cpp-mathematic-limit/bound_number.hpp

//
//  bound_number.hpp
//  utilities
//
//  Created by Sam Jaffe on 10/22/13.
//  Copyright (c) 2013 Sam Jaffe. All rights reserved.
//

#pragma once

#include <stdexcept>

struct {} check_bounds;
using check_bounds_t = decltype(check_bounds);

template <class Tp, Tp MINIMUM_VALUE, Tp MAXIMUM_VALUE>
class bound_number final {
private:
public:
  static_assert(MINIMUM_VALUE <= MAXIMUM_VALUE, "The minimum value must be less than or equal to the maximum");
  
  typedef Tp value_type;
  static constexpr const value_type min = MINIMUM_VALUE;
  static constexpr const value_type max = MAXIMUM_VALUE;
  
  bound_number() = default;
  bound_number(const bound_number& other) = default;
  bound_number(bound_number&& other) = default;
  bound_number& operator=(const bound_number& other) = default;
  bound_number& operator=(bound_number&& other) = default;
  ~bound_number() = default;
  
  bound_number(Tp const & val) :
  value(std::max(MINIMUM_VALUE, std::min(MAXIMUM_VALUE, val))) {
  }
  
  bound_number(check_bounds_t, Tp const & val) :
  value(val) {
    if ( val < MINIMUM_VALUE || MAXIMUM_VALUE < val ) {
      throw std::out_of_range{"Must construct a value within range"};
    }
  }
  
  bound_number& operator --() {
    if (min < value) { --value; }
    return *this;
  }
  
  bound_number& operator ++() {
    if (value < max) { ++value; }
    return *this;
  }
  
  bound_number operator --(int) {
    bound_number tmp = *this;
    operator--();
    return tmp;
  }
  
  bound_number operator ++(int) {
    bound_number tmp = *this;
    operator++();
    return tmp;
  }
  
  operator Tp() const {
    return value;
  }
private:
  Tp value;
};