blic function mod_rewrite_rules() {
		if ( ! $this->using_permalinks() )
			return '';

		$site_root = parse_url( site_url() );
		if ( isset( $site_root['path'] ) )
			$site_root = trailingslashit($site_root['path']);

		$home_root = parse_url(home_url());
		if ( isset( $home_root['path'] ) )
			$home_root = trailingslashit($home_root['path']);
		else
			$home_root = '/';

		$rules = "<IfModule mod_rewrite.c>\n";
		$rules .= "RewriteEngine On\n";
		$rules .= "RewriteBase $home_root\n";

		// Prevent -f checks on index.php.
		$rules .= "RewriteRule ^index\.php$ - [L]\n";

		// Add in the rules that don't redirect to WP's index.php (and thus shouldn't be handled by WP at all).
		foreach ( (array) $this->non_wp_rules as $match => $query) {
			// Apache 1.3 does not support the reluctant (non-greedy) modifier.
			$match = str_replace('.+?', '.+', $match);

			$rules .= 'RewriteRule ^' . $match . ' ' . $home_root . $query . " [QSA,L]\n";
		}

		if ( $this->use_verbose_rules ) {
			$this->matches = '';
			$rewrite = $this->rewrite_rules();
			$num_rules = count($rewrite);
			$rules .= "RewriteCond %{REQUEST_FILENAME} -f [OR]\n" .
				"RewriteCond %{REQUEST_FILENAME} -d\n" .
				"RewriteRule ^.*$ - [S=$num_rules]\n";

			foreach ( (array) $rewrite as $match => $query) {
				// Apache 1.3 does not support the reluctant (non-greedy) modifier.
				$match = str_replace('.+?', '.+', $match);

				if ( strpos($query, $this->index) !== false )
					$rules .= 'RewriteRule ^' . $match . ' ' . $home_root . $query . " [QSA,L]\n";
				else
					$rules .= 'RewriteRule ^' . $match . ' ' . $site_root . $query . " [QSA,L]\n";
			}
		} else {
			$rules .= "RewriteCond %{REQUEST_FILENAME} !-f\n" .
				"RewriteCond %{REQUEST_FILENAME} !-d\n" .
				"RewriteRule . {$home_root}{$this->index} [L]\n";
		}

		$rules .= "</IfModule>\n";

		/**
		 * Filters the list of rewrite rules formatted for output to an .htaccess file.
		 *
		 * @since 1.5.0
		 *
		 * @param string $rules mod_rewrite Rewrite rules formatted for .htaccess.
		 */
		$rules = apply_filters( 'mod_rewrite_rules', $rules );

		/**
		 * Filters the list of rewrite rules formatted for output to an .htaccess file.
		 *
		 * @since 1.5.0
		 * @deprecated 1.5.0 Use the mod_rewrite_rules filter instead.
		 *
		 * @param string $rules mod_rewrite Rewrite rules formatted for .htaccess.
		 */
		return apply_filters( 'rewrite_rules', $rules );
	}

	/**
	 * Retrieves IIS7 URL Rewrite formatted rewrite rules to write to web.config file.
	 *
	 * Does not actually write to the web.config file, but creates the rules for
	 * the process that will.
	 *
	 * @since 2.8.0
	 * @access public
	 *
	 * @param bool $add_parent_tags Optional. Whether to add parent tags to the rewrite rule sets.
	 *                              Default false.
	 * @return string IIS7 URL rewrite rule sets.
	 */
	public function iis7_url_rewrite_rules( $add_parent_tags = false ) {
		if ( ! $this->using_permalinks() )
			return '';
		$rules = '';
		if ( $add_parent_tags ) {
			$rules .= '<configuration>
	<system.webServer>
		<rewrite>
			<rules>';
		}

		$rules .= '
			<rule name="WordPress: ' . esc_attr( home_url() ) . '" patternSyntax="Wildcard">
				<match url="*" />
					<conditions>
						<add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
						<add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
					</conditions>
				<action type="Rewrite" url="index.php" />
			</rule>';

		if ( $add_parent_tags ) {
			$rules .= '
			</rules>
		</rewrite>
	</system.webServer>
</configuration>';
		}

		/**
		 * Filters the list of rewrite rules formatted for output to a web.config.
		 *
		 * @since 2.8.0
		 *
		 * @param string $rules Rewrite rules formatted for IIS web.config.
		 */
		return apply_filters( 'iis7_url_rewrite_rules', $rules );
	}

	/**
	 * Adds a rewrite rule that transforms a URL structure to a set of query vars.
	 *
	 * Any value in the $after parameter that isn't 'bottom' will result in the rule
	 * being placed at the top of the rewrite rules.
	 *
	 * @since 2.1.0
	 * @since 4.4.0 Array support was added to the `$query` parameter.
	 * @access public
	 *
	 * @param string       $regex Regular expression to match request against.
	 * @param string|array $query The corresponding query vars for this rewrite rule.
	 * @param string       $after Optional. Priority of the new rule. Accepts 'top'
	 *                            or 'bottom'. Default 'bottom'.
	 */
	public function add_rule( $regex, $query, $after = 'bottom' ) {
		if ( is_array( $query ) ) {
			$external = false;
			$query = add_query_arg( $query, 'index.php' );
		} else {
			$index = false === strpos( $query, '?' ) ? strlen( $query ) : strpos( $query, '?' );
			$front = substr( $query, 0, $index );

			$external = $front != $this->index;
		}

		// "external" = it doesn't correspond to index.php.
		if ( $external ) {
			$this->add_external_rule( $regex, $query );
		} else {
			if ( 'bottom' == $after ) {
				$this->extra_rules = array_merge( $this->extra_rules, array( $regex => $query ) );
			} else {
				$this->extra_rules_top = array_merge( $this->extra_rules_top, array( $regex => $query ) );
			}
		}
	}

	/**
	 * Adds a rewrite rule that doesn't correspond to index.php.
	 *
	 * @since 2.1.0
	 * @access public
	 *
	 * @param string $regex Regular expression to match request against.
	 * @param string $query The corresponding query vars for this rewrite rule.
	 */
	public function add_external_rule( $regex, $query ) {
		$this->non_wp_rules[ $regex ] = $query;
	}

	/**
	 * Adds an endpoint, like /trackback/.
	 *
	 * @since 2.1.0
	 * @since 3.9.0 $query_var parameter added.
	 * @since 4.3.0 Added support for skipping query var registration by passing `false` to `$query_var`.
	 * @access public
	 *
	 * @see add_rewrite_endpoint() for full documentation.
	 * @global WP $wp
	 *
	 * @param string      $name      Name of the endpoint.
	 * @param int         $places    Endpoint mask describing the places the endpoint should be added.
	 * @param string|bool $query_var Optional. Name of the corresponding query variable. Pass `false` to
	 *                               skip registering a query_var for this endpoint. Defaults to the
	 *                               value of `$name`.
	 */
	public function add_endpoint( $name, $places, $query_var = true ) {
		global $wp;

		// For backward compatibility, if null has explicitly been passed as `$query_var`, assume `true`.
		if ( true === $query_var || null === func_get_arg( 2 ) ) {
			$query_var = $name;
		}
		$this->endpoints[] = array( $places, $name, $query_var );

		if ( $query_var ) {
			$wp->add_query_var( $query_var );
		}
	}

	/**
	 * Adds a new permalink structure.
	 *
	 * A permalink structure (permastruct) is an abstract definition of a set of rewrite rules;
	 * it is an easy way of expressing a set of regular expressions that rewrite to a set of
	 * query strings. The new permastruct is added to the WP_Rewrite::$extra_permastructs array.
	 *
	 * When the rewrite rules are built by WP_Rewrite::rewrite_rules(), all of these extra
	 * permastructs are passed to WP_Rewrite::generate_rewrite_rules() which transforms them
	 * into the regular expressions that many love to hate.
	 *
	 * The `$args` parameter gives you control over how WP_Rewrite::generate_rewrite_rules()
	 * works on the new permastruct.
	 *
	 * @since 2.5.0
	 * @access public
	 *
	 * @param string $name   Name for permalink structure.
	 * @param string $struct Permalink structure (e.g. category/%category%)
	 * @param array  $args   {
	 *     Optional. Arguments for building rewrite rules based on the permalink structure.
	 *     Default empty array.
	 *
	 *     @type bool $with_front  Whether the structure should be prepended with `WP_Rewrite::$front`.
	 *                             Default true.
	 *     @type int  $ep_mask     The endpoint mask defining which endpoints are added to the structure.
	 *                             Accepts `EP_NONE`, `EP_PERMALINK`, `EP_ATTACHMENT`, `EP_DATE`, `EP_YEAR`,
	 *                             `EP_MONTH`, `EP_DAY`, `EP_ROOT`, `EP_COMMENTS`, `EP_SEARCH`, `EP_CATEGORIES`,
	 *                             `EP_TAGS`, `EP_AUTHORS`, `EP_PAGES`, `EP_ALL_ARCHIVES`, and `EP_ALL`.
	 *                             Default `EP_NONE`.
	 *     @type bool $paged       Whether archive pagination rules should be added for the structure.
	 *                             Default true.
	 *     @type bool $feed        Whether feed rewrite rules should be added for the structure. Default true.
	 *     @type bool $forcomments Whether the feed rules should be a query for a comments feed. Default false.
	 *     @type bool $walk_dirs   Whether the 'directories' making up the structure should be walked over
	 *                             and rewrite rules built for each in-turn. Default true.
	 *     @type bool $endpoints   Whether endpoints should be applied to the generated rules. Default true.
	 * }
	 */
	public function add_permastruct( $name, $struct, $args = array() ) {
		// Back-compat for the old parameters: $with_front and $ep_mask.
		if ( ! is_array( $args ) )
			$args = array( 'with_front' => $args );
		if ( func_num_args() == 4 )
			$args['ep_mask'] = func_get_arg( 3 );

		$defaults = array(
			'with_front' => true,
			'ep_mask' => EP_NONE,
			'paged' => true,
			'feed' => true,
			'forcomments' => false,
			'walk_dirs' => true,
			'endpoints' => true,
		);
		$args = array_intersect_key( $args, $defaults );
		$args = wp_parse_args( $args, $defaults );

		if ( $args['with_front'] )
			$struct = $this->front . $struct;
		else
			$struct = $this->root . $struct;
		$args['struct'] = $struct;

		$this->extra_permastructs[ $name ] = $args;
	}

	/**
	 * Removes a permalink structure.
	 *
	 * @since 4.5.0
	 * @access public
	 *
	 * @param string $name Name for permalink structure.
	 */
	public function remove_permastruct( $name ) {
		unset( $this->extra_permastructs[ $name ] );
	}

	/**
	 * Removes rewrite rules and then recreate rewrite rules.
	 *
	 * Calls WP_Rewrite::wp_rewrite_rules() after removing the 'rewrite_rules' option.
	 * If the function named 'save_mod_rewrite_rules' exists, it will be called.
	 *
	 * @since 2.0.1
	 * @access public
	 *
	 * @staticvar bool $do_hard_later
	 *
	 * @param bool $hard Whether to update .htaccess (hard flush) or just update rewrite_rules option (soft flush). Default is true (hard).
	 */
	public function flush_rules( $hard = true ) {
		static $do_hard_later = null;

		// Prevent this action from running before everyone has registered their rewrites.
		if ( ! did_action( 'wp_loaded' ) ) {
			add_action( 'wp_loaded', array( $this, 'flush_rules' ) );
			$do_hard_later = ( isset( $do_hard_later ) ) ? $do_hard_later || $hard : $hard;
			return;
		}

		if ( isset( $do_hard_later ) ) {
			$hard = $do_hard_later;
			unset( $do_hard_later );
		}

		update_option( 'rewrite_rules', '' );
		$this->wp_rewrite_rules();

		/**
		 * Filters whether a "hard" rewrite rule flush should be performed when requested.
		 *
		 * A "hard" flush updates .htaccess (Apache) or web.config (IIS).
		 *
		 * @since 3.7.0
		 *
		 * @param bool $hard Whether to flush rewrite rules "hard". Default true.
		 */
		if ( ! $hard || ! apply_filters( 'flush_rewrite_rules_hard', true ) ) {
			return;
		}
		if ( function_exists( 'save_mod_rewrite_rules' ) )
			save_mod_rewrite_rules();
		if ( function_exists( 'iis7_save_url_rewrite_rules' ) )
			iis7_save_url_rewrite_rules();
	}

	/**
	 * Sets up the object's properties.
	 *
	 * The 'use_verbose_page_rules' object property will be set to true if the
	 * permalink structure begins with one of the following: '%postname%', '%category%',
	 * '%tag%', or '%author%'.
	 *
	 * @since 1.5.0
	 * @access public
	 */
	public function init() {
		$this->extra_rules = $this->non_wp_rules = $this->endpoints = array();
		$this->permalink_structure = get_option('permalink_structure');
		$this->front = substr($this->permalink_structure, 0, strpos($this->permalink_structure, '%'));
		$this->root = '';

		if ( $this->using_index_permalinks() )
			$this->root = $this->index . '/';

		unset($this->author_structure);
		unset($this->date_structure);
		unset($this->page_structure);
		unset($this->search_structure);
		unset($this->feed_structure);
		unset($this->comment_feed_structure);
		$this->use_trailing_slashes = ( '/' == substr($this->permalink_structure, -1, 1) );

		// Enable generic rules for pages if permalink structure doesn't begin with a wildcard.
		if ( preg_match("/^[^%]*%(?:postname|category|tag|author)%/", $this->permalink_structure) )
			 $this->use_verbose_page_rules = true;
		else
			$this->use_verbose_page_rules = false;
	}

	/**
	 * Sets the main permalink structure for the site.
	 *
	 * Will update the 'permalink_structure' option, if there is a difference
	 * between the current permalink structure and the parameter value. Calls
	 * WP_Rewrite::init() after the option is updated.
	 *
	 * Fires the {@see 'permalink_structure_changed'} action once the init call has
	 * processed passing the old and new values
	 *
	 * @since 1.5.0
	 * @access public
	 *
	 * @param string $permalink_structure Permalink structure.
	 */
	public function set_permalink_structure($permalink_structure) {
		if ( $permalink_structure != $this->permalink_structure ) {
			$old_permalink_structure = $this->permalink_structure;
			update_option('permalink_structure', $permalink_structure);

			$this->init();

			/**
			 * Fires after the permalink structure is updated.
			 *
			 * @since 2.8.0
			 *
			 * @param string $old_permalink_structure The previous permalink structure.
			 * @param string $permalink_structure     The new permalink structure.
			 */
			do_action( 'permalink_structure_changed', $old_permalink_structure, $permalink_structure );
		}
	}

	/**
	 * Sets the category base for the category permalink.
	 *
	 * Will update the 'category_base' option, if there is a difference between
	 * the current category base and the parameter value. Calls WP_Rewrite::init()
	 * after the option is updated.
	 *
	 * @since 1.5.0
	 * @access public
	 *
	 * @param string $category_base Category permalink structure base.
	 */
	public function set_category_base($category_base) {
		if ( $category_base != get_option('category_base') ) {
			update_option('category_base', $category_base);
			$this->init();
		}
	}

	/**
	 * Sets the tag base for the tag permalink.
	 *
	 * Will update the 'tag_base' option, if there is a difference between the
	 * current tag base and the parameter value. Calls WP_Rewrite::init() after
	 * the option is updated.
	 *
	 * @since 2.3.0
	 * @access public
	 *
	 * @param string $tag_base Tag permalink structure base.
	 */
	public function set_tag_base( $tag_base ) {
		if ( $tag_base != get_option( 'tag_base') ) {
			update_option( 'tag_base', $tag_base );
			$this->init();
		}
	}

	/**
	 * Constructor - Calls init(), which runs setup.
	 *
	 * @since 1.5.0
	 * @access public
	 *
	 */
	public function __construct() {
		$this->init();
	}
}