Re: [PATCH] lstrlib and match() \0 in pattern strings

[Rene Rebe <rene@...>]

Hi Roberto,

what do yo think about incorporating something like my proposed patch to make a future lua version (like 5.2) string lib pattern matching embedded 0 aware? I'd really like the consistency and reliability, while the increase in code-size is very minimal.

Greetings,
  René

On 12.03.2010, at 23:39, Rene Rebe wrote:

> Hi all,
> 
> I was just drafting some code filtering arbitrary binary data input, relying on Lua strings to handle embedded zeros. While I had no problems with that in the past, I just spotted the pattern of the matching does treat the first \0 as the end of the pattern. I hope I did not over-read a subtile area of the Lua manual that points out embedded zeros are not allowed in the string library pattern matching so that those examples should work as I would expect:
> 
> -- currently acts as if the pattern would be empty
> print (string.gsub("\0x\0", "\0", "_"))
> 
> -- currently matches, although it shouldn't
> print (string.match("x", ".\0$"))
> 
> Please find attached a quick review of the lstrlib. I hope I didn't miss a case. Passes the lua 5.1 test-suite (in normal mode, without the lua core test patch).
> 
> <lstrlib-0s.patch>
> 
> PS: Applies to lua 5.2-work2 with minimal whitespace fixup, likewise.
> 
>  René
> 
> -- 
>  René Rebe, ExactCODE GmbH, Jaegerstr. 67, DE-10117 Berlin
>  http://exactcode.com | http://t2-project.org | http://rene.rebe.de
> 

-- 
  René Rebe, ExactCODE GmbH, Jaegerstr. 67, DE-10117 Berlin
  http://exactcode.com | http://t2-project.org | http://rene.rebe.de