public/lib/escher/util/enum_utils.h

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef LIB_ESCHER_UTIL_ENUM_UTILS_H_
#define LIB_ESCHER_UTIL_ENUM_UTILS_H_

// TODO(ES-147): move EnumCast and EnumCount into this file, and update clients.
#include "lib/escher/util/enum_cast.h"
#include "lib/escher/util/enum_count.h"

namespace escher {

// Cycle through an enum's values, safely wrapping around in either direction.
// The enum must meet the requirements of EnumCount().
template <typename E>
E EnumCycle(E e, bool reverse = false) {
  size_t count = EnumCount<E>();
  auto underlying_value = EnumCast(e);
  underlying_value = (underlying_value + (reverse ? count - 1 : 1)) % count;
  return static_cast<E>(underlying_value);
}

}  // namespace escher

#endif  // LIB_ESCHER_UTIL_ENUM_UTILS_H_