From 609211a7492d40e56d896c709fb2591302b0aa2a Mon Sep 17 00:00:00 2001
From: Subhransu Mohanty <sub.mohanty@samsung.com>
Date: Thu, 27 Aug 2020 12:57:28 +0900
Subject: [PATCH] Improve the logic using Erase-Remove Idiom.

instead of erasing each element found and restarting the
loop again . first find all element and move them to the end
of list and then erase them once using std::erase(std::remove_if()).

This will improve the cache locality as this will avoid lot ofpointer chaseing.
Also avoids expensing Dali::Vector::end() call.

Change-Id: I306de3f017ef23ea7d4d1e6e5202940f84fcf872
---
 dali/devel-api/common/owner-container.h            | 15 +++++
 .../update/animation/scene-graph-animation.cpp     | 77 ++++++++++------------
 2 files changed, 50 insertions(+), 42 deletions(-)

diff --git a/dali/devel-api/common/owner-container.h b/dali/devel-api/common/owner-container.h
index 6890656..c8c37d5 100644
--- a/dali/devel-api/common/owner-container.h
+++ b/dali/devel-api/common/owner-container.h
@@ -86,6 +86,21 @@ public:
   }
 
   /**
+   * Erases a range of elements.(delete from heap).
+   */
+  Iterator Erase(Iterator first, Iterator last)
+  {
+    auto itr = first;
+    while(itr < last)
+    {
+      Delete(*itr);
+      ++itr;
+    }
+
+    return Vector<T>::Erase(first, last);
+  }
+
+  /**
    * Erase an object from OwnerContainer
    * @param object to remove
    */
diff --git a/dali/internal/update/animation/scene-graph-animation.cpp b/dali/internal/update/animation/scene-graph-animation.cpp
index aa01b10..10a735f 100644
--- a/dali/internal/update/animation/scene-graph-animation.cpp
+++ b/dali/internal/update/animation/scene-graph-animation.cpp
@@ -430,60 +430,53 @@ void Animation::UpdateAnimators( BufferIndex bufferIndex, bool bake, bool animat
   const Vector2 playRange( mPlayRange * mDurationSeconds );
   float elapsedSecondsClamped = Clamp( mElapsedSeconds, playRange.x, playRange.y );
 
+  //Remove animators whose PropertyOwner has been destroyed
+  mAnimators.Erase(std::remove_if(mAnimators.begin(),
+                                  mAnimators.end(),
+                                  [](auto animator) { return animator->Orphan(); }),
+                   mAnimators.end());
+
   //Loop through all animators
-  bool applied(true);
-  for ( auto&& iter = mAnimators.Begin(); iter != mAnimators.End(); )
+  for(auto& animator : mAnimators)
   {
-    AnimatorBase *animator = *iter;
-
-    if( animator->Orphan() )
-    {
-      //Remove animators whose PropertyOwner has been destroyed
-      iter = mAnimators.Erase(iter);
-    }
-    else
+    bool applied(true);
+    if(animator->IsEnabled())
     {
-      if( animator->IsEnabled() )
-      {
-        const float intervalDelay( animator->GetIntervalDelay() );
+      const float intervalDelay(animator->GetIntervalDelay());
 
-        if( elapsedSecondsClamped >= intervalDelay )
+      if(elapsedSecondsClamped >= intervalDelay)
+      {
+        // Calculate a progress specific to each individual animator
+        float       progress(1.0f);
+        const float animatorDuration = animator->GetDuration();
+        if(animatorDuration > 0.0f) // animators can be "immediate"
         {
-          // Calculate a progress specific to each individual animator
-          float progress(1.0f);
-          const float animatorDuration = animator->GetDuration();
-          if (animatorDuration > 0.0f) // animators can be "immediate"
-          {
-            progress = Clamp((elapsedSecondsClamped - intervalDelay) / animatorDuration, 0.0f , 1.0f );
-          }
-          animator->Update(bufferIndex, progress, bake);
-
-          if (animatorDuration > 0.0f && (elapsedSecondsClamped - intervalDelay) <= animatorDuration)
-          {
-            mIsActive[bufferIndex] = true;
-          }
+          progress = Clamp((elapsedSecondsClamped - intervalDelay) / animatorDuration, 0.0f, 1.0f);
         }
-        applied = true;
-      }
-      else
-      {
-        applied = false;
-      }
+        animator->Update(bufferIndex, progress, bake);
 
-      if ( animationFinished )
-      {
-        animator->SetActive( false );
+        if (animatorDuration > 0.0f && (elapsedSecondsClamped - intervalDelay) <= animatorDuration)
+        {
+          mIsActive[bufferIndex] = true;
+        }
       }
+      applied = true;
+    }
+    else
+    {
+      applied = false;
+    }
 
-      if (applied)
-      {
-        INCREASE_COUNTER(PerformanceMonitor::ANIMATORS_APPLIED);
-      }
+    if(animationFinished)
+    {
+      animator->SetActive(false);
+    }
 
-      ++iter;
+    if(applied)
+    {
+      INCREASE_COUNTER(PerformanceMonitor::ANIMATORS_APPLIED);
     }
   }
-
 }
 
 } // namespace SceneGraph
-- 
2.7.4