[container] devector merged into Boost.Container

From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2020-08-14 23:14:49

Hi to all,

Many years after the review (it was finished in 2017), I managed to find 
some time to make the review result possible and integrate double-ended 
library's "devector" class in Boost.Container. I merged the 
implementation some days ago in develop branch and I hope we can merge 
it to master soon.

Several changes were needed (C++03 support, similar interface/features 
to other containers, removed some non-essential operations that were not 
present in other containers...) to do a proper integration. It's might 
not be production-ready, documentation might be still lacking, but I 
think it's a good starting point. Initial performance benchmarks seems 
to show I haven't broken anything important;-)

I made no changes to original devector's main design, no experiments 
with growth or data movement policies. There were many good ideas in the 
review and outside boost we have experiments worth trying. Examples:

- https://lists.boost.org/Archives/boost/2017/10/239316.php

- http://larshagencpp.github.io/blog/2016/05/22/devector

I also plan to slowly start sharing more implementation details between 
devector and vector to avoid code duplication and ease maintenance, and 
adding some missing operations in devector that are in vector (like 
default initialization insertions).

Many thanks to Benedek for his patience, and great design/implementation 
(including a detailed test-suite, absolutely essential to ease the work 
I needed to do to integrate devector in the library). Better late than 
never ;-)

Best,

Ion