Parsing

parsing_helps.cs

public class SubstringResponse {
    public string Value { get; set; }
    public int loc1 { get; set; }
    public int loc2 { get; set; }
}

public static SubstringResponse Substring(this string source, string startPos, string endPos) {
    return Substring(source, new List<string>() { startPos }, endPos);
}
public static SubstringResponse Substring(this string source, List<string> startPos, string endPos) {
    var loc1 = source.IndexOf(startPos[0]);
    var loc2 = -1;
    if (loc1 >= 0) {
        loc1 = loc1 + startPos[0].Length;
        if (startPos.Count > 1) {
            for (var i = 1; i < startPos.Count; i++) {
                loc1 = source.IndexOf(startPos[i], loc1);
                if (loc1 < 0) {
                    return new SubstringResponse() { Value = "", loc1 = loc1, loc2 = loc2 };
                } else {
                    loc1 = loc1 + startPos[i].Length;
                }
            }
        }
        loc2 = source.IndexOf(endPos, loc1);
        if (loc2 > loc1) {
            return new SubstringResponse() { Value = source.Substring(loc1, loc2 - loc1), loc1 = loc1, loc2 = loc2 };
        } else {
            return new SubstringResponse() { Value = "", loc1 = loc1, loc2 = loc2 };
        }
    } else {
        return new SubstringResponse() { Value = "", loc1 = loc1, loc2 = loc2 };
    }
}