From: Clifford Heath <clifford.heath@...>
Date: 2012-01-21T20:46:40+09:00
Subject: [ruby-core:42208] Re: [ruby-trunk - Bug #5877] Poor performance of initial and final UTF-8 substrings

On 20/01/2012, at 1:08 PM, Motohiro KOSAKI wrote:
> Bug #5877: Poor performance of initial and final UTF-8 substrings
> https://bugs.ruby-lang.org/issues/5877
> 
> Author: Nathan Weizenbaum
> Status: Feedback
> Priority: Normal
> Assignee: 
> Category: 
> Target version: 
> ruby -v: ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-linux] 
> 
> 
> Currently, taking the substring of a UTF-8 string always takes time proportional to the length of the string. While this is necessary in the general case, there are many common cases where it could be much faster, in particular when the substring is near the beginning of the end of the superstring. In those cases, the operation should only be proportional to the length of the substring.

This discussion from ten years ago is relevant to performance workarounds for UTF-8:
<http://blade.nagaokaut.ac.jp/cgi-bin/vframe.rb/ruby/ruby-talk/45935?45702-47288>

Clifford Heath.