public static IEnumerable ParseCSVLine()

in Amazon.KinesisTap.Common/Utility.cs [110:171]
57 lines of code
8 McCabe index (conditional complexity)

        public static IEnumerable<string> ParseCSVLine(string input, StringBuilder stringBuilder)
        {
            const char columnSeparator = ',';
            if (string.IsNullOrEmpty(input))
            {
                yield break;
            }

            stringBuilder.Clear();

            int index = 0;
            int escapeCount = 0;

            for (; index < input.Length; index++)
            {
                if (input[index] == '"')
                {
                    escapeCount++;
                    stringBuilder.Append('"');
                }
                else if (input[index] == columnSeparator)
                {
                    if ((escapeCount % 2) == 0)
                    {
                        if (escapeCount == 0)
                        {
                            yield return stringBuilder
                                .ToString();
                        }
                        else
                        {
                            yield return stringBuilder
                                .Extract('"')
                                .Replace(@"""""", @"""");
                        }

                        stringBuilder.Clear();
                        escapeCount = 0;
                    }
                    else
                    {
                        stringBuilder.Append(columnSeparator);
                    }
                }
                else
                {
                    stringBuilder.Append(input[index]);
                }
            }

            if (escapeCount == 0)
            {
                yield return stringBuilder
                    .ToString();
            }
            else
            {
                yield return stringBuilder
                    .Extract('"')
                    .Replace(@"""""", @"""");
            }
        }