Interval.hpp

// Copyright (c) 2017 Graphcore Ltd. All rights reserved.
 
#ifndef poplar_Interval_hpp
#define poplar_Interval_hpp
 
#include <cstddef>
#include <ostream>
#include <poplar/exceptions.hpp>
#include <tuple>
 
namespace poplar {
 
template <class T> struct GenericInterval {
private:
  T begin_{};
  T end_{};
 
public:
  GenericInterval() = default;
 
  GenericInterval(T begin, T end) : begin_(begin), end_(end) {
    if (end < begin) {
      throw poplar::index_error("Invalid interval: [" + std::to_string(begin) +
                                "," + std::to_string(end) + ")");
    }
  }
  const T &begin() const { return begin_; }
  const T &end() const { return end_; }
 
  const T &lower() const { return begin_; }
 
  const T &upper() const { return end_; }
 
  T size() const { return T(end_ - begin_); }
};
 
template <class T>
inline bool operator==(const GenericInterval<T> &a,
                       const GenericInterval<T> &b) {
  return std::tie(a.begin(), a.end()) == std::tie(b.begin(), b.end());
}
 
template <class T>
inline bool operator<(const GenericInterval<T> &a,
                      const GenericInterval<T> &b) {
  return std::tie(a.begin(), a.end()) < std::tie(b.begin(), b.end());
}
 
template <class T>
inline bool operator!=(const GenericInterval<T> &a,
                       const GenericInterval<T> &b) {
  return !(a == b);
}
 
template <class T>
inline bool operator>=(const GenericInterval<T> &a,
                       const GenericInterval<T> &b) {
  return !(a < b);
}
 
template <class T>
inline bool operator>(const GenericInterval<T> &a,
                      const GenericInterval<T> &b) {
  return b < a;
}
 
template <class T>
inline bool operator<=(const GenericInterval<T> &a,
                       const GenericInterval<T> &b) {
  return !(b < a);
}
 
template <class T>
inline std::ostream &operator<<(std::ostream &os, const GenericInterval<T> &b) {
  os << "[" << b.begin() << ":" << b.end() << ")";
  return os;
}
 
typedef GenericInterval<std::size_t> Interval;
 
} // namespace poplar
#endif // poplar_Interval_hpp