usb: add ds client api

libraries/libstratosphere/source/usb/impl/usb_util.hpp

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+
+namespace ams::usb::impl {
+
+    constexpr int GetEndpointIndex(u8 address) {
+        int idx = address & UsbEndpointAddressMask_EndpointNumber;
+        if ((address & UsbEndpointAddressMask_Dir) == UsbEndpointAddressMask_DirDevicetoHost) {
+            idx += 0x10;
+        }
+        return idx;
+    }
+
+    template<typename T>
+    class ScopedRefCount {
+        NON_COPYABLE(ScopedRefCount);
+        NON_MOVEABLE(ScopedRefCount);
+        private:
+            T &m_obj;
+        public:
+            ALWAYS_INLINE ScopedRefCount(T &o) : m_obj(o) {
+                ++m_obj;
+            }
+
+            ALWAYS_INLINE ~ScopedRefCount() {
+                --m_obj;
+            }
+    };
+
+}