SimpleCSVParser.cs

public static class SimpleCSVParser {
    static List<List<string>> ParseCSV(string text) {
        var list = new List<List<string>>();
        List<string> row = null;

        var sb = new StringBuilder();
        int i = 0;
        while (i < text.Length) {
            var c = text[i++];
            if (c == '"') {
                ReadString(text, ref i, sb);
            } else if (c == '\r') {
                continue;
            } else if (c == '\n') {
                AddCell(ref row, sb);
                AddRow(list, ref row);
            } else if (c == ',') {
                AddCell(ref row, sb);
            } else {
                sb.Append(c);
            }
        }
        AddCell(ref row, sb);
        AddRow(list, ref row);
        return list;
    }

    static void AddCell(ref List<string> row, StringBuilder sb) {
        if (row == null) {
            row = new List<string>();
        }
        row.Add(sb.ToString());
        sb.Length = 0;
    }

    static void AddRow(List<List<string>> list, ref List<string> row) {
        if (row != null) {
            list.Add(row);
            row = null;
        }
    }

    static void ReadString(string text, ref int i, StringBuilder sb) {
        while (i < text.Length) {
            var c = text[i++];
            if (c == '"') {
                if (i >= text.Length) {
                    return;
                }
                c = text[i++];
                if (c != '"') {
                    i--;
                    return;
                }
            }
            sb.Append(c);
        }
    }
}