Class yii\bootstrap4\LinkPager

                protected function getPageRange()
{
    $currentPage = $this->pagination->getPage();
    $pageCount = $this->pagination->getPageCount();
    $beginPage = max(0, $currentPage - (int)($this->maxButtonCount / 2));
    if (($endPage = $beginPage + $this->maxButtonCount - 1) >= $pageCount) {
        $endPage = $pageCount - 1;
        $beginPage = max(0, $endPage - $this->maxButtonCount + 1);
    }
    return [$beginPage, $endPage];
}

            

                public function init()
{
    parent::init();
    if ($this->pagination === null) {
        throw new InvalidConfigException('The "pagination" property must be set.');
    }
}

            

                protected function registerLinkTags()
{
    $view = $this->getView();
    foreach ($this->pagination->getLinks() as $rel => $href) {
        $view->registerLinkTag(['rel' => $rel, 'href' => $href], $rel);
    }
}

            

                protected function renderPageButton($label, $page, $class, $disabled, $active)
{
    $options = $this->linkContainerOptions;
    $linkWrapTag = ArrayHelper::remove($options, 'tag', 'li');
    Html::addCssClass($options, empty($class) ? $this->pageCssClass : $class);
    $linkOptions = $this->linkOptions;
    $linkOptions['data-page'] = $page;
    if ($active) {
        Html::addCssClass($options, $this->activePageCssClass);
    }
    if ($disabled) {
        Html::addCssClass($options, $this->disabledPageCssClass);
        $disabledItemOptions = $this->disabledListItemSubTagOptions;
        $linkOptions = ArrayHelper::merge($linkOptions, $disabledItemOptions);
        $linkOptions['tabindex'] = '-1';
    }
    return Html::tag($linkWrapTag, Html::a($label, $this->pagination->createUrl($page), $linkOptions), $options);
}

            

                protected function renderPageButtons()
{
    $pageCount = $this->pagination->getPageCount();
    if ($pageCount < 2 && $this->hideOnSinglePage) {
        return '';
    }
    $buttons = [];
    $currentPage = $this->pagination->getPage();
    // first page
    $firstPageLabel = $this->firstPageLabel === true ? '1' : $this->firstPageLabel;
    if ($firstPageLabel !== false) {
        $buttons[] = $this->renderPageButton(
            $firstPageLabel,
            0,
            $this->firstPageCssClass,
            $currentPage <= 0,
            false
        );
    }
    // prev page
    if ($this->prevPageLabel !== false) {
        if (($page = $currentPage - 1) < 0) {
            $page = 0;
        }
        $buttons[] = $this->renderPageButton(
            $this->prevPageLabel,
            $page,
            $this->prevPageCssClass,
            $currentPage <= 0,
            false
        );
    }
    // internal pages
    list($beginPage, $endPage) = $this->getPageRange();
    for ($i = $beginPage; $i <= $endPage; ++$i) {
        $buttons[] = $this->renderPageButton(
            $i + 1,
            $i,
            null,
            $this->disableCurrentPageButton && $i == $currentPage,
            $i == $currentPage
        );
    }
    // next page
    if ($this->nextPageLabel !== false) {
        if (($page = $currentPage + 1) >= $pageCount - 1) {
            $page = $pageCount - 1;
        }
        $buttons[] = $this->renderPageButton(
            $this->nextPageLabel,
            $page,
            $this->nextPageCssClass,
            $currentPage >= $pageCount - 1,
            false
        );
    }
    // last page
    $lastPageLabel = $this->lastPageLabel === true ? $pageCount : $this->lastPageLabel;
    if ($lastPageLabel !== false) {
        $buttons[] = $this->renderPageButton(
            $lastPageLabel,
            $pageCount - 1,
            $this->lastPageCssClass,
            $currentPage >= $pageCount - 1,
            false
        );
    }
    $options = $this->listOptions;
    $tag = ArrayHelper::remove($options, 'tag', 'ul');
    return Html::tag($tag, implode("\n", $buttons), $options);
}

            

                public function run()
{
    if ($this->registerLinkTags) {
        $this->registerLinkTags();
    }
    $options = $this->options;
    $tag = ArrayHelper::remove($options, 'tag', 'nav');
    $html = Html::beginTag($tag, $options);
    $html .= $this->renderPageButtons();
    $html .= Html::endTag($tag);
    return $html;
}