typography_helper.php

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<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package             CodeIgniter
 * @author              ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2006, EllisLab, Inc.
 * @license             http://codeigniter.com/user_guide/license.html
 * @link                http://codeigniter.com
 * @since               Version 1.0
 * @filesource
 */

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

/**
 * CodeIgniter Typography Helpers
 *
 * @package             CodeIgniter
 * @subpackage  Helpers
 * @category    Helpers
 * @author              ExpressionEngine Dev Team
 * @link                http://codeigniter.com/user_guide/helpers/typography_helper.html
 */

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

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

/**
 * Auto Typography Wrapper Function
 *
 *
 * @access      public
 * @param       string
 * @return      string
 */
if ( ! function_exists('auto_typography'))
{
        function auto_typography($str)
        {
                $TYPE = new Auto_typography();
                return $TYPE->convert($str);
        }
}
        
// ------------------------------------------------------------------------

/**
 * Auto Typography Class
 *
 *
 * @access              private
 * @category    Helpers
 * @author              ExpressionEngine Dev Team
 * @link                http://codeigniter.com/user_guide/helpers/
 */
class Auto_typography {

        // Block level elements that should not be wrapped inside <p> tags
        var $block_elements = 'div|blockquote|pre|code|h\d|script|ol|ul';
        
        // Elements that should not have <p> and <br /> tags within them.
        var $skip_elements      = 'pre|ol|ul';
        
        // Tags we want the parser to completely ignore when splitting the string.
        var $ignore_elements = 'a|b|i|em|strong|span|img|li';   


        /**
         * Main Processing Function
         *
         */
        function convert($str)
        {
                if ($str == '')
                {
                        return '';
                }
                
                $str = ' '.$str.' ';
                
                // 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 line
                 * breaks we'll compress them down to a maximum
                 * of two since there's no benefit to more.
                 *
                 */
                $str = preg_replace("/\n\n+/", "\n\n", $str);

                /*
                 * Convert quotes within tags to temporary marker
                 *
                 * We don't want quotes converted within
                 * tags so we'll temporarily convert them to
                 * {@DQ} and {@SQ}
                 *
                 */                     
                if (preg_match_all("#<.+?>#si", $str, $matches))
                {
                        for ($i = 0; $i < count($matches['0']); $i++)
                        {
                                $str = str_replace($matches['0'][$i],
                                                                        str_replace(array("'",'"'), array('{@SQ}', '{@DQ}'), $matches['0'][$i]),
                                                                        $str);
                        }
                }
        

                /*
                 * Add closing/opening paragraph tags before/after "block" elements
                 *
                 * Since block elements (like <blockquotes>, <pre>, etc.) do not get
                 * wrapped in paragraph tags we will add a closing </p> tag just before
                 * each block element starts and an opening <p> tag right after the block element
                 * ends.  Later on we'll do some further clean up.
                 *
                 */
                $str = preg_replace("#(<)(".$this->block_elements.")(.*?>)#", "</p>\\1\\2\\3", $str);
                $str = preg_replace("#(</)(".$this->block_elements.")(.*?>)#", "\\1\\2\\3<p>", $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 < temporarily to: {@TAG}
                 *
                 */             
                $str = preg_replace("#<(/*)(".$this->ignore_elements.")#i", "{@TAG}\\1\\2", $str);      
                
                /*
                 * Split the string at every tag
                 *
                 * This creates an array with this prototype:
                 *
                 *      [array]
                 *      {
                 *              [0] = <opening tag>
                 *              [1] = Content contained between the tags
                 *              [2] = <closing tag>
                 *              Etc...
                 *      }
                 *
                 */                     
                $chunks = preg_split('/(<(?:[^<>]+(?:"[^"]*"|\'[^\']*\')?)+>)/', $str, -1, PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY);
                
                /*
                 * Build our finalized string
                 *
                 * We'll cycle through the array, skipping tags,
                 * and processing the contained text
                 *
                 */                     
                $str = '';
                $process = TRUE;
                foreach ($chunks as $chunk)
                {
                        /*
                         * Are we dealing with a tag?
                         *
                         * If so, we'll skip the processing for this cycle.
                         * Well also set the "process" flag which allows us
                         * to skip <pre> tags and a few other things.
                         *
                         */
                        if (preg_match("#<(/*)(".$this->block_elements.").*?>#", $chunk, $match))
                        {
                                if (preg_match("#".$this->skip_elements."#", $match['2']))
                                {
                                        $process =  ($match['1'] == '/') ? TRUE : FALSE;                
                                }
                
                                $str .= $chunk;
                                continue;
                        }
                
                        if ($process == FALSE)
                        {
                                $str .= $chunk;
                                continue;
                        }
                        
                        //  Convert Newlines into <p> and <br /> tags
                        $str .= $this->format_newlines($chunk);
                }

                // FINAL CLEAN UP
                // IMPORTANT:  DO NOT ALTER THE ORDER OF THE ITEMS BELOW!
                
                /*
                 * Clean up paragraph tags before/after "block" elements
                 *
                 * Earlier we added <p></p> tags before/after block level elements.
                 * Then, we added paragraph tags around double line breaks.  This
                 * potentially created incorrectly formatted paragraphs so we'll
                 * clean it up here.
                 *
                 */
                $str = preg_replace("#<p>({@TAG}.*?)(".$this->block_elements.")(.*?>)#", "\\1\\2\\3", $str);
                $str = preg_replace("#({@TAG}/.*?)(".$this->block_elements.")(.*?>)</p>#", "\\1\\2\\3", $str);

                // Convert Quotes and other characters
                $str = $this->format_characters($str);
                
                // Fix an artifact that happens during the paragraph replacement
                $str = preg_replace('#(<p>\n*</p>)#', '', $str);

                // If the user submitted their own paragraph tags with class data
                // in them we will retain them instead of using our tags.
                $str = preg_replace('#(<p.*?>)<p>#', "\\1", $str);

                // Final clean up
                $str = str_replace(
                                                        array(
                                                                        '</p></p>',
                                                                        '</p><p>',
                                                                        '<p> ',
                                                                        ' </p>',
                                                                        '{@TAG}',
                                                                        '{@DQ}',
                                                                        '{@SQ}',
                                                                        '<p></p>'
                                                                ),
                                                        array(
                                                                        '</p>',
                                                                        '<p>',
                                                                        '<p>',
                                                                        '</p>',
                                                                        '<',
                                                                        '"',
                                                                        "'",
                                                                        ''
                                                                ),
                                                        $str
                                                );
                
                return $str;
        }
        
        // --------------------------------------------------------------------

        /**
         * Format Characters
         *
         * This function mainly converts double and single quotes
         * to entities, but since these are directional, it does
         * it based on some rules.  It also converts em-dashes
         * and a couple other things.
         */
        function format_characters($str)
        {       
                $table = array(
                                                ' "'            => " &#8220;",
                                                '" '            => "&#8221; ",
                                                " '"            => " &#8216;",
                                                "' "            => "&#8217; ",
                                                
                                                '>"'            => ">&#8220;",
                                                '"<'            => "&#8221;<",
                                                ">'"            => ">&#8216;",
                                                "'<"            => "&#8217;<",

                                                "\"."           => "&#8221;.",
                                                "\","           => "&#8221;,",
                                                "\";"           => "&#8221;;",
                                                "\":"           => "&#8221;:",
                                                "\"!"           => "&#8221;!",
                                                "\"?"           => "&#8221;?",
                                                
                                                ".  "           => ".&nbsp; ",
                                                "?  "           => "?&nbsp; ",
                                                "!  "           => "!&nbsp; ",
                                                ":  "           => ":&nbsp; ",
                                        );

                // These deal with quotes within quotes, like:  "'hi here'"
                $start = 0;
                $space = array("\n", "\t", " ");
                
                while(TRUE)
                {
                        $current = strpos(substr($str, $start), "\"'");
                        
                        if ($current === FALSE) break;
                        
                        $one_before = substr($str, $start+$current-1, 1);
                        $one_after = substr($str, $start+$current+2, 1);
                        
                        if ( ! in_array($one_after, $space, TRUE) && $one_after != "<")
                        {
                                $str = str_replace(     $one_before."\"'".$one_after,
                                                                        $one_before."&#8220;&#8216;".$one_after,
                                                                        $str);
                        }
                        elseif ( ! in_array($one_before, $space, TRUE) && (in_array($one_after, $space, TRUE) OR $one_after == '<'))
                        {
                                $str = str_replace(     $one_before."\"'".$one_after,
                                                                        $one_before."&#8221;&#8217;".$one_after,
                                                                        $str);
                        }
                        
                        $start = $start+$current+2;
                }
                
                $start = 0;
                
                while(TRUE)
                {
                        $current = strpos(substr($str, $start), "'\"");
                        
                        if ($current === FALSE) break;
                        
                        $one_before = substr($str, $start+$current-1, 1);
                        $one_after = substr($str, $start+$current+2, 1);
                        
                        if ( in_array($one_before, $space, TRUE) && ! in_array($one_after, $space, TRUE) && $one_after != "<")
                        {
                                $str = str_replace(     $one_before."'\"".$one_after,
                                                                        $one_before."&#8216;&#8220;".$one_after,
                                                                        $str);
                        }
                        elseif ( ! in_array($one_before, $space, TRUE) && $one_before != ">")
                        {
                                $str = str_replace(     $one_before."'\"".$one_after,
                                                                        $one_before."&#8217;&#8221;".$one_after,
                                                                        $str);
                        }
                        
                        $start = $start+$current+2;
                }
                
                // Are there quotes within a word, as in:  ("something")
                if (preg_match_all("/(.)\"(\S+?)\"(.)/", $str, $matches))
                {
                        for ($i=0, $s=sizeof($matches['0']); $i < $s; ++$i)
                        {
                                if ( ! in_array($matches['1'][$i], $space, TRUE) && ! in_array($matches['3'][$i], $space, TRUE))
                                {
                                        $str = str_replace(     $matches['0'][$i],
                                                                                $matches['1'][$i]."&#8220;".$matches['2'][$i]."&#8221;".$matches['3'][$i],
                                                                                $str);
                                }
                        }
                }
                
                if (preg_match_all("/(.)\'(\S+?)\'(.)/", $str, $matches))
                {
                        for ($i=0, $s=sizeof($matches['0']); $i < $s; ++$i)
                        {
                                if ( ! in_array($matches['1'][$i], $space, TRUE) && ! in_array($matches['3'][$i], $space, TRUE))
                                {
                                        $str = str_replace(     $matches['0'][$i],
                                                                                $matches['1'][$i]."&#8216;".$matches['2'][$i]."&#8217;".$matches['3'][$i],
                                                                                $str);
                                }
                        }
                }
                
                // How about one apostrophe, as in Rick's
                $start = 0;
                
                while(TRUE)
                {
                        $current = strpos(substr($str, $start), "'");
                        
                        if ($current === FALSE) break;
                        
                        $one_before = substr($str, $start+$current-1, 1);
                        $one_after = substr($str, $start+$current+1, 1);
                        
                        if ( ! in_array($one_before, $space, TRUE) && ! in_array($one_after, $space, TRUE))
                        {
                                $str = str_replace(     $one_before."'".$one_after,
                                                                        $one_before."&#8217;".$one_after,
                                                                        $str);
                        }
                        
                        $start = $start+$current+2;
                }

                // Em-dashes
                $start = 0;
                while(TRUE)
                {
                        $current = strpos(substr($str, $start), "--");
                        
                        if ($current === FALSE) break;
                        
                        $one_before = substr($str, $start+$current-1, 1);
                        $one_after = substr($str, $start+$current+2, 1);
                        $two_before = substr($str, $start+$current-2, 1);
                        $two_after = substr($str, $start+$current+3, 1);
                        
                        if (( ! in_array($one_before, $space, TRUE) && ! in_array($one_after, $space, TRUE))
                                OR
                                ( ! in_array($two_before, $space, TRUE) && ! in_array($two_after, $space, TRUE) && $one_before == ' ' && $one_after == ' ')
                                )
                        {
                                $str = str_replace(     $two_before.$one_before."--".$one_after.$two_after,
                                                                        $two_before.trim($one_before)."&#8212;".trim($one_after).$two_after,
                                                                        $str);
                        }
                        
                        $start = $start+$current+2;
                }
                
                // Ellipsis
                $str = preg_replace("#(\w)\.\.\.(\s|<br />|</p>)#", "\\1&#8230;\\2", $str);
                $str = preg_replace("#(\s|<br />|</p>)\.\.\.(\w)#", "\\1&#8230;\\2", $str);
                
                // Run the translation array we defined above           
                $str = str_replace(array_keys($table), array_values($table), $str);
                
                // If there are any stray double quotes we'll catch them here
                
                $start = 0;
                
                while(TRUE)
                {
                        $current = strpos(substr($str, $start), '"');
                        
                        if ($current === FALSE) break;
                        
                        $one_before = substr($str, $start+$current-1, 1);
                        $one_after = substr($str, $start+$current+1, 1);
                        
                        if ( ! in_array($one_after, $space, TRUE))
                        {
                                $str = str_replace(     $one_before.'"'.$one_after,
                                                                        $one_before."&#8220;".$one_after,
                                                                        $str);
                        }
                        elseif( ! in_array($one_before, $space, TRUE))
                        {
                                $str = str_replace(     $one_before."'".$one_after,
                                                                        $one_before."&#8221;".$one_after,
                                                                        $str);
                        }
                        
                        $start = $start+$current+2;
                }
                
                $start = 0;
                
                while(TRUE)
                {
                        $current = strpos(substr($str, $start), "'");
                        
                        if ($current === FALSE) break;
                        
                        $one_before = substr($str, $start+$current-1, 1);
                        $one_after = substr($str, $start+$current+1, 1);
                        
                        if ( ! in_array($one_after, $space, TRUE))
                        {
                                $str = str_replace(     $one_before."'".$one_after,
                                                                        $one_before."&#8216;".$one_after,
                                                                        $str);
                        }
                        elseif( ! in_array($one_before, $space, TRUE))
                        {
                                $str = str_replace(     $one_before."'".$one_after,
                                                                        $one_before."&#8217;".$one_after,
                                                                        $str);
                        }
                        
                        $start = $start+$current+2;
                }
                
                return $str;
        }
        
        // --------------------------------------------------------------------

        /**
         * Format Newlines
         *
         * Converts newline characters into either <p> tags or <br />
         *
         */     
        function format_newlines($str)
        {
                if ($str == '')
                {
                        return $str;
                }

                if (strpos($str, "\n") === FALSE)
                {
                        return '<p>'.$str.'</p>';
                }
                        
                $str = str_replace("\n\n", "</p>\n\n<p>", $str);
                $str = preg_replace("/([^\n])(\n)([^\n])/", "\\1<br />\\2\\3", $str);
                
                return '<p>'.$str.'</p>';
        }       
}



/* End of file typography_helper.php */
/* Location: ./system/helpers/typography_helper.php */