From 79c5e0a52d3a797967756a807989dd7c0f4b94c3 Mon Sep 17 00:00:00 2001
From: bubnikv <bubnikv@gmail.com>
Date: Fri, 15 Apr 2016 18:01:08 +0200
Subject: [PATCH] Optimize remove_duplicate_points.

---
 xs/src/libslic3r/MultiPoint.cpp | 28 +++++++++++++++++++++++-----
 xs/src/libslic3r/MultiPoint.hpp |  5 ++++-
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/xs/src/libslic3r/MultiPoint.cpp b/xs/src/libslic3r/MultiPoint.cpp
index 49aceacaf..627420628 100644
--- a/xs/src/libslic3r/MultiPoint.cpp
+++ b/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
diff --git a/xs/src/libslic3r/MultiPoint.hpp b/xs/src/libslic3r/MultiPoint.hpp
index 0f31fd318..e6fe4f2f2 100644
--- a/xs/src/libslic3r/MultiPoint.hpp
+++ b/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);