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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information (qt-info@nokia.com)
**
** This file is part of the BM project on Qt Labs.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 or 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file. Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
** http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at qt-sales@nokia.com.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/
#include "resulthistoryinfo.h"
#include "bmmisc.h"
// ### 2 B DOCUMENTED!
bool ResultHistoryInfo::findTargetPos(
int timestamp, int medianWinSize, int *pos, qreal *distSum) const
{
int pos_ = -1;
// Find target position ...
QList<int>::const_iterator it = qLowerBound(timestamps_.begin(), timestamps_.end(), timestamp);
if (it == timestamps_.begin()) {
Q_ASSERT(timestamp <= timestamps_.first());
if (timestamp == timestamps_.first())
pos_ = 0;
} else if (it == timestamps_.end()) {
Q_ASSERT(timestamp > timestamps_.last());
pos_ = timestamps_.size() - 1;
} else {
Q_ASSERT(timestamp > *(it - 1));
pos_ = (it - 1) - timestamps_.begin();
}
Q_ASSERT(pos_ >= -1);
Q_ASSERT(pos_ < timestamps_.size());
// Return true iff the target position is high enough to accommodate a right-aligned window
// (i.e. a window in which the target value is the rightmost value) ...
if ((pos_ + 1) >= medianWinSize) {
if (pos)
*pos = pos_;
if (distSum) {
// Compute sum of distances to the contributing values ...
*distSum = 0.0;
for (int i = (pos_ - medianWinSize) + 1; i <= pos_; ++i) {
Q_ASSERT(timestamps_.at(i) <= timestamp);
(*distSum) += static_cast<qreal>((timestamp - timestamps_.at(i)));
}
}
return true;
}
return false;
}
// Returns true iff at least \a medianWinSize values exist at or before
// \a timestamp. Passes the zero-based position of the smoothed value (if found) in \a smoothPos.
// If \a cache is true, the previously cached position will be replaced (or initially recorded).
// (Note that the cache capacity is 1, which explains why the \a cache argument needs to be
// passed; only the client knows which timestamp is likely to be requested multiple times!)
// If \a distSum is non-null, it will be set to the sum of the distances between \a timestamp
// and the timestamp of each contributing value.
bool ResultHistoryInfo::getSmoothPos(
int timestamp, int medianWinSize, int *smoothPos, bool cache, qreal *distSum) const
{
Q_ASSERT(timestamp >= 0);
Q_ASSERT(medianWinSize > 0);
if (medianWinSize > timestamps_.size())
return false;
// Return cached position if possible ...
if (timestamp == cachedTimestamp) {
*smoothPos = cachedSmoothPos;
return true;
}
// Find a valid target position if possible ...
int pos = -1;
if (!findTargetPos(timestamp, medianWinSize, &pos, distSum)) {
if (cache)
cachedTimestamp = -1; // Invalidate cache
return false;
}
// Compute value ...
const int lo = (pos - medianWinSize) + 1;
*smoothPos = lo + BMMisc::medianPos(values.mid(lo, medianWinSize));
if (cache) {
// Load cache ...
cachedSmoothPos = *smoothPos;
cachedTimestamp = timestamp;
}
return true;
}
// ### 2 B DOCUMENTED!
bool ResultHistoryInfo::getSmoothValues(int medianWinSize, QList<qreal> *smoothValues) const
{
Q_ASSERT(medianWinSize > 0);
Q_ASSERT(timestamps_.size() == values.size());
Q_ASSERT(smoothValues);
if (timestamps_.isEmpty())
return false;
smoothValues->clear();
for (int pos = 0; pos < timestamps_.size(); ++pos) {
int lo = pos;
int hi = pos;
while (true) {
Q_ASSERT((hi - lo) + 1 <= medianWinSize);
if ((hi - lo) + 1 == medianWinSize) break;
lo = qMax(lo - 1, 0);
if ((hi - lo) + 1 == medianWinSize) break;
hi = qMin(hi + 1, values.size() - 1);
if ((hi - lo) + 1 == medianWinSize) break;
}
const qreal smoothValue = BMMisc::median(values.mid(lo, (hi - lo) + 1));
smoothValues->append(smoothValue);
}
return true;
}
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