refactored SearchExpression

ParadoxSaveParser.Lib/SearchExpression/ExactMatchExpression.cs

@@ -0,0 +1,37 @@
+namespace ParadoxSaveParser.Lib;
+
+/// <summary>A literal key, matched byte for byte.</summary>
+internal sealed class ExactMatchExpression : ISearchExpression
+{
+    public string Key { get; }
+
+    // the key as it appears in the save, so matching needs no encoding at all
+    public byte[] KeyBytes { get; private set; }
+    public ISearchExpression? Next { get; }
+
+    public ExactMatchExpression(string key, Encoding encoding, ISearchExpression? next)
+    {
+        Key = key;
+        Next = next;
+        KeyBytes = encoding.GetBytes(key);
+    }
+
+    public bool DoesMatch(MatchCandidate candidate, out ISearchExpression? nextSearchExpression)
+    {
+        // comparing bytes keeps the candidate's key from becoming a string
+        if (candidate.Key.SequenceEqual(KeyBytes))
+        {
+            nextSearchExpression = Next;
+            return true;
+        }
+
+        nextSearchExpression = null;
+        return false;
+    }
+
+    public void ReEncode(Encoding encoding)
+    {
+        KeyBytes = encoding.GetBytes(Key);
+        Next?.ReEncode(encoding);
+    }
+}