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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.

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About the Author

Jack Handy
Web Developer
United States United States
No Biography provided

Comments and Discussions

 
Generalmp and cp Pinmembertwopieman15-Mar-05 12:59 
GeneralRe: mp and cp Pinmemberradboudp16-Feb-07 2:14 
GeneralOK, but ... PinmemberSam Levy16-Feb-05 5:48 
QuestionWhy make 3 loop ? PinmemberDarkYoda Mickael2-Feb-05 23:22 
AnswerRe: Why make 3 loop ? PinmemberJack Handy13-Feb-05 11:02 
GeneralC# version PinmemberSancy26-Oct-04 7:23 
GeneralRe: C# version PinsussPsyk6621-Dec-04 4:39 
GeneralRe: C# version PinmemberIonut FIlip22-Feb-05 7:15 
GeneralRe: C# version Pinmemberrobagar3-Apr-06 17:58 
hiya
 
Just thought I'd share my version of this code
 
- put the whole shebang into a class with public static methods
- fixed a bug where the pattern '?' matches all strings
- added an early-exit test for patterns that don't actually contain wildcards so it just defaults to normal string comparison
 
cheers
Rob
 

 

     /// <summary>
     /// Class providing wildcard string matching.
     /// </summary>
     public class Wildcard
     {
          private Wildcard()
          {
          }
 
          /// <summary>
          /// Array of valid wildcards
          /// </summary>
          private static char[] Wildcards = new char[]{'*', '?'};
 
          /// <summary>
          /// Returns true if the string matches the pattern which may contain * and ? wildcards.
          /// Matching is done without regard to case.
          /// </summary>
          /// <param name="pattern"></param>
          /// <param name="s"></param>
          /// <returns></returns>
          public static bool Match(string pattern, string s)
          {
               return Match(pattern, s, false);
          }
 
          /// <summary>
          /// Returns true if the string matches the pattern which may contain * and ? wildcards.
          /// </summary>
          /// <param name="pattern"></param>
          /// <param name="s"></param>
          /// <param name="caseSensitive"></param>
          /// <returns></returns>
          public static bool Match(string pattern, string s, bool caseSensitive)
          {
               // if not concerned about case, convert both string and pattern
               // to lower case for comparison
               if (!caseSensitive)
               {
                    pattern = pattern.ToLower();
                    s = s.ToLower();
               }
 
               // if pattern doesn't actually contain any wildcards, use simple equality
               if (pattern.IndexOfAny(Wildcards) == -1)
                    return (s == pattern);
 
               // otherwise do pattern matching
               int i=0;
               int j=0;
               while (i < s.Length && j < pattern.Length && pattern[j] != '*')
               {
                    if ((pattern[j] != s[i]) && (pattern[j] != '?'))
                    {
                         return false;
                    }
                    i++;
                    j++;
               }
 
               // if we have reached the end of the pattern without finding a * wildcard,
               // the match must fail if the string is longer or shorter than the pattern
               if (j == pattern.Length)
                    return s.Length == pattern.Length;
         
               int cp=0;
               int mp=0;
               while (i < s.Length)
               {
                    if (j < pattern.Length && pattern[j] == '*')
                    {
                         if ((j++)>=pattern.Length)
                         {
                              return true;
                         }
                         mp = j;
                         cp = i+1;
                    }
                    else if (j < pattern.Length && (pattern[j] == s[i] || pattern[j] == '?'))
                    {
                         j++;
                         i++;
                    }
                    else
                    {
                         j = mp;
                         i = cp++;
                    }
               }
         
               while (j < pattern.Length && pattern[j] == '*')
               {
                    j++;
               }
 
               return j >= pattern.Length;
          }
     }

GeneralRe: C# version PinmemberSancy5-Jun-06 17:01 

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