Optimize remove_duplicate_points.

xs/src/libslic3r/MultiPoint.cpp

@@ -102,15 +102,33 @@ MultiPoint::bounding_box() const
     return BoundingBox(this->points);
 }
 
-void
+bool 
+MultiPoint::has_duplicate_points() const
+{
+    for (size_t i = 1; i < points.size(); ++i)
+        if (points[i-1].coincides_with(points[i]))
+            return true;
+    return false;
+}
+
+bool
 MultiPoint::remove_duplicate_points()
 {
-    for (size_t i = 1; i < this->points.size(); ++i) {
-        if (this->points.at(i).coincides_with(this->points.at(i-1))) {
-            this->points.erase(this->points.begin() + i);
-            --i;
+    size_t j = 0;
+    for (size_t i = 1; i < points.size(); ++i) {
+        if (points[j].coincides_with(points[i])) {
+            // Just increase index i.
+        } else {
+            ++ j;
+            if (j < i)
+                points[j] = points[i];
         }
     }
+    if (++ j < points.size()) {
+        points.erase(points.begin() + j, points.end());
+        return true;
+    }
+    return false;
 }
 
 void

xs/src/libslic3r/MultiPoint.hpp

@@ -33,7 +33,10 @@ class MultiPoint
     int find_point(const Point &point) const;
     bool has_boundary_point(const Point &point) const;
     BoundingBox bounding_box() const;
-    void remove_duplicate_points();
+    // Return true if there are exact duplicates.
+    bool has_duplicate_points() const;
+    // Remove exact duplicates, return true if any duplicate has been removed.
+    bool remove_duplicate_points();
     void append(const Point &point);
     void append(const Points &points);
     void append(const Points::const_iterator &begin, const Points::const_iterator &end);