); > cb.insert(cb.begin(), 2); // nothing will be inserted
The following should be exactly equivalent: cb.insert(cb.begin(), 2); cb.push_front(2);
As a proposed semantic:
Insertion to the front or back will always be equivalent to a corresponding sequence of push_front or push_back.
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