EDIT

/**

 * Tries to find a tagged text elements that matches the $type and $regex_pattern

 * and returns all preceding elements as new array.

 *

 * @param $tagged_text

 *  The tagged text to crop

 * @param $type

 *  The tagged text type to match

 * @param $regex_pattern

 *  A PREG regex pattern

 *

 * @return array

 *  A new tagged text array

 */

function tagged_text_crop_at(&$tagged_text, $type, $regex_pattern) {

  $cropped_tagged_text = array();

  if (is_array($tagged_text)) {

    for ($i = 0; $i < count($tagged_text); $i++) {

      if ($tagged_text[$i]->type == $type && preg_match($regex_pattern, $tagged_text[$i]->text)) {

        break;

      }

      $cropped_tagged_text[] = $tagged_text[$i];

    }

  }

  return $cropped_tagged_text;

}