1 files changed, 21 insertions, 0 deletions
diff --git a/lib/private/DB/QueryBuilder/Sharded/HashShardMapper.php b/lib/private/DB/QueryBuilder/Sharded/HashShardMapper.php
new file mode 100644
index 00000000000..af778489a2d
--- /dev/null
+++ b/lib/private/DB/QueryBuilder/Sharded/HashShardMapper.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Robin Appelman <robin@icewind.nl>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OC\DB\QueryBuilder\Sharded;
+
+use OCP\DB\QueryBuilder\Sharded\IShardMapper;
+
+/**
+ * Map string key to an int-range by hashing the key
+ */
+class HashShardMapper implements IShardMapper {
+	public function getShardForKey(int $key, int $count): int {
+		$int = unpack('L', substr(md5((string)$key, true), 0, 4))[1];
+		return $int % $count;
+	}
+}