Array length int != long

[GoogleCodeExporter]

When storing array length information, seems StructIO and PointerIO disagree on 
whether the length should be a long or an int. StructIO wants to store 
everything as longs (public long arrayLength = 1;), PointerIO's public 
interfaces all take ints for their array functions (getArray(Pointer<T> 
pointer, long byteOffset, int length)). I'm open to going either to all longs 
or ints, but we should unify the type to avoid any kind of problems. I've 
attached a diff patch to switch the StructIO to ints because it minimized the 
change to the public API.

Original issue reported on code.google.com by frac...@gmail.com on 15 Mar 2011 at 6:04

Attachments:

• arrayLength.diff

[GoogleCodeExporter]

Hi Jay,

Thanks for your interest in BridJ and for your proposal.
The problem here is that there are two types of array lengths in play :
- java arrays (which length *has* to be int, because of new Object[int] / new 
int[int] and Object[].length), returned by Pointer.getArray(int), 
.getInts(int)...
- native arrays (which are of length size_t, so they must be represented as a 
Java long), declared in the @Array annotation and stored in the struct 
representation (StructIO.FieldDesc.arrayLength...), which help define pointer 
bounds information (Pointer.getValidElements()...)

Then there are buffers, which have long lengths (see 
Pointer.getIntBuffer(long)...).
I believe this is all technically consistent, even though it's indeed a shame 
we can't use a single type for it all (with 64 bits JVMs that can deal with 
dozens of gigabytes of RAM, it's a pity that Java arrays can't have more than 2 
billion elements !).

I don't feel like setting all int values to longs either, as people might be 
tempted to ask for arrays of length Integer.MAX_VALUE * 2 and we'd have to 
check more bounds...

If you find other places where the int/long logic is indeed flawed, please let 
me know.

Cheers
--
zOlive

Original comment by olivier.chafik@gmail.com on 15 Mar 2011 at 10:56

• Changed state: WontFix