function _filter_autop

Implements callback_filter_process().

Converts line breaks into <p> and <br> in an intelligent fashion.

Based on: http://photomatt.net/scripts/autop

Related topics

File

drupal/modules/filter/filter.module, line 1698

Framework for handling the filtering of content.

Code

function _filter_autop($text) {

  // All block level tags
  $block = '(?:table|thead|tfoot|caption|colgroup|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|select|form|blockquote|address|p|h[1-6]|hr)';

  // Split at opening and closing PRE, SCRIPT, STYLE, OBJECT, IFRAME tags
  // and comments. We don't apply any processing to the contents of these tags
  // to avoid messing up code. We look for matched pairs and allow basic
  // nesting. For example:
  // "processed <pre> ignored <script> ignored </script> ignored </pre> processed"
  $chunks = preg_split('@(<!--.*?-->|</?(?:pre|script|style|object|iframe|!--)[^>]*>)@i', $text, -1, PREG_SPLIT_DELIM_CAPTURE);

  // Note: PHP ensures the array consists of alternating delimiters and literals
  // and begins and ends with a literal (inserting NULL as required).
  $ignore = FALSE;
  $ignoretag = '';
  $output = '';
  foreach ($chunks as $i => $chunk) {
    if ($i % 2) {
      $comment = substr($chunk, 0, 4) == '<!--';
      if ($comment) {

        // Nothing to do, this is a comment.
        $output .= $chunk;
        continue;
      }

      // Opening or closing tag?
      $open = $chunk[1] != '/';
      list($tag) = preg_split('/[ >]/', substr($chunk, 2 - $open), 2);
      if (!$ignore) {
        if ($open) {
          $ignore = TRUE;
          $ignoretag = $tag;
        }
      }
      elseif (!$open && $ignoretag == $tag) {
        $ignore = FALSE;
        $ignoretag = '';
      }
    }
    elseif (!$ignore) {
      $chunk = preg_replace('|\\n*$|', '', $chunk) . "\n\n";

      // just to make things a little easier, pad the end
      $chunk = preg_replace('|<br />\\s*<br />|', "\n\n", $chunk);
      $chunk = preg_replace('!(<' . $block . '[^>]*>)!', "\n\$1", $chunk);

      // Space things out a little
      $chunk = preg_replace('!(</' . $block . '>)!', "\$1\n\n", $chunk);

      // Space things out a little
      $chunk = preg_replace("/\n\n+/", "\n\n", $chunk);

      // take care of duplicates
      $chunk = preg_replace('/^\\n|\\n\\s*\\n$/', '', $chunk);
      $chunk = '<p>' . preg_replace('/\\n\\s*\\n\\n?(.)/', "</p>\n<p>\$1", $chunk) . "</p>\n";

      // make paragraphs, including one at the end
      $chunk = preg_replace("|<p>(<li.+?)</p>|", "\$1", $chunk);

      // problem with nested lists
      $chunk = preg_replace('|<p><blockquote([^>]*)>|i', "<blockquote\$1><p>", $chunk);
      $chunk = str_replace('</blockquote></p>', '</p></blockquote>', $chunk);
      $chunk = preg_replace('|<p>\\s*</p>\\n?|', '', $chunk);

      // under certain strange conditions it could create a P of entirely whitespace
      $chunk = preg_replace('!<p>\\s*(</?' . $block . '[^>]*>)!', "\$1", $chunk);
      $chunk = preg_replace('!(</?' . $block . '[^>]*>)\\s*</p>!', "\$1", $chunk);
      $chunk = preg_replace('|(?<!<br />)\\s*\\n|', "<br />\n", $chunk);

      // make line breaks
      $chunk = preg_replace('!(</?' . $block . '[^>]*>)\\s*<br />!', "\$1", $chunk);
      $chunk = preg_replace('!<br />(\\s*</?(?:p|li|div|th|pre|td|ul|ol)>)!', '$1', $chunk);
      $chunk = preg_replace('/&([^#])(?![A-Za-z0-9]{1,8};)/', '&amp;$1', $chunk);
    }
    $output .= $chunk;
  }
  return $output;
}