Pager.php

См. документацию.

<?php
 
declare(strict_types=1);
 
namespace Bitrix\Main\Provider\Params;
 
use Bitrix\Main\ArgumentException;
use Bitrix\Main\UI\PageNavigation;

class Pager implements PagerInterface
{
    public function __construct(protected int $limit = 50, protected int $offset = 0)
    {
        $this
            ->setLimit($this->limit)
            ->setOffset($this->offset)
        ;
    }

    public static function buildFromPageNavigation(PageNavigation $pageNavigation): static
    {
        return new static(limit: $pageNavigation->getLimit() ?: 50, offset: $pageNavigation->getOffset() ?: 0);
    }
 
    public function getLimit(): int
    {
        return $this->limit;
    }

    public function setLimit(int $limit): static
    {
        if ($limit < 1)
        {
            throw new ArgumentException('The limit should be a positive number');
        }
 
        $this->limit = $limit;
 
        return $this;
    }
 
    public function getOffset(): int
    {
        return $this->offset;
    }

    public function setOffset(int $offset): static
    {
        if ($offset < 0)
        {
            throw new ArgumentException('The offset should be a not negative number');
        }
 
        $this->offset = $offset;
 
        return $this;
    }

    public function setPage(int $page): static
    {
        if ($page < 1)
        {
            throw new ArgumentException('The page should be a positive number');
        }
 
        $this->offset = ($page - 1) * $this->limit;
 
        return $this;
    }

    public function setSize(int $size): PagerInterface
    {
        return $this->setLimit($size);
    }
}