From 334b5d7bb8812548575cf654d1a8c9654f4d20be Mon Sep 17 00:00:00 2001
From: NukeBird <nukebird.dev@gmail.com>
Date: Mon, 17 Feb 2025 22:50:53 +0300
Subject: [PATCH] std::vector for reusable ids should give more cache benefits

---
 tests/zecsy.cpp |  5 +++++
 zecsy.hpp       | 11 ++++++-----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/tests/zecsy.cpp b/tests/zecsy.cpp
index eb8da86..2eddd4c 100644
--- a/tests/zecsy.cpp
+++ b/tests/zecsy.cpp
@@ -136,6 +136,11 @@ TEST_CASE("Addresses of removed components should be reused")
         }
         else
         {
+            /*
+             * Gotta reverse it because now we reuse ids in LIFO order
+             */
+            std::reverse(addr.begin(), addr.end());
+            
             for(int j = 0; j < N; ++j)
             {
                 REQUIRE(&w.get<ChoosenOne>(entities[j]) == addr[j]);
diff --git a/zecsy.hpp b/zecsy.hpp
index a798e7e..e0717f0 100644
--- a/zecsy.hpp
+++ b/zecsy.hpp
@@ -57,7 +57,7 @@ namespace zecsy
         struct component_pool
         {
             std::vector<uint8_t> data;
-            std::queue<size_t> free_list; // Reusable indices
+            std::vector<size_t> free_list; // Reusable indices
             std::unordered_map<entity_id, size_t> entity_to_index;
             std::unordered_map<size_t, entity_id> index_to_entity;
         };
@@ -111,8 +111,8 @@ namespace zecsy
         size_t index;
         if(!pool.free_list.empty())
         {
-            index = pool.free_list.front();
-            pool.free_list.pop();
+            index = pool.free_list.back();
+            pool.free_list.pop_back();
         }
         else
         {
@@ -142,7 +142,7 @@ namespace zecsy
 
         auto& pool = pools[id];
         auto index = pool.entity_to_index[e];
-        pool.free_list.push(index);
+        pool.free_list.push_back(index);
         pool.entity_to_index.erase(e);
         pool.index_to_entity.erase(index);
     }
@@ -163,7 +163,8 @@ namespace zecsy
 
     template<typename First, typename Second, typename... Rest>
     inline void component_storage::set(entity_id e, const First& comp0,
-                                const Second& comp1, const Rest&... rest_comps)
+                                       const Second& comp1,
+                                       const Rest&... rest_comps)
     {
         set(e, comp0);
         set(e, comp1);