1)
		{
			if (ctype_alpha($str))
			{
				// Add a random digit
				$str[mt_rand(0, $length - 1)] = chr(mt_rand(48, 57));
			}
			elseif (ctype_digit($str))
			{
				// Add a random letter
				$str[mt_rand(0, $length - 1)] = chr(mt_rand(65, 90));
			}
		}
		return $str;
	}
	/**
	 * Reduces multiple slashes in a string to single slashes.
	 *
	 * @param   string  string to reduce slashes of
	 * @return  string
	 */
	public static function reduce_slashes($str)
	{
		return preg_replace('#(? $badword)
		{
			$badwords[$key] = str_replace('\*', '\S*?', preg_quote((string) $badword));
		}
		$regex = '('.implode('|', $badwords).')';
		if ($replace_partial_words === FALSE)
		{
			// Just using \b isn't sufficient when we need to replace a badword that already contains word boundaries itself
			$regex = '(?<=\b|\s|^)'.$regex.'(?=\b|\s|$)';
		}
		$regex = '!'.$regex.'!ui';
		if (mb_strlen($replacement) == 1)
		{
			$regex .= 'e';
			return preg_replace($regex, 'str_repeat($replacement, mb_strlen(\'$1\'))', $str);
		}
		return preg_replace($regex, $replacement, $str);
	}
	/**
	 * Finds the text that is similar between a set of words.
	 *
	 * @param   array   words to find similar text of
	 * @return  string
	 */
	public static function similar(array $words)
	{
		// First word is the word to match against
		$word = current($words);
		for ($i = 0, $max = strlen($word); $i < $max; ++$i)
		{
			foreach ($words as $w)
			{
				// Once a difference is found, break out of the loops
				if ( ! isset($w[$i]) OR $w[$i] !== $word[$i])
					break 2;
			}
		}
		// Return the similar text
		return substr($word, 0, $i);
	}
	/**
	 * An alternative to the php levenshtein() function that work out the
	 * distance between 2 words using the Damerau–Levenshtein algorithm.
	 * Credit: http://forums.devnetwork.net/viewtopic.php?f=50&t=89094
	 *
	 * @see http://en.wikipedia.org/wiki/Damerau%E2%80%93Levenshtein_distance
	 * @param     string    first word
	 * @param     string    second word
	 * @return    int       distance between words
	 */
	public static function distance($string1, $string2)
	{
		$string1_length = strlen($string1);
		$string2_length = strlen($string2);
		// Here we start building the table of values
		$matrix = array();
		// String1 length + 1 = rows.
		for ($i = 0; $i <= $string1_length; ++$i)
		{
			$matrix[$i][0] = $i;
		}
		// String2 length + 1 columns.
		for ($j = 0; $j <= $string2_length; ++$j)
		{
			$matrix[0][$j] = $j;
		}
		for ($i = 1; $i <= $string1_length; ++$i)
		{
			for ($j = 1; $j <= $string2_length; ++$j)
			{
				$cost = substr($string1, $i - 1, 1) == substr($string2, $j - 1, 1) ? 0 : 1;
				$matrix[$i][$j] = min(
					$matrix[$i - 1][$j] + 1,		// deletion
					$matrix[$i][$j - 1] + 1,		// insertion
					$matrix[$i - 1][$j - 1] + $cost	// substitution
				);
				if ($i > 1 && $j > 1 &&	(substr($string1, $i - 1, 1) == substr($string2, $j - 2, 1))
					&& (substr($string1, $i - 2, 1) == substr($string2, $j - 1, 1)))
				{
					$matrix[$i][$j] = min(
						$matrix[$i][$j],
						$matrix[$i - 2][$j - 2] + $cost	// transposition
					);
				}
			}
		}
		return $matrix[$string1_length][$string2_length];
	}
	/**
	 * Converts text anchors into links.
	 *
	 * @param   string   text to auto link
	 * @return  string
	 */
	public static function auto_link_urls($text)
	{
		$regex = '~\\b'
				.'((?:ht|f)tps?://)?' // protocol
				.'(?:[-a-zA-Z0-9]{1,63}\.)+' // host name
				.'(?:[0-9]{1,3}|aero|asia|biz|cat|com|coop|edu|gov|info|int|jobs|mil|mobi|museum|name|net|org|pro|tel|travel|ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|au|aw|ax|az|ba|bb|bd|be|bf|bg|bh|bi|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|cr|cu|cv|cx|cy|cz|de|dj|dk|dm|do|dz|ec|ee|eg|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|gm|gn|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|ir|is|it|je|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|mv|mw|mx|my|mz|na|nc|ne|nf|ng|ni|nl|no|np|nr|nu|nz|om|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|zm|zw)' // tlds
				.'(?:/[!$-/0-9:;=@_\':;!a-zA-Z\x7f-\xff]*?)?' // path
				.'(?:\?[!$-/0-9:;=@_\':;!a-zA-Z\x7f-\xff]+?)?' // query
				.'(?:#[!$-/0-9:;=@_\':;!a-zA-Z\x7f-\xff]+?)?' // fragment
				.'(?=[?.!,;:"]?(?:\s|$))~'; // punctuation and url end
		$result = "";
		$position = 0;
		while (preg_match($regex, $text, $match, PREG_OFFSET_CAPTURE, $position))
		{
			list($url, $url_pos) = $match[0];
			// Add the text before the url
			$result  .= substr($text, $position, $url_pos - $position);
			// Default to http://
			$full_url = empty($match[1][0]) ? 'http://'.$url : $url;
			// Add the hyperlink.
			$result .= html::anchor($full_url, $url);
			// New position to start parsing
			$position = $url_pos + strlen($url);
		}
		return $result.substr($text, $position);
	}
	/**
	 * Converts text email addresses into links.
	 *
	 * @param   string   text to auto link
	 * @return  string
	 */
	public static function auto_link_emails($text)
	{
		// Finds all email addresses that are not part of an existing html mailto anchor
		// Note: The "58;" negative lookbehind prevents matching of existing encoded html mailto anchors
		//       The html entity for a colon (:) is : or : or : etc.
		if (preg_match_all('~\b(?|58;)(?!\.)[-+_a-z0-9.]++(? and 
 markup to text. Basically nl2br() on steroids.
	 *
	 * @param   string   subject
	 * @param   boolean  convert single linebreaks to 
	 * @return  string
	 */
	public static function auto_p($str, $br = TRUE)
	{
		// Trim whitespace
		if (($str = trim($str)) === '')
			return '';
		// Standardize newlines
		$str = str_replace(array("\r\n", "\r"), "\n", $str);
		// Trim whitespace on each line
		$str = preg_replace('~^[ \t]+~m', '', $str);
		$str = preg_replace('~[ \t]+$~m', '', $str);
		// The following regexes only need to be executed if the string contains html
		if ($html_found = (strpos($str, '<') !== FALSE))
		{
			// Elements that should not be surrounded by p tags
			$no_p = '(?:p|div|h[1-6r]|ul|ol|li|blockquote|d[dlt]|pre|t[dhr]|t(?:able|body|foot|head)|c(?:aption|olgroup)|form|s(?:elect|tyle)|a(?:ddress|rea)|ma(?:p|th))';
			// Put at least two linebreaks before and after $no_p elements
			$str = preg_replace('~^<'.$no_p.'[^>]*+>~im', "\n$0", $str);
			$str = preg_replace('~'.$no_p.'\s*+>$~im', "$0\n", $str);
		}
		// Do the 
magic! $str = '
'.trim($str).'
'; $str = preg_replace('~\n{2,}~', "\n\n", $str); // The following regexes only need to be executed if the string contains html if ($html_found !== FALSE) { // Remove p tags around $no_p elements $str = preg_replace('~
(?=?'.$no_p.'[^>]*+>)~i', '', $str); $str = preg_replace('~(?'.$no_p.'[^>]*+>)
~i', '$1', $str); } // Convert single linebreaks to