From 4dc91d18be4e632cd2d8b027fba7bed8336cbb4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Wed, 12 Apr 2023 09:19:55 +0200
Subject: [PATCH] directly use std::multiset as the double keys are not needed

---
 .../Isotropic_remeshing/remesh_impl.h         | 58 ++++++++++---------
 1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h
index a078e446591..9cdb76ac76b 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h
@@ -384,10 +384,6 @@ namespace internal {
     void split_long_edges(const EdgeRange& edge_range,
                           const double& high)
     {
-      typedef boost::bimap<
-        boost::bimaps::set_of<halfedge_descriptor>,
-        boost::bimaps::multiset_of<double, std::greater<double> > >  Boost_bimap;
-      typedef typename Boost_bimap::value_type                       long_edge;
 
 #ifdef CGAL_PMP_REMESHING_VERBOSE
       std::cout << "Split long edges (" << high << ")...";
@@ -396,12 +392,17 @@ namespace internal {
       double sq_high = high*high;
 
       //collect long edges
-      Boost_bimap long_edges;
+      typedef std::pair<halfedge_descriptor, double> H_and_sql;
+      std::multiset< H_and_sql, std::function<bool(H_and_sql,H_and_sql)> >
+        long_edges(
+          [](const H_and_sql& p1, const H_and_sql& p2)
+          { return p1.second > p2.second; }
+        );
       for(edge_descriptor e : edge_range)
       {
         double sqlen = sqlength(e);
         if (sqlen > sq_high)
-          long_edges.insert(long_edge(halfedge(e, mesh_), sqlen));
+          long_edges.emplace(halfedge(e, mesh_), sqlen);
       }
 
       //split long edges
@@ -411,10 +412,10 @@ namespace internal {
       while (!long_edges.empty())
       {
         //the edge with longest length
-        typename Boost_bimap::right_map::iterator eit = long_edges.right.begin();
-        halfedge_descriptor he = eit->second;
-        double sqlen = eit->first;
-        long_edges.right.erase(eit);
+        auto eit = long_edges.begin();
+        halfedge_descriptor he = eit->first;
+        double sqlen = eit->second;
+        long_edges.erase(eit);
 
         //split edge
         Point refinement_point = this->midpoint(he);
@@ -438,8 +439,8 @@ namespace internal {
         if (sqlen_new > sq_high)
         {
           //if it was more than twice the "long" threshold, insert them
-          long_edges.insert(long_edge(hnew, sqlen_new));
-          long_edges.insert(long_edge(next(hnew, mesh_), sqlen_new));
+          long_edges.emplace(hnew, sqlen_new);
+          long_edges.emplace(next(hnew, mesh_), sqlen_new);
         }
 
         //insert new edges to keep triangular faces, and update long_edges
@@ -479,25 +480,26 @@ namespace internal {
     //is split at its midpoint and the two adjacent triangles are bisected (2-4 split)"
     void split_long_edges(const double& high)
     {
-      typedef boost::bimap<
-        boost::bimaps::set_of<halfedge_descriptor>,
-        boost::bimaps::multiset_of<double, std::greater<double> > >  Boost_bimap;
-      typedef typename Boost_bimap::value_type                       long_edge;
-
 #ifdef CGAL_PMP_REMESHING_VERBOSE
       std::cout << "Split long edges (" << high << ")..." << std::endl;
 #endif
       double sq_high = high*high;
 
       //collect long edges
-      Boost_bimap long_edges;
+      typedef std::pair<halfedge_descriptor, double> H_and_sql;
+      std::multiset< H_and_sql, std::function<bool(H_and_sql,H_and_sql)> >
+      long_edges(
+        [](const H_and_sql& p1, const H_and_sql& p2)
+        { return p1.second > p2.second; }
+      );
+
       for(edge_descriptor e : edges(mesh_))
       {
         if (!is_split_allowed(e))
           continue;
         double sqlen = sqlength(e);
         if(sqlen > sq_high)
-          long_edges.insert(long_edge(halfedge(e, mesh_), sqlen));
+          long_edges.emplace(halfedge(e, mesh_), sqlen);
       }
 
       //split long edges
@@ -507,13 +509,13 @@ namespace internal {
       while (!long_edges.empty())
       {
         //the edge with longest length
-        typename Boost_bimap::right_map::iterator eit = long_edges.right.begin();
-        halfedge_descriptor he = eit->second;
-        double sqlen = eit->first;
-        long_edges.right.erase(eit);
+        auto eit = long_edges.begin();
+        halfedge_descriptor he = eit->first;
+        double sqlen = eit->second;
+        long_edges.erase(eit);
 
 #ifdef CGAL_PMP_REMESHING_VERBOSE_PROGRESS
-        std::cout << "\r\t(" << long_edges.left.size() << " long edges, ";
+        std::cout << "\r\t(" << long_edges.size() << " long edges, ";
         std::cout << nb_splits << " splits)";
         std::cout.flush();
 #endif
@@ -550,8 +552,8 @@ namespace internal {
         if (sqlen_new > sq_high)
         {
           //if it was more than twice the "long" threshold, insert them
-          long_edges.insert(long_edge(hnew,              sqlen_new));
-          long_edges.insert(long_edge(next(hnew, mesh_), sqlen_new));
+          long_edges.emplace(hnew, sqlen_new);
+          long_edges.emplace(next(hnew, mesh_), sqlen_new);
         }
 
         //insert new edges to keep triangular faces, and update long_edges
@@ -573,7 +575,7 @@ namespace internal {
           {
             double sql = sqlength(hnew2);
             if (sql > sq_high)
-              long_edges.insert(long_edge(hnew2, sql));
+              long_edges.emplace(hnew2, sql);
           }
         }
 
@@ -596,7 +598,7 @@ namespace internal {
           {
             double sql = sqlength(hnew2);
             if (sql > sq_high)
-              long_edges.insert(long_edge(hnew2, sql));
+              long_edges.emplace(hnew2, sql);
           }
         }
       }