Re: NSData, CFData maximum length question
On Mar 21, 2012, at 10:49 PM, Seth Willits wrote: On Mar 21, 2012, at 6:00 PM, Grandinetti Philip wrote: I am confused about different behavior I'm seeing with CFData and NSData. If I create a new project in XCode 4.3.1 as a Core Foundation command line tool, and enter the code below… You've triggered a bug! And it took me a long time, but I found it. The bug is in __CFDataRoundUpCapacity, and has to do with a bad (1 ….) which should be (1L …). I'll file a report. Filed as 11097403. And yeah, setting the length to anything 0 when the data is created will avoid the bug because the CFData is not growable, and CFDataSetLength is handled a little different for growable CFDatas vs fixed-length mutable ones. I'm not sure what [NSMutableData dataWithCapacity:0] does, but it's not a simple call to CFDataCreateMutable(kCFAllocatorDefault, 0) which is why it behaves differently as well. -- Seth Willits ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: NSData, CFData maximum length question
I'm not sure what [NSMutableData dataWithCapacity:0] does, but it's not a simple call to CFDataCreateMutable(kCFAllocatorDefault, 0) which is why it behaves differently as well. It probably ignores the specified capacity, for a start. NSMutableDictionary does for its equivalent method, as does NSMutableArray IIRC. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: NSData, CFData maximum length question
On Mar 21, 2012, at 6:00 PM, Grandinetti Philip wrote: it crashes with the error message below: length = 1073741824 test(2463) malloc: *** mmap(size=18446744071562067968) failed (error code=12) That is bizarre — it happens to me too. 18446744071562067968 = 0x8000 … so it’s as though something doubled the length parameter, then sign-extended it to 64 bits, before passing it to malloc. Why, I have no idea. —Jens smime.p7s Description: S/MIME cryptographic signature ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: NSData, CFData maximum length question
Found something interesting. If I simply set the capacity to length instead
of 0, then it runs without crashing. Could this be a bug in CFData?
int main(int argc, const char * argv[])
{
CFIndex length = (1ULL 30);
fprintf(stderr, length = %ld\n,length);
CFMutableDataRef data = CFDataCreateMutable(kCFAllocatorDefault, length);
CFDataSetLength(data, length);
}
- Philip
On Mar 21, 2012, at 10:26 PM, Jens Alfke wrote:
On Mar 21, 2012, at 6:00 PM, Grandinetti Philip wrote:
it crashes with the error message below:
length = 1073741824
test(2463) malloc: *** mmap(size=18446744071562067968) failed (error code=12)
That is bizarre — it happens to me too.
18446744071562067968 = 0x8000 … so it’s as though something
doubled the length parameter, then sign-extended it to 64 bits, before
passing it to malloc. Why, I have no idea.
—Jens
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Re: NSData, CFData maximum length question
On Mar 21, 2012, at 6:00 PM, Grandinetti Philip wrote: I am confused about different behavior I'm seeing with CFData and NSData. If I create a new project in XCode 4.3.1 as a Core Foundation command line tool, and enter the code below… You've triggered a bug! And it took me a long time, but I found it. The bug is in __CFDataRoundUpCapacity, and has to do with a bad (1 ….) which should be (1L …). I'll file a report. -- Seth Willits ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
