strepsirrhini/office-gobmx
9
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

reduce dynamic_cast usage in an O(N^2) algorithm

Browse source 
When scrolling down in tdf#130431 this is the major CPU cost.
Move the dynamic_cast out of the loops as much as possible.

Change-Id: I0ea9f457bb17fbdde880f09b059f07dec4b1790b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/94858
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>
This commit is contained in:
Luboš Luňák 2020-05-26 12:29:37 +02:00
parent 3a93748c9c
commit ef4964a4e5
3 changed files with 50 additions and 53 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
drawinglayer/source/primitive2d/borderlineprimitive2d.cxx
View file

@ -305,18 +305,11 @@ namespace drawinglayer::primitive2d
ImplPrimitive2DIDBlock(BorderLinePrimitive2D, PRIMITIVE2D_ID_BORDERLINEPRIMITIVE2D)
Primitive2DReference tryMergeBorderLinePrimitive2D(
const Primitive2DReference& rCandidateA,
const Primitive2DReference& rCandidateB)
const BorderLinePrimitive2D* pCandidateA,
const BorderLinePrimitive2D* pCandidateB)
{
// try to cast to BorderLinePrimitive2D
const primitive2d::BorderLinePrimitive2D* pCandidateA = dynamic_cast< const primitive2d::BorderLinePrimitive2D* >(rCandidateA.get());
const primitive2d::BorderLinePrimitive2D* pCandidateB = dynamic_cast< const primitive2d::BorderLinePrimitive2D* >(rCandidateB.get());
// we need a comparable BorderLinePrimitive2D
if(nullptr == pCandidateA || nullptr == pCandidateB)
{
return Primitive2DReference();
}
assert(pCandidateA);
assert(pCandidateB);
// start of candidate has to match end of this
if(!pCandidateA->getEnd().equal(pCandidateB->getStart()))

12
include/drawinglayer/primitive2d/borderlineprimitive2d.hxx
View file

@ -81,12 +81,6 @@ public:
bool operator==(const BorderLine& rBorderLine) const;
};
/// helper to try to merge two instances of BorderLinePrimitive2D. If it was possible,
/// a merged version is in the returned Primitive2DReference. Lots of preconditions
/// have to be met to allow that, see implementation (and maybe even expand)
Primitive2DReference DRAWINGLAYER_DLLPUBLIC tryMergeBorderLinePrimitive2D(
const Primitive2DReference& rCandidateA, const Primitive2DReference& rCandidateB);
/** BorderLinePrimitive2D class
This is the basic primitive to build frames around objects, e.g. tables.
@ -141,6 +135,12 @@ public:
virtual sal_uInt32 getPrimitive2DID() const override;
};
/// helper to try to merge two instances of BorderLinePrimitive2D. If it was possible,
/// a merged version is in the returned Primitive2DReference. Lots of preconditions
/// have to be met to allow that, see implementation (and maybe even expand)
Primitive2DReference DRAWINGLAYER_DLLPUBLIC tryMergeBorderLinePrimitive2D(
const BorderLinePrimitive2D* pCandidateA, const BorderLinePrimitive2D* pCandidateB);
} // end of namespace drawinglayer::primitive2d
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

76
svx/source/sdr/primitive2d/sdrframeborderprimitive2d.cxx
View file

@ -797,51 +797,55 @@ namespace drawinglayer::primitive2d
for(const auto& aCandidatePartial : aPartial)
{
if(aRetval.empty())
{
// no local data yet, just add as 1st entry, done
aRetval.append(aCandidatePartial);
}
else
{
bool bDidMerge(false);
bool bDidMerge(false);
// This algorithm is O(N^2) and repeated dynamic_cast inside would be quite costly.
// So check first and skip if the primitives aren't BorderLinePrimitive2D.
const drawinglayer::primitive2d::BorderLinePrimitive2D* candidatePartialAsBorder
= dynamic_cast<const drawinglayer::primitive2d::BorderLinePrimitive2D*>(aCandidatePartial.get());
if(candidatePartialAsBorder)
{
for(auto& aCandidateRetval : aRetval)
{
// try to merge by appending new data to existing data
const drawinglayer::primitive2d::Primitive2DReference aMergeRetvalPartial(
drawinglayer::primitive2d::tryMergeBorderLinePrimitive2D(
aCandidateRetval,
aCandidatePartial));
if(aMergeRetvalPartial.is())
const drawinglayer::primitive2d::BorderLinePrimitive2D* candidateRetvalAsBorder
= dynamic_cast<const drawinglayer::primitive2d::BorderLinePrimitive2D*>(aCandidateRetval.get());
if(candidateRetvalAsBorder)
{
// could append, replace existing data with merged data, done
aCandidateRetval = aMergeRetvalPartial;
bDidMerge = true;
break;
}
// try to merge by appending new data to existing data
const drawinglayer::primitive2d::Primitive2DReference aMergeRetvalPartial(
drawinglayer::primitive2d::tryMergeBorderLinePrimitive2D(
candidateRetvalAsBorder,
candidatePartialAsBorder));
// try to merge by appending existing data to new data
const drawinglayer::primitive2d::Primitive2DReference aMergePartialRetval(
drawinglayer::primitive2d::tryMergeBorderLinePrimitive2D(
aCandidatePartial,
aCandidateRetval));
if(aMergeRetvalPartial.is())
{
// could append, replace existing data with merged data, done
aCandidateRetval = aMergeRetvalPartial;
bDidMerge = true;
break;
}
if(aMergePartialRetval.is())
{
// could append, replace existing data with merged data, done
aCandidateRetval = aMergePartialRetval;
bDidMerge = true;
break;
// try to merge by appending existing data to new data
const drawinglayer::primitive2d::Primitive2DReference aMergePartialRetval(
drawinglayer::primitive2d::tryMergeBorderLinePrimitive2D(
candidatePartialAsBorder,
candidateRetvalAsBorder));
if(aMergePartialRetval.is())
{
// could append, replace existing data with merged data, done
aCandidateRetval = aMergePartialRetval;
bDidMerge = true;
break;
}
}
}
}
if(!bDidMerge)
{
// no merge after checking all existing data, append as new segment
aRetval.append(aCandidatePartial);
}
if(!bDidMerge)
{
// no merge after checking all existing data, append as new segment
aRetval.append(aCandidatePartial);
}
}
}