From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Stephen J. Turnbull" Newsgroups: gmane.emacs.devel Subject: Re: Unibyte characters, strings, and buffers Date: Sun, 30 Mar 2014 01:11:08 +0900 Message-ID: <87fvm1nfxf.fsf@uwakimon.sk.tsukuba.ac.jp> References: <831txozsqa.fsf@gnu.org> <83ppl7y30l.fsf@gnu.org> <87r45nouvx.fsf@uwakimon.sk.tsukuba.ac.jp> <8361myyac6.fsf@gnu.org> <87a9capqfr.fsf@uwakimon.sk.tsukuba.ac.jp> <83eh1mfd09.fsf@gnu.org> <87ob0pnyt6.fsf@uwakimon.sk.tsukuba.ac.jp> <83lhvtdzrf.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 X-Trace: ger.gmane.org 1396109505 26620 80.91.229.3 (29 Mar 2014 16:11:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 29 Mar 2014 16:11:45 +0000 (UTC) Cc: Andreas Schwab , monnier@IRO.UMontreal.CA, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Mar 29 17:11:38 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WTvr6-00060O-I1 for ged-emacs-devel@m.gmane.org; Sat, 29 Mar 2014 17:11:36 +0100 Original-Received: from localhost ([::1]:40095 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WTvr5-0006tm-QZ for ged-emacs-devel@m.gmane.org; Sat, 29 Mar 2014 12:11:35 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:41434) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WTvqw-0006tY-NR for emacs-devel@gnu.org; Sat, 29 Mar 2014 12:11:34 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WTvqp-000795-89 for emacs-devel@gnu.org; Sat, 29 Mar 2014 12:11:26 -0400 Original-Received: from mgmt2.sk.tsukuba.ac.jp ([130.158.97.224]:49355) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WTvqh-00076s-3S; Sat, 29 Mar 2014 12:11:11 -0400 Original-Received: from uwakimon.sk.tsukuba.ac.jp (uwakimon.sk.tsukuba.ac.jp [130.158.99.156]) by mgmt2.sk.tsukuba.ac.jp (Postfix) with ESMTP id F0EF49707DD; Sun, 30 Mar 2014 01:11:08 +0900 (JST) Original-Received: by uwakimon.sk.tsukuba.ac.jp (Postfix, from userid 1000) id E33031A28DC; Sun, 30 Mar 2014 01:11:08 +0900 (JST) In-Reply-To: <83lhvtdzrf.fsf@gnu.org> X-Mailer: VM undefined under 21.5 (beta34) "kale" 2a0f42961ed4 XEmacs Lucid (x86_64-unknown-linux) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 130.158.97.224 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:171155 Archived-At: Eli Zaretskii writes: > I think [unibyte] is (or at least was) also a speed optimization. It is. Random access to position N multibyte buffer is average O(N), and O(log N) with a position cache as used in XEmacs and I believe in GNU Emacs too (haven't looked at GNU Emacs's implementation of buffer movement since about v22, though). This slows down mbox-based MUAs like VM and RMail quite a bit if people use 8-bit or binary content-transfer-encodings in their messages. > Reading or writing a huge buffer full of eight-bit characters might > be significantly slower if they are in their multibyte > representation. Perhaps we should measure that. This isn't true (Ben did measurements, as have the Python folks). Coding systems are way faster than I/O.