Create Drupal 7 hash algorithm option

lib/Crypto/Drupal7.php

@@ -0,0 +1,80 @@
+<?php
+/**
+ * Nextcloud - user_sql
+ *
+ * @copyright 2018 Marcin Łojewski <dev@mlojewski.me>
+ * @author    Marcin Łojewski <dev@mlojewski.me>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace OCA\UserSQL\Crypto;
+
+use OCP\IL10N;
+
+require_once "Phpass.php";
+
+/**
+ * Drupal 7 overrides of phpass hash implementation.
+ *
+ * @author BrandonKerr
+ */
+class Drupal7 extends Phpass
+{
+	
+	/**
+	 * The expected (and maximum) number of characters in a hashed password.
+	 */
+	const DRUPAL_HASH_LENGTH = 55;
+
+    /**
+     * @param string $password Password to encrypt.
+     * @param string $setting  Hash settings.
+     *
+     * @return string|null Generated hash. Null on invalid settings.
+     */
+    private function crypt($password, $setting)
+    {
+        $countLog2 = strpos(self::ITOA64, $setting[3]);
+        if ($countLog2 < 7 || $countLog2 > 30) {
+            return null;
+        }
+
+        $count = 1 << $countLog2;
+
+        $salt = substr($setting, 4, 8);
+        if (strlen($salt) !== 8) {
+            return null;
+        }
+
+        $hash = hash('sha512', $salt . $password, true);
+        do {
+            $hash = hash('sha512', $hash . $password, true);
+        } while (--$count);
+
+        $output = substr($setting, 0, 12);
+        $output .= $this->encode64($hash, strlen($hash));
+
+        return substr($output, 0, self::DRUPAL_HASH_LENGTH);
+    }
+
+
+    /**
+     * @inheritdoc
+     */
+    protected function getAlgorithmName()
+    {
+        return "Drupal 7";
+    }
+}