64 bit compatibility

Daniel

The last update to the master branch allows to compile Sparrow without warnings for 64 bit iPhones. So you can compile and link Sparrow to 64 bit games, as well.

However, this will probably require further changes in the future. Actually, I haven't made a decision yet. Anybody interested, please bear with me and read the explanation below -- I'd be interested in your comments!

Here's the problem:

When you look at Sparrow's APIs, you'll see that it uses the "int" data type for most whole numbers. E.g.

- (int)numChildren;

Typical classes of the iOS standard library will use "NSInteger" and "NSUInteger" instead. Like this:

- (NSInteger)count;

On 32 bit systems, that's exactly the same -- NSInteger is just a typedef on "int" (32 bits).

On 64 bit systems, however, "NSInteger" will be a "long" with 64 bits.

Thus, Sparrow now behaves differently than the other "NS" or "UI" classes. You will frequently have to cast one type into the other when you're compiling for 64 bit.

Which means that Sparrow should probably be changed to use those data types, too. What do you think?

Shilo

I say go for it! I think it makes sense. It beats the alternative, like casting and/or creating compile-time checks to change the data types in the methods. Sparrow is not cross platform at the time, so using the specific Apple datatypes would be a valid choice for me. On top of that, users would still be able to freely pass int and uint to NSInteger and NSUInteger in 32 bit apps, if they wanted to.

Was there a drawback to using NSInteger and NSUInteger? (Besides the ugly naming)

Daniel

Thanks for your opinion, Shilo! I agree, this is probably how it should be done.

Well, there are no major drawbacks, except that memory consumption will raise in some places. But that's always the case when switching to 64 bits. One just has to overcome the feeling that you're wasting memory when you only need a few bits out of the 64 *g*. Probably people had the same problem when moving from 16 to 32 bits. 😉

ronyeh

I agree with switching to NSInteger & CGFloat wherever Sparrow interacts with those data types.

On a separate note...
I wonder how big our binaries will be, because they'll combine the 64 and 32 bit binaries into one IPA. I might wait until more devices are 64-bit before switching over... since I'm still supporting iOS 5.0 customers.

Daniel

Yeah, I agree -- since Sparrow supports iOS 5, I'd leave that as a deployment target for the time being. That way, your app will be a pure 32 bit app.