Everywhere: Hoist the Libraries folder to the top-level

Libraries/LibCrypto/BigInt/Algorithms/GCD.cpp

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2020, Ali Mohammad Pur <mpfard@serenityos.org>
+ * Copyright (c) 2020-2021, Dex♪ <dexes.ttp@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "UnsignedBigIntegerAlgorithms.h"
+
+namespace Crypto {
+
+void UnsignedBigIntegerAlgorithms::destructive_GCD_without_allocation(
+    UnsignedBigInteger& temp_a,
+    UnsignedBigInteger& temp_b,
+    UnsignedBigInteger& temp_quotient,
+    UnsignedBigInteger& temp_remainder,
+    UnsignedBigInteger& output)
+{
+    for (;;) {
+        if (temp_a == 0) {
+            output.set_to(temp_b);
+            return;
+        }
+
+        // temp_b %= temp_a
+        divide_without_allocation(temp_b, temp_a, temp_quotient, temp_remainder);
+        temp_b.set_to(temp_remainder);
+        if (temp_b == 0) {
+            output.set_to(temp_a);
+            return;
+        }
+
+        // temp_a %= temp_b
+        divide_without_allocation(temp_a, temp_b, temp_quotient, temp_remainder);
+        temp_a.set_to(temp_remainder);
+    }
+}
+
+}