//--------------------------------------------------------------------------------------
// Copyright 2011 Intel Corporation
// All Rights Reserved
//
// Permission is granted to use, copy, distribute and prepare derivative works of this
// software for any purpose and without fee, provided, that the above copyright notice
// and this statement appear in all copies.  Intel makes no representations about the
// suitability of this software for any purpose.  THIS SOFTWARE IS PROVIDED "AS IS."
// INTEL SPECIFICALLY DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, AND ALL LIABILITY,
// INCLUDING CONSEQUENTIAL AND OTHER INDIRECT DAMAGES, FOR THE USE OF THIS SOFTWARE,
// INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PROPRIETARY RIGHTS, AND INCLUDING THE
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  Intel does not
// assume any responsibility for any errors which may appear in this software nor any
// responsibility to update it.
//
//--------------------------------------------------------------------------------------

#include "StopWatch.h"
#include "TexCompTypes.h"

#include <cassert>

class StopWatchImpl {
  uint64 frequency;
  uint64 start;
  uint64 stop;
  uintptr affinityMask;

  StopWatchImpl() :
    start(0), stop(0), affinityMask(0)
  {
    // Initialize the performance counter frequency.
    LARGE_INTEGER perfQuery;
    BOOL supported = QueryPerformanceFrequency(&perfQuery);
    assert(supported == TRUE);
    this->frequency = perfQuery.QuadPart;
  }
};

StopWatch::StopWatch(const StopWatch &other) {
  impl = new StopWatchImpl();
  memcpy(impl, other.impl, sizeof(StopWatchImpl));
}

StopWatch &StopWatch::operator=(const StopWatch &other) {
  if(impl) {
    delete impl;
  }
  impl = new StopWatchImpl();
  memcpy(impl, other.impl, sizeof(StopWatchImpl));
}

StopWatch::~StopWatch() {
  delete impl;
}

// Start the stopwatch.
void StopWatch::Start()
{
  // MSDN recommends setting the thread affinity to avoid bugs in the BIOS and HAL.
  // Create an affinity mask for the current processor.
  impl->affinityMask = (DWORD_PTR)1 << GetCurrentProcessorNumber();
  HANDLE currThread = GetCurrentThread();
  DWORD_PTR prevAffinityMask = SetThreadAffinityMask(currThread, impl->affinityMask);
  assert(prevAffinityMask != 0);

  // Query the performance counter.
  LARGE_INTEGER perfQuery;
  BOOL result = QueryPerformanceCounter(&perfQuery);
  assert(result);
  impl->start = perfQuery.QuadPart;

  // Restore the thread's affinity mask.
  prevAffinityMask = SetThreadAffinityMask(currThread, prevAffinityMask);
  assert(prevAffinityMask != 0);
}

// Stop the stopwatch.
void StopWatch::Stop()
{
  // MSDN recommends setting the thread affinity to avoid bugs in the BIOS and HAL.
  // Use the affinity mask that was created in the Start function.
  HANDLE currThread = GetCurrentThread();
  DWORD_PTR prevAffinityMask = SetThreadAffinityMask(currThread, impl->affinityMask);
  assert(prevAffinityMask != 0);

  // Query the performance counter.
  LARGE_INTEGER perfQuery;
  BOOL result = QueryPerformanceCounter(&perfQuery);
  assert(result);
  impl->stop = perfQuery.QuadPart;

  // Restore the thread's affinity mask.
  prevAffinityMask = SetThreadAffinityMask(currThread, prevAffinityMask);
  assert(prevAffinityMask != 0);
}

// Reset the stopwatch.
void StopWatch::Reset()
{
  impl->start = 0;
  impl->stop = 0;
  impl->affinityMask = 0;
}

// Get the elapsed time in seconds.
double StopWatch::TimeInSeconds() const
{
  // Return the elapsed time in seconds.
  assert((impl->stop - impl->start) > 0);
  return double(impl->stop - impl->start) / double(frequency);
}

// Get the elapsed time in milliseconds.
double StopWatch::TimeInMilliseconds() const
{
  // Return the elapsed time in milliseconds.
  assert((impl->stop - impl->start) > 0);
  return double(impl->stop - impl->start) / double(frequency) * 1000.0;
}

// Get the elapsed time in microseconds.
double StopWatch::TimeInMicroseconds() const
{
  // Return the elapsed time in microseconds.
  assert((impl->stop - impl->start) > 0);
  return double(impl->stop - impl->start) / double(impl->frequency) * 1000000.0;
}