At 1:32 PM +0000 2/6/09, harry greenmonster wrote:
But why can the compiler not replace the data at the memory location
pointed to by the old 'inputString' without making a second pointer
(with the same name). This would then pose no problems in the
scenarios you put forward.?
If you use an Objective-C 2.0 property (rather than a variable) and
specifying retain semantics, you'll get that behavior -- with a bit
of overhead.
At 12:35 PM +0000 2/6/09, Jeremy Pereira wrote:
On 6 Feb 2009, at 06:32, Martin Wierschin wrote:
This sequence is not safe. As an optimization there is nothing
preventing "inputString" from returning self if "range" is of zero
length. If that ever happened, you could end up deallocating the
string before the following retain occurs.
So retain newString before releasing inputString - or explicitly
test for pointer equality and only do the release and retain if they
are not equal.
Forgetting releasing before retain was a bug -- as a rule you always
want to retain before release.
This is especially important with operations on arrays and
dictionaries as elements could be shared between the source and
result (testing for equality won't help you here).
So there's a complete copy:
while([inputString isMatchedByRegex:regexString])
{
NSAutoreleasePool* pool = [NSAutoreleasePool new];
range = [inputString rangeOfRegex:regexString];
NSString * newString = [[inputString
stringByReplacingCharactersInRange:range withString:@""] retain]; //
retain new inputString
[inputString release]; // release old inputString
inputString = newString;
[pool drain];
}
(the error was probably instructive in this conversation, however)
_______________________________________________
Cocoa-dev mailing list ([email protected])
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:
http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com
This email sent to [email protected]
