Thank you. On Tue, Jan 14, 2014 at 1:55 PM, Krzysztof Czainski <1czajnik@gmail.com>wrote:
2014/1/14 Kenneth Adam Miller
Ah ok. I apologize for posting too fast. I will be sure to go further in exhausting all resources before I post in the future. However, I did find some of the descriptions of the iostreams parts and how they compose (especially examples, that's what I was really looking for) vague, IMHO.
No, I haven't measured performance.
[...]
Those unnecessary allocation copies would, in the worst case, result in a 2-3x slowdown of the entire program
How do you know?
due to the fact that it's literally pausing to repeat something that's unnecessary.
But actually, if this appends my 30k string, I didn't know it. The back_insert_device<string> object wasn't something that I understood very well from the description at http://www.boost.org/doc/libs/1_45_0/libs/iostreams/doc/classes/back_inserte...
From what I had thought though, if my string was empty with 0's,
Right here's your mistake. string(30000,0) creates a non empty string. It's a string of 30k nulls.
and I appended to it, then I would end up with precisely my compressed data. The idea of acquireStringFromPool is that it returns a large string that is always cleared out for the filtering_ostream to fill up as though it were a device. Is that incorrect? How can I get that functionality?
Like I said, you want std::vector::reserve().
Perhaps, however, that reserve approach would be good. I apologize the
email was so long lol.
Btw, you're still top-posting. The idea is to leave the (minimal) context above your reply message ;-)
By top posting you meant just the position of my text. I thought you meant it to be me posting when I could have more fully investigated the issue. I will follow this convention.
Regards, Kris
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