throw if StringSplitOptions is invalid

Author: Guiorgy

src/Enumerators/Split/SpanSplitStringSplitOptionsEnumerator.cs

@@ -29,7 +29,7 @@ public SpanSplitStringSplitOptionsEnumerator(ReadOnlySpan<char> source, char del
         {
             Span = source;
             Delimiter = delimiter;
-            TrimEntries = options.IsTrimEntriesSet();
+            TrimEntries = options.ThrowIfInvalid().IsTrimEntriesSet();
             RemoveEmptyEntries = options.IsRemoveEmptyEntriesSet();
             EnumerationDone = false;
             Current = default;

src/Enumerators/Split/SpanSplitStringSplitOptionsWithCountEnumerator.cs

@@ -34,7 +34,7 @@ public SpanSplitStringSplitOptionsWithCountEnumerator(ReadOnlySpan<char> source,
             Span = source;
             Delimiter = delimiter;
             CurrentCount = count.ThrowIfNegative();
-            TrimEntries = options.IsTrimEntriesSet();
+            TrimEntries = options.ThrowIfInvalid().IsTrimEntriesSet();
             RemoveEmptyEntries = options.IsRemoveEmptyEntriesSet();
             CountExceedingBehaviour = countExceedingBehaviour.ThrowIfInvalid();
             EnumerationDone = count == 0;

src/Enumerators/SplitAny/SpanSplitAnyStringSplitOptionsEnumerator.cs

@@ -29,7 +29,7 @@ public SpanSplitAnyStringSplitOptionsEnumerator(ReadOnlySpan<char> source, ReadO
         {
             Span = source;
             Delimiters = delimiters;
-            TrimEntries = options.IsTrimEntriesSet();
+            TrimEntries = options.ThrowIfInvalid().IsTrimEntriesSet();
             RemoveEmptyEntries = options.IsRemoveEmptyEntriesSet();
             EnumerationDone = false;
             Current = default;

src/Enumerators/SplitAny/SpanSplitAnyStringSplitOptionsWithCountEnumerator.cs

@@ -34,7 +34,7 @@ public SpanSplitAnyStringSplitOptionsWithCountEnumerator(ReadOnlySpan<char> sour
             Span = source;
             Delimiters = delimiters;
             CurrentCount = count.ThrowIfNegative();
-            TrimEntries = options.IsTrimEntriesSet();
+            TrimEntries = options.ThrowIfInvalid().IsTrimEntriesSet();
             RemoveEmptyEntries = options.IsRemoveEmptyEntriesSet();
             CountExceedingBehaviour = countExceedingBehaviour.ThrowIfInvalid();
             EnumerationDone = count == 0;

src/Enumerators/SplitSequence/SpanSplitSequenceStringSplitOptionsEnumerator.cs

@@ -32,7 +32,7 @@ public SpanSplitSequenceStringSplitOptionsEnumerator(ReadOnlySpan<char> source,
             Delimiter = delimiter;
             DelimiterLength = Delimiter.Length;
             DelimiterIsEmpty = Delimiter.IsEmpty;
-            TrimEntries = options.IsTrimEntriesSet();
+            TrimEntries = options.ThrowIfInvalid().IsTrimEntriesSet();
             RemoveEmptyEntries = options.IsRemoveEmptyEntriesSet();
             EnumerationDone = false;
             Current = default;

src/Enumerators/SplitSequence/SpanSplitSequenceStringSplitOptionsWithCountEnumerator.cs

@@ -37,7 +37,7 @@ public SpanSplitSequenceStringSplitOptionsWithCountEnumerator(ReadOnlySpan<char>
             DelimiterLength = Delimiter.Length;
             DelimiterIsEmpty = Delimiter.IsEmpty;
             CurrentCount = DelimiterIsEmpty ? 0 : count.ThrowIfNegative();
-            TrimEntries = options.IsTrimEntriesSet();
+            TrimEntries = options.ThrowIfInvalid().IsTrimEntriesSet();
             RemoveEmptyEntries = options.IsRemoveEmptyEntriesSet();
             CountExceedingBehaviour = countExceedingBehaviour.ThrowIfInvalid();
             EnumerationDone = count == 0;

src/InternalExtensions.cs

@@ -46,6 +46,39 @@ public static int ThrowIfNegative(this int value)
         }
 #endif
 
+#if NETCOREAPP3_0_OR_GREATER
+        /// <summary>
+        /// Throws an <see cref="ArgumentException"/> if <paramref name="options"/> is not a valid flag.
+        /// </summary>
+        /// <param name="options">The argument to validate as a valid flag.</param>
+        /// <param name="paramName">The name of the parameter with which <paramref name="options"/> corresponds.</param>
+        /// <returns><paramref name="options"/>.</returns>
+        public static StringSplitOptions ThrowIfInvalid(this StringSplitOptions options, [CallerArgumentExpression(nameof(options))] string? paramName = null)
+        {
+            if((options & ~CombinationOfAllValidStringSplitOptions) != 0)
+            {
+                throw new ArgumentException("Value of flag is invalid.", paramName);
+            }
+
+            return options;
+        }
+#else
+        /// <summary>
+        /// Throws an <see cref="ArgumentException"/> if <paramref name="options"/> is not a valid flag.
+        /// </summary>
+        /// <param name="options">The argument to validate as a valid flag.</param>
+        /// <returns><paramref name="options"/>.</returns>
+        public static StringSplitOptions ThrowIfInvalid(this StringSplitOptions options)
+        {
+            if((options & ~CombinationOfAllValidStringSplitOptions) != 0)
+            {
+                throw new ArgumentException("Value of flag is invalid.");
+            }
+
+            return options;
+        }
+#endif
+
         /// <summary>
         /// Determines whether the <see cref="StringSplitOptions.RemoveEmptyEntries"/> bit field is set in the current instance.
         /// </summary>
@@ -68,7 +101,7 @@ public static bool IsRemoveEmptyEntriesSet(this StringSplitOptions options)
         public static bool IsTrimEntriesSet(this StringSplitOptions options)
         {
             return options.HasFlag(StringSplitOptions.TrimEntries);
-    }
+        }
 #else
         /// <summary>
         /// Always returns false.
@@ -80,5 +113,28 @@ public static bool IsTrimEntriesSet(this StringSplitOptions options)
             return false;
         }
 #endif
+
+        /// <summary>
+        /// Gets all values of an enum and applies the or operation on them.
+        /// </summary>
+        /// <typeparam name="T">The target enum type.</typeparam>
+        /// <returns>The combination of all valid enum values.</returns>
+        public static T GetCombinationOfAllValidFlags<T>() where T : struct, Enum
+        {
+#if NET5_0_OR_GREATER
+            T[] flags = Enum.GetValues<T>();
+#else
+            T[] flags = (T[])Enum.GetValues(typeof(T));
+#endif
+
+            int combination = 0;
+            foreach(T flag in flags)
+            {
+                combination |= (int)(object)flag;
+            }
+            return (T)(object)combination;
+        }
+
+        static readonly StringSplitOptions CombinationOfAllValidStringSplitOptions = GetCombinationOfAllValidFlags<StringSplitOptions>();
     }
 }