PHP Fine Diff – PHP library to diff strings. I’ve tried a few different implementations and all of them either required an external diff program couldn’t render HTML, or failed to due to enormous resource usage. PHP Fine Diff does all I need and does it fast. It’s also rediculously easy to use:
$fineDiff = new FineDiff($strOrig, $strNew); $htmlDiff = $findDiff->renderDiffToHTML();
Found via this StackOverflow discussion.