aria2/src/SpeedCalc.cc

116 lines
3.2 KiB
C++

/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "SpeedCalc.h"
#include <algorithm>
#include <functional>
#include "wallclock.h"
namespace aria2 {
#define WINDOW_MSEC 15000
SpeedCalc::SpeedCalc()
: accumulatedLength_(0),
bytesWindow_(0),
maxSpeed_(0)
{}
void SpeedCalc::reset()
{
timeSlots_.clear();
start_ = global::wallclock();
accumulatedLength_ = 0;
bytesWindow_ = 0;
maxSpeed_ = 0;
}
void SpeedCalc::removeStaleTimeSlot(int64_t now)
{
while(!timeSlots_.empty()) {
if(now - timeSlots_[0].first <= WINDOW_MSEC) {
break;
} else {
bytesWindow_ -= timeSlots_[0].second;
timeSlots_.pop_front();
}
}
}
int SpeedCalc::calculateSpeed()
{
int64_t now = global::wallclock().getTimeInMillis();
removeStaleTimeSlot(now);
if(timeSlots_.empty()) {
return 0;
}
int64_t elapsed = now - timeSlots_[0].first;
if(elapsed <= 0) {
elapsed = 1;
}
int speed = bytesWindow_*1000/elapsed;
maxSpeed_ = std::max(speed, maxSpeed_);
return speed;
}
void SpeedCalc::update(size_t bytes)
{
int64_t now = global::wallclock().getTimeInMillis();
removeStaleTimeSlot(now);
if(timeSlots_.empty() || now/1000 != timeSlots_.back().first/1000) {
timeSlots_.push_back(std::make_pair(now, bytes));
} else {
timeSlots_.back().second += bytes;
}
bytesWindow_ += bytes;
accumulatedLength_ += bytes;
}
int SpeedCalc::calculateAvgSpeed() const
{
int64_t milliElapsed = start_.differenceInMillis(global::wallclock());
// if milliElapsed is too small, the average speed is rubish, better
// return 0
if(milliElapsed > 4) {
int speed = accumulatedLength_*1000/milliElapsed;
return speed;
} else {
return 0;
}
}
} // namespace aria2