141 lines
4.5 KiB
C++
Executable File
141 lines
4.5 KiB
C++
Executable File
// Copyright (c) 1997
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// Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland),
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// INRIA Sophia-Antipolis (France),
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// Max-Planck-Institute Saarbruecken (Germany),
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// and Tel-Aviv University (Israel). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; either version 3 of the License,
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// or (at your option) any later version.
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//
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// Licensees holding a valid commercial license may use this file in
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// accordance with the commercial license agreement provided with the software.
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//
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// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// $URL$
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// $Id$
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// SPDX-License-Identifier: LGPL-3.0+
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//
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//
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// Author(s) : Lutz Kettner <kettner@inf.ethz.ch>
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// Matthias Baesken <baesken@informatik.uni-halle.de>
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#ifdef CGAL_HEADER_ONLY
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#define CGAL_INLINE_FUNCTION inline
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#else
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#define CGAL_INLINE_FUNCTION
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#endif
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// Determine if the POSIX function getrusage is available, otherwise
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// use the previous solution based on std::clock().
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// First, detect POSIX. We cannot reliably use "unistd.h",
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// but limits.h is part of the C standard.
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#include <climits>
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#ifdef _POSIX_ARG_MAX // now that should be POSIX
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#include <unistd.h>
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#ifdef _POSIX_VERSION
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#ifdef _XOPEN_UNIX // XSI: X/Open System Interfaces Extension
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#define CGAL__GETRUSAGE 1
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#endif
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#endif
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#endif
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#ifdef CGAL__GETRUSAGE
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// types, function prototype and constants for the POSIX function
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// int getrusage (int who, struct rusage *usage);
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#include <sys/resource.h>
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// For the numerical limits
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#else // CGAL__GETRUSAGE //
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// used for clock()
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#include <ctime>
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#endif // CGAL__GETRUSAGE //
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// For the numerical limits
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#include <cfloat>
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namespace CGAL {
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// Member functions for Timer
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// =====================================
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CGAL_INLINE_FUNCTION
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double Timer::user_process_time() const {
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// Depends on the operating system.
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// Returns a (weakly ;-) monotone increasing time in seconds (with
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// possible wrap-around in case of overflow, see max()), or 0.0
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// if the system call for the time failed. If the system call
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// failed the static flag 'm_failed' is set and can be used
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// by the caller.
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#ifdef CGAL__GETRUSAGE
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struct rusage usage;
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int ret = getrusage( RUSAGE_SELF, &usage);
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CGAL_warning_msg( ret == 0, "Call to getrusage() in class CGAL::Timer "
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"failed - timings will be 0.");
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if ( ret == 0) {
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return double( usage.ru_utime.tv_sec) // seconds
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+ double( usage.ru_utime.tv_usec) / 1000000.0; // microseconds
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}
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#else // CGAL__GETRUSAGE //
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std::clock_t clk = std::clock();
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CGAL_warning_msg( clk != (std::clock_t)-1,
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"Call to clock() in class CGAL::Timer failed - timings will be 0.");
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if ( clk != (std::clock_t)-1) {
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return double(clk) / CLOCKS_PER_SEC;
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}
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#endif // CGAL__GETRUSAGE //
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get_static_timer_m_failed() = true;
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return 0.0;
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}
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CGAL_INLINE_FUNCTION
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double Timer::compute_precision() const {
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// Computes timer precision in seconds dynamically. Note that
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// the timer system call is probably non-trivial and will show
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// up in this time here (probably for one call). But that is just
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// fine that the call to the timer itself if reported as noise
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// in the precision.
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double min_res = DBL_MAX;
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for ( int i = 0; i < 5; ++i) {
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double current = user_process_time();
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if ( get_static_timer_m_failed() )
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return -1.0;
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double next = user_process_time();
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while ( current >= next) { // wait until timer increases
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next = user_process_time();
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if ( get_static_timer_m_failed() )
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return -1.0;
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}
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// Get the minimum timing difference of all runs.
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if ( min_res > next - current)
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min_res = next - current;
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}
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return min_res;
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}
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CGAL_INLINE_FUNCTION
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double Timer::precision() const {
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// computes precision upon first call
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// returns -1.0 if timer system call fails.
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static double prec = compute_precision();
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return prec;
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}
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CGAL_INLINE_FUNCTION
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double Timer::max BOOST_PREVENT_MACRO_SUBSTITUTION () const {
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// Depends on the operating system.
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#ifdef CGAL__GETRUSAGE
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return DBL_MAX;
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#else // CGAL__GETRUSAGE //
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return 2146.0;
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#endif // CGAL__GETRUSAGE //
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}
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} //namespace CGAL
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// EOF //
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