From 5a58d2051f6cdb8be138fe554e7b80c25be8eca6 Mon Sep 17 00:00:00 2001
From: Adrian Conlon <98398945+AdrianConlon@users.noreply.github.com>
Date: Mon, 10 Jun 2024 20:47:44 +0100
Subject: [PATCH] use a pre-determined list capacity, if available

---
 M6502/M6502.Symbols/IdentifiableSection.cs | 5 +++--
 M6502/M6502.Symbols/Parser.cs              | 2 ++
 M6502/M6502.Symbols/Section.cs             | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/M6502/M6502.Symbols/IdentifiableSection.cs b/M6502/M6502.Symbols/IdentifiableSection.cs
index e425016..d792ebe 100644
--- a/M6502/M6502.Symbols/IdentifiableSection.cs
+++ b/M6502/M6502.Symbols/IdentifiableSection.cs
@@ -38,16 +38,17 @@
                 protected List<T> TakeReferences<T>(string key, List<T>? from) where T : IdentifiableSection
                 {
                     ArgumentNullException.ThrowIfNull(from);
-                    List<T> returned = [];
                     var ids = this.MaybeTakeMultiple(key);
                     if (ids != null)
                     {
+                        var returned = new List<T>(ids.Count);
                         foreach (var id in ids)
                         {
                             returned.Add(from[id]);
                         }
+                        return returned;
                     }
-                    return returned;
+                    return [];
                 }
 
                 #endregion
diff --git a/M6502/M6502.Symbols/Parser.cs b/M6502/M6502.Symbols/Parser.cs
index 555ff5d..499ab7d 100644
--- a/M6502/M6502.Symbols/Parser.cs
+++ b/M6502/M6502.Symbols/Parser.cs
@@ -300,6 +300,8 @@
                     {
                         throw new InvalidOperationException($"Debugging section: '{key}' is unavailable");
                     }
+                    Debug.Assert(into.Count == 0);
+                    into.Capacity = parsed.Count;
                     foreach (var element in parsed)
                     {
                         var id = element.Key;
diff --git a/M6502/M6502.Symbols/Section.cs b/M6502/M6502.Symbols/Section.cs
index a64b4a3..325fc7b 100644
--- a/M6502/M6502.Symbols/Section.cs
+++ b/M6502/M6502.Symbols/Section.cs
@@ -89,8 +89,8 @@
                 protected static List<string> ExtractCompoundString(string value) => new(value.Split('+'));
                 protected static List<int> ExtractCompoundInteger(string value)
                 {
-                    var returned = new List<int>();
                     var elements = ExtractCompoundString(value);
+                    var returned = new List<int>(elements.Count);
                     foreach (var element in elements)
                     {
                         returned.Add(ExtractInteger(element));