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

        public static PhpArray array_count_values(PhpArray array)
        {
            if (array == null)
            {
                //PhpException.ArgumentNull("array");
                //return null;
                throw new ArgumentNullException();
            }

            PhpArray result = new PhpArray();

            var iterator = array.GetFastEnumerator();
            while (iterator.MoveNext())
            {
                // dereferences value:
                var val = iterator.CurrentValue.GetValue();
                IntStringKey askey;

                switch (val.TypeCode)
                {
                    case PhpTypeCode.Int32:
                    case PhpTypeCode.Long:
                    case PhpTypeCode.String:
                    case PhpTypeCode.WritableString:
                        askey = val.ToIntStringKey();
                        break;
                    default:
                        // TODO: PhpException.Throw(PhpError.Warning, LibResources.GetString("neither_string_nor_integer_value", "count"));
                        throw new ArgumentException();
                }

                var countval = result[askey].ToLong();  // 0 for nonexisting entry
                result[askey] = PhpValue.Create(countval + 1L);
            }

            // no need to deep copy (values are ints):
            return result;
        }