library/ext/Pager.php

   1 <?php
   2         // @title    Pager
   3         // @role     handles paging for large result sets
   4         // @author   Matt Todd <matt@matttoddphoto.com>
   5         // @created      2006-03-15
   6         // @requires extexception.php (extends ExtException class)
   7         // @usage    $p = new Pager($rows, $per_page);
   8         //           $p->page;
   9
  10         // classes
  11         class Pager {
  12                 private $pages = array();
  13                 private $page = null;
  14
  15                 // constructor (vital)
  16                 public function __construct($collection, $per_page) {
  17                         if(!is_array($collection)) $collection = array();
  18                         $this->pages = array_chunk($collection, $per_page);
  19                 }
  20                 public static function paginate($collection, $per_page) {
  21                         return new Pager($collection, $per_page);
  22                 }
  23
  24                 // navigation/iteration functions
  25                 public function next() {
  26                         if(!next($this->pages)) return false;
  27                         return $this;
  28                 }
  29                 public function previous() {
  30                         if(!prev($this->pages)) return false;
  31                         return $this;
  32                 }
  33                 public function first() {
  34                         reset($this->pages);
  35                         return $this;
  36                 }
  37                 public function last() {
  38                         end($this->pages);
  39                         return $this;
  40                 }
  41                 public function current() {
  42                         return current($this->pages);
  43                 }
  44                 public function all() {
  45                         return current($this->pages);
  46                 }
  47                 public function page($page = null) {
  48                         $this->page = $page;
  49                         if($page !== null) return $this->pages[$page - 1];
  50                         return current($this->pages);
  51                 }
  52                 public function all_pages() {
  53                         return $this->pages;
  54                 }
  55                 public function page_numbers() {
  56                         for($i = 0; $i < count($this->pages); $i++) {
  57                                 $page_numbers[] = $i + 1;
  58                         }
  59                         return $page_numbers;
  60                 }
  61                 public function page_number() {
  62                         if($this->page == null) return 1;
  63                         return $this->page;
  64                 }
  65
  66                 // testing functions
  67                 public function has_next() {
  68                         // if the page has been set and the next one is set, then there has to be a next page
  69                         if(!empty($this->page)) {
  70                                 if(!empty($this->pages[($this->page - 1) + 1])) return true; // see note below
  71                                         else return false;
  72                                         // NOTE: the page - 1 + 1 is basically
  73                                         // for semantics because the page value
  74                                         // is actually one greater than the actual
  75                                         // page id in the array
  76                         }
  77                         // skips all this extra complicated crap only if $this->page has been set (by $this->page($page);)
  78                         $pages = $this->pages;
  79                         self::set_pointer($pages);
  80                         if(!next($pages)) return false;
  81                         return true;
  82                 }
  83                 public function has_previous() {
  84                         // if the page has been set and it's above 1, then there has to be a previous page
  85                         if(!empty($this->page)) {
  86                                 if(($this->page - 1) > 0) return true;
  87                                         else return false;
  88                         }
  89                         // skips all this extra complicated crap only if $this->page has been set (by $this->page($page);)
  90                         $pages = $this->pages;
  91                         self::set_pointer($pages);
  92                         if(!prev($pages)) return false;
  93                         return true;
  94                 }
  95                 private function set_pointer(&$pages) {
  96                         foreach($pages as $page) {
  97                                 $res = array_diff(current($this->pages), $page);
  98                                 if(empty($res)) break;
  99                         }
 100                 }
 101
 102                 // magic functions
 103                 public function __get($name) {
 104                         if($name == 'page') return $this->current();
 105                         if($name == 'next_page') return $this->page + 1;
 106                         if($name == 'previous_page') return $this->page - 1;
 107                         if($name == 'count' || $name == 'page_count' || $name == 'sizeof') return count($this->collection);
 108                         // if($name == '') return $x; //
 109                         return false;
 110                 }
 111                 public function __set($name, $value) {
 112                         return false;
 113                 }
 114         }
 115
 116         class PagerException extends StdException {}
 117 ?>