aria2/src/SpeedCalc.cc

118 lines
3.6 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 CHANGE_INTERVAL_SEC 15
SpeedCalc::SpeedCalc():sw_(0), maxSpeed_(0), prevSpeed_(0),
accumulatedLength_(0),
nextInterval_(CHANGE_INTERVAL_SEC)
{
std::fill(&lengthArray_[0], &lengthArray_[2], 0);
}
void SpeedCalc::reset() {
std::fill(&lengthArray_[0], &lengthArray_[2], 0);
std::fill(&cpArray_[0], &cpArray_[2], global::wallclock);
sw_ = 0;
maxSpeed_ = 0;
prevSpeed_ = 0;
start_ = global::wallclock;
accumulatedLength_ = 0;
nextInterval_ = CHANGE_INTERVAL_SEC;
}
unsigned int SpeedCalc::calculateSpeed() {
int64_t milliElapsed = cpArray_[sw_].differenceInMillis(global::wallclock);
if(milliElapsed) {
unsigned int speed = lengthArray_[sw_]*1000/milliElapsed;
prevSpeed_ = speed;
maxSpeed_ = std::max(speed, maxSpeed_);
if(isIntervalOver(milliElapsed)) {
changeSw();
}
return speed;
} else {
return prevSpeed_;
}
}
void SpeedCalc::update(size_t bytes) {
accumulatedLength_ += bytes;
std::transform(&lengthArray_[0], &lengthArray_[2], &lengthArray_[0],
std::bind1st(std::plus<uint64_t>(), (uint64_t)bytes));
if(isIntervalOver()) {
changeSw();
}
}
bool SpeedCalc::isIntervalOver() const {
return nextInterval_ <= cpArray_[sw_].difference(global::wallclock);
}
bool SpeedCalc::isIntervalOver(int64_t milliElapsed) const
{
return nextInterval_ <= milliElapsed/1000;
}
void SpeedCalc::changeSw() {
lengthArray_[sw_] = 0;
cpArray_[sw_] = global::wallclock;
sw_ ^= 0x01u;
nextInterval_ =
cpArray_[sw_].difference(global::wallclock)+CHANGE_INTERVAL_SEC;
}
unsigned int SpeedCalc::calculateAvgSpeed() const {
uint64_t milliElapsed = start_.differenceInMillis(global::wallclock);
// if milliElapsed is too small, the average speed is rubish, better return 0
if(milliElapsed > 4) {
unsigned int speed = accumulatedLength_*1000/milliElapsed;
return speed;
} else {
return 0;
}
}
} // namespace aria2