protected function replace($content)
{
$processed = '';
$positions = array_fill(0, count($this->patterns), -1);
$matches = array();
while ($content) {
// find first match for all patterns
foreach ($this->patterns as $i => $pattern) {
list($pattern, $replacement) = $pattern;
// no need to re-run matches that are still in the part of the
// content that hasn't been processed
if ($positions[$i] >= 0) {
continue;
}
$match = null;
if (preg_match($pattern, $content, $match)) {
$matches[$i] = $match;
// we'll store the match position as well; that way, we
// don't have to redo all preg_matches after changing only
// the first (we'll still know where those others are)
$positions[$i] = strpos($content, $match[0]);
} else {
// if the pattern couldn't be matched, there's no point in
// executing it again in later runs on this same content;
// ignore this one until we reach end of content
unset($matches[$i]);
$positions[$i] = strlen($content);
}
}
// no more matches to find: everything's been processed, break out
if (!$matches) {
$processed .= $content;
break;
}
// see which of the patterns actually found the first thing (we'll
// only want to execute that one, since we're unsure if what the
// other found was not inside what the first found)
$discardLength = min($positions);
$firstPattern = array_search($discardLength, $positions);
$match = $matches[$firstPattern][0];
// execute the pattern that matches earliest in the content string
list($pattern, $replacement) = $this->patterns[$firstPattern];
$replacement = $this->replacePattern($pattern, $replacement, $content);
// figure out which part of the string was unmatched; that's the
// part we'll execute the patterns on again next
$content = substr($content, $discardLength);
$unmatched = (string) substr($content, strpos($content, $match) + strlen($match));
// move the replaced part to $processed and prepare $content to
// again match batch of patterns against
$processed .= substr($replacement, 0, strlen($replacement) - strlen($unmatched));
$content = $unmatched;
// first match has been replaced & that content is to be left alone,
// the next matches will start after this replacement, so we should
// fix their offsets
foreach ($positions as $i => $position) {
$positions[$i] -= $discardLength + strlen($match);
}
}
return $processed;
}
