1: <?php
  2: 
  3: /**
  4:  * This file is part of the Nette Framework (https://nette.org)
  5:  * Copyright (c) 2004 David Grudl (https://davidgrudl.com)
  6:  */
  7: 
  8: namespace Nette\Utils;
  9: 
 10: use Nette;
 11: 
 12: 
 13: /**
 14:  * Paginating math.
 15:  *
 16:  * @property   int $page
 17:  * @property-read int $firstPage
 18:  * @property-read int|NULL $lastPage
 19:  * @property   int $base
 20:  * @property-read bool $first
 21:  * @property-read bool $last
 22:  * @property-read int|NULL $pageCount
 23:  * @property   int $itemsPerPage
 24:  * @property   int|NULL $itemCount
 25:  * @property-read int $offset
 26:  * @property-read int|NULL $countdownOffset
 27:  * @property-read int|NULL $length
 28:  */
 29: class Paginator extends Nette\Object
 30: {
 31:     /** @var int */
 32:     private $base = 1;
 33: 
 34:     /** @var int */
 35:     private $itemsPerPage = 1;
 36: 
 37:     /** @var int */
 38:     private $page;
 39: 
 40:     /** @var int|NULL */
 41:     private $itemCount;
 42: 
 43: 
 44:     /**
 45:      * Sets current page number.
 46:      * @param  int
 47:      * @return static
 48:      */
 49:     public function setPage($page)
 50:     {
 51:         $this->page = (int) $page;
 52:         return $this;
 53:     }
 54: 
 55: 
 56:     /**
 57:      * Returns current page number.
 58:      * @return int
 59:      */
 60:     public function getPage()
 61:     {
 62:         return $this->base + $this->getPageIndex();
 63:     }
 64: 
 65: 
 66:     /**
 67:      * Returns first page number.
 68:      * @return int
 69:      */
 70:     public function getFirstPage()
 71:     {
 72:         return $this->base;
 73:     }
 74: 
 75: 
 76:     /**
 77:      * Returns last page number.
 78:      * @return int|NULL
 79:      */
 80:     public function getLastPage()
 81:     {
 82:         return $this->itemCount === NULL ? NULL : $this->base + max(0, $this->getPageCount() - 1);
 83:     }
 84: 
 85: 
 86:     /**
 87:      * Sets first page (base) number.
 88:      * @param  int
 89:      * @return static
 90:      */
 91:     public function setBase($base)
 92:     {
 93:         $this->base = (int) $base;
 94:         return $this;
 95:     }
 96: 
 97: 
 98:     /**
 99:      * Returns first page (base) number.
100:      * @return int
101:      */
102:     public function getBase()
103:     {
104:         return $this->base;
105:     }
106: 
107: 
108:     /**
109:      * Returns zero-based page number.
110:      * @return int
111:      */
112:     protected function getPageIndex()
113:     {
114:         $index = max(0, $this->page - $this->base);
115:         return $this->itemCount === NULL ? $index : min($index, max(0, $this->getPageCount() - 1));
116:     }
117: 
118: 
119:     /**
120:      * Is the current page the first one?
121:      * @return bool
122:      */
123:     public function isFirst()
124:     {
125:         return $this->getPageIndex() === 0;
126:     }
127: 
128: 
129:     /**
130:      * Is the current page the last one?
131:      * @return bool
132:      */
133:     public function isLast()
134:     {
135:         return $this->itemCount === NULL ? FALSE : $this->getPageIndex() >= $this->getPageCount() - 1;
136:     }
137: 
138: 
139:     /**
140:      * Returns the total number of pages.
141:      * @return int|NULL
142:      */
143:     public function getPageCount()
144:     {
145:         return $this->itemCount === NULL ? NULL : (int) ceil($this->itemCount / $this->itemsPerPage);
146:     }
147: 
148: 
149:     /**
150:      * Sets the number of items to display on a single page.
151:      * @param  int
152:      * @return static
153:      */
154:     public function setItemsPerPage($itemsPerPage)
155:     {
156:         $this->itemsPerPage = max(1, (int) $itemsPerPage);
157:         return $this;
158:     }
159: 
160: 
161:     /**
162:      * Returns the number of items to display on a single page.
163:      * @return int
164:      */
165:     public function getItemsPerPage()
166:     {
167:         return $this->itemsPerPage;
168:     }
169: 
170: 
171:     /**
172:      * Sets the total number of items.
173:      * @param  int (or NULL as infinity)
174:      * @return static
175:      */
176:     public function setItemCount($itemCount)
177:     {
178:         $this->itemCount = ($itemCount === FALSE || $itemCount === NULL) ? NULL : max(0, (int) $itemCount);
179:         return $this;
180:     }
181: 
182: 
183:     /**
184:      * Returns the total number of items.
185:      * @return int|NULL
186:      */
187:     public function getItemCount()
188:     {
189:         return $this->itemCount;
190:     }
191: 
192: 
193:     /**
194:      * Returns the absolute index of the first item on current page.
195:      * @return int
196:      */
197:     public function getOffset()
198:     {
199:         return $this->getPageIndex() * $this->itemsPerPage;
200:     }
201: 
202: 
203:     /**
204:      * Returns the absolute index of the first item on current page in countdown paging.
205:      * @return int|NULL
206:      */
207:     public function getCountdownOffset()
208:     {
209:         return $this->itemCount === NULL
210:             ? NULL
211:             : max(0, $this->itemCount - ($this->getPageIndex() + 1) * $this->itemsPerPage);
212:     }
213: 
214: 
215:     /**
216:      * Returns the number of items on current page.
217:      * @return int|NULL
218:      */
219:     public function getLength()
220:     {
221:         return $this->itemCount === NULL
222:             ? $this->itemsPerPage
223:             : min($this->itemsPerPage, $this->itemCount - $this->getPageIndex() * $this->itemsPerPage);
224:     }
225: 
226: }
227: