1 files changed, 121 insertions, 0 deletions
diff --git a/lib/private/NaturalSort.php b/lib/private/NaturalSort.php
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+++ b/lib/private/NaturalSort.php
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+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+namespace OC;
+
+use Psr\Log\LoggerInterface;
+
+class NaturalSort {
+	private static $instance;
+	private $collator;
+	private $cache = [];
+
+	/**
+	 * Instantiate a new \OC\NaturalSort instance.
+	 * @param object $injectedCollator
+	 */
+	public function __construct($injectedCollator = null) {
+		// inject an instance of \Collator('en_US') to force using the php5-intl Collator
+		// or inject an instance of \OC\NaturalSort_DefaultCollator to force using Owncloud's default collator
+		if (isset($injectedCollator)) {
+			$this->collator = $injectedCollator;
+			\OC::$server->get(LoggerInterface::class)->debug('forced use of ' . get_class($injectedCollator));
+		}
+	}
+
+	/**
+	 * Split the given string in chunks of numbers and strings
+	 * @param string $t string
+	 * @return array of strings and number chunks
+	 */
+	private function naturalSortChunkify($t) {
+		// Adapted and ported to PHP from
+		// http://my.opera.com/GreyWyvern/blog/show.dml/1671288
+		if (isset($this->cache[$t])) {
+			return $this->cache[$t];
+		}
+		$tz = [];
+		$x = 0;
+		$y = -1;
+		$n = null;
+
+		while (isset($t[$x])) {
+			$c = $t[$x];
+			// only include the dot in strings
+			$m = ((!$n && $c === '.') || ($c >= '0' && $c <= '9'));
+			if ($m !== $n) {
+				// next chunk
+				$y++;
+				$tz[$y] = '';
+				$n = $m;
+			}
+			$tz[$y] .= $c;
+			$x++;
+		}
+		$this->cache[$t] = $tz;
+		return $tz;
+	}
+
+	/**
+	 * Returns the string collator
+	 * @return \Collator string collator
+	 */
+	private function getCollator() {
+		if (!isset($this->collator)) {
+			// looks like the default is en_US_POSIX which yields wrong sorting with
+			// German umlauts, so using en_US instead
+			if (class_exists('Collator')) {
+				$this->collator = new \Collator('en_US');
+			} else {
+				$this->collator = new \OC\NaturalSort_DefaultCollator();
+			}
+		}
+		return $this->collator;
+	}
+
+	/**
+	 * Compare two strings to provide a natural sort
+	 * @param string $a first string to compare
+	 * @param string $b second string to compare
+	 * @return int -1 if $b comes before $a, 1 if $a comes before $b
+	 *             or 0 if the strings are identical
+	 */
+	public function compare($a, $b) {
+		// Needed because PHP doesn't sort correctly when numbers are enclosed in
+		// parenthesis, even with NUMERIC_COLLATION enabled.
+		// For example it gave ["test (2).txt", "test.txt"]
+		// instead of ["test.txt", "test (2).txt"]
+		$aa = self::naturalSortChunkify($a);
+		$bb = self::naturalSortChunkify($b);
+
+		for ($x = 0; isset($aa[$x]) && isset($bb[$x]); $x++) {
+			$aChunk = $aa[$x];
+			$bChunk = $bb[$x];
+			if ($aChunk !== $bChunk) {
+				// test first character (character comparison, not number comparison)
+				if ($aChunk[0] >= '0' && $aChunk[0] <= '9' && $bChunk[0] >= '0' && $bChunk[0] <= '9') {
+					$aNum = (int)$aChunk;
+					$bNum = (int)$bChunk;
+					return $aNum - $bNum;
+				}
+				return self::getCollator()->compare($aChunk, $bChunk);
+			}
+		}
+		return count($aa) - count($bb);
+	}
+
+	/**
+	 * Returns a singleton
+	 * @return \OC\NaturalSort instance
+	 */
+	public static function getInstance() {
+		if (!isset(self::$instance)) {
+			self::$instance = new \OC\NaturalSort();
+		}
+		return self::$instance;
+	}
+}