Re: [PATCH v2 0/5] Speed up uNN_chr and uNN_strchr with Boyer-Moore algorithm

[Paolo Bonzini]

On 07/29/2010 12:40 PM, Pádraig Brady wrote:
> I thought of that but thought it would be too much overhead for the
> general case since it seemed like it would need strlen, u8_mbsnlen&  u8_mbtouc,
> with conversions back and forth.

No! You can cheat! :)  Just pass 4 to u8_mbtouc.  There will be no 
out-of-bounds access: if the string ends before that, you get either a 
complete character or an EILSEQ.

The only extra check that you have to do is for an empty needle, which 
is not the same as u8_strchr (s, 0).

Paolo