public static NameValueCollection GetQueryNameValuePairs()

in src/WebJobs.Extensions.DurableTask/HttpRequestMessageExtensions.cs [64:128]
50 lines of code
10 McCabe index (conditional complexity)

        public static NameValueCollection GetQueryNameValuePairs(this HttpRequestMessage request)
        {
            var values = new NameValueCollection(StringComparer.OrdinalIgnoreCase);
            var s = request.RequestUri.Query;
            var separator = '&';

            int l = (s != null) ? s.Length : 0;
            int i = 1; // skip the leading '?' character

            while (i < l)
            {
                // find next & while noting first = on the way (and if there are more)
                int si = i;
                int ti = -1;

                while (i < l)
                {
                    char ch = s[i];

                    if (ch == '=')
                    {
                        if (ti < 0)
                        {
                            ti = i;
                        }
                    }
                    else if (ch == separator) // e.g. '&' or ';'
                    {
                        break;
                    }

                    i++;
                }

                // extract the name / value pair
                string name = null;
                string value = null;

                if (ti >= 0)
                {
                    name = s.Substring(si, ti - si).Trim();
                    value = s.Substring(ti + 1, i - ti - 1).Trim();
                }
                else
                {
                    name = string.Empty;
                    value = s.Substring(si, i - si).Trim();
                }

                // add name / value pair to the collection (nulls are okay for either)
                values.Add(
                    WebUtility.UrlDecode(name),
                    WebUtility.UrlDecode(value));

                // trailing '&'
                if (i == l - 1 && s[i] == separator)
                {
                    values.Add(string.Empty, string.Empty);
                }

                i++;
            }

            return values;
        }