C# Template parsing and matching with text file

Need some ideas how to solve this problem. I have a template file what describes the line in the text file. For example:

Template

[%f1%]|[%f2%]|[%f3%]"[%f4%]"[%f5%]"[%f6%]

Text file

1234|1234567|123"12345"12"123456

Now i need to read in the fields from the text file. In the template file fields are described开发者_开发知识库 with [%some name%]. Allso in the template file there is set what the field separators are, in this example here there are | and ". The lenght of the fields can change through different files but the separators will stay the same. What would be the best way to read in the template and by template read in the text file?

EDIT: Text file has multiple rows, like this:

1234|1234567|123"12345"12"123456"\r\n
1234|field|123"12345"12"asdasd"\r\n
123sd|1234567|123"asdsadf"12"123456"\r\n
45gg|somedata|123"12345"12"somefield"\r\n

EDIT2: Ok, lets make it even harder. Some fields can contain binary data and i know the starting and end position of the binary data field. I should be able to mark those fields in the template and then the parser will know that this field is binary. How to solve this problem?

I would create a regex based on the template and then parse the text file using that:

class Parser
{
    private static readonly Regex TemplateRegex =
        new Regex(@"\[%(?<field>[^]]+)%\](?<delim>[^[]+)?");

    readonly List<string> m_fields = new List<string>();
    private readonly Regex m_textRegex;

    public Parser(string template)
    {
        var textRegexString = '^' + TemplateRegex.Replace(template, Evaluator) + '$';
        m_textRegex = new Regex(textRegexString);
    }

    string Evaluator(Match match)
    {
        // add field name to collection and create regex for the field
        var fieldName = match.Groups["field"].Value;
        m_fields.Add(fieldName);
        string result = "(.*?)";

        // add delimiter to the regex, if it exists
        // TODO: check, that only last field doesn't have delimiter
        var delimGroup = match.Groups["delim"];
        if (delimGroup.Success)
        {
            string delim = delimGroup.Value;
            result += Regex.Escape(delim);
        }
        return result;
    }

    public IDictionary<string, string> Parse(string text)
    {
        var match = m_textRegex.Match(text);
        var groups = match.Groups;

        var result = new Dictionary<string, string>(m_fields.Count);

        for (int i = 0; i < m_fields.Count; i++)
            result.Add(m_fields[i], groups[i + 1].Value);

        return result;
    }
}

You can parse the template using regular expressions. An expression like this will match each field definition and separator:

Match m = Regex.Match(template, @"^(\[%(?<name>.+?)%\](?<separator>.)?)+$")

The match will contain two named groups for (name and separator), each of which will contain a number of captures for each time they matched in the input string. In your example, the separator group would have one less capture than the name group.

You can then iterate over the captures, and use the results to extract the fields from the input string and store the values, like this:

if( m.Success )
{
    Group name = m.Groups["name"];
    Group separator = m.Groups["separator"];
    int index = 0;
    Dictionary<string, string> fields = new Dictionary<string, string>();
    for( int x = 0; x < name.Captures.Count; ++x )
    {
        int separatorIndex = input.Length;
        if( x < separator.Captures.Count )
            separatorIndex = input.IndexOf(separator.Captures[x].Value, index);
        fields.Add(name.Captures[x].Value, input.Substring(index, separatorIndex - index));
        index = separatorIndex + 1;
    }
    // Do something with results.
}

Obviously in a real program you'd have to account for invalid input and such, which I didn't do here.

I would do this with a few lines of code. Loop through your template row, grabbing all text between "[" as the variable name and everything else as a terminator. Read all the text to the terminal, assign it to the variable name, repeat.

1- Use API for that sscanf(line, format, __arglist) check here

2- Use string split Like:

public IEnumerable<int> GetDataFromLines(string[] lines)
{ 
    //handle the output data
    List<int> data = new List<int>();

    foreach (string line in lines)
    {
        string[] seperators = new string[] { "|", "\"" };

        string[] results = line.Split(seperators, StringSplitOptions.RemoveEmptyEntries);

        foreach (string result in results)
        {
            data.Add(int.Parse(result));
        }
    }

    return data;
}

Test it with line:

line = "1234|1234567|123\"12345\"12\"123456";
string[] lines = new string[] { line };

GetDataFromLines(lines);

//output list items are:
1234
1234567
123
12345
12
123456