Wildcard string compare (globbing) - CodeProject

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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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About the Author

Jack Handy

Web Developer

United States

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Re: Yet another version - 25% faster, I think

21 Sep '11 - 2:47

I found small bug, if compare "*a" and "babbba" function return false.
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I used this function but I how I can catch variables from the * ???

20 Oct '09 - 1:55

Dear Jack,
Dear all,

I used this function in comparing two strings the first is Pattern(* KK *) and the second is Text(TT KK ZZ) and the function return pass. thats briliant,but my question how I can edit the function to be able to catch or handle the characters of matched * to save them in variables. for example:

X = TT
Y = ZZ

to deal with them later on in my system.

I tried many times but its not working well so far.

So please any one have an idea to do that please let me know and its will be appreciated.

Best Regards.

Re: I used this function but I how I can catch variables from the * ???

1 Apr '10 - 11:27

It would be easiest if you use regular expressions instead of this function. http://msdn.microsoft.com/en-us/library/system.text.regularexpressions.matchcollection.aspx[^]
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any updates ?

2 Jul '09 - 5:12

code in C# ?? AE
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Improved matching with end-of-text

11 May '09 - 15:20

Great code, but when trying this I realized that the following pattern is a match:

Search: ????????
Text to search: ABC

The problem is that the pattern can be LONGER than the text searched, in which case it should return a not found, but instead returns found.

Also, this example succeeds:

Search: y*n
Text to search: yessir

But of course should fail, since I'm looking for a text that ends with n

So I re-wrote your program to this, to correctly handle this situation.

bool StrWildCmp(char* wildstring, char *matchstring){
 
	
	char stopstring[1];
	*stopstring = 0;
 
	while(*matchstring) {
		if (*wildstring == '*') {
		  if (!*++wildstring) {
			return true;
		  } else {
			  *stopstring = *wildstring;
		  }
		}
 
		if(*stopstring) {
			if(*stopstring == *matchstring ) {
				wildstring++;
				matchstring++;
				*stopstring = 0;
			} else {
				matchstring++;
			}
		} else if((*wildstring == *matchstring) || (*wildstring == '?')) {
				wildstring++;
				matchstring++;
		} else {
			return false;
		}
 
		if(!*matchstring && *wildstring && *wildstring != '*') {
			// matchstring too short
			return false;
		}
	}
 
  return true;
}

Thanks again for the inspiration. Cool | :cool:

Cool | :cool:

Re: Improved matching with end-of-text: some cases don't work properly!

12 Aug '09 - 3:35

some cases don't work properly:

wildstring = "a*bc"
matchstring = "abbc"
should be true, but it returns false

wildstring = "a*b"
matchstring = "a"
should be false, but it returns true

wildstring = "a*?b"
matchstring = "axb"
should be true, but it returns false

wildstring = "a**b"
matchstring = "axb"
should be true, but it returns false (ok, the two ** aren't useful, but they should work)

I solved the last 3 bugs, but the first one is a bit tricky...

bool StrWildCmp(char* wildstring, char *matchstring){
   char stopstring[1];
   *stopstring = '\0';
 
   while(*matchstring != '\0')
   {
      if (*wildstring == '*') 
      {
         do
         {         
            wildstring++;            
         } while (*wildstring == '*');  // if a dork entered two or more * in a row 
                                        // ignore them and go ahead
         
         if (*wildstring == '\0')   // if * was the last char, the strings are equal
         {
            return TRUE;
         }
         else
         {
            *stopstring = *wildstring; // the next char to check after the *
         }
      }
 
      if(*stopstring != '\0')
      {
         if((*stopstring == *matchstring) || (*stopstring == '?') ) 
         {
            wildstring++;
            *stopstring = '\0';
         }
         matchstring++;
      }
      else
         if((*wildstring == *matchstring) || (*wildstring == '?'))
         {
            wildstring++;
            matchstring++;
         }
         else
         {
            return FALSE;
         }
 
      if( (*matchstring == '\0') && (*wildstring != '\0') )
      {
         // matchstring seems to be too short. Check if wildstring has any more chars except '*'
         while (*wildstring == '*') // ignore following '*'
            wildstring++;
         
         if (*wildstring == '\0') // if wildstring endet after '*', strings are equal
            return TRUE;
         else
            return FALSE;
      }
}

PathMatchSpec instead?

25 Mar '09 - 8:55

If you have ability to use Windows code you can use PathMatchSpec: http://msdn.microsoft.com/en-us/library/bb773727(VS.85).aspx[^]
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Re: PathMatchSpec instead?

MandatoryDefault

31 Aug '09 - 10:39

I recommend against PathMatchSpec(). I used that function in my own code and it just bit me. Its wildcard behavior is broken for all but the simplest cases. For example, these two commands incorrectly return false: `::PathMatchSpec("C:\\Windows", "C:\\Windows.*");` `::PathMatchSpec("C:\\Windows", "C:\\Windows.");`
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wchar_t version?

29 Nov '08 - 20:16

Anyone tried converting this to using wchar_t* (essentially Unicode) instead of char*?
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Re: wchar_t version?

31 Mar '11 - 21:49

This is great and got my 5 because is simple, fast and useful!

Here is the wchar_t version:

int wildcmp(const wchar_t *wild, const wchar_t *string)
  {
  const wchar_t *cp = NULL, *mp = NULL;
 
  while ((*string) && (*wild != L'*')) {
    if ((towlower(*wild) != towlower(*string)) && (*wild != L'?')) {
      return 0;
    }
    wild++;
    string++;
  }
 
  while (*string) {
    if (*wild == L'*') {
      if (!*++wild) {
        return 1;
      }
      mp = wild;
      cp = string+1;
    } else if ((towlower(*wild) == towlower(*string)) || (*wild == L'?')) {
      wild++;
      string++;
    } else {
      wild = mp;
      string = cp++;
    }
  }
 
  while (*wild == L'*') {
    wild++;
  }
  return !*wild;
}

Example:

if (wildcmp(L"*bl?h.*", L"asblah.plm")) {
  //we have a match!
   MessageBox(0,"we have a match!","wildcmp wide",MB_TOPMOST);
} else {
  //no match =(
      MessageBox(0,"no match!","wildcmp wide",MB_TOPMOST);
}

General News Suggestion Question Bug Answer Joke Rant Admin

Matches a string against a wildcard string such as "*.*" or "bl?h.*" etc. This is good for file globbing or to match hostmasks.

Type	Article
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First Posted	1 May 2001
Views	683,633
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