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std::vector: Using emplace_back to replace push_back to improve perfo…
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…rmance (#939)
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@nonwill
nonwill authored Jan 26, 2025
1 parent 51bb284 commit baa7014
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Showing 7 changed files with 106 additions and 110 deletions.
14 changes: 7 additions & 7 deletions CPP/Clipper2Lib/include/clipper2/clipper.core.h
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Original file line number Diff line number Diff line change
Expand Up @@ -331,10 +331,10 @@ namespace Clipper2Lib
{
Path<T> result;
result.reserve(4);
result.push_back(Point<T>(left, top));
result.push_back(Point<T>(right, top));
result.push_back(Point<T>(right, bottom));
result.push_back(Point<T>(left, bottom));
result.emplace_back(left, top);
result.emplace_back(right, top);
result.emplace_back(right, bottom);
result.emplace_back(left, bottom);
return result;
}

Expand Down Expand Up @@ -618,13 +618,13 @@ namespace Clipper2Lib
result.reserve(path.size());
typename Path<T>::const_iterator path_iter = path.cbegin();
Point<T> first_pt = *path_iter++, last_pt = first_pt;
result.push_back(first_pt);
result.emplace_back(first_pt);
for (; path_iter != path.cend(); ++path_iter)
{
if (!NearEqual(*path_iter, last_pt, max_dist_sqrd))
{
last_pt = *path_iter;
result.push_back(last_pt);
result.emplace_back(last_pt);
}
}
if (!is_closed_path) return result;
Expand All @@ -642,7 +642,7 @@ namespace Clipper2Lib
for (typename Paths<T>::const_iterator paths_citer = paths.cbegin();
paths_citer != paths.cend(); ++paths_citer)
{
result.push_back(StripNearEqual(*paths_citer, max_dist_sqrd, is_closed_path));
result.emplace_back(std::move(StripNearEqual(*paths_citer, max_dist_sqrd, is_closed_path)));
}
return result;
}
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20 changes: 10 additions & 10 deletions CPP/Clipper2Lib/include/clipper2/clipper.export.h
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Original file line number Diff line number Diff line change
Expand Up @@ -392,9 +392,9 @@ static Path<T> ConvertCPathToPathT(T* path)
T x = *v++, y = *v++;
#ifdef USINGZ
z_type z = Reinterpret<z_type>(*v++);
result.push_back(Point<T>(x, y, z));
result.emplace_back(x, y, z);
#else
result.push_back(Point<T>(x, y));
result.emplace_back(x, y);
#endif
}
return result;
Expand All @@ -419,12 +419,12 @@ static Paths<T> ConvertCPathsToPathsT(T* paths)
T x = *v++, y = *v++;
#ifdef USINGZ
z_type z = Reinterpret<z_type>(*v++);
path.push_back(Point<T>(x, y, z));
path.emplace_back(x, y, z);
#else
path.push_back(Point<T>(x, y));
path.emplace_back(x, y);
#endif
}
result.push_back(path);
result.emplace_back(std::move(path));
}
return result;
}
Expand All @@ -443,9 +443,9 @@ static Path64 ConvertCPathDToPath64WithScale(const CPathD path, double scale)
double y = *v++ * scale;
#ifdef USINGZ
z_type z = Reinterpret<z_type>(*v++);
result.push_back(Point64(x, y, z));
result.emplace_back(x, y, z);
#else
result.push_back(Point64(x, y));
result.emplace_back(x, y);
#endif
}
return result;
Expand All @@ -471,12 +471,12 @@ static Paths64 ConvertCPathsDToPaths64(const CPathsD paths, double scale)
double y = *v++ * scale;
#ifdef USINGZ
z_type z = Reinterpret<z_type>(*v++);
path.push_back(Point64(x, y, z));
path.emplace_back(x, y, z);
#else
path.push_back(Point64(x, y));
path.emplace_back(x, y);
#endif
}
result.push_back(path);
result.emplace_back(std::move(path));
}
return result;
}
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26 changes: 13 additions & 13 deletions CPP/Clipper2Lib/include/clipper2/clipper.h
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Original file line number Diff line number Diff line change
Expand Up @@ -272,14 +272,14 @@ namespace Clipper2Lib {

inline void PolyPathToPaths64(const PolyPath64& polypath, Paths64& paths)
{
paths.push_back(polypath.Polygon());
paths.emplace_back(polypath.Polygon());
for (const auto& child : polypath)
PolyPathToPaths64(*child, paths);
}

inline void PolyPathToPathsD(const PolyPathD& polypath, PathsD& paths)
{
paths.push_back(polypath.Polygon());
paths.emplace_back(polypath.Polygon());
for (const auto& child : polypath)
PolyPathToPathsD(*child, paths);
}
Expand Down Expand Up @@ -348,9 +348,9 @@ namespace Clipper2Lib {
result.reserve(array_size / 2);
for (size_t i = 0; i < array_size; i +=2)
#ifdef USINGZ
result.push_back( U{ an_array[i], an_array[i + 1], 0} );
result.emplace_back( an_array[i], an_array[i + 1], 0 );
#else
result.push_back( U{ an_array[i], an_array[i + 1]} );
result.emplace_back( an_array[i], an_array[i + 1] );
#endif
}

Expand Down Expand Up @@ -518,20 +518,20 @@ namespace Clipper2Lib {
}

prevIt = srcIt++;
dst.push_back(*prevIt);
dst.emplace_back(*prevIt);
for (; srcIt != stop; ++srcIt)
{
if (!IsCollinear(*prevIt, *srcIt, *(srcIt + 1)))
{
prevIt = srcIt;
dst.push_back(*prevIt);
dst.emplace_back(*prevIt);
}
}

if (is_open_path)
dst.push_back(*srcIt);
dst.emplace_back(*srcIt);
else if (!IsCollinear(*prevIt, *stop, dst[0]))
dst.push_back(*stop);
dst.emplace_back(*stop);
else
{
while (dst.size() > 2 &&
Expand Down Expand Up @@ -603,10 +603,10 @@ namespace Clipper2Lib {
double dx = co, dy = si;
Path<T> result;
result.reserve(steps);
result.push_back(Point<T>(center.x + radiusX, static_cast<double>(center.y)));
result.emplace_back(center.x + radiusX, static_cast<double>(center.y));
for (size_t i = 1; i < steps; ++i)
{
result.push_back(Point<T>(center.x + radiusX * dx, center.y + radiusY * dy));
result.emplace_back(center.x + radiusX * dx, center.y + radiusY * dy);
double x = dx * co - dy * si;
dy = dy * co + dx * si;
dx = x;
Expand Down Expand Up @@ -700,7 +700,7 @@ namespace Clipper2Lib {
Path<T> result;
result.reserve(len);
for (typename Path<T>::size_type i = 0; i < len; ++i)
if (!flags[i]) result.push_back(path[i]);
if (!flags[i]) result.emplace_back(path[i]);
return result;
}

Expand All @@ -711,7 +711,7 @@ namespace Clipper2Lib {
Paths<T> result;
result.reserve(paths.size());
for (const auto& path : paths)
result.push_back(SimplifyPath(path, epsilon, isClosedPath));
result.emplace_back(std::move(SimplifyPath(path, epsilon, isClosedPath)));
return result;
}

Expand Down Expand Up @@ -749,7 +749,7 @@ namespace Clipper2Lib {
result.reserve(len);
for (typename Path<T>::size_type i = 0; i < len; ++i)
if (flags[i])
result.push_back(path[i]);
result.emplace_back(path[i]);
return result;
}

Expand Down
14 changes: 7 additions & 7 deletions CPP/Clipper2Lib/include/clipper2/clipper.minkowski.h
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,7 @@ namespace Clipper2Lib
Path64 path2(pattern.size());
std::transform(pattern.cbegin(), pattern.cend(),
path2.begin(), [p](const Point64& pt2) {return p + pt2; });
tmp.push_back(path2);
tmp.emplace_back(std::move(path2));
}
}
else
Expand All @@ -45,7 +45,7 @@ namespace Clipper2Lib
Path64 path2(pattern.size());
std::transform(pattern.cbegin(), pattern.cend(),
path2.begin(), [p](const Point64& pt2) {return p - pt2; });
tmp.push_back(path2);
tmp.emplace_back(std::move(path2));
}
}

Expand All @@ -59,14 +59,14 @@ namespace Clipper2Lib
Path64 quad;
quad.reserve(4);
{
quad.push_back(tmp[g][h]);
quad.push_back(tmp[i][h]);
quad.push_back(tmp[i][j]);
quad.push_back(tmp[g][j]);
quad.emplace_back(tmp[g][h]);
quad.emplace_back(tmp[i][h]);
quad.emplace_back(tmp[i][j]);
quad.emplace_back(tmp[g][j]);
};
if (!IsPositive(quad))
std::reverse(quad.begin(), quad.end());
result.push_back(quad);
result.emplace_back(std::move(quad));
h = j;
}
g = i;
Expand Down
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