System.Xml.XmlBaseReader.GetAttributeNode C# (CSharp) Méthode

        private XmlAttributeNode GetAttributeNode(string name)
        {
            if (name == null)
                throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(new ArgumentNullException(nameof(name)));
            if (!_node.CanGetAttribute)
                return null;
            int index = name.IndexOf(':');
            string prefix;
            string localName;
            if (index == -1)
            {
                if (name == xmlns)
                {
                    prefix = xmlns;
                    localName = string.Empty;
                }
                else
                {
                    prefix = string.Empty;
                    localName = name;
                }
            }
            else
            {
                // If this function becomes a performance issue because of the allocated strings then we can
                // make a version of Equals that takes an offset and count into the string.
                prefix = name.Substring(0, index);
                localName = name.Substring(index + 1);
            }
            XmlAttributeNode[] attributeNodes = _attributeNodes;
            int attributeCount = _attributeCount;
            int attributeIndex = _attributeStart;
            for (int i = 0; i < attributeCount; i++)
            {
                if (++attributeIndex >= attributeCount)
                {
                    attributeIndex = 0;
                }
                XmlAttributeNode attributeNode = attributeNodes[attributeIndex];
                if (attributeNode.IsPrefixAndLocalName(prefix, localName))
                {
                    _attributeStart = attributeIndex;
                    return attributeNode;
                }
            }
            return null;
        }