System.Xml.Serialization.XmlSerializationReader.ParseArrayType C# (CSharp) Method

        private SoapArrayInfo ParseArrayType(string value)
        {
            if (value == null)
            {
                throw new ArgumentNullException(SR.Format(SR.XmlMissingArrayType, CurrentTag()));
            }

            if (value.Length == 0)
            {
                throw new ArgumentException(SR.Format(SR.XmlEmptyArrayType, CurrentTag()), nameof(value));
            }

            char[] chars = value.ToCharArray();
            int charsLength = chars.Length;

            SoapArrayInfo soapArrayInfo = new SoapArrayInfo();

            // Parse backwards to get length first, then optional dimensions, then qname.
            int pos = charsLength - 1;

            // Must end with ]
            if (chars[pos] != ']')
            {
                throw new ArgumentException(SR.XmlInvalidArraySyntax, nameof(value));
            }
            pos--;

            // Find [
            while (pos != -1 && chars[pos] != '[')
            {
                if (chars[pos] == ',')
                    throw new ArgumentException(SR.Format(SR.XmlInvalidArrayDimentions, CurrentTag()), nameof(value));
                pos--;
            }
            if (pos == -1)
            {
                throw new ArgumentException(SR.XmlMismatchedArrayBrackets, nameof(value));
            }

            int len = charsLength - pos - 2;
            if (len > 0)
            {
                string lengthString = new String(chars, pos + 1, len);
                try
                {
                    soapArrayInfo.length = Int32.Parse(lengthString, CultureInfo.InvariantCulture);
                }
                catch (Exception e)
                {
                    if (e is OutOfMemoryException)
                    {
                        throw;
                    }
                    throw new ArgumentException(SR.Format(SR.XmlInvalidArrayLength, lengthString), nameof(value));
                }
            }
            else
            {
                soapArrayInfo.length = -1;
            }

            pos--;

            soapArrayInfo.jaggedDimensions = 0;
            while (pos != -1 && chars[pos] == ']')
            {
                pos--;
                if (pos < 0)
                    throw new ArgumentException(SR.XmlMismatchedArrayBrackets, nameof(value));
                if (chars[pos] == ',')
                    throw new ArgumentException(SR.Format(SR.XmlInvalidArrayDimentions, CurrentTag()), nameof(value));
                else if (chars[pos] != '[')
                    throw new ArgumentException(SR.XmlInvalidArraySyntax, nameof(value));
                pos--;
                soapArrayInfo.jaggedDimensions++;
            }

            soapArrayInfo.dimensions = 1;

            // everything else is qname - validation of qnames?
            soapArrayInfo.qname = new String(chars, 0, pos + 1);
            return soapArrayInfo;
        }