1// i_dont_like_the_default_duration_behavior.cpp ----------------------------------------------------------//
2
3// Copyright 2008 Howard Hinnant
4// Copyright 2008 Beman Dawes
5// Copyright 2009 Vicente J. Botet Escriba
6
7// Distributed under the Boost Software License, Version 1.0.
8// See http://www.boost.org/LICENSE_1_0.txt
9
10/*
11This code was extracted by Vicente J. Botet Escriba from Beman Dawes time2_demo.cpp which
12was derived by Beman Dawes from Howard Hinnant's time2_demo prototype.
13Many thanks to Howard for making his code available under the Boost license.
14The original code was modified to conform to Boost conventions and to section
1520.9 Time utilities [time] of the C++ committee's working paper N2798.
16See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2798.pdf.
17
18time2_demo contained this comment:
19
20 Much thanks to Andrei Alexandrescu,
21 Walter Brown,
22 Peter Dimov,
23 Jeff Garland,
24 Terry Golubiewski,
25 Daniel Krugler,
26 Anthony Williams.
27*/
28
29#include <boost/chrono/chrono.hpp>
30#include <boost/type_traits.hpp>
31
32#include <iostream>
33
34namespace I_dont_like_the_default_duration_behavior
35{
36
37// Here's how you override the duration's default constructor to do anything you want (in this case zero)
38
39template <class R>
40class zero_default
41{
42public:
43 typedef R rep;
44
45private:
46 rep rep_;
47public:
48 zero_default(rep i = 0) : rep_(i) {}
49 operator rep() const {return rep_;}
50
51 zero_default& operator+=(zero_default x) {rep_ += x.rep_; return *this;}
52 zero_default& operator-=(zero_default x) {rep_ -= x.rep_; return *this;}
53 zero_default& operator*=(zero_default x) {rep_ *= x.rep_; return *this;}
54 zero_default& operator/=(zero_default x) {rep_ /= x.rep_; return *this;}
55
56 zero_default operator+ () const {return *this;}
57 zero_default operator- () const {return zero_default(-rep_);}
58 zero_default& operator++() {++rep_; return *this;}
59 zero_default operator++(int) {return zero_default(rep_++);}
60 zero_default& operator--() {--rep_; return *this;}
61 zero_default operator--(int) {return zero_default(rep_--);}
62
63 friend zero_default operator+(zero_default x, zero_default y) {return x += y;}
64 friend zero_default operator-(zero_default x, zero_default y) {return x -= y;}
65 friend zero_default operator*(zero_default x, zero_default y) {return x *= y;}
66 friend zero_default operator/(zero_default x, zero_default y) {return x /= y;}
67
68 friend bool operator==(zero_default x, zero_default y) {return x.rep_ == y.rep_;}
69 friend bool operator!=(zero_default x, zero_default y) {return !(x == y);}
70 friend bool operator< (zero_default x, zero_default y) {return x.rep_ < y.rep_;}
71 friend bool operator<=(zero_default x, zero_default y) {return !(y < x);}
72 friend bool operator> (zero_default x, zero_default y) {return y < x;}
73 friend bool operator>=(zero_default x, zero_default y) {return !(x < y);}
74};
75
76typedef boost::chrono::duration<zero_default<long long>, boost::nano > nanoseconds;
77typedef boost::chrono::duration<zero_default<long long>, boost::micro > microseconds;
78typedef boost::chrono::duration<zero_default<long long>, boost::milli > milliseconds;
79typedef boost::chrono::duration<zero_default<long long> > seconds;
80typedef boost::chrono::duration<zero_default<long long>, boost::ratio<60> > minutes;
81typedef boost::chrono::duration<zero_default<long long>, boost::ratio<3600> > hours;
82
83void test()
84{
85 milliseconds ms;
86 std::cout << ms.count() << '\n';
87}
88
89} // I_dont_like_the_default_duration_behavior
90
91
92int main()
93{
94 I_dont_like_the_default_duration_behavior::test();
95 return 0;
96}
97
98

source code of boost/libs/chrono/example/i_dont_like_the_default_duration_behavior.cpp