From: Tanaka Akira <akr@...>
Date: 2009-02-23T01:00:41+09:00
Subject: [ruby-core:22332] Re: [Feature #908] Should be an easy way  of reading N characters from am I/O stream

In article <6.0.0.20.2.20090220134502.0823ee98@localhost>,
  Martin Duerst <duerst@it.aoyama.ac.jp> writes:

> Very much so. A typical example would be Georgia, where
> many names are as long as some of the longer ones in
> Europe, but they require 3 bytes per character.

I see.  The name of the President of Georgia needs 30
characters and 84 bytes.

http://en.wikipedia.org/wiki/Mikheil_Saakashvili

> Can you give more specific explanations of why reading a number
> of characters might not be secure?

I considered ISO-2022-JP, Unicode combining characters and
Punycode.

In these encodings, fixed number of characters doesn't limit
the number of bytes.

However they may not cause problem now because Ruby doesn't
support combining characters, etc.  But Ruby's encoding
system is extensible.  It is possible to define an encoding
which makes the character-wise limit insecure.
-- 
Tanaka Akira