Simple PHP Pagination Class

<?php

/*******************************************************************************
*                                  Pagination class                            *
*                             Created: 12th January 2009                       *
*                             Updated: 9th September 2009                      *
*                             ©Copyright Jay Gilford 2009                      *
*                              http://www.jaygilford.com                       *
*                            email: jay [at] jaygilford.com                    *
*******************************************************************************/
 
class pagination
{
    ################################
    # PRIVATE VARS - DO NOT ALTER  #
    ################################
    private $_query = '';
    private $_current_page = 1;
    private $_padding = 2;
    private $_results_resource;
    private $_output;
 
    ################################
    #       RESULTS VARS           #
    ################################
    public $results_per_page = 10;          #Number of results to display at a time
    public $total_results = 0;              #Total number of records
    public $total_pages = 0;                #Total number of pages
 
    public $link_prefix = '/?page=';        #String for link to go before the page number
    public $link_suffix = '';               #String for link to go after the page number
    public $page_nums_separator = ' | ';    #String to go between the page number links
 
    ################################
    #      ERROR HOLDING VAR       #
    ################################
    public $error = null;
 
    ################################
    # PAGINATION TEMPLATE DEFAULTS #
    ################################
    public $tpl_first = '<a href="{link}">&laquo;</a> | ';
    public $tpl_last = ' | <a href="{link}">&raquo;</a> ';
 
    public $tpl_prev = '<a href="{link}">&lsaquo;</a> | ';
    public $tpl_next = ' | <a href="{link}">&rsaquo;</a> ';
 
    public $tpl_page_nums = '<span><a href="{link}">{page}</a></span>';
    public $tpl_cur_page_num = '<span>{page}</span>';
 
    /**
     * In the above templates {link} is where the link will be inserted and {page} is
     * where the page numbers will be inserted. Other than that, you can modify them
     * as you please
     *
     * NOTE: You should have a separator of some sort at the right of $tpl_first and
     * $tpl_prev as above in the defaults, and also have a separator of some sort
     * before the $tpl_next and $tpl_last templates
     **/
 
 
    ##################################################################################
 
 
    public function __construct($page, $query)
    {
        #Check page number is a positive integer greater than 0 and assign it to $this->_current_page
        if ((int)$page > 0)
            $this->_current_page = (int)$page;
 
        #Remove any LIMIT clauses in the query string and set if
        $query = trim(preg_replace('/[\s]+LIMIT[\s]+\d+([\s,]*,[^\d]*\d+)?/i', '', $query));
        if (empty($query)) {
            return false;
        } else {
            $this->_query = $query;
        }
    }
 
    /**
     * pagination::paginate()
     *
     * Processes all values and query strings and if successful
     * returns a string of html text for use with pagination bar
     *
     * @return string;
     */
    public function paginate()
    {
        $output = '';
 
        #########################################
        # GET TOTAL NUMBER OF RESULTS AND PAGES #
        #########################################
        $result = mysql_query($this->_query);
        if (!$result) {
            $this->error = __line__ . ' - ' . mysql_error();
            return false;
        }
        $this->total_results = mysql_num_rows($result);
        $this->total_pages = ceil($this->total_results / $this->results_per_page);
 
        ########################
        # FREE RESULT RESOURCE #
        ########################
 
        ################################
        # IF TOTAL PAGES <= 1 RETURN 1 #
        ################################
        if ($this->total_pages <= 1)
        {
        	$this->_results_resource = $result;
			$this->_output = '1';
			return $this->_output;
        }
 
        mysql_free_result($result);
 
        ###################################################
        # CHECK CURRENT PAGE ISN'T GREATER THAN MAX PAGES #
        ###################################################
        if ($this->_current_page > $this->total_pages)
            $this->_current_page = $this->total_pages;
 
        ######################################
        # SET FIRST AND LAST PAGE VALUES AND #
        # ERROR CHECK AGAINST INVALID VALUES #
        ######################################
        $start = ($this->_current_page - $this->_padding > 0) ? $this->_current_page - $this->
            _padding : '1';
        $finish = ($this->_current_page + $this->_padding <= $this->total_pages) ? $this->
            _current_page + $this->_padding : $this->total_pages;
 
        ###########################################
        # CREATE LIMIT CLAUSE AND ASSIGN TO QUERY #
        ###########################################
        $limit = ' LIMIT ' . ($this->results_per_page * ($this->_current_page - 1)) .
            ',' . $this->results_per_page;
        $query = $this->_query . $limit;
 
        #############################################
        # RUN QUERY AND ASSIGN TO $_result_resource #
        #############################################
        $result = mysql_query($query);
        if ($result === false) {
            $this->error = __line__ . ' - ' . mysql_error();
            return false;
        }
        $this->_results_resource = $result;
 
        ###########################################
        # ADD FIRST TO OUTPUT IF CURRENT PAGE > 1 #
        ###########################################
        if ($this->_current_page > 1) {
            $output .= preg_replace('/\{link\}/i', $this->link_prefix . '1' . $this->
                link_suffix, $this->tpl_first);
        }
 
        ##########################################
        # ADD PREV TO OUTPUT IF CURRENT PAGE > 1 #
        ##########################################
        if ($this->_current_page > 1) {
            $output .= preg_replace('/\{link\}/i', $this->link_prefix . ($this->
                _current_page - 1) . $this->link_suffix, $this->tpl_prev);
        }
 
        ################################################
        # GET LIST OF LINKED NUMBERS AND ADD TO OUTPUT #
        ################################################
        $nums = array();
        for ($i = $start; $i <= $finish; $i++) {
            if ($i == $this->_current_page) {
                $nums[] = preg_replace('/\{page\}/i', $i, $this->tpl_cur_page_num);
            } else {
                $patterns = array('/\{link\}/i', '/\{page\}/i');
                $replaces = array($this->link_prefix . $i . $this->link_suffix, $i);
                $nums[] = preg_replace($patterns, $replaces, $this->tpl_page_nums);
            }
        }
        $output .= implode($this->page_nums_separator, $nums);
 
        ##################################################
        # ADD NEXT TO OUTPUT IF CURRENT PAGE < MAX PAGES #
        ##################################################
        if ($this->_current_page < $this->total_pages) {
            $output .= preg_replace('/\{link\}/i', $this->link_prefix . ($this->
                _current_page + 1) . $this->link_suffix, $this->tpl_next);
        }
 
        ############################################
        # ADD LAST TO OUTPUT IF FINISH < MAX PAGES #
        ############################################
        if ($this->_current_page < $finish) {
            $output .= preg_replace('/\{link\}/i', $this->link_prefix . $this->total_pages, $this->
                tpl_last);
        }
 
        $this->_output = $output;
        return $output;
    }
 
 
    /**
     * pagination::padding()
     *
     * Sets the padding for the pagination string
     *
     * @param int $val
     * @return bool
     */
    public function padding($val)
    {
        if ((int)$val < 1)
            return false;
 
        $this->_padding = (int)$val;
        return true;
    }
 
 
    /**
     * pagination::resource()
     *
     * Returns the resource of the results query
     *
     * @return resource
     */
    function resource()
    {
        return $this->_results_resource;
    }
 
 
    /**
     * pagination::__tostring()
     * returns the last pagination output
     *
     * @return string
     */
    function __tostring()
    {
        if (trim($this->_output)) {
            return trim($this->_output);
        }else{
        	return '';
        }
    }
}