Re: [PHP-DEV] str_replace: boyer

[Sascha Schumann]

> What is that "boyer" parameter doing there? It seems that it selects a
> different algorithm for str_replace, but what is the difference?

It is an algorithm which uses suffix-automata to speed up
locating the search pattern (Boyer-Moore algorithm).

- Sascha Experience IRCG
  http://schumann.cx/http://schumann.cx/ircg


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Re: [PHP-DEV] str_replace: boyer

[Sterling Hughes]

On Sun, 9 Sep 2001, Derick Rethans wrote:

> Hello,
>
> the proto for str_replace shows this:
>
> /* {{{ proto mixed str_replace(mixed search, mixed replace, mixed subject [, bool 
>boyer])
>Replaces all occurrences of search in haystack with replace */
>
> What is that "boyer" parameter doing there? It seems that it selects a
> different algorithm for str_replace, but what is the difference?
>

m = pattern length
n = string length

Boyer-Moore is a faster algorithm, especially for larger strings
(O(m + partial) + O(mn), best performance is O(n / m)).  I see no
reason why this can't be merged as the default argument, but I'm
sure sascha had a reason.  sascha? :)

-Sterling


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