ExpressionEngine get/strip "no_results" conditionals

gistfile1.php

/**
 * @author Abed Islam
 *
 * Use and abuse to your liking.
 *
 * Needed a solution for "no_results"-like tags.
 * (Where "no_results" can be customized to whatever tag you want.)
 * Stephen Lewis of Experience Internet talks about it and provides a solution here:
 * @link http://experienceinternet.co.uk/blog/ee-gotchas-nested-no-results-tags/
 * 
 * But that would break if you so much as added another {if...}{/if} conditional
 * within the custom {if no_results} {/if}. If that doesn't matter to you
 * then you can refer to his sample add-on here:
 * @link https://github.com/experience/no_results.ee_addon
 *
 * Otherwise read on.
 *
 * The following functions are simple but more effective ways of getting either
 * the content within or outside of {if no_results}{/if} conditionals:
 *
 * get_simple_conditional($tagname, $tagdata);
 * strip_simple_conditional($tagname, $tagdata);
 *
 * Some assumptions are made: 
 * -The conditional itself will not be used as an advanced conditional, e.g.
 *  WRONG: {if no_results}Not found{if:else}Found{/if}
 *  RIGHT: Found {if no_results}Not found{/if} 
 * -Your code is valid/well-written (there should be matching /if's to your if's!)
 * -I forget what else
 *
 */

// am too lazy to make a helper
if ( ! function_exists('strpos_recursive'))
{
  /**
   * Return positions of all occurences of needle in haystack
   *
   * Slightly modified from the original, 
   * returns key->value pair instead of just value
   *
   * @access public
   * @param string 
   * @param string
   * @param int
   * @param array
   * @return array
   * @link http://php.net/manual/en/function.strpos.php#107678 
   */
  function strpos_recursive($haystack, $needle, $offset = 0, &$results = array())
  {
    $offset = strpos($haystack, $needle, $offset);
    if($offset === false)
    {
      return $results;            
    }
    else 
    {
      $results[$offset] = $offset;
      return strpos_recursive($haystack, $needle, ($offset + 1), $results);
    }
  }
} // end strpos_recursive

if ( ! function_exists('simple_conditional_positions'))
{
  /**
   * Function for finding start/end positions of no_results-like tagname conditionals
   *
   * @access public
   * @param string conditional tag name e.g. no_results (please use something different)
   * @param string subject/haystack to search in
   * @return mixed tagdata if tagname not found, array pair of open tag positon => close tag position | k => v, sorted by k low to high
   */
  function simple_conditional_positions($tagname = 'no_results', $tagdata = '')
  {
    if (empty($tagdata)) return $tagdata;
    if (strpos($tagdata, '{if '.$tagname) === FALSE) return $tagdata;
    
    $o1 = strpos_recursive($tagdata, '{if');
    // there should be no if:else as a part of {if $tagname...
    // if tag_name is meant as a simple conditional, a replacement for no_results
    $o2 = strpos_recursive($tagdata, '{if:else');
    $open_tags = array_diff($o1, $o2);
    $close_tags = strpos_recursive($tagdata, '{/if}');
    if (count($open_tags) != count($close_tags)) return $tagdata;
    
    $pairs = array();
    $open_tags_walk = $open_tags;
    // Formula is something like
    // Iterate through the close tags from left to right
    // For each close tag sort between all values of open tag less than it
    // The open/close pair is the max of the above
    // remove the paired open tag from the pool of open tags
    foreach ($close_tags as $key_c => $close_tag_position)
    {
      $temp = array();
      foreach($open_tags_walk as $key_o => $open_tag_position)
      {      
        // The moment the value is greater than we stop collecting
        if ($open_tag_position >= $close_tag_position)
        {
          //unset($open_tags_walk[$key_o]);
          break;
        }
        else
        {
          $temp[$open_tag_position] = $open_tag_position;
        }
      }
      if ( ! empty($temp)) // should NOT be empty
      {
        $m = max($temp);
        unset($open_tags_walk[$m]);
        $pairs[$m] = $close_tag_position;
      }
    }
    
    $tagname_open_tags = strpos_recursive($tagdata, '{if '.$tagname.'}');
    // assume these are never nested in each other
    $tagname_pairs = array_intersect_key($pairs, $tagname_open_tags);
    ksort($tagname_pairs);
    return $tagname_pairs;
  }
}

if ( ! function_exists('get_simple_conditional'))
{
  /**
   * Return no_results-like conditional content
   *
   * @access public
   * @param string tagname (default: no_results)
   * @param string tagdata (default: empty)
   * @return string
   */
  function get_simple_conditional($tagname = 'no_results', $tagdata = '')
  {
    $tagname_pairs = simple_conditional_positions($tagname, $tagdata);
    if ($tagname_pairs == $tagdata) return $tagdata;
    // return what's in between {if tagname} and {/if}
    $open_tag_length = strlen('{if '.$tagname.'}');
    //$close_tag_length = 5;
    $get = '';
    foreach ($tagname_pairs as $open_tag_position => $close_tag_position)
    {
      $get .= substr($tagdata, $open_tag_position + $open_tag_length, $close_tag_position - ($open_tag_position + $open_tag_length));
    }
    return $get;
  }
}

if ( ! function_exists('strip_simple_conditional'))
{
  /**
   * Return string with no_results-like conditionals removed
   *
   * @param string tagname (default: no_results)
   * @param string tagdata (default: empty)
   * @return string
   */
  function strip_simple_conditional($tagname = 'no_results', $tagdata = '')
  {
    $tagname_pairs = simple_conditional_positions($tagname, $tagdata);
    if ($tagname_pairs == $tagdata) return $tagdata;
    // return what's outside of {if tagname}[...]{/if}
    $open_tag_length = strlen('{if '.$tagname.'}');
    $close_tag_length = 5;
    $get = '';
    $previous_close_tag_position = 0;
    foreach ($tagname_pairs as $open_tag_position => $close_tag_position)
    {
      $get .= substr($tagdata, $previous_close_tag_position, $open_tag_position - $previous_close_tag_position);
      $previous_close_tag_position = $close_tag_position + $close_tag_length;
    }
    return $get . substr($tagdata, $previous_close_tag_position);
  }
}