dir/include/html2plain.php

<?php
require_once "html2bbcode.php";

function breaklines($line, $level)
{
	$wraplen = 75-$level;

	$newlines = array();

	do {
		$oldline = $line;

		$subline = substr($line, 0, $wraplen);

		$pos = strrpos($subline, ' ');

		if ($pos == 0)
			$pos = strpos($line, ' ');

		if (($pos > 0) and strlen($line) > $wraplen) {
			$newline = trim(substr($line, 0, $pos));
			if ($level > 0)
                		$newline = str_repeat(">", $level).' '.$newline;

			$newlines[] = $newline." ";
			$line = substr($line, $pos+1);
		}

	} while ((strlen($line) > $wraplen) and !($oldline == $line));

	if ($level > 0)
		$line = str_repeat(">", $level).' '.$line;

	$newlines[] = $line;


	return(implode($newlines, "\n"));
}

function quotelevel($message)
{
	$lines = explode("\n", $message);

	$newlines = array();
	$level = 0;
	foreach($lines as $line) {;
		$line = trim($line);
		$startquote = false;
		while (strpos("*".$line, '[quote]') > 0) {
			$level++;
			$pos = strpos($line, '[quote]');
			$line = substr($line, 0, $pos).substr($line, $pos+7);
			$startquote = true;
		}

		$currlevel = $level;

		while (strpos("*".$line, '[/quote]') > 0) {
			$level--;
			if ($level < 0)
				$level = 0;

			$pos = strpos($line, '[/quote]');
			$line = substr($line, 0, $pos).substr($line, $pos+8);
		}

		if (!$startquote or ($line != ''))
			$newlines[] = breaklines($line, $currlevel);
	}
	return(implode($newlines, "\n"));
}

function html2plain($html)
{
	global $lang;

	$message = str_replace("\r", "", $html);

	$doc = new DOMDocument();
	$doc->preserveWhiteSpace = false;

	$message = mb_convert_encoding($message, 'HTML-ENTITIES', "UTF-8");

	@$doc->loadHTML($message);

	$xpath = new DomXPath($doc);
	$list = $xpath->query("//pre");
	foreach ($list as $node) {
		$node->nodeValue = str_replace("\n", "\r", $node->nodeValue);
	}

	$message = $doc->saveHTML();
	$message = str_replace(array("\n<", ">\n", "\r", "\n", "\xC3\x82\xC2\xA0"), array("<", ">", "<br>", " ", ""), $message);
	$message = preg_replace('= [\s]*=i', " ", $message);

	// nach <a href="...">...</a> suchen, die ... miteinander vergleichen und bei Gleichheit durch ein einzelnes ... ersetzen.
	$pattern = '/<a.*?href="(.*?)".*?>(.*?)<\/a>/is';
	preg_match_all($pattern, $message, $result, PREG_SET_ORDER);

	foreach ($result as $treffer) {
		if ($treffer[1] == $treffer[2]) {
			$search = '<a href="'.$treffer[1].'" target="_blank">'.$treffer[1].'</a>';
			$message = str_replace($search, $treffer[1], $message);
		}
	}
	@$doc->loadHTML($message);

	node2bbcode($doc, 'html', array(), '', '');
	node2bbcode($doc, 'body', array(), '', '');

	// MyBB-Auszeichnungen
	node2bbcode($doc, 'span', array('style'=>'text-decoration: underline;'), '_', '_');
	node2bbcode($doc, 'span', array('style'=>'font-style: italic;'), '/', '/');
	node2bbcode($doc, 'span', array('style'=>'font-weight: bold;'), '*', '*');

	node2bbcode($doc, 'strong', array(), '*', '*');
	node2bbcode($doc, 'b', array(), '*', '*');
	node2bbcode($doc, 'i', array(), '/', '/');
	node2bbcode($doc, 'u', array(), '_', '_');

	node2bbcode($doc, 'blockquote', array(), '[quote]', "[/quote]\n");

	node2bbcode($doc, 'br', array(), "\n", '');

	node2bbcode($doc, 'span', array(), "", "");
	node2bbcode($doc, 'pre', array(), "", "");
	node2bbcode($doc, 'div', array(), "\r", "\r");
	node2bbcode($doc, 'p', array(), "\n", "\n");

	//node2bbcode($doc, 'ul', array(), "\n[list]", "[/list]\n");
	//node2bbcode($doc, 'ol', array(), "\n[list=1]", "[/list]\n");
	node2bbcode($doc, 'li', array(), "\n* ", "\n");

	node2bbcode($doc, 'hr', array(), str_repeat("-", 70), "");

	node2bbcode($doc, 'tr', array(), "\n", "");
	node2bbcode($doc, 'td', array(), "\t", "");

	node2bbcode($doc, 'h1', array(), "\n\n*", "*\n");
	node2bbcode($doc, 'h2', array(), "\n\n*", "*\n");
	node2bbcode($doc, 'h3', array(), "\n\n*", "*\n");
	node2bbcode($doc, 'h4', array(), "\n\n*", "*\n");
	node2bbcode($doc, 'h5', array(), "\n\n*", "*\n");
	node2bbcode($doc, 'h6', array(), "\n\n*", "*\n");

	node2bbcode($doc, 'a', array('href'=>'/(.+)/'), ' $1', '', true);
	node2bbcode($doc, 'img', array('alt'=>'/(.+)/'), '$1', '');
	node2bbcode($doc, 'img', array('title'=>'/(.+)/'), '$1', '');
	node2bbcode($doc, 'img', array(), '', '');
	node2bbcode($doc, 'img', array('src'=>'/(.+)/'), '[img]$1', '[/img]');

	$message = $doc->saveHTML();

	$message = str_replace("[img]", "", $message);
	$message = str_replace("[/img]", "", $message);

	// was ersetze ich da?
	// Irgendein stoerrisches UTF-Zeug
	$message = str_replace(chr(194).chr(160), ' ', $message);

	$message = str_replace("&nbsp;", " ", $message);

	// Aufeinanderfolgende DIVs
	$message = preg_replace('=\r *\r=i', "\n", $message);
	$message = str_replace("\r", "\n", $message);

	$message = strip_tags($message);

	$message = html_entity_decode($message, ENT_QUOTES, 'UTF-8');

	do {
		$oldmessage = $message;
		$message = str_replace("\n\n\n", "\n\n", $message);
	} while ($oldmessage != $message);

	$message = quotelevel(trim($message));

	return(trim($message));
}
?>