How to determine if a File Matches a File Mask?

Question

I need to decide whether file name fits to file mask. The file mask could contain * or ? characters. Is there any simple solution for this?

bool bFits = Fits         


        

Answer 1

Fastest version of the previously proposed function:

    public static bool FitsMasks(string filePath, params string[] fileMasks)
            // or
    public static Regex FileMasksToRegex(params string[] fileMasks)
    {
        if (!_maskRegexes.ContainsKey(fileMasks))
        {
            StringBuilder sb = new StringBuilder("^");
            bool first = true;
            foreach (string fileMask in fileMasks)
            {
                if(first) first =false; else sb.Append("|");
                sb.Append('(');
                foreach (char c in fileMask)
                {
                    switch (c)
                    {
                        case '*': sb.Append(@".*"); break;
                        case '?': sb.Append(@"."); break;
                        default:
                                sb.Append(Regex.Escape(c.ToString()));
                            break;
                    }
                }
                sb.Append(')');
            }
            sb.Append("$");
            _maskRegexes[fileMasks] = new Regex(sb.ToString(), RegexOptions.IgnoreCase);
        }
        return _maskRegexes[fileMasks].IsMatch(filePath);
                    // or
        return _maskRegexes[fileMasks];
    }
    static readonly Dictionary _maskRegexes = new Dictionary(/*unordered string[] comparer*/);

Notes:

1. Re-using Regex objects.
2. Using StringBuilder to optimize Regex creation (multiple .Replace() calls are slow).
3. Multiple masks, combined with OR.
4. Another version returning the Regex.