Implements some micro-optimizations

PkmnLib.Static/Utils/StringKey.cs

@@ -1,3 +1,4 @@
+using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
 
 namespace PkmnLib.Static.Utils;
@@ -8,9 +9,12 @@ namespace PkmnLib.Static.Utils;
 /// <remarks>
 /// This is a struct, as it's effectively just a wrapper around a single reference object. Heap allocation would be silly.  
 /// </remarks>
-public readonly record struct StringKey
+public readonly struct StringKey : IEquatable<StringKey>, IEquatable<string>
 {
+    private static readonly ConcurrentDictionary<string, int> HashCodes = new();
+
     private readonly string _key;
+    private readonly int _hashCode;
 
     /// <inheritdoc cref="StringKey"/>
     public StringKey(string key)
@@ -18,6 +22,10 @@ public readonly record struct StringKey
         if (string.IsNullOrWhiteSpace(key))
             throw new ArgumentException("Key cannot be null or whitespace.", nameof(key));
         _key = key;
+        if (!HashCodes.TryGetValue(_key, out _hashCode))
+        {
+            _hashCode = HashCodes[_key] = StringComparer.InvariantCultureIgnoreCase.GetHashCode(_key);
+        }
     }
 
     /// <summary>
@@ -45,19 +53,24 @@ public readonly record struct StringKey
     public override string ToString() => _key.ToLowerInvariant();
 
     /// <inheritdoc />
-    public bool Equals(StringKey other) => string.Equals(_key, other._key, StringComparison.InvariantCultureIgnoreCase);
+    public override bool Equals(object? obj)
+    {
+        return obj switch
+        {
+            StringKey other => Equals(other),
+            string str => Equals(str),
+            _ => false,
+        };
+    }
+
+    /// <inheritdoc />
+    public bool Equals(StringKey other) => _hashCode == other._hashCode;
 
     /// <inheritdoc cref="Equals(StringKey)"/>
     public bool Equals(string other) => string.Equals(_key, other, StringComparison.InvariantCultureIgnoreCase);
 
     /// <inheritdoc />
-    public override int GetHashCode() => StringComparer.InvariantCultureIgnoreCase.GetHashCode(_key);
-
-    /// <inheritdoc cref="Equals(StringKey)"/>
-    public static bool operator ==(StringKey left, string right) => left.Equals(right);
-
-    /// <inheritdoc cref="Equals(StringKey)"/>
-    public static bool operator !=(StringKey left, string right) => !(left == right);
+    public override int GetHashCode() => _hashCode;
 
     /// <inheritdoc cref="Equals(StringKey)"/>
     public static bool operator ==(StringKey? left, string? right) =>