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// Copyright (c) 1997
// Utrecht University (The Netherlands),
// ETH Zurich (Switzerland),
// INRIA Sophia-Antipolis (France),
// Max-Planck-Institute Saarbruecken (Germany),
// and Tel-Aviv University (Israel). All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1/Profiling_tools/include/CGAL/Real_timer_impl.h $
// $Id: include/CGAL/Real_timer_impl.h b26b07a1242 $
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s) : Lutz Kettner <kettner@inf.ethz.ch>
// Matthias Baesken <baesken@informatik.uni-halle.de>
#ifdef CGAL_HEADER_ONLY
#define CGAL_INLINE_FUNCTION inline
#else
#define CGAL_INLINE_FUNCTION
#endif
#if defined (_MSC_VER)
# include <sys/timeb.h>
# include <sys/types.h>
#elif defined (__MINGW32__)
# include <sys/timeb.h>
# include <sys/types.h>
#else
// If none of the above PC compilers, use POSIX fct. gettimeofday()
# include <sys/time.h>
#endif
namespace CGAL {
// Member functions for Real_timer
// =====================================
CGAL_INLINE_FUNCTION
double Real_timer::get_real_time() const {
// Depends on the operating system.
// Returns a (weakly ;-) monotone increasing time in seconds (with
// possible wrap-around in case of overflow, see max()), or 0.0
// if the system call for the time failed. If the system call
// failed the static flag 'm_failed' is set and can be used
// by the caller.
#if defined(_MSC_VER)
struct _timeb t;
_ftime_s(&t);
return double(t.time) + double(t.millitm) / 1000.0;
#elif defined (__MINGW32__)
struct timeb t;
ftime(&t);
return double(t.time) + double(t.millitm) / 1000.0;
#else // ! _MSC_VER && ! __MINGW32__//
struct timeval t;
int ret = gettimeofday( &t, nullptr);
CGAL_warning_msg( ret == 0, "Call to gettimeofday() in class "
"CGAL::Real_timer failed - timings will be 0.");
if ( ret == 0) {
return double(t.tv_sec) + double(t.tv_usec) / 1000000;
}
get_static_realtimer_m_failed() = true;
return 0.0;
#endif // ! _MSC_VER && ! __MINGW32__//
}
CGAL_INLINE_FUNCTION
double Real_timer::compute_precision() const {
// Computes timer precision in seconds dynamically. Note that
// the timer system call is probably non-trivial and will show
// up in this time here (probably for one call). But that is just
// fine that the call to the timer itself if reported as noise
// in the precision.
double min_res = DBL_MAX;
for ( int i = 0; i < 5; ++i) {
double current = get_real_time();
if ( get_static_realtimer_m_failed() )
return -1.0;
double next = get_real_time();
while ( current >= next) { // wait until timer increases
next = get_real_time();
if ( get_static_realtimer_m_failed() )
return -1.0;
}
// Get the minimum timing difference of all runs.
if ( min_res > next - current)
min_res = next - current;
}
return min_res;
}
CGAL_INLINE_FUNCTION
double Real_timer::precision() const {
// computes precision upon first call
// returns -1.0 if timer system call fails.
static double prec = compute_precision();
return prec;
}
} //namespace CGAL
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