// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2009 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_BENCH_TIMERR_H
#define EIGEN_BENCH_TIMERR_H

#if defined(_WIN32) || defined(__CYGWIN__)
# ifndef NOMINMAX
#   define NOMINMAX
#   define EIGEN_BT_UNDEF_NOMINMAX
# endif
# ifndef WIN32_LEAN_AND_MEAN
#   define WIN32_LEAN_AND_MEAN
#   define EIGEN_BT_UNDEF_WIN32_LEAN_AND_MEAN
# endif
# include <windows.h>
#elif defined(__APPLE__)
#include <mach/mach_time.h>
#else
# include <unistd.h>
#endif

static void escape(void *p) {
  asm volatile("" : : "g"(p) : "memory");
}

static void clobber() {
  asm volatile("" : : : "memory");
}

#include <Eigen/Core>

namespace Eigen
{

enum {
  CPU_TIMER = 0,
  REAL_TIMER = 1
};

/** Elapsed time timer keeping the best try.
  *
  * On POSIX platforms we use clock_gettime with CLOCK_PROCESS_CPUTIME_ID.
  * On Windows we use QueryPerformanceCounter
  *
  * Important: on linux, you must link with -lrt
  */
class BenchTimer
{
public:

  BenchTimer()
  {
#if defined(_WIN32) || defined(__CYGWIN__)
    LARGE_INTEGER freq;
    QueryPerformanceFrequency(&freq);
    m_frequency = (double)freq.QuadPart;
#endif
    reset();
  }

  ~BenchTimer() {}

  inline void reset()
  {
    m_bests.fill(1e9);
    m_worsts.fill(0);
    m_totals.setZero();
  }
  inline void start()
  {
    m_starts[CPU_TIMER]  = getCpuTime();
    m_starts[REAL_TIMER] = getRealTime();
  }
  inline void stop()
  {
    m_times[CPU_TIMER] = getCpuTime() - m_starts[CPU_TIMER];
    m_times[REAL_TIMER] = getRealTime() - m_starts[REAL_TIMER];
    #if EIGEN_VERSION_AT_LEAST(2,90,0)
    m_bests = m_bests.cwiseMin(m_times);
    m_worsts = m_worsts.cwiseMax(m_times);
    #else
    m_bests(0) = std::min(m_bests(0),m_times(0));
    m_bests(1) = std::min(m_bests(1),m_times(1));
    m_worsts(0) = std::max(m_worsts(0),m_times(0));
    m_worsts(1) = std::max(m_worsts(1),m_times(1));
    #endif
    m_totals += m_times;
  }

  /** Return the elapsed time in seconds between the last start/stop pair
    */
  inline double value(int TIMER = CPU_TIMER) const
  {
    return m_times[TIMER];
  }

  /** Return the best elapsed time in seconds
    */
  inline double best(int TIMER = CPU_TIMER) const
  {
    return m_bests[TIMER];
  }

  /** Return the worst elapsed time in seconds
    */
  inline double worst(int TIMER = CPU_TIMER) const
  {
    return m_worsts[TIMER];
  }

  /** Return the total elapsed time in seconds.
    */
  inline double total(int TIMER = CPU_TIMER) const
  {
    return m_totals[TIMER];
  }

  inline double getCpuTime() const
  {
#ifdef _WIN32
    LARGE_INTEGER query_ticks;
    QueryPerformanceCounter(&query_ticks);
    return query_ticks.QuadPart/m_frequency;
#elif __APPLE__
    return double(mach_absolute_time())*1e-9;
#else
    timespec ts;
    clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
    return double(ts.tv_sec) + 1e-9 * double(ts.tv_nsec);
#endif
  }

  inline double getRealTime() const
  {
#ifdef _WIN32
    SYSTEMTIME st;
    GetSystemTime(&st);
    return (double)st.wSecond + 1.e-3 * (double)st.wMilliseconds;
#elif __APPLE__
    return double(mach_absolute_time())*1e-9;
#else
    timespec ts;
    clock_gettime(CLOCK_REALTIME, &ts);
    return double(ts.tv_sec) + 1e-9 * double(ts.tv_nsec);
#endif
  }

protected:
#if defined(_WIN32) || defined(__CYGWIN__)
  double m_frequency;
#endif
  Vector2d m_starts;
  Vector2d m_times;
  Vector2d m_bests;
  Vector2d m_worsts;
  Vector2d m_totals;

public:
  EIGEN_MAKE_ALIGNED_OPERATOR_NEW
};

#define BENCH(TIMER,TRIES,REP,CODE) { \
    TIMER.reset(); \
    for(int uglyvarname1=0; uglyvarname1<TRIES; ++uglyvarname1){ \
      TIMER.start(); \
      for(int uglyvarname2=0; uglyvarname2<REP; ++uglyvarname2){ \
        CODE; \
      } \
      TIMER.stop(); \
      clobber(); \
    } \
  }

}

// clean #defined tokens
#ifdef EIGEN_BT_UNDEF_NOMINMAX
# undef EIGEN_BT_UNDEF_NOMINMAX
# undef NOMINMAX
#endif

#ifdef EIGEN_BT_UNDEF_WIN32_LEAN_AND_MEAN
# undef EIGEN_BT_UNDEF_WIN32_LEAN_AND_MEAN
# undef WIN32_LEAN_AND_MEAN
#endif

#endif // EIGEN_BENCH_TIMERR_H