Replaced StartsWith, EndsWith and Contains for strings with much faster equivalents. Thanks to [email protected] who suggested these changes in a Google Groups discussion.

Author: rstam

Bson/IO/BsonWriter.cs

@@ -607,14 +607,14 @@ protected void CheckElementName(string name)
         {
             if (_checkUpdateDocument)
             {
-                _checkElementNames = !name.StartsWith("$");
+                _checkElementNames = (name[0] != '$');
                 _checkUpdateDocument = false;
                 return;
             }
 
             if (_checkElementNames)
             {
-                if (name.StartsWith("$"))
+                if (name[0] == '$')
                 {
                     // a few element names starting with $ have to be allowed for historical reasons
                     switch (name)
@@ -631,7 +631,7 @@ protected void CheckElementName(string name)
                             throw new BsonSerializationException(message);
                     }
                 }
-                if (name.Contains('.'))
+                if (name.IndexOf('.') != -1)
                 {
                     var message = string.Format("Element name '{0}' is not valid because it contains a '.'.", name);
                     throw new BsonSerializationException(message);
@@ -673,10 +673,10 @@ protected void ThrowInvalidState(string methodName, params BsonWriterState[] val
             string message;
             if (_state == BsonWriterState.Initial || _state == BsonWriterState.ScopeDocument || _state == BsonWriterState.Done)
             {
-                if (!methodName.StartsWith("End") && methodName != "WriteName")
+                if (!methodName.StartsWith("End", StringComparison.Ordinal) && methodName != "WriteName")
                 {
                     var typeName = methodName.Substring(5);
-                    if (typeName.StartsWith("Start"))
+                    if (typeName.StartsWith("Start", StringComparison.Ordinal))
                     {
                         typeName = typeName.Substring(5);
                     }

Bson/IO/JsonReader.cs

@@ -1066,7 +1066,7 @@ private DateTime ParseJavaScriptDateTimeString(string dateTimeString)
                     var secondsString = match.Groups["seconds"].Value;
                     int seconds;
                     double milliseconds;
-                    if (secondsString.Contains("."))
+                    if (secondsString.IndexOf('.') != -1)
                     {
                         var timeSpan = TimeSpan.FromSeconds(double.Parse(secondsString));
                         seconds = timeSpan.Seconds;

Bson/ObjectModel/BsonRegularExpression.cs

@@ -296,19 +296,19 @@ public override int GetHashCode()
         public Regex ToRegex()
         {
             var options = RegexOptions.None;
-            if (_options.Contains("i"))
+            if (_options.IndexOf('i') != -1)
             {
                 options |= RegexOptions.IgnoreCase;
             }
-            if (_options.Contains("m"))
+            if (_options.IndexOf('m') != -1)
             {
                 options |= RegexOptions.Multiline;
             }
-            if (_options.Contains("x"))
+            if (_options.IndexOf('x') != -1)
             {
                 options |= RegexOptions.IgnorePatternWhitespace;
             }
-            if (_options.Contains("s"))
+            if (_options.IndexOf('s') != -1)
             {
                 options |= RegexOptions.Singleline;
             }

Bson/Serialization/BsonClassMap.cs

@@ -276,7 +276,7 @@ public static string GetTypeNameDiscriminator(Type type)
                 foreach (var genericType in type.GetGenericArguments())
                 {
                     var genericTypeName = GetTypeNameDiscriminator(genericType);
-                    if (genericTypeName.Contains(','))
+                    if (genericTypeName.IndexOf(',') != -1)
                     {
                         genericTypeName = "[" + genericTypeName + "]";
                     }

Bson/Serialization/Serializers/DictionaryGenericSerializer.cs

@@ -232,7 +232,7 @@ public override void Serialize(
                         foreach (object key in dictionary.Keys)
                         {
                             var name = key as string; // check for null and type string at the same time
-                            if (name == null || name.StartsWith("$") || name.Contains("."))
+                            if (name == null || name[0] == '$' || name.IndexOf('.') != -1)
                             {
                                 representation = DictionaryRepresentation.ArrayOfArrays;
                                 break;

Bson/Serialization/Serializers/DictionarySerializer.cs

@@ -240,7 +240,7 @@ public override void Serialize(
                     foreach (object key in dictionary.Keys)
                     {
                         var name = key as string; // check for null and type string at the same time
-                        if (name == null || name.StartsWith("$") || name.Contains("."))
+                        if (name == null || name[0] == '$' || name.IndexOf('.') != -1)
                         {
                             representation = DictionaryRepresentation.ArrayOfArrays;
                             break;

BsonUnitTests/Jira/CSharp310Tests.cs

@@ -56,7 +56,7 @@ private static void InitializeSerialization()
             var conventions = new ConventionProfile();
             conventions.SetDefaultValueConvention(new EmptyGuidDefaultValueConvention());
             conventions.SetSerializeDefaultValueConvention(new NeverSerializeDefaultValueConvention());
-            BsonClassMap.RegisterConventions(conventions, type => type.FullName.StartsWith("MongoDB.BsonUnitTests.Jira.CSharp310Tests"));
+            BsonClassMap.RegisterConventions(conventions, type => type.FullName.StartsWith("MongoDB.BsonUnitTests.Jira.CSharp310Tests", StringComparison.Ordinal));
         }
 
         [Test]

Driver/Core/MongoCollection.cs

@@ -1592,7 +1592,7 @@ internal static void ValidateCollectionName(string name)
                 throw new ArgumentNullException("name");
             }
             if (name == "" ||
-                name.Contains('\0') ||
+                name.IndexOf('\0') != -1 ||
                 Encoding.UTF8.GetBytes(name).Length > 121)
             {
                 throw new ArgumentException("Invalid collection name", "name");

Driver/Core/MongoCredentials.cs

@@ -40,7 +40,7 @@ public class MongoCredentials : IEquatable<MongoCredentials>
         public MongoCredentials(string username, string password)
         {
             ValidatePassword(password);
-            if (username.EndsWith("(admin)"))
+            if (username.EndsWith("(admin)", StringComparison.Ordinal))
             {
                 _username = username.Substring(0, username.Length - 7);
                 _password = password;

Driver/Core/MongoDatabase.cs

@@ -143,7 +143,7 @@ public static MongoDatabase Create(MongoUrl url)
         /// </returns>
         public static MongoDatabase Create(string connectionString)
         {
-            if (connectionString.StartsWith("mongodb://"))
+            if (connectionString.StartsWith("mongodb://", StringComparison.Ordinal))
             {
                 MongoUrl url = MongoUrl.Create(connectionString);
                 return Create(url);
@@ -649,8 +649,8 @@ public virtual IEnumerable<string> GetCollectionNames()
             foreach (var @namespace in namespaces.FindAll())
             {
                 string collectionName = @namespace["name"].AsString;
-                if (!collectionName.StartsWith(prefix)) { continue; }
-                if (collectionName.Contains('$')) { continue; }
+                if (!collectionName.StartsWith(prefix, StringComparison.Ordinal)) { continue; }
+                if (collectionName.IndexOf('$') != -1) { continue; }
                 collectionNames.Add(collectionName.Substring(prefix.Length));
             }
             collectionNames.Sort();