Click here to Skip to main content
11,641,064 members (63,627 online)
Click here to Skip to main content

Wildcard string compare (globbing)

, 15 Feb 2005 814.7K 94
Rate this:
Please Sign up or sign in to vote.
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

Share

About the Author

Jack Handy
Web Developer
United States United States
No Biography provided

You may also be interested in...

Comments and Discussions

 
Generaldelphi port Pin
vovach77723-Dec-14 3:38
membervovach77723-Dec-14 3:38 
QuestionMy vote of 5+ Pin
Sanmayce29-Nov-13 7:47
memberSanmayce29-Nov-13 7:47 
GeneralMy vote of 5 Pin
Franc Morales29-May-13 15:47
memberFranc Morales29-May-13 15:47 
Questionhelp required for wilcard matching * and # Pin
SaimaAsif23-Feb-12 23:56
memberSaimaAsif23-Feb-12 23:56 
GeneralMy vote of 5 Pin
Plamen Petrov13-Dec-11 21:37
memberPlamen Petrov13-Dec-11 21:37 
SuggestionModification with '#' as wildcard joker for digits Pin
Thomas Haase25-Sep-11 23:16
memberThomas Haase25-Sep-11 23:16 
QuestionLicence Question Pin
randommark23-Nov-10 0:33
memberrandommark23-Nov-10 0:33 
AnswerAnother C# version, with a twist Pin
tomlev29-Jun-10 14:50
membertomlev29-Jun-10 14:50 
GeneralObscurity Pin
Chuck O'Toole25-Apr-10 18:18
memberChuck O'Toole25-Apr-10 18:18 
AnswerMy C# contribution - recursive, of course! Pin
RenniePet26-Mar-10 5:21
memberRenniePet26-Mar-10 5:21 
GeneralRe: My C# contribution - recursive, of course! Pin
Erwin de GRoot29-Mar-10 1:58
memberErwin de GRoot29-Mar-10 1:58 
GeneralDepends on whether you need to optimize the last few nanoseconds out of it... Pin
RenniePet29-Mar-10 7:45
memberRenniePet29-Mar-10 7:45 
GeneralSorry - revised numbers Pin
RenniePet29-Mar-10 8:35
memberRenniePet29-Mar-10 8:35 
GeneralRe: Depends on whether you need to optimize the last few nanoseconds out of it... Pin
Erwin de GRoot29-Mar-10 8:37
memberErwin de GRoot29-Mar-10 8:37 
GeneralYet another version - 25% faster, I think [modified] Pin
RenniePet1-Apr-10 8:24
memberRenniePet1-Apr-10 8:24 
If at first you don't succeed...

Here's my third version, where I say to hell with minimizing lines of code and try to optimize the speed. No "unsafe" code though, unless you consider "goto" to be unsafe coding. Smile | :)

   public class MString
   {
      /// <summary>
      /// Compare two strings, where strA may contain wildcard characters '*' and '?'. 
      /// </summary>
      /// <param name="strA">string which may contain wildcards, may be empty, 
      ///                    must not be null</param>
      /// <param name="strB">string to compare to, no wildcard processing, may be empty, 
      ///                    must not be null</param>
      /// <param name="ignoreCase">true = ignore upper/lower case, false = observe case</param>
      /// <returns>true = match, false = non-match</returns>
      public static bool CompareWWc(string strA, string strB, bool ignoreCase)
      {
         if (ignoreCase)
            return CompareWWc(strA.ToLower(), strB.ToLower());
         else 
            return CompareWWc(strA, strB);
      }
 
      
      /// <summary>
      /// Compare two strings, where strA may contain wildcard characters '*' and '?'. 
      /// 
      /// In the comments, the word 'segment' is used to talk about the portions of strA that
      /// fall between two '*' characters, or between the start of the string and the first '*'
      /// or between the last '*' and the end of the string.
      /// </summary>
      /// <param name="strA">string which may contain wildcards, may be empty, 
      ///                    must not be null</param>
      /// <param name="strB">string to compare to, no wildcard processing, may be empty, 
      ///                    must not be null</param>
      /// <returns>true = match, false = non-match</returns>
      public static bool CompareWWc(string strA, string strB)
      {
         int starPtr = 0;  // Points at the '*' in strA

         // This part of the code handles the first segment in strA, or the case where strA
         //  does not contain any '*' character at all. The first segment is fairly simple to
         //  handle because it must match from the start of strB - no need to have a sliding 
         //  match loop.

         // Check strB long enough so we don't need to test for hitting its end while scanning
         if (strB.Length >= strA.Length)
         {
            // Simple optimized scan of first segment of strA and comparison with strB
            for (;; starPtr++)
            {
               if (starPtr == strA.Length)
                  return strA.Length == strB.Length;  // No '*' in strA and no mismatch
               if (strA[starPtr] == '*')
                  goto firstSegmentMatches;
               if (strA[starPtr] != strB[starPtr] && strA[starPtr] != '?')
                  return false;  // Mismatch
            }
         }
         else
         {
            // When strB is shorter than strA a match is not likely. But if strA contains 
            //  enough '*' characters it is possible, so we have to give it a try.
            for (;; starPtr++)
            {
               if (strA[starPtr] == '*')
                  goto firstSegmentMatches;
               if (starPtr == strB.Length)
                  return false;  // No '*' in strA before end of strB encountered
               if (strA[starPtr] != strB[starPtr] && strA[starPtr] != '?')
                  return false;  // Mismatch
            }
         }
 
         // The rest of the code handles the case where strA does contain one or more '*' 
         //  characters, and the first segment does match the start of strB.

      firstSegmentMatches:
 
         int indexA;  // Start of segment in strA
         int indexB = starPtr;  // Sliding match location in strB
         
         // Loop to process the segments in strA
         while (true)
         {
            // Test if next segment is last and empty
            indexA = ++starPtr;  // Point past '*'
            if (indexA == strA.Length)
               return true;  // Last segment empty - matches irrespective of strB content

            // Scan over the next segment in strA
            for (;; starPtr++)
               if (starPtr == strA.Length || strA[starPtr] == '*')
                  break;
 
            // Try to find match for this segment somewhere in strB
            for (;; indexB++)
            {
               if (starPtr - indexA > strB.Length - indexB)
                  return false;  // Mismatch if not enough characters left in strB

               for (int i = indexA, j = indexB; i < starPtr; i++, j++)
                  if (strA[i] != strB[j] && strA[i] != '?')
                     goto tryStringBAgain;
               
               goto findNextSegment;  // Match found for this segment in strB 

            tryStringBAgain:
               continue;
            }
 
            // Was that last segment? Return if so, loop if not.
         findNextSegment:
            indexB += starPtr - indexA;  // Point past matching portion of strB
            if (starPtr == strA.Length)
               return indexB == strB.Length;  // Return if that was last segment
         }
      }
 
   }

And here are my timing results (which I'm not totally sure of, I'm not used to timing code):

My original version:  243 nanoseconds    17 lines of code
Erwin's version:       76 nanoseconds    42 lines of code
My second version:    111 nanoseconds    16 lines of code
My third version:      56 nanoseconds    52 lines of code

I'd appreciate it if someone would check this out and let me know if they find any bugs or anything.
GeneralRe: Yet another version - 25% faster, I think Pin
aleks1k21-Sep-11 2:47
memberaleks1k21-Sep-11 2:47 
QuestionI used this function but I how I can catch variables from the * ??? Pin
moh.hijjawi20-Oct-09 1:55
membermoh.hijjawi20-Oct-09 1:55 
AnswerRe: I used this function but I how I can catch variables from the * ??? Pin
RenniePet1-Apr-10 11:27
memberRenniePet1-Apr-10 11:27 
Questionany updates ? Pin
alhambra-eidos2-Jul-09 5:12
memberalhambra-eidos2-Jul-09 5:12 
GeneralImproved matching with end-of-text Pin
Anders Heie11-May-09 15:20
memberAnders Heie11-May-09 15:20 
GeneralRe: Improved matching with end-of-text: some cases don't work properly! Pin
roadrunner31412-Aug-09 3:35
memberroadrunner31412-Aug-09 3:35 
GeneralRe: Improved matching with end-of-text: some cases don't work properly! Pin
sdiazdiaz20-Jun-13 1:50
membersdiazdiaz20-Jun-13 1:50 
QuestionPathMatchSpec instead? Pin
kintz25-Mar-09 8:55
memberkintz25-Mar-09 8:55 
AnswerRe: PathMatchSpec instead? Pin
MandatoryDefault31-Aug-09 10:39
memberMandatoryDefault31-Aug-09 10:39 
Questionwchar_t version? Pin
rmorales8729-Nov-08 20:16
memberrmorales8729-Nov-08 20:16 
AnswerRe: wchar_t version? Pin
razvar31-Mar-11 21:49
memberrazvar31-Mar-11 21:49 
Generalwildcmp in XBLite Pin
CodeGibbon27-Nov-08 13:56
memberCodeGibbon27-Nov-08 13:56 
GeneralWildcard string compare in C# Pin
haiquang10-Nov-08 22:15
memberhaiquang10-Nov-08 22:15 
GeneralRe: Wildcard string compare in C# Pin
haiquang3-Aug-09 22:22
memberhaiquang3-Aug-09 22:22 
GeneralC# Direct Port Pin
hempels23-Sep-08 15:10
memberhempels23-Sep-08 15:10 
General...and yet another C# port [modified] Pin
DVF27-Aug-10 16:59
memberDVF27-Aug-10 16:59 
GeneralRe: ...and yet another C# port Pin
VUnreal21-Sep-10 11:22
memberVUnreal21-Sep-10 11:22 
General[Message Removed] Pin
stonber18-Sep-08 14:22
memberstonber18-Sep-08 14:22 
GeneralUsing in Artistic Style Pin
jimp023-Apr-08 4:43
memberjimp023-Apr-08 4:43 
GeneralGeez... Pin
larryfr5-Mar-08 9:39
memberlarryfr5-Mar-08 9:39 
QuestionConvert to a replace? Pin
williaps20-Mar-07 8:31
memberwilliaps20-Mar-07 8:31 
GeneralC# RexExp version Pin
spinsane4-Nov-06 6:30
memberspinsane4-Nov-06 6:30 
GeneralKudos Pin
quantumred14-Oct-06 4:37
memberquantumred14-Oct-06 4:37 
GeneralRe: Kudos Pin
milkplus24-Feb-10 11:19
membermilkplus24-Feb-10 11:19 
Generalwildcmp(&quot;*&amp;lt;*&amp;gt;&quot;, &quot;&amp;lt;field1&amp;gt;&amp;lt;field2&amp;gt;&quot;) not working [modified] Pin
Daniel B.6-Sep-06 13:14
memberDaniel B.6-Sep-06 13:14 
GeneralRe: wildcmp(&quot;*&amp;lt;*&amp;gt;&quot;, &quot;&amp;lt;field1&amp;gt;&amp;lt;field2&amp;gt;&quot;) not working Pin
radboudp16-Feb-07 0:35
memberradboudp16-Feb-07 0:35 
Generalreturn value type Pin
wdx048-Jan-06 15:49
memberwdx048-Jan-06 15:49 
General*? case match Pin
talimu3-Nov-05 23:42
membertalimu3-Nov-05 23:42 
GeneralRe: *? case match Pin
kuhnm15-Sep-06 2:18
memberkuhnm15-Sep-06 2:18 
GeneralRe: *? case match Pin
kuhnm18-Sep-06 4:48
memberkuhnm18-Sep-06 4:48 
GeneralGets my 5 Pin
Franc Morales18-Oct-05 17:05
memberFranc Morales18-Oct-05 17:05 
Generalmp and cp Pin
twopieman15-Mar-05 11:59
membertwopieman15-Mar-05 11:59 
GeneralRe: mp and cp Pin
radboudp16-Feb-07 1:14
memberradboudp16-Feb-07 1:14 
GeneralOK, but ... Pin
Sam Levy16-Feb-05 4:48
memberSam Levy16-Feb-05 4:48 
QuestionWhy make 3 loop ? Pin
DarkYoda Mickael2-Feb-05 22:22
memberDarkYoda Mickael2-Feb-05 22:22 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

| Advertise | Privacy | Terms of Use | Mobile
Web03 | 2.8.150731.1 | Last Updated 15 Feb 2005
Article Copyright 2001 by Jack Handy
Everything else Copyright © CodeProject, 1999-2015
Layout: fixed | fluid