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<?php |
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/** |
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* File containing the {@link PaginationHelper} class |
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* |
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* @access public |
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* @package Application Utils |
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* @subpackage Misc |
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* @see PaginationHelper |
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*/ |
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declare(strict_types=1); |
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namespace AppUtils; |
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/** |
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* Simple pagination calculator that can be used to |
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* determine previous / next pages depending on the |
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* amount of items. |
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* |
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* @access public |
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* @package Application Utils |
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* @subpackage Misc |
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* @author Sebastian Mordziol <[email protected]> |
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*/ |
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class PaginationHelper |
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{ |
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/** |
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* @var int |
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*/ |
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protected $total; |
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/** |
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* @var int |
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*/ |
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protected $perPage; |
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/** |
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* @var int |
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*/ |
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protected $current; |
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/** |
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* @var int |
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*/ |
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protected $next = 0; |
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/** |
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* @var int |
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*/ |
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protected $prev = 0; |
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/** |
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* @var int |
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*/ |
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protected $last = 0; |
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/** |
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* @var int |
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*/ |
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protected $adjacentPages = 3; |
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/** |
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* @var int |
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*/ |
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protected $offsetEnd = 0; |
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/** |
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* @var int |
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*/ |
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protected $offsetStart = 0; |
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/** |
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* @param int $totalItems The total amount of items available. |
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* @param int $itemsPerPage How many items to display per page. |
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* @param int $currentPage The current page number (1-based) |
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*/ |
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public function __construct(int $totalItems, int $itemsPerPage, int $currentPage) |
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{ |
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$this->total = $totalItems; |
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$this->perPage = $itemsPerPage; |
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$this->current = $currentPage; |
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$this->calculate(); |
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} |
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/** |
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* Sets the amount of adjacent pages to display next to the |
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* current one when using the pages list. |
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* |
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* @param int $amount |
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* @return PaginationHelper |
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*/ |
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public function setAdjacentPages(int $amount) : PaginationHelper |
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{ |
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$this->adjacentPages = $amount; |
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return $this; |
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} |
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/** |
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* Whether there is a next page after the current page. |
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* @return bool |
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*/ |
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public function hasNextPage() : bool |
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{ |
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return $this->next > 0; |
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} |
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/** |
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* The next page number. Returns the last page |
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* number if there is no next page. |
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* |
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* @return int |
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*/ |
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public function getNextPage() : int |
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{ |
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if($this->next === 0) { |
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return $this->last; |
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} |
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return $this->next; |
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} |
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/** |
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* Whether there is a previous page before the current page. |
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* @return bool |
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*/ |
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public function hasPreviousPage() : bool |
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{ |
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return $this->prev > 0; |
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} |
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/** |
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* The previous page number. Returns the first page |
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* number if there is no previous page. |
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* |
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* @return int |
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*/ |
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public function getPreviousPage() : int |
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{ |
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if($this->prev === 0) { |
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return 1; |
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} |
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return $this->prev; |
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} |
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/** |
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* Retrieves the last page number. |
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* @return int |
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*/ |
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public function getLastPage() : int |
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{ |
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return $this->last; |
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} |
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/** |
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* Whether there is more than one page, i.e. whether |
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* pagination is required at all. |
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* |
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* @return bool |
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*/ |
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public function hasPages() : bool |
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{ |
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return $this->last > 1; |
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} |
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public function getCurrentPage() : int |
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{ |
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return $this->current; |
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} |
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/** |
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* Retrieves a list of page numbers for a page |
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* navigator, to quickly jump between pages. |
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* |
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* @return int[] |
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*/ |
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public function getPageNumbers() : array |
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{ |
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$adjacent = $this->adjacentPages; |
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// adjust the adjacent value if it exceeds the |
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// total amount of pages |
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$adjacentTotal = ($adjacent * 2) + 1; |
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if($adjacentTotal > $this->last) |
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{ |
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$adjacent = (int)floor($this->last / 2); |
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} |
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// determine the maximum amount of |
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// pages that one can go forward or |
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// back from the current position. |
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$maxBack = $this->current - 1; |
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$maxFwd = $this->last - $this->current; |
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$back = 0; |
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$fwd = 0; |
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if($maxBack >= $adjacent) { |
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$back = $adjacent; |
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} else { |
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$back = $maxBack; |
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} |
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if($maxFwd >= $adjacent) { |
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$fwd = $adjacent; |
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} else { |
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$fwd = $maxFwd; |
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} |
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// now calculate the amount of pages to add |
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// left or right, depending on whether we |
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// are at the beginning of the list, or at |
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// the end. |
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$backDiff = $adjacent - $back; |
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$fwdDiff = $adjacent - $fwd; |
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$fwd += $backDiff; |
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$back += $fwdDiff; |
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if($fwd > $maxFwd) { $fwd = $maxFwd; } |
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if($back > $maxBack) { $back = $maxBack; } |
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// calculate the first and last page in the list |
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$prev = $this->current - $back; |
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$next = $this->current + $fwd; |
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// failsafe so we stay within the bounds |
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if($prev < 1) { $prev = 1; } |
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if($next > $this->last) { $next = $this->last; } |
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// create and return the page numbers list |
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$numbers = range($prev, $next); |
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/* |
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print_r(array( |
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'current' => $this->current, |
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'totalPages' => $this->last, |
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'adjacent' => $adjacent, |
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'maxBack' => $maxBack, |
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'maxFwd' => $maxFwd, |
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'back' => $back, |
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'fwd' => $fwd, |
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'backDiff' => $backDiff, |
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'fwdDiff' => $fwdDiff, |
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'prev' => $prev, |
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'next' => $next, |
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'numbers' => $numbers |
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));*/ |
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return $numbers; |
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} |
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/** |
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* Whether the specified page number is the current page. |
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* |
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* @param int $pageNumber |
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* @return bool |
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*/ |
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public function isCurrentPage(int $pageNumber) : bool |
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{ |
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return $pageNumber === $this->current; |
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} |
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/** |
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* Retrieves the 1-based starting offset of |
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* items currently displayed in the page. |
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* |
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* Note: Use this to create a text like |
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* "showing entries x to y". |
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* |
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* @return int |
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* @see PaginationHelper::getOffsetEnd() |
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*/ |
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public function getItemsStart() : int |
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{ |
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return $this->getOffsetStart() + 1; |
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} |
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/** |
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* Retrieves the 1-based ending offset of |
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* items currently displayed in the page. |
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* |
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* Note: Use this to create a text like |
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* "showing entries x to y". |
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* |
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* @return int |
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* @see PaginationHelper::getOffsetStart() |
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*/ |
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public function getItemsEnd() : int |
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{ |
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return $this->getOffsetEnd() + 1; |
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} |
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/** |
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* Retrieves the 0-based starting offset of |
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* items currently displayed in the page. |
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* |
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* @return int |
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* @see PaginationHelper::getItemsStart() |
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*/ |
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public function getOffsetStart() : int |
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{ |
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return $this->offsetStart; |
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} |
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/** |
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* Retrieves the 0-based ending offset of |
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* items currently displayed in the page. |
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* |
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* @return int |
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* @see PaginationHelper::getItemsEnd() |
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*/ |
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public function getOffsetEnd() : int |
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{ |
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return $this->offsetEnd; |
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} |
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protected function calculate() : void |
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{ |
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$pages = (int)ceil($this->total / $this->perPage); |
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if($this->current < 1) |
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{ |
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$this->current = 1; |
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} |
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else if($this->current > $pages) |
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{ |
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$this->current = $pages; |
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} |
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$this->last = $pages; |
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$nextPage = $this->current + 1; |
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if($nextPage <= $pages) { |
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$this->next = $nextPage; |
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} |
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$prevPage = $this->current - 1; |
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if($prevPage > 0) { |
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$this->prev = $prevPage; |
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} |
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$this->offsetStart = ($this->current - 1) * $this->perPage; |
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$this->offsetEnd = $this->offsetStart + $this->perPage; |
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if($this->offsetEnd > ($this->total - 1)) { |
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$this->offsetEnd = ($this->total - 1); |
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} |
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} |
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} |
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