iPhone - encoding and decoding a NSValue

Question

So I read here on SO that I can encode a CGLayerRef to a NSValue using

NSValue *myCopy = [[NSValue alloc] initWithBytes:&myLayer objCType:@encode(CGLayerRef)];

but how do I recreate the CGLayerRef from myCopy?

thanks

score 6 · Accepted Answer · answered Jun 02 '11 at 01:11

6

This should work:

CGLayerRef giveMeBackTheLayer;
[myCopy getValue:&giveMeBackTheLayer];

answered Jun 02 '11 at 01:11

just a bit off topic... do you know how can I discover the number of bytes myCopy is using?... thanks. – Duck Jun 02 '11 at 02:05
@Digital The number of bytes in the whole instance or the number of bytes needed to store a `CGLayerRef`? It’s probably a combination of `class_getInstanceSize()` and `sizeof CGLayerRef`. The actual layer `struct` is opaque, though. – Jun 02 '11 at 02:10
You'd need to store that information separately. You can't get it from the `NSValue`. – Rob Keniger Jun 02 '11 at 02:10
@Bavarious - the number of bytes needed to store CGLayerRef – Duck Jun 02 '11 at 02:25
@Digi `sizeof CGLayerRef`, then. Note that `CGLayerRef` is a pointer, so it has the same size as any other pointer in your target platform: 32 bits. – Jun 02 '11 at 02:27

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