range.h

/*
 * SPDX-FileCopyrightText: 2013 Barefoot Networks, Inc.
 * Copyright 2013-present Barefoot Networks, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef LIB_RANGE_H_
#define LIB_RANGE_H_
 
#include <iostream>
 
namespace P4 {
 
template <class T>
class RangeIter {
    int incr;
    T cur, fin;
    explicit RangeIter(T end) : incr(0), cur(end), fin(end) {}
 
 public:
    RangeIter(T start, T end)
        : incr(start <= end ? 1 : -1), cur(start), fin(static_cast<T>(end + incr)) {}
    RangeIter begin() const { return *this; }
    RangeIter end() const { return RangeIter(fin); }
    T operator*() const { return cur; }
    bool operator==(const RangeIter &a) const { return cur == a.cur; }
    bool operator!=(const RangeIter &a) const { return cur != a.cur; }
    RangeIter &operator++() {
        cur = static_cast<T>(cur + incr);
        return *this;
    }
    template <class U>
    friend std::ostream &operator<<(std::ostream &, const RangeIter<U> &);
};
 
template <class T>
static inline RangeIter<T> Range(T a, T b) {
    return RangeIter<T>(a, b);
}
template <class T>
static inline RangeIter<T> Range(std::pair<T, T> p) {
    return RangeIter<T>(p.first, p.second);
}
template <class T>
static inline RangeIter<T> ReverseRange(std::pair<T, T> p) {
    return RangeIter<T>(p.second, p.first);
}
 
template <class T>
std::ostream &operator<<(std::ostream &out, const RangeIter<T> &r) {
    out << r.cur;
    if (r.cur + r.incr != r.fin) out << ".." << (r.fin - r.incr);
    return out;
}
 
}  // namespace P4
 
#endif /* LIB_RANGE_H_ */