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<?php

/*************************************************************************

 *                                                                       *

 * class.html2text.inc                                                   *

 *                                                                       *

 *************************************************************************

 *                                                                       *

 * Converts HTML to formatted plain text                                 *

 *                                                                       *

 * Copyright (c) 2005 Jon Abernathy <jon@chuggnutt.com>                  *

 * All rights reserved.                                                  *

 *                                                                       *

 * This script is free software; you can redistribute it and/or modify   *

 * it under the terms of the GNU General Public License as published by  *

 * the Free Software Foundation; either version 2 of the License, or     *

 * (at your option) any later version.                                   *

 *                                                                       *

 * The GNU General Public License can be found at                        *

 * http://www.gnu.org/copyleft/gpl.html.                                 *

 *                                                                       *

 * This script is distributed in the hope that it will be useful,        *

 * but WITHOUT ANY WARRANTY; without even the implied warranty of        *

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the          *

 * GNU General Public License for more details.                          *

 *                                                                       *

 * Author(s): Jon Abernathy <jon@chuggnutt.com>                          *

 *                                                                       *

 * Last modified: 11/02/06                                               *

 *                                                                       *

 *************************************************************************/

/**

 *  Takes HTML and converts it to formatted, plain text.

 *

 *  Thanks to Alexander Krug (http://www.krugar.de/) to pointing out and

 *  correcting an error in the regexp search array. Fixed 7/30/03.

 *

 *  Updated set_html() function's file reading mechanism, 9/25/03.

 *

 *  Thanks to Joss Sanglier (http://www.dancingbear.co.uk/) for adding

 *  several more HTML entity codes to the $search and $replace arrays.

 *  Updated 11/7/03.

 *

 *  Thanks to Darius Kasperavicius (http://www.dar.dar.lt/) for

 *  suggesting the addition of $allowed_tags and its supporting function

 *  (which I slightly modified). Updated 3/12/04.

 *

 *  Thanks to Justin Dearing for pointing out that a replacement for the

 *  <TH> tag was missing, and suggesting an appropriate fix.

 *  Updated 8/25/04.

 *

 *  Thanks to Mathieu Collas (http://www.myefarm.com/) for finding a

 *  display/formatting bug in the _build_link_list() function: email

 *  readers would show the left bracket and number ("[1") as part of the

 *  rendered email address.

 *  Updated 12/16/04.

 *

 *  Thanks to Wojciech Bajon (http://histeria.pl/) for submitting code

 *  to handle relative links, which I hadn't considered. I modified his

 *  code a bit to handle normal HTTP links and MAILTO links. Also for

 *  suggesting three additional HTML entity codes to search for.

 *  Updated 03/02/05.

 *

 *  Thanks to Jacob Chandler for pointing out another link condition

 *  for the _build_link_list() function: "https".

 *  Updated 04/06/05.

 *

 *  Thanks to Marc Bertrand (http://www.dresdensky.com/) for

 *  suggesting a revision to the word wrapping functionality; if you

 *  specify a $width of 0 or less, word wrapping will be ignored.

 *  Updated 11/02/06.

 *

 *  @author Jon Abernathy <jon@chuggnutt.com>

 *  @version 0.6.2

 *  @since PHP 4.0.2

 */

class html2text

{

    /**

     *  Contains the HTML content to convert.

     *

     *  @var string $html

     *  @access public

     */

    var $html;

    /**

     *  Contains the converted, formatted text.

     *

     *  @var string $text

     *  @access public

     */

    var $text;

    /**

     *  Maximum width of the formatted text, in columns.

     *

     *  Set this value to 0 (or less) to ignore word wrapping

     *  and not constrain text to a fixed-width column.

     *

     *  @var integer $width

     *  @access public

     */

    var $width = 70;

    /**

     *  List of preg* regular expression patterns to search for,

     *  used in conjunction with $replace.

     *

     *  @var array $search

     *  @access public

     *  @see $replace

     */

    var $search = array(

        "/\r/",                                  // Non-legal carriage return

        "/[\n\t]+/",                             // Newlines and tabs

        '/<script[^>]*>.*?<\/script>/i',         // <script>s -- which strip_tags supposedly has problems with

        //'/<!-- .* -->/',                         // Comments -- which strip_tags might have problem a with

        '/<h[123][^>]*>(.+?)<\/h[123]>/ie',      // H1 - H3

        '/<h[456][^>]*>(.+?)<\/h[456]>/ie',      // H4 - H6

        '/<p[^>]*>/i',                           // <P>

        '/<br[^>]*>/i',                          // <br>

        '/<b[^>]*>(.+?)<\/b>/ie',                // <b>

        '/<i[^>]*>(.+?)<\/i>/i',                 // <i>

        '/(<ul[^>]*>|<\/ul>)/i',                 // <ul> and </ul>

        '/(<ol[^>]*>|<\/ol>)/i',                 // <ol> and </ol>

        '/<li[^>]*>/i',                          // <li>

        '/<a href="([^"]+)"[^>]*>(.+?)<\/a>/ie', // <a href="">

        '/<hr[^>]*>/i',                          // <hr>

        '/(<table[^>]*>|<\/table>)/i',           // <table> and </table>

        '/(<tr[^>]*>|<\/tr>)/i',                 // <tr> and </tr>

        '/<td[^>]*>(.+?)<\/td>/i',               // <td> and </td>

        '/<th[^>]*>(.+?)<\/th>/i',               // <th> and </th>

        '/ /i',

        '/"/i',

        '/>/i',

        '/</i',

        '/&/i',

        '/©/i',

        '/™/i',

        '/“/',

        '/”/',

        '/–/',

        '/’/',

        '/&/',

        '/©/',

        '/™/',

        '/—/',

        '/“/',

        '/”/',

        '/•/',

        '/®/i',

        '/•/i',

        '/&[&;]+;/i'

    );

    /**

     *  List of pattern replacements corresponding to patterns searched.

     *

     *  @var array $replace

     *  @access public

     *  @see $search

     */

    var $replace = array(

        '',                                     // Non-legal carriage return

        ' ',                                    // Newlines and tabs

        '',                                     // <script>s -- which strip_tags supposedly has problems with

        //'',                                     // Comments -- which strip_tags might have problem a with

        "strtoupper(\"\n\n\\1\n\n\")",          // H1 - H3

        "ucwords(\"\n\n\\1\n\n\")",             // H4 - H6

        "\n\n\t",                               // <P>

        "\n",                                   // <br>

        'strtoupper("\\1")',                    // <b>

        '_\\1_',                                // <i>

        "\n\n",                                 // <ul> and </ul>

        "\n\n",                                 // <ol> and </ol>

        "\t*",                                  // <li>

        '$this->_build_link_list($link_count++, "\\1", "\\2")',

                                                // <a href="">

        "\n-------------------------\n",        // <hr>

        "\n\n",                                 // <table> and </table>

        "\n",                                   // <tr> and </tr>

        "\t\t\\1\n",                            // <td> and </td>

        "strtoupper(\"\t\t\\1\n\")",            // <th> and </th>

        ' ',

        '"',

        '>',

        '<',

        '&',

        '(c)',

        '(tm)',

        '"',

        '"',

        '-',

        "'",

        '&',

        '(c)',

        '(tm)',

        '--',

        '"',

        '"',

        '*',

        '(R)',

        '*',

        ''

    );

    /**

     *  Contains a list of HTML tags to allow in the resulting text.

     *

     *  @var string $allowed_tags

     *  @access public

     *  @see set_allowed_tags()

     */

    var $allowed_tags = '';

    /**

     *  Contains the base URL that relative links should resolve to.

     *

     *  @var string $url

     *  @access public

     */

    var $url;

    /**

     *  Indicates whether content in the $html variable has been converted yet.

     *

     *  @var boolean $converted

     *  @access private

     *  @see $html, $text

     */

    var $_converted = false;

    /**

     *  Contains URL addresses from links to be rendered in plain text.

     *

     *  @var string $link_list

     *  @access private

     *  @see _build_link_list()

     */

    var $_link_list;

    /**

     *  Constructor.

     *

     *  If the HTML source string (or file) is supplied, the class

     *  will instantiate with that source propagated, all that has

     *  to be done it to call get_text().

     *

     *  @param string $source HTML content

     *  @param boolean $from_file Indicates $source is a file to pull content from

     *  @access public

     *  @return void

     */

    function html2text( $source = '', $from_file = false )

    {

        if ( !empty($source) ) {

            $this->set_html($source, $from_file);

        }

        $this->set_base_url();

    }

    /**

     *  Loads source HTML into memory, either from $source string or a file.

     *

     *  @param string $source HTML content

     *  @param boolean $from_file Indicates $source is a file to pull content from

     *  @access public

     *  @return void

     */

    function set_html( $source, $from_file = false )

    {

        $this->html = $source;

        if ( $from_file && file_exists($source) ) {

            $fp = fopen($source, 'r');

            $this->html = fread($fp, filesize($source));

            fclose($fp);

        }

        $this->_converted = false;

    }

    /**

     *  Returns the text, converted from HTML.

     *

     *  @access public

     *  @return string

     */

    function get_text()

    {

        if ( !$this->_converted ) {

            $this->_convert();

        }

        return $this->text;

    }

    /**

     *  Prints the text, converted from HTML.

     *

     *  @access public

     *  @return void

     */

    function print_text()

    {

        print $this->get_text();

    }

    /**

     *  Alias to print_text(), operates identically.

     *

     *  @access public

     *  @return void

     *  @see print_text()

     */

    function p()

    {

        print $this->get_text();

    }

    /**

     *  Sets the allowed HTML tags to pass through to the resulting text.

     *

     *  Tags should be in the form "<p>", with no corresponding closing tag.

     *

     *  @access public

     *  @return void

     */

    function set_allowed_tags( $allowed_tags = '' )

    {

        if ( !empty($allowed_tags) ) {

            $this->allowed_tags = $allowed_tags;

        }

    }

    /**

     *  Sets a base URL to handle relative links.

     *

     *  @access public

     *  @return void

     */

    function set_base_url( $url = '' )

    {

        if ( empty($url) ) {

            $this->url = 'http://' . $_SERVER['HTTP_HOST'];

        } else {

            // Strip any trailing slashes for consistency (relative

            // URLs may already start with a slash like "/file.html")

            if ( substr($url, -1) == '/' ) {

                $url = substr($url, 0, -1);

            }

            $this->url = $url;

        }

    }

    /**

     *  Workhorse function that does actual conversion.

     *

     *  First performs custom tag replacement specified by $search and

     *  $replace arrays. Then strips any remaining HTML tags, reduces whitespace

     *  and newlines to a readable format, and word wraps the text to

     *  $width characters.

     *

     *  @access private

     *  @return void

     */

    function _convert()

    {

        // Variables used for building the link list

        $link_count = 1;

        $this->_link_list = '';

        $text = trim(stripslashes($this->html));

        // Run our defined search-and-replace

        $text = preg_replace($this->search, $this->replace, $text);

        // Strip any other HTML tags

        $text = strip_tags($text, $this->allowed_tags);

        // Bring down number of empty lines to 2 max

        $text = preg_replace("/\n\s+\n/", "\n", $text);

        $text = preg_replace("/[\n]{3,}/", "\n\n", $text);

        // Add link list

        if ( !empty($this->_link_list) ) {

            $text .= "\n\nLinks:\n------\n" . $this->_link_list;

        }

        // Wrap the text to a readable format

        // for PHP versions >= 4.0.2. Default width is 75

        // If width is 0 or less, don't wrap the text.

        if ( $this->width > 0 ) {

        	$text = wordwrap($text, $this->width);

        }

        $this->text = $text;

        $this->_converted = true;

    }

    /**

     *  Helper function called by preg_replace() on link replacement.

     *

     *  Maintains an internal list of links to be displayed at the end of the

     *  text, with numeric indices to the original point in the text they

     *  appeared. Also makes an effort at identifying and handling absolute

     *  and relative links.

     *

     *  @param integer $link_count Counter tracking current link number

     *  @param string $link URL of the link

     *  @param string $display Part of the text to associate number with

     *  @access private

     *  @return string

     */

    function _build_link_list($link_count, $link, $display)

    {

        if ( substr($link, 0, 7) == 'http://' || substr($link, 0, 8) == 'https://' ||

             substr($link, 0, 7) == 'mailto:' ) {

            $this->_link_list .= "[$link_count] $link\n";

        } else {

            $this->_link_list .= "[$link_count] " . $this->url;

            if ( substr($link, 0, 1) != '/' ) {

                $this->_link_list .= '/';

            }

            $this->_link_list .= "$link\n";

        }

        return $display . ' [' . $link_count . ']';

    }

}

?>