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;
}

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Jack Handy

Web Developer
United States

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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:

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;
      }
}

if you use "Circle_hole_pX3.BMP" as matchstring and "*_PX?.*" as wildstring the return value is FALSE.

Here is the updated code:

BOOL StrWildCmp(char* wildstring, char *matchstring)
{
   char stopstring[1];
   *stopstring = '\0';
   char *wildstringNew=wildstring;
 
   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
         {
  	    if(*wildstring != '\0')
		wildstring=wildstringNew;
	    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;
      }
   }
}

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
Licence
First Posted	1 May 2001
Views	687,284
Bookmarked	89 times

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