system/libraries/Typography.php - code-igniter-v3-giggi - Gitiles

 <?php
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP
  *
  * This content is released under the MIT License (MIT)
  *
  * Copyright (c) 2014 - 2018, British Columbia Institute of Technology
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  *
  * @package	CodeIgniter
  * @author	EllisLab Dev Team
  * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
  * @copyright	Copyright (c) 2014 - 2018, British Columbia Institute of Technology (http://bcit.ca/)
  * @license	http://opensource.org/licenses/MIT	MIT License
  * @link	https://codeigniter.com
  * @since	Version 1.0.0
  * @filesource
  */
 defined('BASEPATH') OR exit('No direct script access allowed');

 /**
  * Typography Class
  *
  * @package		CodeIgniter
  * @subpackage	Libraries
  * @category	Helpers
  * @author		EllisLab Dev Team
  * @link		https://codeigniter.com/user_guide/libraries/typography.html
  */
 class CI_Typography {

 	/**
 	 * Block level elements that should not be wrapped inside <p> tags
 	 *
 	 * @var string
 	 */
 	public $block_elements = 'address|blockquote|div|dl|fieldset|form|h\d|hr|noscript|object|ol|p|pre|script|table|ul';

 	/**
 	 * Elements that should not have <p> and <br /> tags within them.
 	 *
 	 * @var string
 	 */
 	public $skip_elements	= 'p|pre|ol|ul|dl|object|table|h\d';

 	/**
 	 * Tags we want the parser to completely ignore when splitting the string.
 	 *
 	 * @var string
 	 */
 	public $inline_elements = 'a|abbr|acronym|b|bdo|big|br|button|cite|code|del|dfn|em|i|img|ins|input|label|map|kbd|q|samp|select|small|span|strong|sub|sup|textarea|tt|var';

 	/**
 	 * array of block level elements that require inner content to be within another block level element
 	 *
 	 * @var array
 	 */
 	public $inner_block_required = array('blockquote');

 	/**
 	 * the last block element parsed
 	 *
 	 * @var string
 	 */
 	public $last_block_element = '';

 	/**
 	 * whether or not to protect quotes within { curly braces }
 	 *
 	 * @var bool
 	 */
 	public $protect_braced_quotes = FALSE;

 	/**
 	 * Auto Typography
 	 *
 	 * This function converts text, making it typographically correct:
 	 *	- Converts double spaces into paragraphs.
 	 *	- Converts single line breaks into <br /> tags
 	 *	- Converts single and double quotes into correctly facing curly quote entities.
 	 *	- Converts three dots into ellipsis.
 	 *	- Converts double dashes into em-dashes.
 	 *  - Converts two spaces into entities
 	 *
 	 * @param	string
 	 * @param	bool	whether to reduce more then two consecutive newlines to two
 	 * @return	string
 	 */
 	public function auto_typography($str, $reduce_linebreaks = FALSE)
 	{
 		if ($str === '')
 		{
 			return '';
 		}

 		// Standardize Newlines to make matching easier
 		if (strpos($str, "\r") !== FALSE)
 		{
 			$str = str_replace(array("\r\n", "\r"), "\n", $str);
 		}

 		// Reduce line breaks.  If there are more than two consecutive linebreaks
 		// we'll compress them down to a maximum of two since there's no benefit to more.
 		if ($reduce_linebreaks === TRUE)
 		{
 			$str = preg_replace("/\n\n+/", "\n\n", $str);
 		}

 		// HTML comment tags don't conform to patterns of normal tags, so pull them out separately, only if needed
 		$html_comments = array();
 		if (strpos($str, '<!--') !== FALSE && preg_match_all('#(<!\-\-.*?\-\->)#s', $str, $matches))
 		{
 			for ($i = 0, $total = count($matches[0]); $i < $total; $i++)
 			{
 				$html_comments[] = $matches[0][$i];
 				$str = str_replace($matches[0][$i], '{@HC'.$i.'}', $str);
 			}
 		}

 		// match and yank <pre> tags if they exist.  It's cheaper to do this separately since most content will
 		// not contain <pre> tags, and it keeps the PCRE patterns below simpler and faster
 		if (strpos($str, '<pre') !== FALSE)
 		{
 			$str = preg_replace_callback('#<pre.*?>.*?</pre>#si', array($this, '_protect_characters'), $str);
 		}

 		// Convert quotes within tags to temporary markers.
 		$str = preg_replace_callback('#<.+?>#si', array($this, '_protect_characters'), $str);

 		// Do the same with braces if necessary
 		if ($this->protect_braced_quotes === TRUE)
 		{
 			$str = preg_replace_callback('#\{.+?\}#si', array($this, '_protect_characters'), $str);
 		}

 		// Convert "ignore" tags to temporary marker.  The parser splits out the string at every tag
 		// it encounters.  Certain inline tags, like image tags, links, span tags, etc. will be
 		// adversely affected if they are split out so we'll convert the opening bracket < temporarily to: {@TAG}
 		$str = preg_replace('#<(/*)('.$this->inline_elements.')([ >])#i', '{@TAG}\\1\\2\\3', $str);

 		/* Split the string at every tag. This expression creates an array with this prototype:
 		 *
 		 *	[array]
 		 *	{
 		 *		[0] = <opening tag>
 		 *		[1] = Content...
 		 *		[2] = <closing tag>
 		 *		Etc...
 		 *	}
 		 */
 		$chunks = preg_split('/(<(?:[^<>]+(?:"[^"]*"|\'[^\']*\')?)+>)/', $str, -1, PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY);

 		// Build our finalized string.  We cycle through the array, skipping tags, and processing the contained text
 		$str = '';
 		$process = TRUE;

 		for ($i = 0, $c = count($chunks) - 1; $i <= $c; $i++)
 		{
 			// Are we dealing with a tag? If so, we'll skip the processing for this cycle.
 			// Well also set the "process" flag which allows us to skip <pre> tags and a few other things.
 			if (preg_match('#<(/*)('.$this->block_elements.').*?>#', $chunks[$i], $match))
 			{
 				if (preg_match('#'.$this->skip_elements.'#', $match[2]))
 				{
 					$process = ($match[1] === '/');
 				}

 				if ($match[1] === '')
 				{
 					$this->last_block_element = $match[2];
 				}

 				$str .= $chunks[$i];
 				continue;
 			}

 			if ($process === FALSE)
 			{
 				$str .= $chunks[$i];
 				continue;
 			}

 			//  Force a newline to make sure end tags get processed by _format_newlines()
 			if ($i === $c)
 			{
 				$chunks[$i] .= "\n";
 			}

 			//  Convert Newlines into <p> and <br /> tags
 			$str .= $this->_format_newlines($chunks[$i]);
 		}

 		// No opening block level tag? Add it if needed.
 		if ( ! preg_match('/^\s*<(?:'.$this->block_elements.')/i', $str))
 		{
 			$str = preg_replace('/^(.*?)<('.$this->block_elements.')/i', '<p>$1</p><$2', $str);
 		}

 		// Convert quotes, elipsis, em-dashes, non-breaking spaces, and ampersands
 		$str = $this->format_characters($str);

 		// restore HTML comments
 		for ($i = 0, $total = count($html_comments); $i < $total; $i++)
 		{
 			// remove surrounding paragraph tags, but only if there's an opening paragraph tag
 			// otherwise HTML comments at the ends of paragraphs will have the closing tag removed
 			// if '<p>{@HC1}' then replace <p>{@HC1}</p> with the comment, else replace only {@HC1} with the comment
 			$str = preg_replace('#(?(?=<p>\{@HC'.$i.'\})<p>\{@HC'.$i.'\}(\s*</p>)|\{@HC'.$i.'\})#s', $html_comments[$i], $str);
 		}

 		// Final clean up
 		$table = array(

 						// If the user submitted their own paragraph tags within the text
 						// we will retain them instead of using our tags.
 						'/(<p[^>*?]>)<p>/'	=> '$1', // <?php BBEdit syntax coloring bug fix

 						// Reduce multiple instances of opening/closing paragraph tags to a single one
 						'#(</p>)+#'			=> '</p>',
 						'/(<p>\W*<p>)+/'	=> '<p>',

 						// Clean up stray paragraph tags that appear before block level elements
 						'#<p></p><('.$this->block_elements.')#'	=> '<$1',

 						// Clean up stray non-breaking spaces preceding block elements
 						'#(&nbsp;\s*)+<('.$this->block_elements.')#'	=> '  <$2',

 						// Replace the temporary markers we added earlier
 						'/\{@TAG\}/'		=> '<',
 						'/\{@DQ\}/'			=> '"',
 						'/\{@SQ\}/'			=> "'",
 						'/\{@DD\}/'			=> '--',
 						'/\{@NBS\}/'		=> '  ',

 						// An unintended consequence of the _format_newlines function is that
 						// some of the newlines get truncated, resulting in <p> tags
 						// starting immediately after <block> tags on the same line.
 						// This forces a newline after such occurrences, which looks much nicer.
 						"/><p>\n/"			=> ">\n<p>",

 						// Similarly, there might be cases where a closing </block> will follow
 						// a closing </p> tag, so we'll correct it by adding a newline in between
 						'#</p></#'			=> "</p>\n</"
 						);

 		// Do we need to reduce empty lines?
 		if ($reduce_linebreaks === TRUE)
 		{
 			$table['#<p>\n*</p>#'] = '';
 		}
 		else
 		{
 			// If we have empty paragraph tags we add a non-breaking space
 			// otherwise most browsers won't treat them as true paragraphs
 			$table['#<p></p>#'] = '<p>&nbsp;</p>';
 		}

 		return preg_replace(array_keys($table), $table, $str);

 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Format Characters
 	 *
 	 * This function mainly converts double and single quotes
 	 * to curly entities, but it also converts em-dashes,
 	 * double spaces, and ampersands
 	 *
 	 * @param	string
 	 * @return	string
 	 */
 	public function format_characters($str)
 	{
 		static $table;

 		if ( ! isset($table))
 		{
 			$table = array(
 							// nested smart quotes, opening and closing
 							// note that rules for grammar (English) allow only for two levels deep
 							// and that single quotes are _supposed_ to always be on the outside
 							// but we'll accommodate both
 							// Note that in all cases, whitespace is the primary determining factor
 							// on which direction to curl, with non-word characters like punctuation
 							// being a secondary factor only after whitespace is addressed.
 							'/\'"(\s|$)/'					=> '&#8217;&#8221;$1',
 							'/(^|\s|<p>)\'"/'				=> '$1&#8216;&#8220;',
 							'/\'"(\W)/'						=> '&#8217;&#8221;$1',
 							'/(\W)\'"/'						=> '$1&#8216;&#8220;',
 							'/"\'(\s|$)/'					=> '&#8221;&#8217;$1',
 							'/(^|\s|<p>)"\'/'				=> '$1&#8220;&#8216;',
 							'/"\'(\W)/'						=> '&#8221;&#8217;$1',
 							'/(\W)"\'/'						=> '$1&#8220;&#8216;',

 							// single quote smart quotes
 							'/\'(\s|$)/'					=> '&#8217;$1',
 							'/(^|\s|<p>)\'/'				=> '$1&#8216;',
 							'/\'(\W)/'						=> '&#8217;$1',
 							'/(\W)\'/'						=> '$1&#8216;',

 							// double quote smart quotes
 							'/"(\s|$)/'						=> '&#8221;$1',
 							'/(^|\s|<p>)"/'					=> '$1&#8220;',
 							'/"(\W)/'						=> '&#8221;$1',
 							'/(\W)"/'						=> '$1&#8220;',

 							// apostrophes
 							"/(\w)'(\w)/"					=> '$1&#8217;$2',

 							// Em dash and ellipses dots
 							'/\s?\-\-\s?/'					=> '&#8212;',
 							'/(\w)\.{3}/'					=> '$1&#8230;',

 							// double space after sentences
 							'/(\W)  /'						=> '$1&nbsp; ',

 							// ampersands, if not a character entity
 							'/&(?!#?[a-zA-Z0-9]{2,};)/'		=> '&amp;'
 						);
 		}

 		return preg_replace(array_keys($table), $table, $str);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Format Newlines
 	 *
 	 * Converts newline characters into either <p> tags or <br />
 	 *
 	 * @param	string
 	 * @return	string
 	 */
 	protected function _format_newlines($str)
 	{
 		if ($str === '' OR (strpos($str, "\n") === FALSE && ! in_array($this->last_block_element, $this->inner_block_required)))
 		{
 			return $str;
 		}

 		// Convert two consecutive newlines to paragraphs
 		$str = str_replace("\n\n", "</p>\n\n<p>", $str);

 		// Convert single spaces to <br /> tags
 		$str = preg_replace("/([^\n])(\n)([^\n])/", '\\1<br />\\2\\3', $str);

 		// Wrap the whole enchilada in enclosing paragraphs
 		if ($str !== "\n")
 		{
 			// We trim off the right-side new line so that the closing </p> tag
 			// will be positioned immediately following the string, matching
 			// the behavior of the opening <p> tag
 			$str =  '<p>'.rtrim($str).'</p>';
 		}

 		// Remove empty paragraphs if they are on the first line, as this
 		// is a potential unintended consequence of the previous code
 		return preg_replace('/<p><\/p>(.*)/', '\\1', $str, 1);
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Protect Characters
 	 *
 	 * Protects special characters from being formatted later
 	 * We don't want quotes converted within tags so we'll temporarily convert them to {@DQ} and {@SQ}
 	 * and we don't want double dashes converted to emdash entities, so they are marked with {@DD}
 	 * likewise double spaces are converted to {@NBS} to prevent entity conversion
 	 *
 	 * @param	array
 	 * @return	string
 	 */
 	protected function _protect_characters($match)
 	{
 		return str_replace(array("'",'"','--','  '), array('{@SQ}', '{@DQ}', '{@DD}', '{@NBS}'), $match[0]);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Convert newlines to HTML line breaks except within PRE tags
 	 *
 	 * @param	string
 	 * @return	string
 	 */
 	public function nl2br_except_pre($str)
 	{
 		$newstr = '';
 		for ($ex = explode('pre>', $str), $ct = count($ex), $i = 0; $i < $ct; $i++)
 		{
 			$newstr .= (($i % 2) === 0) ? nl2br($ex[$i]) : $ex[$i];
 			if ($ct - 1 !== $i)
 			{
 				$newstr .= 'pre>';
 			}
 		}

 		return $newstr;
 	}

 }
	<?php
	/**
	* CodeIgniter
	*
	* An open source application development framework for PHP
	*
	* This content is released under the MIT License (MIT)
	*
	* Copyright (c) 2014 - 2018, British Columbia Institute of Technology
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*
	* @package CodeIgniter
	* @author EllisLab Dev Team
	* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
	* @copyright Copyright (c) 2014 - 2018, British Columbia Institute of Technology (http://bcit.ca/)
	* @license http://opensource.org/licenses/MIT MIT License
	* @link https://codeigniter.com
	* @since Version 1.0.0
	* @filesource
	*/
	defined('BASEPATH') OR exit('No direct script access allowed');

	/**
	* Typography Class
	*
	* @package CodeIgniter
	* @subpackage Libraries
	* @category Helpers
	* @author EllisLab Dev Team
	* @link https://codeigniter.com/user_guide/libraries/typography.html
	*/
	class CI_Typography {

	/**
	* Block level elements that should not be wrapped inside <p> tags
	*
	* @var string
	*/
	public $block_elements = 'address\|blockquote\|div\|dl\|fieldset\|form\|h\d\|hr\|noscript\|object\|ol\|p\|pre\|script\|table\|ul';

	/**
	* Elements that should not have <p> and <br /> tags within them.
	*
	* @var string
	*/
	public $skip_elements = 'p\|pre\|ol\|ul\|dl\|object\|table\|h\d';

	/**
	* Tags we want the parser to completely ignore when splitting the string.
	*
	* @var string
	*/
	public $inline_elements = 'a\|abbr\|acronym\|b\|bdo\|big\|br\|button\|cite\|code\|del\|dfn\|em\|i\|img\|ins\|input\|label\|map\|kbd\|q\|samp\|select\|small\|span\|strong\|sub\|sup\|textarea\|tt\|var';

	/**
	* array of block level elements that require inner content to be within another block level element
	*
	* @var array
	*/
	public $inner_block_required = array('blockquote');

	/**
	* the last block element parsed
	*
	* @var string
	*/
	public $last_block_element = '';

	/**
	* whether or not to protect quotes within { curly braces }
	*
	* @var bool
	*/
	public $protect_braced_quotes = FALSE;

	/**
	* Auto Typography
	*
	* This function converts text, making it typographically correct:
	* - Converts double spaces into paragraphs.
	* - Converts single line breaks into <br /> tags
	* - Converts single and double quotes into correctly facing curly quote entities.
	* - Converts three dots into ellipsis.
	* - Converts double dashes into em-dashes.
	* - Converts two spaces into entities
	*
	* @param string
	* @param bool whether to reduce more then two consecutive newlines to two
	* @return string
	*/
	public function auto_typography($str, $reduce_linebreaks = FALSE)
	{
	if ($str === '')
	{
	return '';
	}

	// Standardize Newlines to make matching easier
	if (strpos($str, "\r") !== FALSE)
	{
	$str = str_replace(array("\r\n", "\r"), "\n", $str);
	}

	// Reduce line breaks. If there are more than two consecutive linebreaks
	// we'll compress them down to a maximum of two since there's no benefit to more.
	if ($reduce_linebreaks === TRUE)
	{
	$str = preg_replace("/\n\n+/", "\n\n", $str);
	}

	// HTML comment tags don't conform to patterns of normal tags, so pull them out separately, only if needed
	$html_comments = array();
	if (strpos($str, '<!--') !== FALSE && preg_match_all('#(<!\-\-.*?\-\->)#s', $str, $matches))
	{
	for ($i = 0, $total = count($matches[0]); $i < $total; $i++)
	{
	$html_comments[] = $matches[0][$i];
	$str = str_replace($matches[0][$i], '{@HC'.$i.'}', $str);
	}
	}

	// match and yank <pre> tags if they exist. It's cheaper to do this separately since most content will
	// not contain <pre> tags, and it keeps the PCRE patterns below simpler and faster
	if (strpos($str, '<pre') !== FALSE)
	{
	$str = preg_replace_callback('#<pre.?>.?</pre>#si', array($this, '_protect_characters'), $str);
	}

	// Convert quotes within tags to temporary markers.
	$str = preg_replace_callback('#<.+?>#si', array($this, '_protect_characters'), $str);

	// Do the same with braces if necessary
	if ($this->protect_braced_quotes === TRUE)
	{
	$str = preg_replace_callback('#\{.+?\}#si', array($this, '_protect_characters'), $str);
	}

	// Convert "ignore" tags to temporary marker. The parser splits out the string at every tag
	// it encounters. Certain inline tags, like image tags, links, span tags, etc. will be
	// adversely affected if they are split out so we'll convert the opening bracket < temporarily to: {@TAG}
	$str = preg_replace('#<(/*)('.$this->inline_elements.')([ >])#i', '{@TAG}\\1\\2\\3', $str);

	/* Split the string at every tag. This expression creates an array with this prototype:
	*
	* [array]
	* {
	* [0] = <opening tag>
	* [1] = Content...
	* [2] = <closing tag>
	* Etc...
	* }
	*/
	$chunks = preg_split('/(<(?:[^<>]+(?:"[^"]"\|\'[^\']\')?)+>)/', $str, -1, PREG_SPLIT_DELIM_CAPTURE\|PREG_SPLIT_NO_EMPTY);

	// Build our finalized string. We cycle through the array, skipping tags, and processing the contained text
	$str = '';
	$process = TRUE;

	for ($i = 0, $c = count($chunks) - 1; $i <= $c; $i++)
	{
	// Are we dealing with a tag? If so, we'll skip the processing for this cycle.
	// Well also set the "process" flag which allows us to skip <pre> tags and a few other things.
	if (preg_match('#<(/)('.$this->block_elements.').?>#', $chunks[$i], $match))
	{
	if (preg_match('#'.$this->skip_elements.'#', $match[2]))
	{
	$process = ($match[1] === '/');
	}

	if ($match[1] === '')
	{
	$this->last_block_element = $match[2];
	}

	$str .= $chunks[$i];
	continue;
	}

	if ($process === FALSE)
	{
	$str .= $chunks[$i];
	continue;
	}

	// Force a newline to make sure end tags get processed by _format_newlines()
	if ($i === $c)
	{
	$chunks[$i] .= "\n";
	}

	// Convert Newlines into <p> and <br /> tags
	$str .= $this->_format_newlines($chunks[$i]);
	}

	// No opening block level tag? Add it if needed.
	if ( ! preg_match('/^\s*<(?:'.$this->block_elements.')/i', $str))
	{
	$str = preg_replace('/^(.*?)<('.$this->block_elements.')/i', '<p>$1</p><$2', $str);
	}

	// Convert quotes, elipsis, em-dashes, non-breaking spaces, and ampersands
	$str = $this->format_characters($str);

	// restore HTML comments
	for ($i = 0, $total = count($html_comments); $i < $total; $i++)
	{
	// remove surrounding paragraph tags, but only if there's an opening paragraph tag
	// otherwise HTML comments at the ends of paragraphs will have the closing tag removed
	// if '<p>{@HC1}' then replace <p>{@HC1}</p> with the comment, else replace only {@HC1} with the comment
	$str = preg_replace('#(?(?=<p>\{@HC'.$i.'\})<p>\{@HC'.$i.'\}(\s*</p>)\|\{@HC'.$i.'\})#s', $html_comments[$i], $str);
	}

	// Final clean up
	$table = array(

	// If the user submitted their own paragraph tags within the text
	// we will retain them instead of using our tags.
	'/(<p[^>*?]>)<p>/' => '$1', // <?php BBEdit syntax coloring bug fix

	// Reduce multiple instances of opening/closing paragraph tags to a single one
	'#(</p>)+#' => '</p>',
	'/(<p>\W*<p>)+/' => '<p>',

	// Clean up stray paragraph tags that appear before block level elements
	'#<p></p><('.$this->block_elements.')#' => '<$1',

	// Clean up stray non-breaking spaces preceding block elements
	'#( \s*)+<('.$this->block_elements.')#' => ' <$2',

	// Replace the temporary markers we added earlier
	'/\{@TAG\}/' => '<',
	'/\{@DQ\}/' => '"',
	'/\{@SQ\}/' => "'",
	'/\{@DD\}/' => '--',
	'/\{@NBS\}/' => ' ',

	// An unintended consequence of the _format_newlines function is that
	// some of the newlines get truncated, resulting in <p> tags
	// starting immediately after <block> tags on the same line.
	// This forces a newline after such occurrences, which looks much nicer.
	"/><p>\n/" => ">\n<p>",

	// Similarly, there might be cases where a closing </block> will follow
	// a closing </p> tag, so we'll correct it by adding a newline in between
	'#</p></#' => "</p>\n</"
	);

	// Do we need to reduce empty lines?
	if ($reduce_linebreaks === TRUE)
	{
	$table['#<p>\n*</p>#'] = '';
	}
	else
	{
	// If we have empty paragraph tags we add a non-breaking space
	// otherwise most browsers won't treat them as true paragraphs
	$table['#<p></p>#'] = '<p> </p>';
	}

	return preg_replace(array_keys($table), $table, $str);

	}

	// --------------------------------------------------------------------

	/**
	* Format Characters
	*
	* This function mainly converts double and single quotes
	* to curly entities, but it also converts em-dashes,
	* double spaces, and ampersands
	*
	* @param string
	* @return string
	*/
	public function format_characters($str)
	{
	static $table;

	if ( ! isset($table))
	{
	$table = array(
	// nested smart quotes, opening and closing
	// note that rules for grammar (English) allow only for two levels deep
	// and that single quotes are _supposed_ to always be on the outside
	// but we'll accommodate both
	// Note that in all cases, whitespace is the primary determining factor
	// on which direction to curl, with non-word characters like punctuation
	// being a secondary factor only after whitespace is addressed.
	'/\'"(\s\|$)/' => '’”$1',
	'/(^\|\s\|<p>)\'"/' => '$1‘“',
	'/\'"(\W)/' => '’”$1',
	'/(\W)\'"/' => '$1‘“',
	'/"\'(\s\|$)/' => '”’$1',
	'/(^\|\s\|<p>)"\'/' => '$1“‘',
	'/"\'(\W)/' => '”’$1',
	'/(\W)"\'/' => '$1“‘',

	// single quote smart quotes
	'/\'(\s\|$)/' => '’$1',
	'/(^\|\s\|<p>)\'/' => '$1‘',
	'/\'(\W)/' => '’$1',
	'/(\W)\'/' => '$1‘',

	// double quote smart quotes
	'/"(\s\|$)/' => '”$1',
	'/(^\|\s\|<p>)"/' => '$1“',
	'/"(\W)/' => '”$1',
	'/(\W)"/' => '$1“',

	// apostrophes
	"/(\w)'(\w)/" => '$1’$2',

	// Em dash and ellipses dots
	'/\s?\-\-\s?/' => '—',
	'/(\w)\.{3}/' => '$1…',

	// double space after sentences
	'/(\W) /' => '$1  ',

	// ampersands, if not a character entity
	'/&(?!#?[a-zA-Z0-9]{2,};)/' => '&'
	);
	}

	return preg_replace(array_keys($table), $table, $str);
	}

	// --------------------------------------------------------------------

	/**
	* Format Newlines
	*
	* Converts newline characters into either <p> tags or <br />
	*
	* @param string
	* @return string
	*/
	protected function _format_newlines($str)
	{
	if ($str === '' OR (strpos($str, "\n") === FALSE && ! in_array($this->last_block_element, $this->inner_block_required)))
	{
	return $str;
	}

	// Convert two consecutive newlines to paragraphs
	$str = str_replace("\n\n", "</p>\n\n<p>", $str);

	// Convert single spaces to <br /> tags
	$str = preg_replace("/([^\n])(\n)([^\n])/", '\\1<br />\\2\\3', $str);

	// Wrap the whole enchilada in enclosing paragraphs
	if ($str !== "\n")
	{
	// We trim off the right-side new line so that the closing </p> tag
	// will be positioned immediately following the string, matching
	// the behavior of the opening <p> tag
	$str = '<p>'.rtrim($str).'</p>';
	}

	// Remove empty paragraphs if they are on the first line, as this
	// is a potential unintended consequence of the previous code
	return preg_replace('/<p><\/p>(.*)/', '\\1', $str, 1);
	}

	// ------------------------------------------------------------------------

	/**
	* Protect Characters
	*
	* Protects special characters from being formatted later
	* We don't want quotes converted within tags so we'll temporarily convert them to {@DQ} and {@SQ}
	* and we don't want double dashes converted to emdash entities, so they are marked with {@DD}
	* likewise double spaces are converted to {@NBS} to prevent entity conversion
	*
	* @param array
	* @return string
	*/
	protected function _protect_characters($match)
	{
	return str_replace(array("'",'"','--',' '), array('{@SQ}', '{@DQ}', '{@DD}', '{@NBS}'), $match[0]);
	}

	// --------------------------------------------------------------------

	/**
	* Convert newlines to HTML line breaks except within PRE tags
	*
	* @param string
	* @return string
	*/
	public function nl2br_except_pre($str)
	{
	$newstr = '';
	for ($ex = explode('pre>', $str), $ct = count($ex), $i = 0; $i < $ct; $i++)
	{
	$newstr .= (($i % 2) === 0) ? nl2br($ex[$i]) : $ex[$i];
	if ($ct - 1 !== $i)
	{
	$newstr .= 'pre>';
	}
	}

	return $newstr;
	}

	}