220 lines
6.1 KiB
C++
220 lines
6.1 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2006 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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//$Id: geom_util.hpp 39 2005-04-10 20:39:53Z pavlenko $
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#ifndef GEOM_UTIL_HPP
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#define GEOM_UTIL_HPP
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// mapnik
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#include <mapnik/envelope.hpp>
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#include <mapnik/vertex.hpp>
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// boost
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#include <boost/tuple/tuple.hpp>
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// stl
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#include <cmath>
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namespace mapnik
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{
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template <typename T>
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bool clip_test(T p,T q,double& tmin,double& tmax)
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{
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double r;
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bool result=true;
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if (p<0.0)
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{
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r=q/p;
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if (r>tmax) result=false;
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else if (r>tmin) tmin=r;
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}
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else if (p>0.0)
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{
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r=q/p;
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if (r<tmin) result=false;
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else if (r<tmax) tmax=r;
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} else if (q<0.0) result=false;
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return result;
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}
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template <typename T,typename Image>
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bool clip_line(T& x0,T& y0,T& x1,T& y1,Envelope<T> const& box)
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{
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double tmin=0.0;
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double tmax=1.0;
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double dx=x1-x0;
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if (clip_test<double>(-dx,x0,tmin,tmax))
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{
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if (clip_test<double>(dx,box.width()-x0,tmin,tmax))
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{
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double dy=y1-y0;
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if (clip_test<double>(-dy,y0,tmin,tmax))
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{
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if (clip_test<double>(dy,box.height()-y0,tmin,tmax))
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{
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if (tmax<1.0)
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{
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x1=static_cast<T>(x0+tmax*dx);
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y1=static_cast<T>(y0+tmax*dy);
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}
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if (tmin>0.0)
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{
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x0+=static_cast<T>(tmin*dx);
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y0+=static_cast<T>(tmin*dy);
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}
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return true;
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}
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}
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}
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}
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return false;
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}
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template <typename Iter>
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inline bool point_inside_path(double x,double y,Iter start,Iter end)
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{
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bool inside=false;
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double x0=boost::get<0>(*start);
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double y0=boost::get<1>(*start);
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double x1,y1;
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while (++start!=end)
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{
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if ( boost::get<2>(*start) == SEG_MOVETO)
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{
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x0 = boost::get<0>(*start);
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y0 = boost::get<1>(*start);
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continue;
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}
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x1=boost::get<0>(*start);
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y1=boost::get<1>(*start);
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if ((((y1 <= y) && (y < y0)) ||
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((y0 <= y) && (y < y1))) &&
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( x < (x0 - x1) * (y - y1)/ (y0 - y1) + x1))
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inside=!inside;
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x0=x1;
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y0=y1;
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}
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return inside;
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}
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inline bool point_in_circle(double x,double y,double cx,double cy,double r)
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{
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double dx = x - cx;
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double dy = y - cy;
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double d2 = dx * dx + dy * dy;
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return (d2 <= r * r);
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}
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template <typename T>
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inline T sqr(T x)
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{
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return x * x;
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}
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inline double distance2(double x0,double y0,double x1,double y1)
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{
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double dx = x1 - x0;
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double dy = y1 - y0;
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return sqr(dx) + sqr(dy);
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}
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inline double distance(double x0,double y0, double x1,double y1)
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{
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return std::sqrt(distance2(x0,y0,x1,y1));
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}
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inline double point_to_segment_distance(double x, double y,
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double ax, double ay,
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double bx, double by)
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{
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double len2 = distance2(ax,ay,bx,by);
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if (len2 < 1e-14)
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{
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return distance(x,y,ax,ay);
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}
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double r = ((x - ax)*(bx - ax) + (y - ay)*(by -ay))/len2;
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if ( r < 0 )
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{
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return distance(x,y,ax,ay);
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}
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else if (r > 1)
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{
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return distance(x,y,bx,by);
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}
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double s = ((ay - y)*(bx - ax) - (ax - x)*(by - ay))/len2;
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return std::fabs(s) * std::sqrt(len2);
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}
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template <typename Iter>
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inline bool point_on_path(double x,double y,Iter start,Iter end, double tol)
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{
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double x0=boost::get<0>(*start);
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double y0=boost::get<1>(*start);
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double x1,y1;
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while (++start != end)
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{
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if ( boost::get<2>(*start) == SEG_MOVETO)
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{
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x0 = boost::get<0>(*start);
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y0 = boost::get<1>(*start);
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continue;
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}
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x1=boost::get<0>(*start);
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y1=boost::get<1>(*start);
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double distance = point_to_segment_distance(x,y,x0,y0,x1,y1);
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if (distance < tol)
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return true;
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x0=x1;
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y0=y1;
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}
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return false;
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}
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// filters
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struct filter_in_box
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{
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Envelope<double> box_;
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explicit filter_in_box(const Envelope<double>& box)
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: box_(box) {}
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bool pass(const Envelope<double>& extent) const
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{
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return extent.intersects(box_);
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}
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};
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struct filter_at_point
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{
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coord2d pt_;
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explicit filter_at_point(const coord2d& pt)
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: pt_(pt) {}
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bool pass(const Envelope<double>& extent) const
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{
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return extent.contains(pt_);
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}
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};
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}
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#endif //GEOM_UTIL_HPP
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