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Re: [Gnucap-devel] waves branch and wave copy constructor

From: Felix Salfelder
Subject: Re: [Gnucap-devel] waves branch and wave copy constructor
Date: Sat, 20 Dec 2014 22:20:53 +0100
User-agent: Mutt/1.5.21 (2010-09-15)

On Sat, Dec 20, 2014 at 01:43:53PM -0500, al davis wrote:
> There are lots of such copies in the current implementation.  
> Every time the map is accessed, either in or out, something is 
> copied and something is deleted. 

std::map<X,Y>::operator[](const&X) returns a Y&, which acts more or less
like a Y* here. thus, no copy is involved when accessing existant entry
(speaking of c++98).

FWIW, in c++11, not even upon creating a new pair (accessing a
nonexisting map element) the copy constructor of Y is called. they did a
great job in avoiding unnecessary copies, which they are totally aware

i'm not fully convinced that the current implementation calls more
copies than it should. but sure, i might be missing something.


PS: i am still not against removal of the WAVE copy constructor, anyway,
we should better not try to reinvent stl :)

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