Pchp.Library.Arrays.array_unique C# (CSharp) Method

        public static PhpArray array_unique(Context ctx, PhpArray array, ComparisonMethod sortFlags = ComparisonMethod.String)
        {
            if (array == null)
            {
                //PhpException.ArgumentNull("array");
                //return null;
                throw new ArgumentNullException();
            }

            IComparer<PhpValue> comparer;
            switch (sortFlags)
            {
                case ComparisonMethod.Regular:
                    comparer = PhpComparer.Default; break;
                case ComparisonMethod.Numeric:
                    comparer = PhpNumericComparer.Default; break;
                case ComparisonMethod.String:
                    comparer = new PhpStringComparer(ctx); break;
                case ComparisonMethod.LocaleString:
                //comparer = new PhpLocaleStringComparer(ctx); break;
                default:
                    //PhpException.ArgumentValueNotSupported("sortFlags", (int)sortFlags);
                    //return null;
                    throw new ArgumentException(nameof(sortFlags));
            }

            var result = new PhpArray(array.Count);

            var/*!*/identitySet = new HashSet<object>();

            // get only unique values - first found
            using (var enumerator = array.GetFastEnumerator())
                while (enumerator.MoveNext())
                {
                    if (identitySet.Add(enumerator.CurrentValue.GetValue()))
                    {
                        result.Add(enumerator.Current);
                    }
                }

            //result.InplaceCopyOnReturn = true;
            return result;
        }