From b80945fd5af649d90bf070f4f99395b3c48ef9c1 Mon Sep 17 00:00:00 2001
From: Dominik Drexler <dominik.drexler@gmx.net>
Date: Sat, 29 Jun 2024 17:39:24 +0200
Subject: [PATCH] made segmented vector more stl like, added emplace_back and
 back functionalities

---
 include/loki/details/pddl/factory.hpp         |  3 +-
 .../loki/details/utils/segmented_vector.hpp   | 33 +++++++++++++++++--
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/include/loki/details/pddl/factory.hpp b/include/loki/details/pddl/factory.hpp
index 920617f2..472fcd79 100644
--- a/include/loki/details/pddl/factory.hpp
+++ b/include/loki/details/pddl/factory.hpp
@@ -76,8 +76,7 @@ class PDDLFactory
         assert(identifier == m_persistent_vector.size());
 
         // Explicitly call the constructor of T to give exclusive access to the factory.
-        auto element = HolderType(std::move(SubType(identifier, std::forward<Args>(args)...)));
-        const auto* element_ptr = &(m_persistent_vector.push_back(std::move(element)));
+        const auto* element_ptr = &m_persistent_vector.emplace_back(SubType(identifier, std::forward<Args>(args)...));
         // The pointer to the location in persistent memory.
         assert(element_ptr);
 
diff --git a/include/loki/details/utils/segmented_vector.hpp b/include/loki/details/utils/segmented_vector.hpp
index f08de2be..6c3cc29e 100644
--- a/include/loki/details/utils/segmented_vector.hpp
+++ b/include/loki/details/utils/segmented_vector.hpp
@@ -71,7 +71,7 @@ class SegmentedVector
     /**
      * Modifiers
      */
-    const T& push_back(T value)
+    void push_back(T value)
     {
         // Increase capacity if necessary
         if (m_size >= m_capacity)
@@ -83,9 +83,24 @@ class SegmentedVector
         // Take ownership of memory
         segment.push_back(std::move(value));
         ++m_size;
+    }
+
+    template<typename... Args>
+    T& emplace_back(Args&&... args)
+    {
+        // Increase capacity if necessary
+        if (m_size >= m_capacity)
+        {
+            increase_capacity();
+        }
+
+        auto& segment = m_data[segment_index(size())];
+
+        // Emplace the new element directly in the segment
+        auto& element = segment.emplace_back(std::forward<Args>(args)...);
+        ++m_size;
 
-        // Fetch return value
-        return segment.back();
+        return element;
     }
 
     void pop_back()
@@ -124,6 +139,18 @@ class SegmentedVector
         return m_data[segment_index(pos)].at(element_index(pos));
     }
 
+    T& back()
+    {
+        range_check(size() - 1);
+        return m_data[segment_index(size() - 1)].at(element_index(size() - 1));
+    }
+
+    const T& back() const
+    {
+        range_check(size() - 1);
+        return m_data[segment_index(size() - 1)].at(element_index(size() - 1));
+    }
+
     /**
      * Iterators
      */