enum_iterator.h

/*
 * Copyright (c) 2021 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#include <type_traits>
 
template <typename C, C begin_val, C end_val>
class Iterator {
  typedef typename std::underlying_type<C>::type val_t;
  int val;
 
 public:
  Iterator(const C& f) : val(static_cast<val_t>(f)) {}
 
  Iterator() : val(static_cast<val_t>(begin_val)) {}
 
  Iterator operator++() {
    ++val;
    return *this;
  }
 
  C operator*() { return static_cast<C>(val); }
 
  Iterator begin() { return *this; }  // default ctor is good
 
  Iterator end() {
    static const Iterator endIter = ++Iterator(end_val);  // cache it
    return endIter;
  }
 
  bool operator!=(const Iterator& i) { return val != i.val; }
};