Using NS[Int]Number for dictionary keys

[Mark Dalrymple]

Greetings,

I'm working with some folks that are wanting to put a large number of  
objects into a dictionary, keyed by number.  When using string keys  
created with

     string1 = [NSString stringWithFormat:@"%d", clauseNumber];
     [clauseHashTable setObject:currentClause forKey:string1];

with clauseNumber going from 1 to a bit over 1 million, It takes  
about 6 seconds (2-way G5 running OS X) to populate a dictionary.

When using NSNumbers,

      number = [NSNumber numberWithInt: clauseNumber];
      [clauseHashTable setObject: currentClause
                       forKey: number];

It takes about 21 minutes.  Using the same code with Apple's Cocoa  
libraries takes about 3 seconds.

Using the 'sample' utility over a span of about 2 minutes (sampling 3  
miliseconds), I get:

              40313 -[GSMutableDictionary setObject:forKey:]
                14758 objc_msg_lookup
                  14758 objc_msg_lookup
                12556 _GLOBAL__I_Cyrillic_conv_base
                  12556 _GLOBAL__I_Cyrillic_conv_base
                12060 -[NSNumber isEqual:]
                  9524 -[NSNumber isEqualToNumber:]
                    7295 -[NSIntNumber compare:]
                      2206 GSNumberInfoFromObject

That Cyrillic_conv_base thing is a bit odd, and there's a lot of time  
eaten in NSNumber isEqual and friends.  Using NSIntNumber rather than  
NSNumber gave similar results.

So my question is, is NSNumber not suited to being used for  
dictionary keys in GNUstep, or could it be a problem with the  
hashing / equality functions?

Thank you for your time,
++Mark Dalrymple, markd@borkware.com
  http://borkware.com