CMake/Source/cmDuration.h
Wouter Klouwen ff62b00522 CTest: add safe conversion from cmDuration to integer types
A problem area by recent refactoring of time to std::chrono has been the
unsafe conversion from duration<double> to std::chrono::seconds, which
is of an unspecified integer type.

This commit adds a template function that for a given type provides a
safe conversion, effectively clamping a duration<double> into what fits
safely in that type. A specialisation for int and unsigned int are
provided.

It changes the protential problem areas to use this safe function.
2018-01-23 10:05:12 -05:00

25 lines
845 B
C++

/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
file Copyright.txt or https://cmake.org/licensing for details. */
#pragma once
#include <chrono>
#include <ratio>
typedef std::chrono::duration<double, std::ratio<1>> cmDuration;
/*
* This function will return number of seconds in the requested type T.
*
* A duration_cast from duration<double> to duration<T> will not yield what
* one might expect if the double representation does not fit into type T.
* This function aims to safely convert, by clamping the double value between
* the permissible valid values for T.
*/
template <typename T>
T cmDurationTo(const cmDuration& duration);
#ifndef CMDURATION_CPP
extern template int cmDurationTo<int>(const cmDuration&);
extern template unsigned int cmDurationTo<unsigned int>(const cmDuration&);
#endif