Re: [boost] [bitstream] Copy stream buffer or pass pointer?

Subject: Re: [boost] [bitstream] Copy stream buffer or pass pointer?
From: Dave Abrahams (dave_at_[hidden])
Date: 2013-07-18 03:27:37

on Wed Jul 17 2013, Daryle Walker <darylew-AT-hotmail.com> wrote:

>> Date: Wed, 17 Jul 2013 22:09:08 -0500
>> From: plong_at_[hidden]
>> 
>> For example, the following snippet prints 
>> "hello, goodbye".
>
>> 
>> char c[BUFSIZ] = "hello";
>> istringstream iss(c);
>> strcpy(c, "goodbye");
>> cout << iss.str() << ", " << c;
>> 
>> However, the library I'm working on doesn't copy. Instead, pointers are 
>> passed in and out. So, for example, this code prints "goodbye, goodbye".
>> 
>> char c[BUFSIZ] = "hello";
>> ibitstream ibs(c);
>> strcpy(c, "goodbye");
>> cout << ibs.data() << ", " << c;
>> 
>> I don't think either way is more correct than the other. The reason I 
>> don't copy is for memory and CPU performance, thinking that the streams 
>> a bit-stream library typically processes are larger than the streams 
>> that a string-stream library processes and are more time critical. I 
>> very well may be mistaken, though. Anyway, what do you people think? 
>> Copy or don't copy? Maybe I should do copies just to follow the 
>> semantics of std::stringstream.
>
> I would suggest copying.  

But when the source is an rvalue, move instead.  That handles the
efficiency issues.

-- 
Dave Abrahams