From 49fe1968d930f306c28f6e08291a0d8d96b6ed88 Mon Sep 17 00:00:00 2001
From: Peter Butzhammer <peter.butzhammer@evopro-ag.de>
Date: Tue, 6 Feb 2024 13:19:32 +0100
Subject: [PATCH] Optimize dictionary access

---
 Sharp7.Rx/S7VariableNameParser.cs | 69 +++++++++++++------------------
 1 file changed, 29 insertions(+), 40 deletions(-)

diff --git a/Sharp7.Rx/S7VariableNameParser.cs b/Sharp7.Rx/S7VariableNameParser.cs
index 4820717..b65f4c7 100644
--- a/Sharp7.Rx/S7VariableNameParser.cs
+++ b/Sharp7.Rx/S7VariableNameParser.cs
@@ -12,7 +12,7 @@ namespace Sharp7.Rx
     {
         private static readonly Regex regex = new Regex(@"^(?<operand>db{1})(?<dbNr>\d{1,4})\.?(?<type>dbx|x|s|string|b|dbb|d|int|dbw|w|dint|dul|dulint|dulong|){1}(?<start>\d+)(\.(?<bitOrLength>\d+))?$", RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.CultureInvariant);
 
-        private readonly Dictionary<string, DbType> types = new Dictionary<string, DbType>
+        private static readonly IReadOnlyDictionary<string, DbType> types = new Dictionary<string, DbType>(StringComparer.InvariantCultureIgnoreCase)
         {
             {"x", DbType.Bit},
             {"dbx", DbType.Bit},
@@ -30,16 +30,17 @@ namespace Sharp7.Rx
             {"dulong", DbType.ULong }
         };
 
-
         public S7VariableAddress Parse(string input)
         {
             var match = regex.Match(input);
             if (match.Success)
             {
                 var operand = (Operand)Enum.Parse(typeof(Operand), match.Groups["operand"].Value, true);
-                var dbNr = ushort.Parse(match.Groups["dbNr"].Value, NumberStyles.Integer);
-                var start = ushort.Parse(match.Groups["start"].Value, NumberStyles.Integer);
-                var type = ParseType(match.Groups["type"].Value);
+                var dbNr = ushort.Parse(match.Groups["dbNr"].Value, NumberStyles.Integer, CultureInfo.InvariantCulture);
+                var start = ushort.Parse(match.Groups["start"].Value, NumberStyles.Integer, CultureInfo.InvariantCulture);
+                if (!types.TryGetValue(match.Groups["type"].Value, out var type))
+                    return null;
+
 
                 var s7VariableAddress = new S7VariableAddress
                 {
@@ -49,34 +50,30 @@ namespace Sharp7.Rx
                     Type = type,
                 };
 
-                if (type == DbType.Bit)
+                switch (type)
                 {
-                    s7VariableAddress.Length = 1;
-                    s7VariableAddress.Bit = byte.Parse(match.Groups["bitOrLength"].Value);
-                }
-                else if (type == DbType.Byte)
-                {
-                    s7VariableAddress.Length = match.Groups["bitOrLength"].Success ? ushort.Parse(match.Groups["bitOrLength"].Value) : (ushort)1;
-                }
-                else if (type == DbType.String)
-                {
-                    s7VariableAddress.Length = match.Groups["bitOrLength"].Success ? ushort.Parse(match.Groups["bitOrLength"].Value) : (ushort)0;
-                }
-                else if (type == DbType.Integer)
-                {
-                    s7VariableAddress.Length = 2;
-                }
-                else if (type == DbType.DInteger)
-                {
-                    s7VariableAddress.Length = 4;
-                }
-                else if (type == DbType.ULong)
-                {
-                    s7VariableAddress.Length = 8;
-                }
-                else if (type == DbType.Double)
-                {
-                    s7VariableAddress.Length = 4;
+                    case DbType.Bit:
+                        s7VariableAddress.Length = 1;
+                        s7VariableAddress.Bit = byte.Parse(match.Groups["bitOrLength"].Value);
+                        break;
+                    case DbType.Byte:
+                        s7VariableAddress.Length = match.Groups["bitOrLength"].Success ? ushort.Parse(match.Groups["bitOrLength"].Value) : (ushort)1;
+                        break;
+                    case DbType.String:
+                        s7VariableAddress.Length = match.Groups["bitOrLength"].Success ? ushort.Parse(match.Groups["bitOrLength"].Value) : (ushort)0;
+                        break;
+                    case DbType.Integer:
+                        s7VariableAddress.Length = 2;
+                        break;
+                    case DbType.DInteger:
+                        s7VariableAddress.Length = 4;
+                        break;
+                    case DbType.ULong:
+                        s7VariableAddress.Length = 8;
+                        break;
+                    case DbType.Double:
+                        s7VariableAddress.Length = 4;
+                        break;
                 }
 
                 return s7VariableAddress;
@@ -84,13 +81,5 @@ namespace Sharp7.Rx
 
             return null;
         }
-
-        private DbType ParseType(string value)
-        {
-            return types
-                .Where(pair => pair.Key.Equals(value, StringComparison.InvariantCultureIgnoreCase))
-                .Select(pair => pair.Value)
-                .FirstOrDefault();
-        }
     }
 }
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