/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* 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/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#include <segmenttree.hxx>
#include <o3tl/safeint.hxx>
#include <mdds/flat_segment_tree.hpp>
#include <sal/log.hxx>
#include <algorithm>
#include <limits>
#include <string_view>
#include <global.hxx>
#include <rtl/strbuf.hxx>
using ::std::numeric_limits;
namespace {
template<typename ValueType_, typename ExtValueType_ = ValueType_>
class ScFlatSegmentsImpl
{
public:
typedef ValueType_ ValueType;
typedef ExtValueType_ ExtValueType;
struct RangeData
{
SCCOLROW mnPos1;
SCCOLROW mnPos2;
ValueType mnValue;
};
ScFlatSegmentsImpl(SCCOLROW nMax, ValueType nDefault);
ScFlatSegmentsImpl(const ScFlatSegmentsImpl& r);
bool setValue(SCCOLROW nPos1, SCCOLROW nPos2, ValueType nValue);
void setValueIf(SCCOLROW nPos1, SCCOLROW nPos2, ValueType nValue, const std::function<bool(ValueType)>& rPredicate);
ValueType getValue(SCCOLROW nPos);
sal_uInt64 getSumValue(SCCOLROW nPos1, SCCOLROW nPos2);
bool getRangeData(SCCOLROW nPos, RangeData& rData);
bool getRangeDataLeaf(SCCOLROW nPos, RangeData& rData);
void removeSegment(SCCOLROW nPos1, SCCOLROW nPos2);
void insertSegment(SCCOLROW nPos, SCCOLROW nSize, bool bSkipStartBoundary);
SCCOLROW findLastTrue(ValueType nValue) const;
// range iteration
bool getFirst(RangeData& rData);
bool getNext(RangeData& rData);
void enableTreeSearch(bool b)
{
mbTreeSearchEnabled = b;
}
void makeReady();
private:
typedef ::mdds::flat_segment_tree<SCCOLROW, ValueType> fst_type;
fst_type maSegments;
typename fst_type::const_iterator maItr;
bool mbTreeSearchEnabled:1;
};
}
template<typename ValueType_, typename ExtValueType_>
ScFlatSegmentsImpl<ValueType_, ExtValueType_>::ScFlatSegmentsImpl(SCCOLROW nMax, ValueType nDefault) :
maSegments(0, nMax+1, nDefault),
mbTreeSearchEnabled(true)
{
}
template<typename ValueType_, typename ExtValueType_>
ScFlatSegmentsImpl<ValueType_, ExtValueType_>::ScFlatSegmentsImpl(const ScFlatSegmentsImpl<ValueType_, ExtValueType_>& r) :
maSegments(r.maSegments),
mbTreeSearchEnabled(r.mbTreeSearchEnabled)
{
}
template<typename ValueType_, typename ExtValueType_>
bool ScFlatSegmentsImpl<ValueType_, ExtValueType_>::setValue(SCCOLROW nPos1, SCCOLROW nPos2, ValueType nValue)
{
::std::pair<typename fst_type::const_iterator, bool> ret;
ret = maSegments.insert(maItr, nPos1, nPos2+1, nValue);
maItr = ret.first;
return ret.second;
}
template<typename ValueType_, typename ExtValueType_>
void ScFlatSegmentsImpl<ValueType_, ExtValueType_>::setValueIf(SCCOLROW nPos1, SCCOLROW nPos2,
ValueType nValue, const std::function<bool(ValueType)>& rPredicate)
{
SCCOLROW nCurrentStartRow = nPos1;
while (nCurrentStartRow <= nPos2)
{
RangeData aRangeData;
getRangeData(nCurrentStartRow, aRangeData);
if (rPredicate(aRangeData.mnValue))
{
// set value from current iteration point on, til end of range.
// Note that aRangeData may well contain much lower values for nPos1
setValue(nCurrentStartRow, std::min<SCCOLROW>(nPos2, aRangeData.mnPos2), nValue);
}
// even if nPos2 is bigger than nPos2 this should terminate the loop
nCurrentStartRow = aRangeData.mnPos2 + 1;
}
}
template<typename ValueType_, typename ExtValueType_>
typename ScFlatSegmentsImpl<ValueType_, ExtValueType_>::ValueType ScFlatSegmentsImpl<ValueType_, ExtValueType_>::getValue(SCCOLROW nPos)
{
ValueType nValue = 0;
if (!mbTreeSearchEnabled)
{
maSegments.search(nPos, nValue);
return nValue;
}
if (!maSegments.is_tree_valid())
{
assert(!ScGlobal::bThreadedGroupCalcInProgress);
maSegments.build_tree();
}
maSegments.search_tree(nPos, nValue);
return nValue;
}
template<typename ValueType_, typename ExtValueType_>
sal_uInt64 ScFlatSegmentsImpl<ValueType_, ExtValueType_>::getSumValue(SCCOLROW nPos1, SCCOLROW nPos2)
{
if (mbTreeSearchEnabled)
{
if (!maSegments.is_tree_valid())
{
assert(!ScGlobal::bThreadedGroupCalcInProgress);
maSegments.build_tree();
}
RangeData aData;
auto [it, found] = maSegments.search_tree(nPos1, aData.mnValue, &aData.mnPos1, &aData.mnPos2);
if (!found)
return 0;
aData.mnPos2 = aData.mnPos2-1; // end point is not inclusive.
sal_uInt64 nValue = 0;
SCROW nCurPos = nPos1;
SCROW nEndPos = aData.mnPos2;
while (nEndPos <= nPos2)
{
sal_uInt64 nRes;
if (o3tl::checked_multiply<sal_uInt64>(aData.mnValue, nEndPos - nCurPos + 1, nRes))
{
SAL_WARN("sc.core", "row height overflow");
nRes = SAL_MAX_INT64;
}
nValue = o3tl::saturating_add(nValue, nRes);
nCurPos = nEndPos + 1;
auto itPair = maSegments.search(it, nCurPos, aData.mnValue, &aData.mnPos1, &aData.mnPos2);
if (!itPair.second)
break;
it = itPair.first;
aData.mnPos2 = aData.mnPos2-1; // end point is not inclusive.
nEndPos = aData.mnPos2;
}
if (nCurPos <= nPos2)
{
nEndPos = ::std::min(nEndPos, nPos2);
sal_uInt64 nRes;
if (o3tl::checked_multiply<sal_uInt64>(aData.mnValue, nEndPos - nCurPos + 1, nRes))
{
SAL_WARN("sc.core", "row height overflow");
nRes = SAL_MAX_INT64;
}
nValue = o3tl::saturating_add(nValue, nRes);
}
return nValue;
}
else
{
RangeData aData;
if (!getRangeDataLeaf(nPos1, aData))
return 0;
sal_uInt64 nValue = 0;
SCROW nCurPos = nPos1;
SCROW nEndPos = aData.mnPos2;
while (nEndPos <= nPos2)
{
sal_uInt64 nRes;
if (o3tl::checked_multiply<sal_uInt64>(aData.mnValue, nEndPos - nCurPos + 1, nRes))
{
SAL_WARN("sc.core", "row height overflow");
nRes = SAL_MAX_INT64;
}
nValue = o3tl::saturating_add(nValue, nRes);
nCurPos = nEndPos + 1;
if (!getRangeDataLeaf(nCurPos, aData))
break;
nEndPos = aData.mnPos2;
}
if (nCurPos <= nPos2)
{
nEndPos = ::std::min(nEndPos, nPos2);
sal_uInt64 nRes;
if (o3tl::checked_multiply<sal_uInt64>(aData.mnValue, nEndPos - nCurPos + 1, nRes))
{
SAL_WARN("sc.core", "row height overflow");
nRes = SAL_MAX_INT64;
}
nValue = o3tl::saturating_add(nValue, nRes);
}
return nValue;
}
}
template<typename ValueType_, typename ExtValueType_>
bool ScFlatSegmentsImpl<ValueType_, ExtValueType_>::getRangeData(SCCOLROW nPos, RangeData& rData)
{
if (!mbTreeSearchEnabled)
return getRangeDataLeaf(nPos, rData);
if (!maSegments.is_tree_valid())
{
assert(!ScGlobal::bThreadedGroupCalcInProgress);
maSegments.build_tree();
}
auto [it,found] = maSegments.search_tree(nPos, rData.mnValue, &rData.mnPos1, &rData.mnPos2);
if (!found)
return false;
maItr = std::move(it); // cache the iterator to speed up ForwardIterator.
rData.mnPos2 = rData.mnPos2-1; // end point is not inclusive.
return true;
}
template<typename ValueType_, typename ExtValueType_>
bool ScFlatSegmentsImpl<ValueType_, ExtValueType_>::getRangeDataLeaf(SCCOLROW nPos, RangeData& rData)
{
// Conduct leaf-node only search. Faster when searching between range insertion.
const ::std::pair<typename fst_type::const_iterator, bool> &ret =
maSegments.search(maItr, nPos, rData.mnValue, &rData.mnPos1, &rData.mnPos2);
if (!ret.second)
return false;
maItr = ret.first;
rData.mnPos2 = rData.mnPos2-1; // end point is not inclusive.
return true;
}
template<typename ValueType_, typename ExtValueType_>
void ScFlatSegmentsImpl<ValueType_, ExtValueType_>::removeSegment(SCCOLROW nPos1, SCCOLROW nPos2)
{
maSegments.shift_left(nPos1, nPos2);
maItr = maSegments.begin();
}
template<typename ValueType_, typename ExtValueType_>
void ScFlatSegmentsImpl<ValueType_, ExtValueType_>::insertSegment(SCCOLROW nPos, SCCOLROW nSize, bool bSkipStartBoundary)
{
maSegments.shift_right(nPos, nSize, bSkipStartBoundary);
maItr = maSegments.begin();
}
template<typename ValueType_, typename ExtValueType_>
SCCOLROW ScFlatSegmentsImpl<ValueType_, ExtValueType_>::findLastTrue(ValueType nValue) const
{
SCCOLROW nPos = numeric_limits<SCCOLROW>::max(); // position not found.
typename fst_type::const_reverse_iterator itr = maSegments.rbegin(), itrEnd = maSegments.rend();
// Note that when searching in reverse direction, we need to skip the first
// node, since the right-most leaf node does not store a valid value.
for (++itr; itr != itrEnd; ++itr)
{
if (itr->second != nValue)
{
nPos = (--itr)->first - 1;
break;
}
}
return nPos;
}
template<typename ValueType_, typename ExtValueType_>
bool ScFlatSegmentsImpl<ValueType_, ExtValueType_>::getFirst(RangeData& rData)
{
maItr = maSegments.begin();
return getNext(rData);
}
template<typename ValueType_, typename ExtValueType_>
bool ScFlatSegmentsImpl<ValueType_, ExtValueType_>::getNext(RangeData& rData)
{
typename fst_type::const_iterator itrEnd = maSegments.end();
if (maItr == itrEnd)
return false;
rData.mnPos1 = maItr->first;
rData.mnValue = maItr->second;
++maItr;
if (maItr == itrEnd)
return false;
rData.mnPos2 = maItr->first - 1;
return true;
}
template<typename ValueType_, typename ExtValueType_>
void ScFlatSegmentsImpl<ValueType_, ExtValueType_>::makeReady()
{
assert(!ScGlobal::bThreadedGroupCalcInProgress);
if (!maSegments.is_tree_valid())
maSegments.build_tree();
}
class ScFlatUInt16SegmentsImpl : public ScFlatSegmentsImpl<sal_uInt16, sal_uInt32>
{
public:
explicit ScFlatUInt16SegmentsImpl(SCCOLROW nMax, sal_uInt16 nDefault) :
ScFlatSegmentsImpl<sal_uInt16, sal_uInt32>(nMax, nDefault)
{
}
};
class ScFlatBoolSegmentsImpl : public ScFlatSegmentsImpl<bool>
{
public:
explicit ScFlatBoolSegmentsImpl(SCCOLROW nMax) :
ScFlatSegmentsImpl<bool>(nMax, false)
{
}
bool setTrue(SCCOLROW nPos1, SCCOLROW nPos2);
bool setFalse(SCCOLROW nPos1, SCCOLROW nPos2);
};
bool ScFlatBoolSegmentsImpl::setTrue(SCCOLROW nPos1, SCCOLROW nPos2)
{
return setValue(nPos1, nPos2, true);
}
bool ScFlatBoolSegmentsImpl::setFalse(SCCOLROW nPos1, SCCOLROW nPos2)
{
return setValue(nPos1, nPos2, false);
}
ScFlatBoolRowSegments::ForwardIterator::ForwardIterator(ScFlatBoolRowSegments& rSegs) :
mrSegs(rSegs), mnCurPos(0), mnLastPos(-1), mbCurValue(false)
{
}
bool ScFlatBoolRowSegments::ForwardIterator::getValue(SCROW nPos, bool& rVal)
{
if (nPos >= mnCurPos)
// It can only go in a forward direction.
mnCurPos = nPos;
if (mnCurPos > mnLastPos)
{
// position not in the current segment. Update the current value.
ScFlatBoolRowSegments::RangeData aData;
if (!mrSegs.getRangeData(mnCurPos, aData))
return false;
mbCurValue = aData.mbValue;
mnLastPos = aData.mnRow2;
}
rVal = mbCurValue;
return true;
}
ScFlatBoolRowSegments::RangeIterator::RangeIterator(ScFlatBoolRowSegments const & rSegs) :
mrSegs(rSegs)
{
}
bool ScFlatBoolRowSegments::RangeIterator::getFirst(RangeData& rRange)
{
ScFlatBoolSegmentsImpl::RangeData aData;
if (!mrSegs.mpImpl->getFirst(aData))
return false;
rRange.mnRow1 = static_cast<SCROW>(aData.mnPos1);
rRange.mnRow2 = static_cast<SCROW>(aData.mnPos2);
rRange.mbValue = static_cast<bool>(aData.mnValue);
return true;
}
bool ScFlatBoolRowSegments::RangeIterator::getNext(RangeData& rRange)
{
ScFlatBoolSegmentsImpl::RangeData aData;
if (!mrSegs.mpImpl->getNext(aData))
return false;
rRange.mnRow1 = static_cast<SCROW>(aData.mnPos1);
rRange.mnRow2 = static_cast<SCROW>(aData.mnPos2);
rRange.mbValue = static_cast<bool>(aData.mnValue);
return true;
}
ScFlatBoolRowSegments::ScFlatBoolRowSegments(SCROW nMaxRow) :
mpImpl(new ScFlatBoolSegmentsImpl(nMaxRow))
{
}
ScFlatBoolRowSegments::ScFlatBoolRowSegments(const ScFlatBoolRowSegments& r) :
mpImpl(new ScFlatBoolSegmentsImpl(*r.mpImpl))
{
}
ScFlatBoolRowSegments::~ScFlatBoolRowSegments()
{
}
bool ScFlatBoolRowSegments::setTrue(SCROW nRow1, SCROW nRow2)
{
return mpImpl->setTrue(static_cast<SCCOLROW>(nRow1), static_cast<SCCOLROW>(nRow2));
}
bool ScFlatBoolRowSegments::setFalse(SCROW nRow1, SCROW nRow2)
{
return mpImpl->setFalse(static_cast<SCCOLROW>(nRow1), static_cast<SCCOLROW>(nRow2));
}
bool ScFlatBoolRowSegments::getRangeData(SCROW nRow, RangeData& rData) const
{
ScFlatBoolSegmentsImpl::RangeData aData;
if (!mpImpl->getRangeData(static_cast<SCCOLROW>(nRow), aData))
return false;
rData.mbValue = aData.mnValue;
rData.mnRow1 = static_cast<SCROW>(aData.mnPos1);
rData.mnRow2 = static_cast<SCROW>(aData.mnPos2);
return true;
}
bool ScFlatBoolRowSegments::getRangeDataLeaf(SCROW nRow, RangeData& rData)
{
ScFlatBoolSegmentsImpl::RangeData aData;
if (!mpImpl->getRangeDataLeaf(static_cast<SCCOLROW>(nRow), aData))
return false;
rData.mbValue = aData.mnValue;
rData.mnRow1 = static_cast<SCROW>(aData.mnPos1);
rData.mnRow2 = static_cast<SCROW>(aData.mnPos2);
return true;
}
void ScFlatBoolRowSegments::removeSegment(SCROW nRow1, SCROW nRow2)
{
mpImpl->removeSegment(static_cast<SCCOLROW>(nRow1), static_cast<SCCOLROW>(nRow2));
}
void ScFlatBoolRowSegments::insertSegment(SCROW nRow, SCROW nSize)
{
mpImpl->insertSegment(static_cast<SCCOLROW>(nRow), static_cast<SCCOLROW>(nSize), true/*bSkipStartBoundary*/);
}
SCROW ScFlatBoolRowSegments::findLastTrue() const
{
return mpImpl->findLastTrue(false);
}
void ScFlatBoolRowSegments::makeReady()
{
mpImpl->makeReady();
}
OString ScFlatBoolRowSegments::dumpAsString()
{
OStringBuffer aOutput(4096);
RangeData aRange;
SCROW nRow = 0;
while (getRangeData(nRow, aRange))
{
if (!nRow)
aOutput.append(aRange.mbValue ? '1' : '0').append(':');
aOutput.append(OString::number(aRange.mnRow2) + " ");
nRow = aRange.mnRow2 + 1;
}
return aOutput.makeStringAndClear();
}
ScFlatBoolColSegments::ScFlatBoolColSegments(SCCOL nMaxCol) :
mpImpl(new ScFlatBoolSegmentsImpl(nMaxCol))
{
}
ScFlatBoolColSegments::ScFlatBoolColSegments(const ScFlatBoolColSegments& r) :
mpImpl(new ScFlatBoolSegmentsImpl(*r.mpImpl))
{
}
ScFlatBoolColSegments::~ScFlatBoolColSegments()
{
}
bool ScFlatBoolColSegments::setTrue(SCCOL nCol1, SCCOL nCol2)
{
return mpImpl->setTrue(static_cast<SCCOLROW>(nCol1), static_cast<SCCOLROW>(nCol2));
}
bool ScFlatBoolColSegments::setFalse(SCCOL nCol1, SCCOL nCol2)
{
return mpImpl->setFalse(static_cast<SCCOLROW>(nCol1), static_cast<SCCOLROW>(nCol2));
}
bool ScFlatBoolColSegments::getRangeData(SCCOL nCol, RangeData& rData)
{
ScFlatBoolSegmentsImpl::RangeData aData;
if (!mpImpl->getRangeData(static_cast<SCCOLROW>(nCol), aData))
return false;
rData.mbValue = aData.mnValue;
rData.mnCol1 = static_cast<SCCOL>(aData.mnPos1);
rData.mnCol2 = static_cast<SCCOL>(aData.mnPos2);
return true;
}
void ScFlatBoolColSegments::removeSegment(SCCOL nCol1, SCCOL nCol2)
{
mpImpl->removeSegment(static_cast<SCCOLROW>(nCol1), static_cast<SCCOLROW>(nCol2));
}
void ScFlatBoolColSegments::insertSegment(SCCOL nCol, SCCOL nSize)
{
mpImpl->insertSegment(static_cast<SCCOLROW>(nCol), static_cast<SCCOLROW>(nSize), true/*bSkipStartBoundary*/);
}
void ScFlatBoolColSegments::makeReady()
{
mpImpl->makeReady();
}
OString ScFlatBoolColSegments::dumpAsString()
{
OStringBuffer aOutput(4096);
RangeData aRange;
SCCOL nCol = 0;
while (getRangeData(nCol, aRange))
{
if (!nCol)
aOutput.append(aRange.mbValue ? '1' : '0').append(':');
aOutput.append(OString::number(aRange.mnCol2) + " ");
nCol = aRange.mnCol2 + 1;
}
return aOutput.makeStringAndClear();
}
ScFlatUInt16RowSegments::ForwardIterator::ForwardIterator(ScFlatUInt16RowSegments& rSegs) :
mrSegs(rSegs), mnCurPos(0), mnLastPos(-1), mnCurValue(0)
{
}
bool ScFlatUInt16RowSegments::ForwardIterator::getValue(SCROW nPos, sal_uInt16& rVal)
{
if (nPos >= mnCurPos)
// It can only go in a forward direction.
mnCurPos = nPos;
if (mnCurPos > mnLastPos)
{
// position not in the current segment. Update the current value.
ScFlatUInt16SegmentsImpl::RangeData aData;
if (mnLastPos == -1)
{
// first time in this method, use the tree search based method
if (!mrSegs.mpImpl->getRangeData(mnCurPos, aData))
return false;
}
else
{
// but on subsequent calls, use the leaf method, which is faster
// because we have a cached iterator.
if (!mrSegs.mpImpl->getRangeDataLeaf(mnCurPos, aData))
return false;
}
mnCurValue = aData.mnValue;
mnLastPos = aData.mnPos2;
}
rVal = mnCurValue;
return true;
}
ScFlatUInt16RowSegments::ScFlatUInt16RowSegments(SCROW nMaxRow, sal_uInt16 nDefault) :
mpImpl(new ScFlatUInt16SegmentsImpl(nMaxRow, nDefault))
{
}
ScFlatUInt16RowSegments::ScFlatUInt16RowSegments(const ScFlatUInt16RowSegments& r) :
mpImpl(new ScFlatUInt16SegmentsImpl(*r.mpImpl))
{
}
ScFlatUInt16RowSegments::~ScFlatUInt16RowSegments()
{
}
void ScFlatUInt16RowSegments::setValue(SCROW nRow1, SCROW nRow2, sal_uInt16 nValue)
{
mpImpl->setValue(static_cast<SCCOLROW>(nRow1), static_cast<SCCOLROW>(nRow2), nValue);
}
sal_uInt16 ScFlatUInt16RowSegments::getValue(SCROW nRow)
{
return mpImpl->getValue(static_cast<SCCOLROW>(nRow));
}
sal_uInt64 ScFlatUInt16RowSegments::getSumValue(SCROW nRow1, SCROW nRow2)
{
return mpImpl->getSumValue(static_cast<SCCOLROW>(nRow1), static_cast<SCCOLROW>(nRow2));
}
bool ScFlatUInt16RowSegments::getRangeData(SCROW nRow, RangeData& rData)
{
ScFlatUInt16SegmentsImpl::RangeData aData;
if (!mpImpl->getRangeData(static_cast<SCCOLROW>(nRow), aData))
return false;
rData.mnRow1 = aData.mnPos1;
rData.mnRow2 = aData.mnPos2;
rData.mnValue = aData.mnValue;
return true;
}
void ScFlatUInt16RowSegments::removeSegment(SCROW nRow1, SCROW nRow2)
{
mpImpl->removeSegment(static_cast<SCCOLROW>(nRow1), static_cast<SCCOLROW>(nRow2));
}
void ScFlatUInt16RowSegments::insertSegment(SCROW nRow, SCROW nSize)
{
mpImpl->insertSegment(static_cast<SCCOLROW>(nRow), static_cast<SCCOLROW>(nSize), false/*bSkipStartBoundary*/);
}
SCROW ScFlatUInt16RowSegments::findLastTrue(sal_uInt16 nValue) const
{
return mpImpl->findLastTrue(nValue);
}
void ScFlatUInt16RowSegments::enableTreeSearch(bool bEnable)
{
mpImpl->enableTreeSearch(bEnable);
}
void ScFlatUInt16RowSegments::setValueIf(SCROW nRow1, SCROW nRow2, sal_uInt16 nValue, const std::function<bool(sal_uInt16)>& rPredicate)
{
mpImpl->setValueIf(static_cast<SCCOLROW>(nRow1), static_cast<SCCOLROW>(nRow2), nValue, rPredicate);
}
void ScFlatUInt16RowSegments::makeReady()
{
mpImpl->makeReady();
}
OString ScFlatUInt16RowSegments::dumpAsString()
{
OStringBuffer aOutput(4096);
RangeData aRange;
SCROW nRow = 0;
while (getRangeData(nRow, aRange))
{
aOutput.append(OString::number(aRange.mnValue) + ":" + OString::number(aRange.mnRow2) + " ");
nRow = aRange.mnRow2 + 1;
}
return aOutput.makeStringAndClear();
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
↑ V530 The return value of function 'append' is required to be utilized.
↑ V530 The return value of function 'append' is required to be utilized.