From 8945efaf107dfb2a7e73fd34ff7c6c67d73a0cf6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tim=20K=C3=A4chele?= <mail@timkaechele.me>
Date: Thu, 12 Dec 2024 10:54:04 +0100
Subject: [PATCH] Start using an object pool for shipments

---
 lib/planet_express_express.rb                 |  2 ++
 lib/planet_express_express/shipment.rb        | 10 +++++++
 lib/planet_express_express/shipment_pool.rb   | 24 +++++++++++++++++
 lib/planet_express_express/shipment_reader.rb | 27 ++++++++-----------
 4 files changed, 47 insertions(+), 16 deletions(-)
 create mode 100644 lib/planet_express_express/shipment.rb
 create mode 100644 lib/planet_express_express/shipment_pool.rb

diff --git a/lib/planet_express_express.rb b/lib/planet_express_express.rb
index 3c7b1ab..205ec02 100644
--- a/lib/planet_express_express.rb
+++ b/lib/planet_express_express.rb
@@ -2,6 +2,8 @@
 
 require_relative "planet_express_express/version"
 require_relative "planet_express_express/constants"
+require_relative "planet_express_express/shipment"
+require_relative "planet_express_express/shipment_pool"
 require_relative "planet_express_express/shipment_reader"
 require_relative "planet_express_express/rules"
 require_relative "planet_express_express/discount_budget"
diff --git a/lib/planet_express_express/shipment.rb b/lib/planet_express_express/shipment.rb
new file mode 100644
index 0000000..23fa95b
--- /dev/null
+++ b/lib/planet_express_express/shipment.rb
@@ -0,0 +1,10 @@
+module PlanetExpressExpress
+ Shipment = Struct.new(
+      :date,
+      :size,
+      :provider,
+      :price,
+      :discount,
+      keyword_init: true
+    )
+end
diff --git a/lib/planet_express_express/shipment_pool.rb b/lib/planet_express_express/shipment_pool.rb
new file mode 100644
index 0000000..5ac4c5b
--- /dev/null
+++ b/lib/planet_express_express/shipment_pool.rb
@@ -0,0 +1,24 @@
+module PlanetExpressExpress
+  # A very simple implementation of an object pool for
+  # shipments.
+  #
+  # Using it you can reduce the memory allocations
+  class ShipmentPool
+    def initialize(size: 100)
+      @entries = []
+      size.times do
+        @entries.push(Shipment.new())
+      end
+    end
+
+    def get()
+      entry = @entries.pop
+      return entry if entry
+      Shipment.new
+    end
+
+    def put_back(shipment_entries)
+      @entries.push(*shipment_entries)
+    end
+  end
+end
diff --git a/lib/planet_express_express/shipment_reader.rb b/lib/planet_express_express/shipment_reader.rb
index f04d583..a83f9b0 100644
--- a/lib/planet_express_express/shipment_reader.rb
+++ b/lib/planet_express_express/shipment_reader.rb
@@ -1,15 +1,8 @@
 module PlanetExpressExpress
   require "date"
   class ShipmentReader
-    Shipment = Struct.new(
-      :date,
-      :size,
-      :provider,
-      :price,
-      :discount,
-      keyword_init: true
-    )
-    def initialize(prices)
+    def initialize(prices, shipment_pool: ShipmentPool.new(size: 10))
+      @shipment_pool = shipment_pool
       @prices = prices
       @id = 0
     end
@@ -31,6 +24,8 @@ module PlanetExpressExpress
 
         if shipment.date.year != current_year || shipment.date.month != current_month
           yield shipments
+
+          @shipment_pool.put_back(shipments[:all])
           shipments.each do |_,v|
             v.clear
           end
@@ -52,13 +47,13 @@ module PlanetExpressExpress
     def parse(line)
       parts = line.split(" ")
 
-      shipment = Shipment.new(
-        date: Date.strptime(parts[0], "%Y-%m-%d"),
-        size: parts[1]&.to_sym,
-        provider: parts[2]&.to_sym,
-        price: 0,
-        discount: 0
-      )
+      shipment = @shipment_pool.get
+
+      shipment.date = Date.strptime(parts[0], "%Y-%m-%d")
+      shipment.size = parts[1]&.to_sym
+      shipment.provider = parts[2]&.to_sym
+      shipment.price = 0
+      shipment.discount = 0
 
       shipment.price = prices[
         [