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Wildcard string compare (globbing)

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15 Feb 2005 1.1M   96   144
Matches a string against a wildcard string such as "*.*" or "bl?h.*" etc. This is good for file globbing or to match hostmasks.

Usage:

This is a fast, lightweight, and simple pattern matching function.

if (wildcmp("bl?h.*", "blah.jpg")) {
  //we have a match!
} else {
  //no match =(
}

Function:

int wildcmp(const char *wild, const char *string) {
  // Written by Jack Handy - <A href="mailto:jakkhandy@hotmail.com">jakkhandy@hotmail.com</A>
  const char *cp = NULL, *mp = NULL;

  while ((*string) && (*wild != '*')) {
    if ((*wild != *string) && (*wild != '?')) {
      return 0;
    }
    wild++;
    string++;
  }

  while (*string) {
    if (*wild == '*') {
      if (!*++wild) {
        return 1;
      }
      mp = wild;
      cp = string+1;
    } else if ((*wild == *string) || (*wild == '?')) {
      wild++;
      string++;
    } else {
      wild = mp;
      string = cp++;
    }
  }

  while (*wild == '*') {
    wild++;
  }
  return !*wild;
}

License

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Comments and Discussions

 
AnswerAnother C# version, with a twist Pin
Thomas Levesque29-Jun-10 14:50
professionalThomas Levesque29-Jun-10 14:50 
Just for fun... a C# version with almost the same syntax as the original C version Smile | :)

public static bool wildcmp(string pattern, string text) {

  var wild = new StringScanner(pattern);
  var @string = new StringScanner(text);

  var mp = wild;
  var cp = @string;

  while (@string && wild != '*') {
    if (wild != @string && wild != '?') {
      return false;
    }
    wild++;
    @string++;
  }

  while (@string) {
    if (@wild == '*') {
      if (!++wild) {
        return true;
      }
      mp = wild;
      cp = @string + 1;
    } else if (wild == @string || wild == '?') {
      wild++;
      @string++;
    } else {
      wild = mp;
      @string = cp++;
    }
  }

  while (wild == '*') {
    wild++;
  }
  return !wild;
}

public struct StringScanner
{
    private string _string;
    private int _position;
    
    public StringScanner(string s)
    {
        _string = s;
        _position = 0;
    }
    
    public string String
    {
        get { return _string; }
    }
    
    public int Position
    {
        get { return _position; }
    }
        
    public bool Finished
    {
        get { return _position == _string.Length;}
    }
    
    public char Current
    {
        get { return Finished ? '\0' : _string[_position]; }
    }
    
    public bool MoveNext()
    {
        if (Finished)
            return false;
        _position++;
        return true;
    }
    
    public static StringScanner operator ++(StringScanner scanner)
    {
        scanner.MoveNext();
        return scanner;
    }
    
    public static StringScanner operator +(StringScanner scanner, int n)
    {
        return new StringScanner(scanner.String)
        {
            _position = Math.Min(scanner.Position + n, scanner.String.Length)
        };
    }
    
    public static implicit operator bool(StringScanner scanner)
    {
        return !scanner.Finished;
    }
    
    public static implicit operator char(StringScanner scanner)
    {
        return scanner.Current;
    }
    
    public static bool operator ==(StringScanner scanner1, StringScanner scanner2)
    {
        return scanner1.Current == scanner2.Current;
    }
    
    public static bool operator !=(StringScanner scanner1, StringScanner scanner2)
    {
        return scanner1.Current != scanner2.Current;
    }
}

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