220 13427 <41983d24-efb2-4255-b09b-f84cff7bf56d@isocpp.org> article Path: news.gmane.org!not-for-mail From: Matthew Fioravante Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Proposal: Strongly Typed Bitset Date: Wed, 1 Oct 2014 08:03:14 -0700 (PDT) Lines: 120 Approved: news@gmane.org Message-ID: <41983d24-efb2-4255-b09b-f84cff7bf56d@isocpp.org> References: <113390b2-9c74-47e2-a943-5d27dd48bdf1@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_20_1582199149.1412175794805" X-Trace: ger.gmane.org 1412175806 4351 80.91.229.3 (1 Oct 2014 15:03:26 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 1 Oct 2014 15:03:26 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDELF54RTIGRBNFPWCQQKGQEQIV4EJQ@isocpp.org Wed Oct 01 17:03:20 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oi0-f69.google.com ([209.85.218.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XZLQz-0006TW-UU for gclcip-std-proposals@m.gmane.org; Wed, 01 Oct 2014 17:03:18 +0200 Original-Received: by mail-oi0-f69.google.com with SMTP id u20sf4472333oif.8 for ; Wed, 01 Oct 2014 08:03:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=/u0xaSfQ0Dqa182XMqWIuFGYd6vB+Ai+g9VPf28tPlQ=; b=wqTGwJ9cRqGQWGG5H4Z8VonJXPxLDxE3iiLznf7/DytnSRgPTxTpEbpixx+Cb2d36s 3Vfvn5xLMkAWnXQJ4F1KUfr5U99I5+YDqnteSOtU6Ap8xBDM8ng9Awkq+ZKdWlWpa3+Y 9ahQpGMpag222GA9s7rjkiOgTcn3r33lJy5vyb8M7WqUYf4Qi9uJ7R4RB0r9CntfB+GQ L2hvOgsqYb8dEs3SJXKhJ8EPDJkYgj2DmV7EHLIFbqHyFrTu3QRFQRz2Sow4yXzbo5MV e1V8ZgcyV/2VMxu4COgdMpr96NisNedHR+r1QLzQ1vstBLQcs6+fwqV4pWxPz86XxMjN Nznw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:x-original-sender:reply-to:precedence :mailing-list:list-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=/u0xaSfQ0Dqa182XMqWIuFGYd6vB+Ai+g9VPf28tPlQ=; b=QRsiCuWjinUq7eFsC2GuZhyQ2ad2rtTpD/DaZ6G4IAKFN79585Ahmg7q8LhoytJ95P g1WI3Cyr/LlC5jDYQHaHZlNcoDmZGKoEZVys+i9GorMVfFVa0cfqaQ+25KsbMDPD9v0v NTp84Cv/0wxrGCQfSKxagP6/ja/+rii8JZDh8RTnxcxs/p/IGddqFIBp/6bJK7MEU60T OnN9r1wcm6T1o78xbpaWrjTkraoPKw27zZdehN09foDlBYpSrISebCx0ljDXBjaMiGs9 gJRYPz6c5oKb/EaJumt8OE/66Rh6Ik/meI/t8a6a3iayDuuGsgsLQFYTf3Wh9R8xtWgp d0gw== X-Gm-Message-State: ALoCoQkaI4Z3KTukPy47H/0WNn9VYHVArhdCiWWn4L9Q5MzNsdVs4lezvlTN40GVkfj0L1+5eNH+ X-Received: by 10.182.199.4 with SMTP id jg4mr46271198obc.43.1412175796961; Wed, 01 Oct 2014 08:03:16 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.81.82 with SMTP id e76ls431726qgd.87.gmail; Wed, 01 Oct 2014 08:03:16 -0700 (PDT) X-Received: by 10.140.107.71 with SMTP id g65mr3992qgf.39.1412175796186; Wed, 01 Oct 2014 08:03:16 -0700 (PDT) In-Reply-To: X-Original-Sender: fmatthew5876@gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:13427 Archived-At: ------=_Part_20_1582199149.1412175794805 Content-Type: text/plain; charset=UTF-8 On Wednesday, October 1, 2014 10:27:58 AM UTC-4, Nevin ":-)" Liber wrote: > > On 1 October 2014 08:17, > wrote: > >> However, I am dubious about the implementator guide of optimizing for >> speed over size. In contrast, some may prefer to optimize for size over >> speed. >> > > We really should have *two* different types (or possibly yet another > template parameter) to address this... > A separate type would be better: template using fast_bitset = bitset template using small_bitset = bitset The small variant is somewhat ambiguous. Does it only optimize for size or also alignment? If it's the second one, then we probably end up with bitset which likely performs the worst. Maybe we only need a fast_bitset and let the users optimize for size themselves. -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/. ------=_Part_20_1582199149.1412175794805 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Wednesday, October 1, 2014 10:27:58 AM UTC-4, N= evin ":-)" Liber wrote:
On 1 October 2014 08:17, <rick...@hotmail.com> wrote:
However, I am dub= ious about the implementator guide of optimizing for speed over size. = In contrast, some may prefer to optimi= ze for size over speed.

We really sh= ould have *two* different types (or possibly yet another template parameter= ) to address this...

A separate type w= ould be better:

template = <typena= me N> using fast_bitset =3D bitset<N, /= * Implementation defined */>
template <typename N> using small_bitset =3D bitset<N, /* Imp= lementation defined */>

The small variant is somewhat ambig= uous. Does it only optimize for size or also alignment? If it's the second = one, then we probably end up with bitset<N,uint8_t> which likely perf= orms the worst. Maybe we only need a fast_bitset and let the users optimize= for size themselves.



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