perf: minor perf optimization for FlyleafLib

- Avoid boxing in Set method of NotifyPropertyChanged
- Use IEquatable<T> for struct implemantion
- Prevents unnecessary string conversion in Language string parsing

Author: umlx5h

FlyleafLib/Engine/Globals.cs

@@ -133,7 +133,7 @@ public enum VideoFilters
     StereoAdjustment    = 0x80
 }
 
-public struct AspectRatio
+public struct AspectRatio : IEquatable<AspectRatio>
 {
     public static readonly AspectRatio Keep     = new(-1, 1);
     public static readonly AspectRatio Fill     = new(-2, 1);
@@ -173,12 +173,12 @@ public AspectRatio(float value) : this(value, 1) { }
     public AspectRatio(float num, float den) { Num = num; Den = den; }
     public AspectRatio(string value) { Num = Invalid.Num; Den = Invalid.Den; FromString(value); }
 
-    public override bool Equals(object obj) => (obj == null) || !GetType().Equals(obj.GetType()) ? false : Num == ((AspectRatio)obj).Num && Den == ((AspectRatio)obj).Den;
+    public bool Equals(AspectRatio other) => Num == other.Num && Den == other.Den;
+    public override bool Equals(object obj) => obj is AspectRatio o && Equals(o);
+    public override int GetHashCode() => HashCode.Combine(Num, Den);
     public static bool operator ==(AspectRatio a, AspectRatio b) => a.Equals(b);
     public static bool operator !=(AspectRatio a, AspectRatio b) => !(a == b);
 
-    public override int GetHashCode() => (int)(Value * 1000);
-
     public void FromString(string value)
     {
         if (value == "Keep")
@@ -230,7 +230,7 @@ protected bool Set<T>(ref T field, T value, bool check = true, [CallerMemberName
     {
         //Utils.Log($"[===| {propertyName} |===] | Set | {IsUI()}");
 
-        if (!check || (field == null && value != null) || (field != null && !field.Equals(value)))
+        if (!check || !EqualityComparer<T>.Default.Equals(field, value))
         {
             field = value;
 
@@ -247,7 +247,7 @@ protected bool SetUI<T>(ref T field, T value, bool check = true, [CallerMemberNa
     {
         //Utils.Log($"[===| {propertyName} |===] | SetUI | {IsUI()}");
 
-        if (!check || (field == null && value != null) || (field != null && !field.Equals(value)))
+        if (!check || !EqualityComparer<T>.Default.Equals(field, value))
         {
             field = value;
 

FlyleafLib/Engine/Language.cs

@@ -126,7 +126,7 @@ public static Language Get(string name)
 
     public static CultureInfo StringToCulture(string lang)
     {
-        if (string.IsNullOrWhiteSpace(lang) || lang.Length < 2)
+        if (string.IsNullOrWhiteSpace(lang) || lang.Length < 2 || lang == "und")
             return null;
 
         string langLower = lang.ToLower();
@@ -137,10 +137,12 @@ public static CultureInfo StringToCulture(string lang)
             ret = lang.Length == 3 ? ThreeLetterToCulture(langLower) : CultureInfo.GetCultureInfo(langLower);
         } catch { }
 
+        StringComparer cmp = StringComparer.OrdinalIgnoreCase;
+
         // TBR: Check also -Country/region two letters?
         if (ret == null || ret.ThreeLetterISOLanguageName == "")
             foreach (var cult in CultureInfo.GetCultures(CultureTypes.AllCultures))
-                if (cult.Name.ToLower() == langLower || cult.NativeName.ToLower() == langLower || cult.EnglishName.ToLower() == langLower)
+                if (cmp.Equals(cult.Name, langLower) || cmp.Equals(cult.NativeName, langLower) || cmp.Equals(cult.EnglishName, langLower))
                     return cult;
 
         return ret;