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Wildcard string compare (globbing)

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15 Feb 2005 1.2M   96   144
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

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Comments and Discussions

 
QuestionPathMatchSpec (shlwapi.h)? Pin
peterchen28-Jun-04 6:56
peterchen28-Jun-04 6:56 
AnswerRe: PathMatchSpec (shlwapi.h)? Pin
Jack Handy13-Feb-05 9:56
Jack Handy13-Feb-05 9:56 
peterchen wrote:
Just a thought:
the PathMatchSpec SLWU API could provide similar. I guess it does have some differences (e.g. allowing to specify multiple specs, separated by semicolon), but it might be a simple alternative for many similar tasks.


The wildcmp() function is meant to be lightweight and fast.

If the extra functionality of multple specs is needed and you don't want to parse the input yourself then you can go ahead and use the PathMatchSpec() API.

Just make sure you don't mind these limitations:

1. Adding another dependancy to your executable by including the lib
2. Not portable (wildcmp() compiles fine under unix)
3. More memory overhead (larger code footprint)
4. The horrible slowness

I have ran some benchmarks and pasted the results below. I can provide the .cpp file for the benchmarks if anyone is interested.

-Jack

10MM iterations.<br />
Compiled as a console app using vc6 in release mode with /O2 optimization.<br />
Ran on a pM 1.7ghz<br />
<br />
"C:\\T*s*.t?t", "C:\\Test\\File.txt"<br />
PathMatchSpec MATCH => 20.5090s<br />
wildcmp MATCH => 1.0320s<br />
<br />
"C:\\T*s*.t??t", "C:\\Test\\File.txt"<br />
PathMatchSpec NO MATCH => 45.7760s<br />
wildcmp NO MATCH => 0.8910s



There are 10 types of people in this world, those that understand binary and those who don't.


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