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Wildcard string compare (globbing)

, 15 Feb 2005
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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

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

Jack Handy
Web Developer
United States United States
No Biography provided

Comments and Discussions

 
AnswerAnother C# version, with a twist Pinmembertomlev29-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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