[Javascript] Wildcard string matching / globbing

Most Javascript programmers are more than happy with regular expressions. However, there are times when something like wildcards ('?' for one character and '*' for many) would be helpful.

Jack Handy's first and last (it seems) article on CodeProject implemented a wildcard string compare (also known as 'globbing') function in C. Below I present my port of that function to Javascript.

As a newbie Javascript programmer (4 weeks in as of 2010-11-30), I've pleasantly surprised by the expressive power of Javascript. What has caught my eye recently is the power of .prototype., so this implementation of matchesWild() is declared as a prototype extending the String class.

Here's the code, with some commentary:

String.prototype.matchesWild = function( wildCard ) {
        // Written by Jack Handy - jakkhandy@hotmail.com
        //  http://www.codeproject.com/KB/string/wildcmp.aspx
        // Made to work in javascript by Bruce M. Axtens - bruce@strapper.net

Apart from the comments, notice the way Javascript adds a method to an object, defining an anonymous function with, in this case, one parameter, and assigning it as a prototype.

        var nCp = 0;
        var nMp = 0;
        var nWild = 0;
        var nThis = 0;

The C version did all kinds of interesting things with pointers. Javascript doesn't have that kind of stuff (AFAICT), so I had to do the equivalent with numeric offsets and substr().

Perhaps there are better ways of doing this. I have tried to do this kind of thing before, but this code seems to do a pretty good job of it and hasn't failed thus far.

What should be noted, and perhaps dealt with, is that there is no explicit check for calling the method without a parameter. If one does this, an error is raised. Chrome's V8 raises "TypeError: Cannot call method 'substr' of undefined".

        while ( ( this.substr( nThis, 1 ) ) && ( wildCard.substr( nWild, 1 ) !== '*')) {
                if ( ( wildCard.substr( nWild, 1 ) !== this.substr( nThis, 1 ) ) && 
                        ( wildCard.substr( nWild, 1 ) !== '?') ) 
                                return false;
                nWild++;
                nThis++;
        }

        while ( this.substr( nThis, 1 ) ) {
                if ( wildCard.substr( nWild, 1 ) === '*' ) {
                        if ( !wildCard.substr( ++nWild, 1 ) ) 
                                return true;
                        nMp = nWild;
                        nCp = nThis+1;
                } else if ( ( wildCard.substr( nWild, 1 ) === this.substr( nThis, 1 ) ) || 
                        ( wildCard.substr( nWild, 1 ) === '?' ) ) {
                                nWild++;
                                nThis++;
                } else {
                        nWild = nMp;
                        nThis = nCp++;
                }
        }

        while ( wildCard.substr( nWild, 1 ) === '*' ) 
                nWild++;
        return !wildCard.substr( nWild, 1 );
}

And now some examples (evaluated using macports's JavaScript-C 1.7.0 2007-10-03)

        var i;
        var a = ['kangaroo', 'koala', 'goanna', 'quoll', 'bunyip', 'yowie', 'bandicoot', 'numbat'];

        print('select everything with an \'o\' at the second character position');
        for ( i = 0; i < a.length; i++ ) {
                if ( a[ i ].matchesWild( '?o*' ) )  print( 'item(' + i + ')=' + a[i] );
        }
        print("--------------------");
        print('select everything ending with \'a\'');
        for ( i = 0; i < a.length; i++ ) {
                if ( a[ i ].matchesWild( '*a' ) )  print( 'item(' + i + ')=' + a[i] );
        }
        print("--------------------");
        print('select everything with at least two \'a\' characters');
        for ( i = 0; i < a.length; i++ ) {
                if ( a[ i ].matchesWild( '*a*a*' ) )  print( 'item(' + i + ')=' + a[i] );
        }
        print("--------------------");
        print('select everything with an \'oo\'' );
        for ( i = 0; i < a.length; i++ ) {
                if ( a[ i ].matchesWild( '*oo*' ) )  print( 'item(' + i + ')=' + a[i] );
        }
        print("--------------------");
        print('select everything with at least one \'z\' character');
        for ( i = 0; i < a.length; i++ ) {
                if ( a[ i ].matchesWild( '*z*' ) )  print( 'item(' + i + ')=' + a[i] );
        }
        print("--------------------");

Outputs:

select everything with an 'o' at the second character position
item(1)=koala
item(2)=goanna
item(5)=yowie
--------------------
select everything ending with 'a'
item(1)=koala
item(2)=goanna
--------------------
select everything with at least two 'a' characters
item(0)=kangaroo
item(1)=koala
item(2)=goanna
--------------------
select everything with an 'oo'
item(0)=kangaroo
item(6)=bandicoot
--------------------
select everything with at least one 'z' character
--------------------

More Javascript coming soon. In the meantime, enjoy.

© Bruce M. Axtens, 2010

[iSync] Nokia 5000d-2

After looking around for a while I finally figured out how to get Apple iSync to talk reliably to my Nokia 5000d-2. Most of the other 'solutions' assume that the 5000 is a Series 60 phone. It is in fact a series 40 phone, thus the family.com.nokia.series40.3rdEd.bus.bt.

The image for the phone was downloaded from ericfish.com and copied into the /Applications/iSync.app/Contents/PlugIns/ApplePhoneConduit.syncdevice/Contents/PlugIns/PhoneModelsSync.phoneplugin/Contents/Resources/ folder.

The following code was merged into the MetaClasses.plist file in /Applications/iSync.app/Contents/PlugIns/ApplePhoneConduit.syncdevice/Contents/PlugIns/PhoneModelsSync.phoneplugin/Contents/Resources/

        <key>com.nokia.5000d-2</key>
        <dict>
                <key>Identification</key>
                <dict>
                        <key>com.apple.gmi+gmm</key>
                        <string>Nokia+Nokia 5000d-2</string>
                </dict>
                <key>InheritsFrom</key>
                <array>
                        <string>family.com.nokia.series40.3rdEd.bus.bt</string>
                </array>
                <key>Services</key>
                <array>
                        <dict>
                                <key>ServiceName</key>
                                        <string>com.apple.model</string>
                                <key>ServiceProperties</key>
                                        <dict>
                                        <key>ModelName</key>
                                                <string>5000d-2</string>
                                        <key>PhoneIcon</key>
                                                <string>NOK5000.tiff</string>
                                        </dict>
                        </dict>
                </array>
        </dict>

I hope someone finds this helpful. It certainly makes things a bit easier for me. Now all I have to do is figure out how to manage the SMS subsystem. Gammu looks promising, once I figure out the link error. More on that another time.

© Bruce M. Axtens, 2010