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lib/pkp/classes/core/VirtualArrayIterator.php

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+<?php
+
+/**
+ * @file classes/core/VirtualArrayIterator.php
+ *
+ * Copyright (c) 2014-2021 Simon Fraser University
+ * Copyright (c) 2000-2021 John Willinsky
+ * Distributed under the GNU GPL v3. For full terms see the file docs/COPYING.
+ *
+ * @class VirtualArrayIterator
+ *
+ * @ingroup db
+ *
+ * @brief Provides paging and iteration for "virtual" arrays -- arrays for which only
+ * the current "page" is available, but are much bigger in entirety.
+ */
+
+namespace PKP\core;
+
+use PKP\db\DBResultRange;
+
+class VirtualArrayIterator extends ItemIterator
+{
+    /** @var array The array of contents of this iterator. */
+    public $theArray;
+
+    /** @var int Number of items to iterate through on this page */
+    public $itemsPerPage;
+
+    /** @var int The current page. */
+    public $page;
+
+    /** @var int The total number of items. */
+    public $count;
+
+    /** @var bool Whether or not the iterator was empty from the start */
+    public $wasEmpty;
+
+    /**
+     * Constructor.
+     *
+     * @param array $theArray The array of items to iterate through
+     * @param int $totalItems The total number of items in the virtual "larger" array
+     * @param int $page the current page number
+     * @param int $itemsPerPage Number of items to display per page
+     */
+    public function __construct($theArray, $totalItems, $page = -1, $itemsPerPage = -1)
+    {
+        parent::__construct();
+        if ($page >= 1 && $itemsPerPage >= 1) {
+            $this->page = $page;
+        } else {
+            $this->page = 1;
+            $this->itemsPerPage = max(count($this->theArray), 1);
+        }
+        $this->theArray = $theArray;
+        $this->count = $totalItems;
+        $this->itemsPerPage = $itemsPerPage;
+        $this->wasEmpty = count($this->theArray) == 0;
+        reset($this->theArray);
+    }
+
+    /**
+     * Factory Method.
+     * Extracts the appropriate page items from the whole array and
+     * calls the constructor.
+     *
+     * @param array $wholeArray The whole array of items
+     * @param DBResultRange $rangeInfo The number of items per page
+     *
+     * @return object VirtualArrayIterator
+     */
+    public static function factory($wholeArray, $rangeInfo)
+    {
+        if ($rangeInfo->isValid()) {
+            $slicedArray = array_slice($wholeArray, $rangeInfo->getCount() * ($rangeInfo->getPage() - 1), $rangeInfo->getCount(), true);
+        }
+        return new VirtualArrayIterator($slicedArray, count($wholeArray), $rangeInfo->getPage(), $rangeInfo->getCount());
+    }
+
+    /**
+     * Return the next item in the iterator.
+     *
+     * @return ?object
+     */
+    public function &next()
+    {
+        if (!is_array($this->theArray)) {
+            $nullVar = null;
+            return $nullVar;
+        }
+        $value = current($this->theArray);
+        if (next($this->theArray) == null) {
+            $this->theArray = null;
+        }
+        return $value;
+    }
+
+    /**
+     * Return the next item in the iterator, with key.
+     *
+     * @return array (key, value)
+     */
+    public function nextWithKey()
+    {
+        $key = key($this->theArray);
+        $value = $this->next();
+        return [$key, $value];
+    }
+
+    /**
+     * Check whether or not this iterator is for the first page of a sequence
+     *
+     * @return bool
+     */
+    public function atFirstPage()
+    {
+        return $this->page == 1;
+    }
+
+    /**
+     * Check whether or not this iterator is for the last page of a sequence
+     *
+     * @return bool
+     */
+    public function atLastPage()
+    {
+        return ($this->page * $this->itemsPerPage) + 1 > $this->count;
+    }
+
+    /**
+     * Get the page number that this iterator represents
+     *
+     * @return int
+     */
+    public function getPage()
+    {
+        return $this->page;
+    }
+
+    /**
+     * Get the total number of items in the virtual array
+     *
+     * @return int
+     */
+    public function getCount()
+    {
+        return $this->count;
+    }
+
+    /**
+     * Get the total number of pages in the virtual array
+     *
+     * @return int
+     */
+    public function getPageCount()
+    {
+        return max(1, ceil($this->count / $this->itemsPerPage));
+    }
+
+    /**
+     * Return a boolean indicating whether or not we've reached the end of results
+     * Note: This implementation requires that next() be called before every eof() will
+     * function properly (except the first call).
+     *
+     * @return bool
+     */
+    public function eof()
+    {
+        return (($this->theArray == null) || (count($this->theArray) == 0));
+    }
+
+    /**
+     * Return a boolean indicating whether or not this iterator was empty from the beginning
+     *
+     * @return bool
+     */
+    public function wasEmpty()
+    {
+        return $this->wasEmpty;
+    }
+
+    /**
+     * Convert the iterator into an array
+     *
+     * @return array
+     */
+    public function &toArray()
+    {
+        return $this->theArray;
+    }
+}
+
+if (!PKP_STRICT_MODE) {
+    class_alias('\PKP\core\VirtualArrayIterator', '\VirtualArrayIterator');
+}