CppQuickStart/utils.hpp

#ifndef DEF_utils
#define DEF_utils

#include <ostream>
#include <utility>

#define PRINT_VAR(x) std::cout << #x << "\t= " << (x) << "\n"
#define PRINT_VEC(x);	{std::cout << #x << "\t= "; \
						for(unsigned int i_print_vec = 0 ; i_print_vec < (x).size() ; i_print_vec++) \
							std::cout << (x)[i_print_vec] << "\t"; \
						std::cout << "\n";}
#define PRINT_STR(x) std::cout << (x) << "\n"

template<typename T, typename T2> auto min(const T & a, const T2 & b) -> decltype(a | b) { return (a < b) ? T(a) : T(b); }
template<typename T, typename T2> auto max(const T & a, const T2 & b) -> decltype(a | b) { return (a < b) ? T(b) : T(a); }

/// To be sure that floating point numbers won't be casted to integers in ::abs()...
template<typename T> T sureAbs(const T & x) { return (x < T(0)) ? -x : x; }


/*
/// Generic operator<< for ostream, (to print std::vector, etd::list, std::map, etc). Can generate conflicts with specialized operator<< overloads.
template<typename T, template<class,class...> class C, class... Args>
std::ostream& operator<<(std::ostream& os, const C<T,Args...>& objs)
{
    for (auto const& obj : objs)
        os << obj << ' ';
    return os;
}//*/

/// define UTILS_NO_CHRONO to deactivate chronometer
#ifndef UTILS_NO_CHRONO

#include <iostream>
#include <chrono>
#include <ratio>
#include <ctime>

/// Convenience macro to create a Chronometer object that will measure the execution time of its scope.
#define TIMER(str) Chronometer __chrono((str))

/// Convenience macro to create a Chronometer object that will measure the execution time of its scope, with a for-loop enveloping the code to time.
///
/// Usage : TIMER_FOR("My timer", N, /* The code will be executed N times ! */)
#define TIMER_FOR(str, N, code) {Chronometer __chrono((str)); for(size_t i_TIMER_FOR = 0 ; i_TIMER_FOR < N ; i_TIMER_FOR++) {code} }

/// \class Chronometer class. Used to measure the execution time of its scope.
///
/// Usage :
/// \code{.cpp}
/// {
///     TIMER("My timer");
///     /* some code to be profiled */
/// }// <--- the chronometer measures the time between the call to its constructor and the call to its destructor.
/// \endcode
///
/// Possible output :
///
///     My timer : 0.12317568 s (+/- 1e-09 s)
///
/// Alternate usage :
/// \code{.cpp}
/// {
///	    Chronometer chronom("", false);
///	    /* some code to time */
///	    chronom.MeasureTimeElapsed();// prints how much time elapsed since the creation of the object
///	    /* some code to time */
///	    chronom.MeasureTimeElapsed();// prints how much time elapsed since the creation of the object
///	    chronom.Reset();// resets the timer to 0
///	    /* some code to time */
///	    chronom.MeasureTimeElapsed();// prints how much time elapsed since the last reset
/// } // no message is displayed because displayAtDestruction_ is set to false
/// \endcode
///
template<int T=1>
struct Chronometer
{
	std::string name;
	std::chrono::high_resolution_clock::time_point t0;
	bool displayAtDestruction;

	/// Creates the Chronometer object with the provided name and stores the time.
	///
	/// \param name_                        : Name to display
	/// \param displayAtDestruction_        : if true, a message is printed to the console during the destruction of the object.
	Chronometer(const std::string & name_ = "", bool displayAtDestruction_ = true)
		:	name(name_),
			t0(std::chrono::high_resolution_clock::now()),
			displayAtDestruction(displayAtDestruction_)
	{}

	/// Measures the time elapsed between the creation of the object and its destruction, and prints the result in std::cout.
	~Chronometer() { if(displayAtDestruction) { MeasureTimeElapsed(); } }

	/// Resets the timer. Allows the measurement of the execution time of several sub-intervals in the current scope.
	void Reset() { t0 = std::chrono::high_resolution_clock::now(); }

	double GetTime() const
	{
		std::chrono::high_resolution_clock::time_point t1 = std::chrono::high_resolution_clock::now();
		std::chrono::duration<double> time_span = std::chrono::duration_cast<std::chrono::duration<double>>(t1 - t0);
		return time_span.count();
	}

	double GetResolution() const
	{
		auto resolution_ratio = std::chrono::high_resolution_clock::period();
		return double(resolution_ratio.num)/resolution_ratio.den;
	}

	/// Measures the time elapsed between the creation of the object and its destruction, and prints the result in std::cout.
	void MeasureTimeElapsed() const
	{
		// measure time since object creation and print it in the console
		std::cout.precision(16);
		std::cout << name.c_str() << "\t: " << GetTime() << " s (+/- " << GetResolution() << " s)" << std::endl;// use of c_str() so that there is no ambiguity with the generic operator<<
	}
};

#else// chronometer
	#define TIMER(str)
	#define TIMER_FOR(str, N, code) { for(size_t i_TIMER_FOR = 0 ; i_TIMER_FOR < N ; i_TIMER_FOR++) {code} }
#endif// chronometer

#endif