Re: MD5

[Richard Frith-Macdonald]

On Friday, January 24, 2003, at 10:13  am, David Ayers wrote:
> Currently base exports -(NSData *)MD5Digest (but personnally I would 
> have preferred md5Digest :-)...)

I'm happy to change that.... will do it next.

> > >| - (NSString *)md5StringUsingEncoding: (NSStringEncoding) enc;
> >
> > >| - (NSString *)md5String; /* uses default encoding.*/

As regards other methods, my feeling is that most of them are trivial 
and should not really be put in the base library
(or common additions).

I like the idea you (I think) suggested in an earlier email, of a new 
category method of NSData ...

- (NSString*)hexadecimalRepresentation;

Then to get a hexadecimal digest of any string you would just write -

myDigest = [[[myString dataUsingEncoding: myStringEncoding] md5Digest] 
hexadecimalRepresentation];

though perhaps it should be ...

- (NSData*)hexadecimalRepresentation;

So that the above code to generate 'myDigest' would return an NSData 
object containing 32 bytes of ascii
hexadecimal values that could easily be plugged into an email message, 
and you could get a string value
by myStringDigest = AUTORELEASE([[NSString alloc] initWithData: 
myDigest encoding: NSASCIIStringEncoding]);

While we could obviously have some convenience methods encapsulating 
this, my impulse is to keep the API
as small and simple as possible, and write code like that above, making 
it clearer what the code is doing.

I don't want to be dogmatic about it though ... if the majority of 
people want to include several convenience methods,
I'll do that.

What are the preferences about a hexadecimal representation method 
returning NSString or NSData ?