A slow regex

[roger64]

Hi

While usually regex are executed at flash speed with the Calibre editor, this one takes a lot of time to process. It's working but I wonder if I did not write something which slows it?

{
      "case_sensitive": false, 
      "dot_all": false, 
      "find": "([CLXVI|clxvi]+)<sup>e</sup>\\s?siècle", 
      "mode": "regex", 
      "name": "span century 1 (remplacement global)", 
      "replace": "<span class=\"century\">\\1</span><sup>e</sup> siècle"
    }